event: restore Err() logging when ErrorStackMarshaler returns nil (#763)

Commit f6fbd33 added `case nil: return e` in Event.Err() so that when
ErrorStackMarshaler returns nil (the error has no stack trace), the
function returns early without logging the error itself.

This was a regression. The previous behaviour was to fall through the
switch and always call AnErr(ErrorFieldName, err), ensuring the error
message is logged even when no stack is attached.

Libraries such as elastic/ecs-logging-go-zerolog (and plain fmt.Errorf
errors) rely on the old behaviour: calling Stack().Err(err) should
always log the error field; the stack field is additional and optional.

Change the `nil` case from `return e` to a comment (fall-through) so
that AnErr is called unconditionally. Update the test that was written
to match the incorrect behaviour.

Fixes #762

Signed-off-by: alliasgher <alliasgher123@gmail.com>

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+  - package-ecosystem: gomod
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/test.yml

@@ -0,0 +1,36 @@
+on: [push, pull_request]
+name: Test
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [1.23.x, 1.24.x]
+        os: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Install Go
+      uses: actions/setup-go@v6
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: Checkout code
+      uses: actions/checkout@v6
+    - uses: actions/cache@v5
+      with:
+        path: ~/go/pkg/mod
+        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-go-
+    - name: Test
+      run: go test -race -bench . -benchmem ./...
+    - name: Test CBOR
+      run: go test -tags binary_log -race ./...
+  coverage:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Update coverage report
+      uses: ncruces/go-coverage-report@main
+      with:
+        report: 'true'
+        chart: 'true'
+        amend: 'true'
+      continue-on-error: true

.gitignore

@@ -6,6 +6,7 @@
 # Folders
 _obj
 _test
+tmp
 
 # Architecture specific extensions/prefixes
 *.[568vq]
@@ -22,3 +23,5 @@ _testmain.go
 *.exe
 *.test
 *.prof
+
+coverage.out

.travis.yml

@@ -1,10 +0,0 @@
-language: go
-go:
-- 1.7
-- 1.8
-- tip
-matrix:
-  allow_failures:
-      - go: tip
-script:
-    go test -v -race -cpu=1,2,4 ./...

CONTRIBUTING.md

@@ -0,0 +1,43 @@
+# Contributing to Zerolog
+
+Thank you for your interest in contributing to **Zerolog**!
+
+Zerolog is a **feature-complete**, high-performance logging library designed to be **lean** and **non-bloated**. The focus of ongoing development is on **bug fixes**, **performance improvements**, and **modernization efforts** (such as keeping up with Go best practices and compatibility with newer Go versions).
+
+## What We're Looking For
+
+We welcome contributions in the following areas:
+
+- **Bug Fixes**: If you find an issue or unexpected behavior, please open an issue and/or submit a fix.
+- **Performance Optimizations**: Improvements that reduce memory usage, allocation count, or CPU cycles without introducing complexity are appreciated.
+- **Modernization**: Compatibility updates for newer Go versions or idiomatic improvements that do not increase library size or complexity.
+- **Documentation Enhancements**: Corrections, clarifications, and improvements to documentation or code comments.
+
+## What We're *Not* Looking For
+
+Zerolog is intended to remain **minimalistic and efficient**. Therefore, we are **not accepting**:
+
+- New features that add optional behaviors or extend API surface area.
+- Built-in support for frameworks or external systems (e.g., bindings, integrations).
+- General-purpose abstractions or configuration helpers.
+
+If you're unsure whether a change aligns with the project's philosophy, feel free to open an issue for discussion before submitting a PR.
+
+## Contributing Guidelines
+
+1. **Fork the repository**
+2. **Create a branch** for your fix or improvement
+3. **Write tests** to cover your changes
+4. Ensure `go test ./...` passes
+5. Run `go fmt` and `go vet` to ensure code consistency
+6. **Submit a pull request** with a clear explanation of the motivation and impact
+
+## Code Style
+
+- Keep the code simple, efficient, and idiomatic.
+- Avoid introducing new dependencies.
+- Preserve backwards compatibility unless explicitly discussed.
+
+---
+
+We appreciate your effort in helping us keep Zerolog fast, minimal, and reliable!

README.md

@@ -1,65 +1,315 @@
 # Zero Allocation JSON Logger
 
-[![godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/rs/zerolog) [![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/rs/zerolog/master/LICENSE) [![Build Status](https://travis-ci.org/rs/zerolog.svg?branch=master)](https://travis-ci.org/rs/zerolog) [![Coverage](http://gocover.io/_badge/github.com/rs/zerolog)](http://gocover.io/github.com/rs/zerolog)
+[![godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/rs/zerolog) [![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/rs/zerolog/master/LICENSE) [![Build Status](https://github.com/rs/zerolog/actions/workflows/test.yml/badge.svg)](https://github.com/rs/zerolog/actions/workflows/test.yml) [![Go Coverage](https://github.com/rs/zerolog/wiki/coverage.svg)](https://raw.githack.com/wiki/rs/zerolog/coverage.html)
 
 The zerolog package provides a fast and simple logger dedicated to JSON output.
 
-Zerolog's API is designed to provide both a great developer experience and stunning [performance](#performance). Its unique chaining API allows zerolog to write JSON log events by avoiding allocations and reflection.
+Zerolog's API is designed to provide both a great developer experience and stunning [performance](#benchmarks). Its unique chaining API allows zerolog to write JSON (or CBOR) log events by avoiding allocations and reflection.
 
-The uber's [zap](https://godoc.org/go.uber.org/zap) library pioneered this approach. Zerolog is taking this concept to the next level with simpler to use API and even better performance.
+Uber's [zap](https://godoc.org/go.uber.org/zap) library pioneered this approach. Zerolog is taking this concept to the next level with a simpler to use API and even better performance.
 
-To keep the code base and the API simple, zerolog focuses on JSON logging only. Pretty logging on the console is made possible using the provided `zerolog.ConsoleWriter`.
+To keep the code base and the API simple, zerolog focuses on efficient structured logging only. Pretty logging on the console is made possible using the provided (but inefficient) [`zerolog.ConsoleWriter`](#pretty-logging).
+
+![Pretty Logging Image](pretty.png)
+
+## Who uses zerolog
+
+Find out [who uses zerolog](https://github.com/rs/zerolog/wiki/Who-uses-zerolog) and add your company / project to the list.
 
 ## Features
 
-* Blazing fast
-* Low to zero allocation
-* Level logging
-* Sampling
-* Contextual fields
-* `context.Context` integration
-* `net/http` helpers
-* Pretty logging for development
+- [Blazing fast](#benchmarks)
+- [Low to zero allocation](#benchmarks)
+- [Leveled logging](#leveled-logging)
+- [Sampling](#log-sampling)
+- [Hooks](#hooks)
+- [Contextual fields](#contextual-logging)
+- [`context.Context` integration](#contextcontext-integration)
+- [Integration with `net/http`](#integration-with-nethttp)
+- [JSON and CBOR encoding formats](#binary-encoding)
+- [Pretty logging for development](#pretty-logging)
+- [Error Logging (with optional Stacktrace)](#error-logging)
+- [`log/slog` integration](#integration-with-logslog)
 
-## Usage
+## Installation
 
-```go
-import "github.com/rs/zerolog/log"
+```bash
+go get -u github.com/rs/zerolog/log
 ```
 
-### A global logger can be use for simple logging
+## Getting Started
+
+### Simple Logging Example
+
+For simple logging, import the global logger package **github.com/rs/zerolog/log**
 
 ```go
-log.Info().Msg("hello world")
+package main
 
-// Output: {"level":"info","time":1494567715,"message":"hello world"}
+import (
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    // UNIX Time is faster and smaller than most timestamps
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+    log.Print("hello world")
+}
+
+// Output: {"time":1516134303,"level":"debug","message":"hello world"}
 ```
 
-NOTE: To import the global logger, import the `log` subpackage `github.com/rs/zerolog/log`.
+> Note: By default log writes to `os.Stderr`
+> Note: The default log level for `log.Print` is _trace_
+
+### Contextual Logging
+
+**zerolog** allows data to be added to log messages in the form of key:value pairs. The data added to the message adds "context" about the log event that can be critical for debugging as well as myriad other purposes. An example of this is below:
 
 ```go
-log.Fatal().
-    Err(err).
-    Str("service", service).
-    Msgf("Cannot start %s", service)
+package main
 
-// Output: {"level":"fatal","time":1494567715,"message":"Cannot start myservice","error":"some error","service":"myservice"}
-// Exit 1
+import (
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+    log.Debug().
+        Str("Scale", "833 cents").
+        Float64("Interval", 833.09).
+        Msg("Fibonacci is everywhere")
+
+    log.Debug().
+        Str("Name", "Tom").
+        Send()
+}
+
+// Output: {"level":"debug","Scale":"833 cents","Interval":833.09,"time":1562212768,"message":"Fibonacci is everywhere"}
+// Output: {"level":"debug","Name":"Tom","time":1562212768}
 ```
 
-NOTE: Using `Msgf` generates one allocation even when the logger is disabled.
+> You'll note in the above example that when adding contextual fields, the fields are strongly typed. You can find the full list of supported fields [here](#standard-types)
 
-### Fields can be added to log messages
+### Leveled Logging
+
+#### Simple Leveled Logging Example
 
 ```go
-log.Info().
-    Str("foo", "bar").
-    Int("n", 123).
-    Msg("hello world")
+package main
 
-// Output: {"level":"info","time":1494567715,"foo":"bar","n":123,"message":"hello world"}
+import (
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+    log.Info().Msg("hello world")
+}
+
+// Output: {"time":1516134303,"level":"info","message":"hello world"}
 ```
 
+> It is very important to note that when using the **zerolog** chaining API, as shown above (`log.Info().Msg("hello world"`), the chain must have either the `Msg` or `Msgf` method call. If you forget to add either of these, the log will not occur and there is no compile time error to alert you of this.
+
+**zerolog** allows for logging at the following levels (from highest to lowest):
+
+- panic (`zerolog.PanicLevel`, 5)
+- fatal (`zerolog.FatalLevel`, 4)
+- error (`zerolog.ErrorLevel`, 3)
+- warn (`zerolog.WarnLevel`, 2)
+- info (`zerolog.InfoLevel`, 1)
+- debug (`zerolog.DebugLevel`, 0)
+- trace (`zerolog.TraceLevel`, -1)
+
+You can set the Global logging level to any of these options using the `SetGlobalLevel` function in the zerolog package, passing in one of the given constants above, e.g. `zerolog.InfoLevel` would be the "info" level. Whichever level is chosen, all logs with a level greater than or equal to that level will be written. To turn off logging entirely, pass the `zerolog.Disabled` constant.
+
+#### Setting Global Log Level
+
+This example uses command-line flags to demonstrate various outputs depending on the chosen log level.
+
+```go
+package main
+
+import (
+    "flag"
+
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+    debug := flag.Bool("debug", false, "sets log level to debug")
+
+    flag.Parse()
+
+    // Default level for this example is info, unless debug flag is present
+    zerolog.SetGlobalLevel(zerolog.InfoLevel)
+    if *debug {
+        zerolog.SetGlobalLevel(zerolog.DebugLevel)
+    }
+
+    log.Debug().Msg("This message appears only when log level set to Debug")
+    log.Info().Msg("This message appears when log level set to Debug or Info")
+
+    if e := log.Debug(); e.Enabled() {
+        // Compute log output only if enabled.
+        value := "bar"
+        e.Str("foo", value).Msg("some debug message")
+    }
+}
+```
+
+Info Output (no flag)
+
+```bash
+$ ./logLevelExample
+{"time":1516387492,"level":"info","message":"This message appears when log level set to Debug or Info"}
+```
+
+Debug Output (debug flag set)
+
+```bash
+$ ./logLevelExample -debug
+{"time":1516387573,"level":"debug","message":"This message appears only when log level set to Debug"}
+{"time":1516387573,"level":"info","message":"This message appears when log level set to Debug or Info"}
+{"time":1516387573,"level":"debug","foo":"bar","message":"some debug message"}
+```
+
+#### Logging without Level or Message
+
+You may choose to log without a specific level by using the `Log` method. You may also write without a message by setting an empty string in the `msg string` parameter of the `Msg` method. Both are demonstrated in the example below.
+
+```go
+package main
+
+import (
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+    log.Log().
+        Str("foo", "bar").
+        Msg("")
+}
+
+// Output: {"time":1494567715,"foo":"bar"}
+```
+
+### Error Logging
+
+You can log errors using the `Err` method
+
+```go
+package main
+
+import (
+    "errors"
+
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+    err := errors.New("seems we have an error here")
+    log.Error().Err(err).Msg("")
+}
+
+// Output: {"level":"error","error":"seems we have an error here","time":1609085256}
+```
+
+> The default field name for errors is `error`, you can change this by setting `zerolog.ErrorFieldName` to meet your needs.
+
+#### Error Logging with Stacktrace
+
+Using `github.com/pkg/errors`, you can add a formatted stacktrace to your errors.
+
+```go
+package main
+
+import (
+    "github.com/pkg/errors"
+    "github.com/rs/zerolog/pkgerrors"
+
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+    zerolog.ErrorStackMarshaler = pkgerrors.MarshalStack
+
+    err := outer()
+    log.Error().Stack().Err(err).Msg("")
+}
+
+func inner() error {
+    return errors.New("seems we have an error here")
+}
+
+func middle() error {
+    err := inner()
+    if err != nil {
+        return err
+    }
+    return nil
+}
+
+func outer() error {
+    err := middle()
+    if err != nil {
+        return err
+    }
+    return nil
+}
+
+// Output: {"level":"error","stack":[{"func":"inner","line":"20","source":"errors.go"},{"func":"middle","line":"24","source":"errors.go"},{"func":"outer","line":"32","source":"errors.go"},{"func":"main","line":"15","source":"errors.go"},{"func":"main","line":"204","source":"proc.go"},{"func":"goexit","line":"1374","source":"asm_amd64.s"}],"error":"seems we have an error here","time":1609086683}
+```
+
+> zerolog.ErrorStackMarshaler must be set in order for the stack to output anything.
+
+#### Logging Fatal Messages
+
+```go
+package main
+
+import (
+    "errors"
+
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    err := errors.New("A repo man spends his life getting into tense situations")
+    service := "myservice"
+
+    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+    log.Fatal().
+        Err(err).
+        Str("service", service).
+        Msgf("Cannot start %s", service)
+}
+
+// Output: {"time":1516133263,"level":"fatal","error":"A repo man spends his life getting into tense situations","service":"myservice","message":"Cannot start myservice"}
+//         exit status 1
+```
+
+> NOTE: Using `Msgf` generates one allocation even when the logger is disabled.
+
 ### Create logger instance to manage different outputs
 
 ```go
@@ -74,40 +324,78 @@ logger.Info().Str("foo", "bar").Msg("hello world")
 
 ```go
 sublogger := log.With().
-                 Str("component": "foo").
+                 Str("component", "foo").
                  Logger()
 sublogger.Info().Msg("hello world")
 
 // Output: {"level":"info","time":1494567715,"message":"hello world","component":"foo"}
 ```
 
-### Level logging
-
-```go
-zerolog.SetGlobalLevel(zerolog.InfoLevel)
-
-log.Debug().Msg("filtered out message")
-log.Info().Msg("routed message")
-
-if e := log.Debug(); e.Enabled() {
-    // Compute log output only if enabled.
-    value := compute()
-    e.Str("foo": value).Msg("some debug message")
-}
-
-// Output: {"level":"info","time":1494567715,"message":"routed message"}
-```
-
 ### Pretty logging
 
+To log a human-friendly, colorized output, use `zerolog.ConsoleWriter`:
+
 ```go
-if isConsole {
-    log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
-}
+log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
 
 log.Info().Str("foo", "bar").Msg("Hello world")
 
-// Output: 1494567715 |INFO| Hello world foo=bar
+// Output: 3:04PM INF Hello World foo=bar
+```
+
+To customize the configuration and formatting:
+
+```go
+output := zerolog.ConsoleWriter{Out: os.Stdout, TimeFormat: time.RFC3339}
+output.FormatLevel = func(i interface{}) string {
+    return strings.ToUpper(fmt.Sprintf("| %-6s|", i))
+}
+output.FormatMessage = func(i interface{}) string {
+    return fmt.Sprintf("***%s****", i)
+}
+output.FormatFieldName = func(i interface{}) string {
+    return fmt.Sprintf("%s:", i)
+}
+output.FormatFieldValue = func(i interface{}) string {
+    return strings.ToUpper(fmt.Sprintf("%s", i))
+}
+
+log := zerolog.New(output).With().Timestamp().Logger()
+
+log.Info().Str("foo", "bar").Msg("Hello World")
+
+// Output: 2006-01-02T15:04:05Z07:00 | INFO  | ***Hello World**** foo:BAR
+```
+
+To use custom advanced formatting:
+
+```go
+output := zerolog.ConsoleWriter{Out: os.Stdout, NoColor: true,
+    PartsOrder:    []string{"level", "one", "two", "three", "message"},
+    FieldsExclude: []string{"one", "two", "three"}}
+output.FormatLevel = func(i interface{}) string { return strings.ToUpper(fmt.Sprintf("%-6s", i)) }
+output.FormatFieldName = func(i interface{}) string { return fmt.Sprintf("%s:", i) }
+output.FormatPartValueByName = func(i interface{}, s string) string {
+    var ret string
+    switch s {
+    case "one":
+        ret = strings.ToUpper(fmt.Sprintf("%s", i))
+    case "two":
+        ret = strings.ToLower(fmt.Sprintf("%s", i))
+    case "three":
+        ret = strings.ToLower(fmt.Sprintf("(%s)", i))
+    }
+    return ret
+}
+log := zerolog.New(output)
+
+log.Info().Str("foo", "bar").
+    Str("two", "TEST_TWO").
+    Str("one", "test_one").
+    Str("three", "test_three").
+    Msg("Hello World")
+
+// Output: INFO   TEST_ONE test_two (test_three) Hello World foo:bar
 ```
 
 ### Sub dictionary
@@ -117,7 +405,7 @@ log.Info().
     Str("foo", "bar").
     Dict("dict", zerolog.Dict().
         Str("bar", "baz").
-        Int("n", 1)
+        Int("n", 1),
     ).Msg("hello world")
 
 // Output: {"level":"info","time":1494567715,"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
@@ -135,33 +423,97 @@ log.Info().Msg("hello world")
 // Output: {"l":"info","t":1494567715,"m":"hello world"}
 ```
 
-### Log with no level nor message
-
-```go
-log.Log().Str("foo","bar").Msg("")
-
-// Output: {"time":1494567715,"foo":"bar"}
-```
-
 ### Add contextual fields to the global logger
 
 ```go
 log.Logger = log.With().Str("foo", "bar").Logger()
 ```
 
+### Add file and line number to log
+
+Equivalent of `Llongfile`:
+
+```go
+log.Logger = log.With().Caller().Logger()
+log.Info().Msg("hello world")
+
+// Output: {"level": "info", "message": "hello world", "caller": "/go/src/your_project/some_file:21"}
+```
+
+Equivalent of `Lshortfile`:
+
+```go
+zerolog.CallerMarshalFunc = func(pc uintptr, file string, line int) string {
+    return filepath.Base(file) + ":" + strconv.Itoa(line)
+}
+log.Logger = log.With().Caller().Logger()
+log.Info().Msg("hello world")
+
+// Output: {"level": "info", "message": "hello world", "caller": "some_file:21"}
+```
+
+### Thread-safe, lock-free, non-blocking writer
+
+If your writer might be slow or not thread-safe and you need your log producers to never get slowed down by a slow writer, you can use a `diode.Writer` as follows:
+
+```go
+wr := diode.NewWriter(os.Stdout, 1000, 10*time.Millisecond, func(missed int) {
+        fmt.Printf("Logger Dropped %d messages", missed)
+    })
+log := zerolog.New(wr)
+log.Print("test")
+```
+
+You will need to install `code.cloudfoundry.org/go-diodes` to use this feature.
+
 ### Log Sampling
 
 ```go
-sampled := log.Sample(10)
+sampled := log.Sample(&zerolog.BasicSampler{N: 10})
 sampled.Info().Msg("will be logged every 10 messages")
 
-// Output: {"time":1494567715,"sample":10,"message":"will be logged every 10 messages"}
+// Output: {"time":1494567715,"level":"info","message":"will be logged every 10 messages"}
+```
+
+More advanced sampling:
+
+```go
+// Will let 5 debug messages per period of 1 second.
+// Over 5 debug message, 1 every 100 debug messages are logged.
+// Other levels are not sampled.
+sampled := log.Sample(zerolog.LevelSampler{
+    DebugSampler: &zerolog.BurstSampler{
+        Burst: 5,
+        Period: 1*time.Second,
+        NextSampler: &zerolog.BasicSampler{N: 100},
+    },
+})
+sampled.Debug().Msg("hello world")
+
+// Output: {"time":1494567715,"level":"debug","message":"hello world"}
+```
+
+### Hooks
+
+```go
+type SeverityHook struct{}
+
+func (h SeverityHook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
+    if level != zerolog.NoLevel {
+        e.Str("severity", level.String())
+    }
+}
+
+hooked := log.Hook(SeverityHook{})
+hooked.Warn().Msg("")
+
+// Output: {"level":"warn","severity":"warn"}
 ```
 
 ### Pass a sub-logger by context
 
 ```go
-ctx := log.With("component", "module").Logger().WithContext(ctx)
+ctx := log.With().Str("component", "module").Logger().WithContext(ctx)
 
 log.Ctx(ctx).Info().Msg("hello world")
 
@@ -183,6 +535,58 @@ stdlog.Print("hello world")
 // Output: {"foo":"bar","message":"hello world"}
 ```
 
+### context.Context integration
+
+Go contexts are commonly passed throughout Go code, and this can help you pass
+your Logger into places it might otherwise be hard to inject. The `Logger`
+instance may be attached to Go context (`context.Context`) using
+`Logger.WithContext(ctx)` and extracted from it using `zerolog.Ctx(ctx)`.
+For example:
+
+```go
+func f() {
+    logger := zerolog.New(os.Stdout)
+    ctx := context.Background()
+
+    // Attach the Logger to the context.Context
+    ctx = logger.WithContext(ctx)
+    someFunc(ctx)
+}
+
+func someFunc(ctx context.Context) {
+    // Get Logger from the go Context. if it's nil, then
+    // `zerolog.DefaultContextLogger` is returned, if
+    // `DefaultContextLogger` is nil, then a disabled logger is returned.
+    logger := zerolog.Ctx(ctx)
+    logger.Info().Msg("Hello")
+}
+```
+
+A second form of `context.Context` integration allows you to pass the current
+`context.Context` into the logged event, and retrieve it from hooks. This can be
+useful to log trace and span IDs or other information stored in the go context,
+and facilitates the unification of logging and tracing in some systems:
+
+```go
+type TracingHook struct{}
+
+func (h TracingHook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
+    ctx := e.GetCtx()
+    spanId := getSpanIdFromContext(ctx) // as per your tracing framework
+    e.Str("span-id", spanId)
+}
+
+func f() {
+    // Setup the logger
+    logger := zerolog.New(os.Stdout)
+    logger = logger.Hook(TracingHook{})
+
+    ctx := context.Background()
+    // Use the Ctx function to make the context available to the hook
+    logger.Info().Ctx(ctx).Msg("Hello")
+}
+```
+
 ### Integration with `net/http`
 
 The `github.com/rs/zerolog/hlog` package provides some helpers to integrate zerolog with `http.Handler`.
@@ -202,11 +606,11 @@ c := alice.New()
 c = c.Append(hlog.NewHandler(log))
 
 // Install some provided extra handler to set some request's context fields.
-// Thanks to those handler, all our logs will come with some pre-populated fields.
+// Thanks to that handler, all our logs will come with some prepopulated fields.
 c = c.Append(hlog.AccessHandler(func(r *http.Request, status, size int, duration time.Duration) {
     hlog.FromRequest(r).Info().
         Str("method", r.Method).
-        Str("url", r.URL.String()).
+        Stringer("url", r.URL).
         Int("status", status).
         Int("size", size).
         Dur("duration", duration).
@@ -236,94 +640,219 @@ if err := http.ListenAndServe(":8080", nil); err != nil {
 }
 ```
 
+## Multiple Log Output
+
+`zerolog.MultiLevelWriter` may be used to send the log message to multiple outputs.
+
+In this example, we send the log message to both `os.Stdout` and the in-built `ConsoleWriter`.
+
+```go
+func main() {
+    consoleWriter := zerolog.ConsoleWriter{Out: os.Stdout}
+    multi := zerolog.MultiLevelWriter(consoleWriter, os.Stdout)
+    logger := zerolog.New(multi).With().Timestamp().Logger()
+    logger.Info().Msg("Hello World!")
+}
+
+// Output (Line 1: Console; Line 2: Stdout)
+// 12:36PM INF Hello World!
+// {"level":"info","time":"2019-11-07T12:36:38+03:00","message":"Hello World!"}
+```
+
 ## Global Settings
 
-Some settings can be changed and will by applied to all loggers:
+Some settings can be changed and will be applied to all loggers:
 
-* `log.Logger`: You can set this value to customize the global logger (the one used by package level methods).
-* `zerolog.SetGlobalLevel`: Can raise the minimum level of all loggers. Set this to `zerolog.Disable` to disable logging altogether (quiet mode).
-* `zerolog.DisableSampling`: If argument is `true`, all sampled loggers will stop sampling and issue 100% of their log events.
-* `zerolog.TimestampFieldName`: Can be set to customize `Timestamp` field name.
-* `zerolog.LevelFieldName`: Can be set to customize level field name.
-* `zerolog.MessageFieldName`: Can be set to customize message field name.
-* `zerolog.ErrorFieldName`: Can be set to customize `Err` field name.
-* `zerolog.SampleFieldName`: Can be set to customize the field name added when sampling is enabled.
-* `zerolog.TimeFieldFormat`: Can be set to customize `Time` field value formatting. If set with an empty string, times are formated as UNIX timestamp.
-	// DurationFieldUnit defines the unit for time.Duration type fields added
-	// using the Dur method.
-* `DurationFieldUnit`: Sets the unit of the fields added by `Dur` (default: `time.Millisecond`).
-* `DurationFieldInteger`: If set to true, `Dur` fields are formatted as integers instead of floats.
+- `log.Logger`: You can set this value to customize the global logger (the one used by package level methods).
+- `zerolog.SetGlobalLevel`: Can raise the minimum level of all loggers. Call this with `zerolog.Disabled` to disable logging altogether (quiet mode).
+- `zerolog.DisableSampling`: If argument is `true`, all sampled loggers will stop sampling and issue 100% of their log events.
+- `zerolog.TimestampFieldName`: Can be set to customize `Timestamp` field name.
+- `zerolog.LevelFieldName`: Can be set to customize level field name.
+- `zerolog.MessageFieldName`: Can be set to customize message field name.
+- `zerolog.ErrorFieldName`: Can be set to customize `Err` field name.
+- `zerolog.TimeFieldFormat`: Can be set to customize `Time` field value formatting. If set with `zerolog.TimeFormatUnix`, `zerolog.TimeFormatUnixMs` or `zerolog.TimeFormatUnixMicro`, times are formatted as UNIX timestamp.
+- `zerolog.DurationFieldUnit`: Can be set to customize the unit for time.Duration type fields added by `Dur` (default: `time.Millisecond`).
+- `zerolog.DurationFieldFormat`: Can be set to `DurationFormatFloat`, `DurationFormatInt`, or `DurationFormatString` (default: `DurationFormatFloat`) to append the `Duration` as a `Float64`, `Int64`, or by calling `String()` (respectively).
+- `zerolog.DurationFieldInteger`: If set to `true`, `Dur` fields are formatted as integers instead of floats (default: `false`). Deprecated: Use `zerolog.DurationFieldFormat = DurationFormatInt` instead.
+- `zerolog.ErrorHandler`: Called whenever zerolog fails to write an event on its output. If not set, an error is printed on the stderr. This handler must be thread safe and non-blocking.
+- `zerolog.FloatingPointPrecision`: If set to a value other than -1, controls the number of digits when formatting float numbers in JSON. See [strconv.FormatFloat](https://pkg.go.dev/strconv#FormatFloat)
+  for more details.
 
 ## Field Types
 
 ### Standard Types
 
-* `Str`
-* `Bool`
-* `Int`, `Int8`, `Int16`, `Int32`, `Int64`
-* `Uint`, `Uint8`, `Uint16`, `Uint32`, `Uint64`
-* `Float32`, `Float64`
+- `Str`
+- `Bool`
+- `Int`, `Int8`, `Int16`, `Int32`, `Int64`
+- `Uint`, `Uint8`, `Uint16`, `Uint32`, `Uint64`
+- `Float32`, `Float64`
 
 ### Advanced Fields
 
-* `Err`: Takes an `error` and render it as a string using the `zerolog.ErrorFieldName` field name.
-* `Timestamp`: Insert a timestamp field with `zerolog.TimestampFieldName` field name and formatted using `zerolog.TimeFieldFormat`.
-* `Time`: Adds a field with the time formated with the `zerolog.TimeFieldFormat`.
-* `Dur`: Adds a field with a `time.Duration`.
-* `Dict`: Adds a sub-key/value as a field of the event.
-* `Interface`: Uses reflection to marshal the type.
+- `Err`: Takes an `error` and renders it as a string using the `zerolog.ErrorFieldName` field name.
+- `Func`: Run a `func` only if the level is enabled.
+- `Timestamp`: Inserts a timestamp field with `zerolog.TimestampFieldName` field name, formatted using `zerolog.TimeFieldFormat`.
+- `Time`: Adds a field with time formatted with `zerolog.TimeFieldFormat`.
+- `Dur`: Adds a field with `time.Duration`.
+- `Dict`: Adds a sub-key/value as a field of the event.
+- `RawJSON`: Adds a field with an already encoded JSON (`[]byte`)
+- `Hex`: Adds a field with value formatted as a hexadecimal string (`[]byte`)
+- `Interface`: Uses reflection to marshal the type.
+- `IPAddr`: Adds a field with `net.IP`.
+- `IPPrefix`: Adds a field with `net.IPNet`.
+- `MACAddr`: Adds a field with `net.HardwareAddr`
 
-## Performance
+Most fields are also available in the slice format (`Strs` for `[]string`, `Errs` for `[]error` etc.)
 
-All operations are allocation free (those numbers *include* JSON encoding):
+## Binary Encoding
 
-```
-BenchmarkLogEmpty-8        100000000    19.1 ns/op	   0 B/op       0 allocs/op
-BenchmarkDisabled-8        500000000     4.07 ns/op	   0 B/op       0 allocs/op
-BenchmarkInfo-8            30000000	    42.5 ns/op	   0 B/op       0 allocs/op
-BenchmarkContextFields-8   30000000	    44.9 ns/op	   0 B/op       0 allocs/op
-BenchmarkLogFields-8       10000000	   184 ns/op	   0 B/op       0 allocs/op
+In addition to the default JSON encoding, `zerolog` can produce binary logs using [CBOR](https://cbor.io) encoding. The choice of encoding can be decided at compile time using the build tag `binary_log` as follows:
+
+```bash
+go build -tags binary_log .
 ```
 
-Using Uber's zap [comparison benchmark](https://github.com/uber-go/zap#performance):
+To decode binary encoded log files you can use any CBOR decoder. One has been tested to work
+with zerolog library is [CSD](https://github.com/toravir/csd/).
+
+## Integration with `log/slog`
+
+zerolog provides a `slog.Handler` implementation that routes `log/slog` records through a zerolog logger. This lets you use the standard library's `slog` API while keeping zerolog's performance and encoding:
+
+```go
+package main
+
+import (
+    "log/slog"
+
+    "github.com/rs/zerolog"
+    "github.com/rs/zerolog/log"
+)
+
+func main() {
+    zl := log.Logger
+    handler := zerolog.NewSlogHandler(zl)
+    logger := slog.New(handler)
+
+    logger.Info("user logged in", "user", "alice", "role", "admin")
+}
+
+// Output: {"level":"info","user":"alice","role":"admin","time":"...","message":"user logged in"}
+```
+
+The handler supports all `slog` features including `WithAttrs`, `WithGroup`, nested groups, and `LogValuer` resolution. slog levels are mapped to zerolog levels (e.g. `slog.LevelDebug` to `zerolog.DebugLevel`).
+
+## Related Projects
+
+- [grpc-zerolog](https://github.com/cheapRoc/grpc-zerolog): Implementation of `grpclog.LoggerV2` interface using `zerolog`
+- [overlog](https://github.com/Trendyol/overlog): Implementation of `Mapped Diagnostic Context` interface using `zerolog`
+- [zerologr](https://github.com/go-logr/zerologr): Implementation of `logr.LogSink` interface using `zerolog`
+- [logze](https://github.com/maxbolgarin/logze): Implementation of `log/slog` interface using `zerolog`
+
+## Benchmarks
+
+See [logbench](http://bench.zerolog.io/) for more comprehensive and up-to-date benchmarks.
+
+All operations are allocation free (those numbers _include_ JSON encoding):
+
+```text
+BenchmarkLogEmpty-8        100000000    19.1 ns/op     0 B/op       0 allocs/op
+BenchmarkDisabled-8        500000000    4.07 ns/op     0 B/op       0 allocs/op
+BenchmarkInfo-8            30000000     42.5 ns/op     0 B/op       0 allocs/op
+BenchmarkContextFields-8   30000000     44.9 ns/op     0 B/op       0 allocs/op
+BenchmarkLogFields-8       10000000     184 ns/op      0 B/op       0 allocs/op
+```
+
+There are a few Go logging benchmarks and comparisons that include zerolog.
+
+- [imkira/go-loggers-bench](https://github.com/imkira/go-loggers-bench)
+- [uber-common/zap](https://github.com/uber-go/zap#performance)
+
+Using Uber's zap comparison benchmark:
 
 Log a message and 10 fields:
 
-| Library | Time | Bytes Allocated | Objects Allocated |
-| :--- | :---: | :---: | :---: |
-| zerolog | 767 ns/op | 552 B/op | 6 allocs/op |
-| :zap: zap | 848 ns/op | 704 B/op | 2 allocs/op |
-| :zap: zap (sugared) | 1363 ns/op | 1610 B/op | 20 allocs/op |
-| go-kit | 3614 ns/op | 2895 B/op | 66 allocs/op |
-| lion | 5392 ns/op | 5807 B/op | 63 allocs/op |
-| logrus | 5661 ns/op | 6092 B/op | 78 allocs/op |
-| apex/log | 15332 ns/op | 3832 B/op | 65 allocs/op |
-| log15 | 20657 ns/op | 5632 B/op | 93 allocs/op |
+| Library             |    Time     | Bytes Allocated | Objects Allocated |
+| :------------------ | :---------: | :-------------: | :---------------: |
+| zerolog             |  767 ns/op  |    552 B/op     |    6 allocs/op    |
+| :zap: zap           |  848 ns/op  |    704 B/op     |    2 allocs/op    |
+| :zap: zap (sugared) | 1363 ns/op  |    1610 B/op    |   20 allocs/op    |
+| go-kit              | 3614 ns/op  |    2895 B/op    |   66 allocs/op    |
+| lion                | 5392 ns/op  |    5807 B/op    |   63 allocs/op    |
+| logrus              | 5661 ns/op  |    6092 B/op    |   78 allocs/op    |
+| apex/log            | 15332 ns/op |    3832 B/op    |   65 allocs/op    |
+| log15               | 20657 ns/op |    5632 B/op    |   93 allocs/op    |
 
 Log a message with a logger that already has 10 fields of context:
 
-| Library | Time | Bytes Allocated | Objects Allocated |
-| :--- | :---: | :---: | :---: |
-| zerolog | 52 ns/op | 0 B/op | 0 allocs/op |
-| :zap: zap | 283 ns/op | 0 B/op | 0 allocs/op |
-| :zap: zap (sugared) | 337 ns/op | 80 B/op | 2 allocs/op |
-| lion | 2702 ns/op | 4074 B/op | 38 allocs/op |
-| go-kit | 3378 ns/op | 3046 B/op | 52 allocs/op |
-| logrus | 4309 ns/op | 4564 B/op | 63 allocs/op |
-| apex/log | 13456 ns/op | 2898 B/op | 51 allocs/op |
-| log15 | 14179 ns/op | 2642 B/op | 44 allocs/op |
+| Library             |    Time     | Bytes Allocated | Objects Allocated |
+| :------------------ | :---------: | :-------------: | :---------------: |
+| zerolog             |  52 ns/op   |     0 B/op      |    0 allocs/op    |
+| :zap: zap           |  283 ns/op  |     0 B/op      |    0 allocs/op    |
+| :zap: zap (sugared) |  337 ns/op  |     80 B/op     |    2 allocs/op    |
+| lion                | 2702 ns/op  |    4074 B/op    |   38 allocs/op    |
+| go-kit              | 3378 ns/op  |    3046 B/op    |   52 allocs/op    |
+| logrus              | 4309 ns/op  |    4564 B/op    |   63 allocs/op    |
+| apex/log            | 13456 ns/op |    2898 B/op    |   51 allocs/op    |
+| log15               | 14179 ns/op |    2642 B/op    |   44 allocs/op    |
 
 Log a static string, without any context or `printf`-style templating:
 
-| Library | Time | Bytes Allocated | Objects Allocated |
-| :--- | :---: | :---: | :---: |
-| zerolog | 50 ns/op | 0 B/op | 0 allocs/op |
-| :zap: zap | 236 ns/op | 0 B/op | 0 allocs/op |
-| standard library | 453 ns/op | 80 B/op | 2 allocs/op |
-| :zap: zap (sugared) | 337 ns/op | 80 B/op | 2 allocs/op |
-| go-kit | 508 ns/op | 656 B/op | 13 allocs/op |
-| lion | 771 ns/op | 1224 B/op | 10 allocs/op |
-| logrus | 1244 ns/op | 1505 B/op | 27 allocs/op |
-| apex/log | 2751 ns/op | 584 B/op | 11 allocs/op |
-| log15 | 5181 ns/op | 1592 B/op | 26 allocs/op |
+| Library             |    Time    | Bytes Allocated | Objects Allocated |
+| :------------------ | :--------: | :-------------: | :---------------: |
+| zerolog             |  50 ns/op  |     0 B/op      |    0 allocs/op    |
+| :zap: zap           | 236 ns/op  |     0 B/op      |    0 allocs/op    |
+| standard library    | 453 ns/op  |     80 B/op     |    2 allocs/op    |
+| :zap: zap (sugared) | 337 ns/op  |     80 B/op     |    2 allocs/op    |
+| go-kit              | 508 ns/op  |    656 B/op     |   13 allocs/op    |
+| lion                | 771 ns/op  |    1224 B/op    |   10 allocs/op    |
+| logrus              | 1244 ns/op |    1505 B/op    |   27 allocs/op    |
+| apex/log            | 2751 ns/op |    584 B/op     |   11 allocs/op    |
+| log15               | 5181 ns/op |    1592 B/op    |   26 allocs/op    |
 
+## Caveats
+
+### Field duplication
+
+Note that zerolog does no de-duplication of fields. Using the same key multiple times creates multiple keys in final JSON:
+
+```go
+logger := zerolog.New(os.Stderr).With().Timestamp().Logger()
+logger.Info().
+       Timestamp().
+       Msg("dup")
+// Output: {"level":"info","time":1494567715,"time":1494567715,"message":"dup"}
+```
+
+In this case, many consumers will take the last value, but this is not guaranteed; check yours if in doubt.
+
+### Concurrency safety
+
+Be careful when calling `UpdateContext`. It is not concurrency safe. Use the `With()` method to create a child logger:
+
+```go
+func handler(w http.ResponseWriter, r *http.Request) {
+    // Create a child logger for concurrency safety
+    logger := log.Logger.With().Logger()
+
+    // Add context fields, for example User-Agent from HTTP headers
+    logger.UpdateContext(func(c zerolog.Context) zerolog.Context {
+        ...
+    })
+}
+```
+
+The `Event` object returned from the `Logger` level-specific message functions (e.g. `Log()`, `Trace()`, `Debug()`, etc.)
+is allocated in `sync.Pool` memory that will be returned to the pool as soon as the `Msg()`, `Msgf()`, `Send()`,
+or `MsgFunc()` writes the message and **must not** be accessed afterwards.
+
+**Do not** hold a reference to the `*Event` while in callback functions or your own code. This is especially important in
+`Hook.Run()` and `HookFunc` functions or `MarshalZerologObject(e *Event)` callback (e.g. `LogObjectMarshaler` implementations).
+
+Any `Array` objects returned from `Context.CreateArray()` or `Event.CreateArray()` are from a `sync.Pool` so **do not** hold
+references to them from within any `MarshalZerologArray(a *Array)` callback (e.g. `LogArrayMarshaler` implementations) or your
+own code as they will be cleared and returned to the pool after being buffered by a call to `Context.Array()` or `Event.Array()`.
+
+Any _dictionary_ `Event` returned from `Context.CreateDict()` or `Event.CreateDict()` **must not** be referenced after being
+buffered by a call to `Array.Dict()`, `Context.Dict()`, or `Event.Dict()` as they will be cleared and returned to the pool.

array.go

@@ -1,10 +1,10 @@
 package zerolog
 
 import (
+	"context"
+	"net"
 	"sync"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 var arrayPool = &sync.Pool{
@@ -15,155 +15,262 @@ var arrayPool = &sync.Pool{
 	},
 }
 
+// Array is used to prepopulate an array of items
+// which can be re-used to add to log messages.
 type Array struct {
-	buf []byte
+	buf   []byte
+	stack bool            // enable error stack trace
+	ctx   context.Context // Optional Go context
+	ch    []Hook          // hooks
+}
+
+func putArray(a *Array) {
+	// prevent any subsequent use of the Array contextual state and truncate the buffer
+	a.stack = false
+	a.ctx = nil
+	a.ch = nil
+	a.buf = a.buf[:0]
+
+	// Proper usage of a sync.Pool requires each entry to have approximately
+	// the same memory cost. To obtain this property when the stored type
+	// contains a variably-sized buffer, we add a hard limit on the maximum buffer
+	// to place back in the pool.
+	//
+	// See https://golang.org/issue/23199
+	const maxSize = 1 << 16 // 64KiB
+	if cap(a.buf) <= maxSize {
+		arrayPool.Put(a)
+	}
 }
 
 // Arr creates an array to be added to an Event or Context.
+// WARNING: This function is deprecated because it does not preserve
+// the stack, hooks, and context from the parent event.
+// Deprecated: Use Event.CreateArray or Context.CreateArray instead.
 func Arr() *Array {
 	a := arrayPool.Get().(*Array)
 	a.buf = a.buf[:0]
+	a.stack = false
+	a.ctx = nil
+	a.ch = nil
 	return a
 }
 
+// MarshalZerologArray method here is no-op - since data is
+// already in the needed format.
 func (*Array) MarshalZerologArray(*Array) {
+	// untestable: there's no code to be covered
 }
 
 func (a *Array) write(dst []byte) []byte {
-	if len(a.buf) == 0 {
-		dst = append(dst, `[]`...)
-	} else {
-		a.buf[0] = '['
-		dst = append(append(dst, a.buf...), ']')
+	dst = enc.AppendArrayStart(dst)
+	if len(a.buf) > 0 {
+		dst = append(dst, a.buf...)
 	}
-	arrayPool.Put(a)
+	dst = enc.AppendArrayEnd(dst)
+	putArray(a)
 	return dst
 }
 
 // Object marshals an object that implement the LogObjectMarshaler
-// interface and append it to the array.
+// interface and appends it to the array.
 func (a *Array) Object(obj LogObjectMarshaler) *Array {
-	a.buf = append(a.buf, ',')
-	e := Dict()
-	obj.MarshalZerologObject(e)
-	e.buf = append(e.buf, '}')
-	a.buf = append(a.buf, e.buf...)
+	a.buf = appendObject(enc.AppendArrayDelim(a.buf), obj, a.stack, a.ctx, a.ch)
 	return a
 }
 
-// Str append the val as a string to the array.
+// Str appends the val as a string to the array.
 func (a *Array) Str(val string) *Array {
-	a.buf = json.AppendString(append(a.buf, ','), val)
+	a.buf = enc.AppendString(enc.AppendArrayDelim(a.buf), val)
 	return a
 }
 
-// Bytes append the val as a string to the array.
+// Bytes appends the val as a string to the array.
 func (a *Array) Bytes(val []byte) *Array {
-	a.buf = json.AppendBytes(append(a.buf, ','), val)
+	a.buf = enc.AppendBytes(enc.AppendArrayDelim(a.buf), val)
 	return a
 }
 
-// Err append the err as a string to the array.
+// Hex appends the val as a hex string to the array.
+func (a *Array) Hex(val []byte) *Array {
+	a.buf = enc.AppendHex(enc.AppendArrayDelim(a.buf), val)
+	return a
+}
+
+// RawJSON adds already encoded JSON to the array.
+func (a *Array) RawJSON(val []byte) *Array {
+	a.buf = appendJSON(enc.AppendArrayDelim(a.buf), val)
+	return a
+}
+
+// Err serializes and appends the err to the array.
 func (a *Array) Err(err error) *Array {
-	a.buf = json.AppendError(append(a.buf, ','), err)
+	switch m := ErrorMarshalFunc(err).(type) {
+	case nil:
+		a.buf = enc.AppendNil(enc.AppendArrayDelim(a.buf))
+	case LogObjectMarshaler:
+		a = a.Object(m)
+	case error:
+		if !isNilValue(m) {
+			a.buf = enc.AppendString(enc.AppendArrayDelim(a.buf), m.Error())
+		}
+	case string:
+		a.buf = enc.AppendString(enc.AppendArrayDelim(a.buf), m)
+	default:
+		a.buf = enc.AppendInterface(enc.AppendArrayDelim(a.buf), m)
+	}
+
 	return a
 }
 
-// Bool append the val as a bool to the array.
+// Errs serializes and appends errors to the array.
+func (a *Array) Errs(errs []error) *Array {
+	for _, err := range errs {
+		switch m := ErrorMarshalFunc(err).(type) {
+		case nil:
+			a = a.Interface(nil)
+		case LogObjectMarshaler:
+			a = a.Object(m)
+		case error:
+			if !isNilValue(m) {
+				a = a.Str(m.Error())
+			}
+		case string:
+			a = a.Str(m)
+		default:
+			a = a.Interface(m)
+		}
+	}
+	return a
+}
+
+// Bool appends the val as a bool to the array.
 func (a *Array) Bool(b bool) *Array {
-	a.buf = json.AppendBool(append(a.buf, ','), b)
+	a.buf = enc.AppendBool(enc.AppendArrayDelim(a.buf), b)
 	return a
 }
 
-// Int append i as a int to the array.
+// Int appends i as a int to the array.
 func (a *Array) Int(i int) *Array {
-	a.buf = json.AppendInt(append(a.buf, ','), i)
+	a.buf = enc.AppendInt(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int8 append i as a int8 to the array.
+// Int8 appends i as a int8 to the array.
 func (a *Array) Int8(i int8) *Array {
-	a.buf = json.AppendInt8(append(a.buf, ','), i)
+	a.buf = enc.AppendInt8(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int16 append i as a int16 to the array.
+// Int16 appends i as a int16 to the array.
 func (a *Array) Int16(i int16) *Array {
-	a.buf = json.AppendInt16(append(a.buf, ','), i)
+	a.buf = enc.AppendInt16(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int32 append i as a int32 to the array.
+// Int32 appends i as a int32 to the array.
 func (a *Array) Int32(i int32) *Array {
-	a.buf = json.AppendInt32(append(a.buf, ','), i)
+	a.buf = enc.AppendInt32(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int64 append i as a int64 to the array.
+// Int64 appends i as a int64 to the array.
 func (a *Array) Int64(i int64) *Array {
-	a.buf = json.AppendInt64(append(a.buf, ','), i)
+	a.buf = enc.AppendInt64(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint append i as a uint to the array.
+// Uint appends i as a uint to the array.
 func (a *Array) Uint(i uint) *Array {
-	a.buf = json.AppendUint(append(a.buf, ','), i)
+	a.buf = enc.AppendUint(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint8 append i as a uint8 to the array.
+// Uint8 appends i as a uint8 to the array.
 func (a *Array) Uint8(i uint8) *Array {
-	a.buf = json.AppendUint8(append(a.buf, ','), i)
+	a.buf = enc.AppendUint8(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint16 append i as a uint16 to the array.
+// Uint16 appends i as a uint16 to the array.
 func (a *Array) Uint16(i uint16) *Array {
-	a.buf = json.AppendUint16(append(a.buf, ','), i)
+	a.buf = enc.AppendUint16(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint32 append i as a uint32 to the array.
+// Uint32 appends i as a uint32 to the array.
 func (a *Array) Uint32(i uint32) *Array {
-	a.buf = json.AppendUint32(append(a.buf, ','), i)
+	a.buf = enc.AppendUint32(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint64 append i as a uint64 to the array.
+// Uint64 appends i as a uint64 to the array.
 func (a *Array) Uint64(i uint64) *Array {
-	a.buf = json.AppendUint64(append(a.buf, ','), i)
+	a.buf = enc.AppendUint64(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Float32 append f as a float32 to the array.
+// Float32 appends f as a float32 to the array.
 func (a *Array) Float32(f float32) *Array {
-	a.buf = json.AppendFloat32(append(a.buf, ','), f)
+	a.buf = enc.AppendFloat32(enc.AppendArrayDelim(a.buf), f, FloatingPointPrecision)
 	return a
 }
 
-// Float64 append f as a float64 to the array.
+// Float64 appends f as a float64 to the array.
 func (a *Array) Float64(f float64) *Array {
-	a.buf = json.AppendFloat64(append(a.buf, ','), f)
+	a.buf = enc.AppendFloat64(enc.AppendArrayDelim(a.buf), f, FloatingPointPrecision)
 	return a
 }
 
-// Time append t formated as string using zerolog.TimeFieldFormat.
+// Time appends t formatted as string using zerolog.TimeFieldFormat.
 func (a *Array) Time(t time.Time) *Array {
-	a.buf = json.AppendTime(append(a.buf, ','), t, TimeFieldFormat)
+	a.buf = enc.AppendTime(enc.AppendArrayDelim(a.buf), t, TimeFieldFormat)
 	return a
 }
 
-// Dur append d to the array.
+// Dur appends d to the array.
 func (a *Array) Dur(d time.Duration) *Array {
-	a.buf = json.AppendDuration(append(a.buf, ','), d, DurationFieldUnit, DurationFieldInteger)
+	a.buf = enc.AppendDuration(enc.AppendArrayDelim(a.buf), d, DurationFieldUnit, DurationFieldFormat, DurationFieldInteger, FloatingPointPrecision)
 	return a
 }
 
-// Interface append i marshaled using reflection.
+// Interface appends i marshaled using reflection.
 func (a *Array) Interface(i interface{}) *Array {
 	if obj, ok := i.(LogObjectMarshaler); ok {
 		return a.Object(obj)
 	}
-	a.buf = json.AppendInterface(append(a.buf, ','), i)
+	a.buf = enc.AppendInterface(enc.AppendArrayDelim(a.buf), i)
+	return a
+}
+
+// IPAddr adds a net.IP IPv4 or IPv6 address to the array
+func (a *Array) IPAddr(ip net.IP) *Array {
+	a.buf = enc.AppendIPAddr(enc.AppendArrayDelim(a.buf), ip)
+	return a
+}
+
+// IPPrefix adds a net.IPNet IPv4 or IPv6 Prefix (IP + mask) to the array
+func (a *Array) IPPrefix(pfx net.IPNet) *Array {
+	a.buf = enc.AppendIPPrefix(enc.AppendArrayDelim(a.buf), pfx)
+	return a
+}
+
+// MACAddr adds a net.HardwareAddr MAC (Ethernet) address to the array
+func (a *Array) MACAddr(ha net.HardwareAddr) *Array {
+	a.buf = enc.AppendMACAddr(enc.AppendArrayDelim(a.buf), ha)
+	return a
+}
+
+// Dict adds the dict Event to the array
+func (a *Array) Dict(dict *Event) *Array {
+	dict.buf = enc.AppendEndMarker(dict.buf)
+	a.buf = append(enc.AppendArrayDelim(a.buf), dict.buf...)
+	putEvent(dict)
+	return a
+}
+
+// Type adds the val's type using reflection to the array.
+func (a *Array) Type(val interface{}) *Array {
+	a.buf = enc.AppendType(enc.AppendArrayDelim(a.buf), val)
 	return a
 }

array_test.go

@@ -1,6 +1,8 @@
 package zerolog
 
 import (
+	"fmt"
+	"net"
 	"testing"
 	"time"
 )
@@ -18,13 +20,47 @@ func TestArray(t *testing.T) {
 		Uint16(8).
 		Uint32(9).
 		Uint64(10).
-		Float32(11).
-		Float64(12).
+		Float32(11.98122).
+		Float64(12.987654321).
 		Str("a").
+		Bytes([]byte("b")).
+		Hex([]byte{0x1f}).
+		RawJSON([]byte(`{"some":"json"}`)).
+		RawJSON([]byte(`{"longer":[1111,2222,3333,4444,5555]}`)).
 		Time(time.Time{}).
-		Dur(0)
-	want := `[true,1,2,3,4,5,6,7,8,9,10,11,12,"a","0001-01-01T00:00:00Z",0]`
-	if got := string(a.write([]byte{})); got != want {
+		IPAddr(net.IP{192, 168, 0, 10}).
+		IPPrefix(net.IPNet{IP: net.IP{127, 0, 0, 0}, Mask: net.CIDRMask(24, 32)}).
+		MACAddr(net.HardwareAddr{0x01, 0x23, 0x45, 0x67, 0x89, 0xab}).
+		Interface(struct {
+			Pub  string
+			Tag  string `json:"tag"`
+			priv int
+		}{"A", "j", -5}).
+		Interface(logObjectMarshalerImpl{
+			name: "ZOT",
+			age:  35,
+		}).
+		Dur(0).
+		Dict(Dict().
+			Str("bar", "baz").
+			Int("n", 1),
+		).
+		Err(nil).
+		Err(fmt.Errorf("failure")).
+		Err(loggableError{fmt.Errorf("oops")}).
+		Object(logObjectMarshalerImpl{
+			name: "ZIT",
+			age:  22,
+		}).
+		Type(3.14)
+
+	want := `[true,1,2,3,4,5,6,7,8,9,10,11.98122,12.987654321,"a","b","1f",{"some":"json"},{"longer":[1111,2222,3333,4444,5555]},"0001-01-01T00:00:00Z","192.168.0.10","127.0.0.0/24","01:23:45:67:89:ab",{"Pub":"A","tag":"j"},{"name":"zot","age":-35},0,{"bar":"baz","n":1},null,"failure",{"l":"OOPS"},{"name":"zit","age":-22},"float64"]`
+	if got := decodeObjectToStr(a.write([]byte{})); got != want {
 		t.Errorf("Array.write()\ngot:  %s\nwant: %s", got, want)
 	}
 }
+
+func TestArray_MarshalZerologArray(t *testing.T) {
+	a := Arr()
+	a.MarshalZerologArray(nil) // no-op method, should not panic
+}

benchmark_test.go

@@ -2,7 +2,7 @@ package zerolog
 
 import (
 	"errors"
-	"io/ioutil"
+	"io"
 	"testing"
 	"time"
 )
@@ -13,7 +13,7 @@ var (
 )
 
 func BenchmarkLogEmpty(b *testing.B) {
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
@@ -23,7 +23,7 @@ func BenchmarkLogEmpty(b *testing.B) {
 }
 
 func BenchmarkDisabled(b *testing.B) {
-	logger := New(ioutil.Discard).Level(Disabled)
+	logger := New(io.Discard).Level(Disabled)
 	b.ResetTimer()
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
@@ -33,7 +33,7 @@ func BenchmarkDisabled(b *testing.B) {
 }
 
 func BenchmarkInfo(b *testing.B) {
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
@@ -43,7 +43,7 @@ func BenchmarkInfo(b *testing.B) {
 }
 
 func BenchmarkContextFields(b *testing.B) {
-	logger := New(ioutil.Discard).With().
+	logger := New(io.Discard).With().
 		Str("string", "four!").
 		Time("time", time.Time{}).
 		Int("int", 123).
@@ -57,8 +57,20 @@ func BenchmarkContextFields(b *testing.B) {
 	})
 }
 
+func BenchmarkContextAppend(b *testing.B) {
+	logger := New(io.Discard).With().
+		Str("foo", "bar").
+		Logger()
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			logger.With().Str("bar", "baz")
+		}
+	})
+}
+
 func BenchmarkLogFields(b *testing.B) {
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
@@ -72,125 +84,142 @@ func BenchmarkLogFields(b *testing.B) {
 	})
 }
 
-type obj struct {
-	Pub  string
-	Tag  string `json:"tag"`
-	priv int
-}
-
-func (o obj) MarshalZerologObject(e *Event) {
-	e.Str("Pub", o.Pub).
-		Str("Tag", o.Tag).
-		Int("priv", o.priv)
+func BenchmarkLogArrayObject(b *testing.B) {
+	obj1 := fixtureObj{"a", "b", 2}
+	obj2 := fixtureObj{"c", "d", 3}
+	obj3 := fixtureObj{"e", "f", 4}
+	logger := New(io.Discard)
+	b.ResetTimer()
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		arr := Arr()
+		arr.Object(&obj1)
+		arr.Object(&obj2)
+		arr.Object(&obj3)
+		logger.Info().Array("objects", arr).Msg("test")
+	}
 }
 
 func BenchmarkLogFieldType(b *testing.B) {
-	bools := []bool{true, false, true, false, true, false, true, false, true, false}
-	ints := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
-	floats := []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
-	strings := []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j"}
-	durations := []time.Duration{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
-	times := []time.Time{
-		time.Unix(0, 0),
-		time.Unix(1, 0),
-		time.Unix(2, 0),
-		time.Unix(3, 0),
-		time.Unix(4, 0),
-		time.Unix(5, 0),
-		time.Unix(6, 0),
-		time.Unix(7, 0),
-		time.Unix(8, 0),
-		time.Unix(9, 0),
-	}
-	interfaces := []struct {
-		Pub  string
-		Tag  string `json:"tag"`
-		priv int
-	}{
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-		{"a", "a", 0},
-	}
-	objects := []obj{
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-		obj{"a", "a", 0},
-	}
-	errs := []error{errors.New("a"), errors.New("b"), errors.New("c"), errors.New("d"), errors.New("e")}
+	fixtures := makeFieldFixtures()
 	types := map[string]func(e *Event) *Event{
+		"Any": func(e *Event) *Event {
+			return e.Any("k", fixtures.Interfaces[0])
+		},
 		"Bool": func(e *Event) *Event {
-			return e.Bool("k", bools[0])
+			return e.Bool("k", fixtures.Bools[0])
 		},
 		"Bools": func(e *Event) *Event {
-			return e.Bools("k", bools)
+			return e.Bools("k", fixtures.Bools)
+		},
+		"Bytes": func(e *Event) *Event {
+			return e.Bytes("k", fixtures.Bytes)
+		},
+		"Hex": func(e *Event) *Event {
+			return e.Hex("k", fixtures.Bytes)
 		},
 		"Int": func(e *Event) *Event {
-			return e.Int("k", ints[0])
+			return e.Int("k", fixtures.Ints[0])
 		},
 		"Ints": func(e *Event) *Event {
-			return e.Ints("k", ints)
+			return e.Ints("k", fixtures.Ints)
 		},
-		"Float": func(e *Event) *Event {
-			return e.Float64("k", floats[0])
+		"Float32": func(e *Event) *Event {
+			return e.Float32("k", fixtures.Floats32[0])
 		},
-		"Floats": func(e *Event) *Event {
-			return e.Floats64("k", floats)
+		"Floats32": func(e *Event) *Event {
+			return e.Floats32("k", fixtures.Floats32)
+		},
+		"Float64": func(e *Event) *Event {
+			return e.Float64("k", fixtures.Floats64[0])
+		},
+		"Floats64": func(e *Event) *Event {
+			return e.Floats64("k", fixtures.Floats64)
 		},
 		"Str": func(e *Event) *Event {
-			return e.Str("k", strings[0])
+			return e.Str("k", fixtures.Strings[0])
 		},
 		"Strs": func(e *Event) *Event {
-			return e.Strs("k", strings)
+			return e.Strs("k", fixtures.Strings)
+		},
+		"StrsV": func(e *Event) *Event {
+			return e.StrsV("k", fixtures.Strings...)
+		},
+		"Stringer": func(e *Event) *Event {
+			return e.Stringer("k", fixtures.Stringers[0])
+		},
+		"Stringers": func(e *Event) *Event {
+			return e.Stringers("k", fixtures.Stringers)
+		},
+		"StringersV": func(e *Event) *Event {
+			return e.StringersV("k", fixtures.Stringers...)
 		},
 		"Err": func(e *Event) *Event {
-			return e.Err(errs[0])
+			return e.Err(fixtures.Errs[0])
 		},
 		"Errs": func(e *Event) *Event {
-			return e.Errs("k", errs)
+			return e.Errs("k", fixtures.Errs)
+		},
+		"Ctx": func(e *Event) *Event {
+			return e.Ctx(fixtures.Ctx)
 		},
 		"Time": func(e *Event) *Event {
-			return e.Time("k", times[0])
+			return e.Time("k", fixtures.Times[0])
 		},
 		"Times": func(e *Event) *Event {
-			return e.Times("k", times)
+			return e.Times("k", fixtures.Times)
 		},
 		"Dur": func(e *Event) *Event {
-			return e.Dur("k", durations[0])
+			return e.Dur("k", fixtures.Durations[0])
 		},
 		"Durs": func(e *Event) *Event {
-			return e.Durs("k", durations)
+			return e.Durs("k", fixtures.Durations)
 		},
 		"Interface": func(e *Event) *Event {
-			return e.Interface("k", interfaces[0])
+			return e.Interface("k", fixtures.Interfaces[0])
 		},
 		"Interfaces": func(e *Event) *Event {
-			return e.Interface("k", interfaces)
+			return e.Interface("k", fixtures.Interfaces)
 		},
 		"Interface(Object)": func(e *Event) *Event {
-			return e.Interface("k", objects[0])
+			return e.Interface("k", fixtures.Objects[0])
 		},
 		"Interface(Objects)": func(e *Event) *Event {
-			return e.Interface("k", objects)
+			return e.Interface("k", fixtures.Objects)
 		},
 		"Object": func(e *Event) *Event {
-			return e.Object("k", objects[0])
+			return e.Object("k", fixtures.Objects[0])
+		},
+		"Objects": func(e *Event) *Event {
+			return e.Objects("k", fixtures.Objects)
+		},
+		"ObjectsV": func(e *Event) *Event {
+			return e.ObjectsV("k", fixtures.Objects...)
+		},
+		"Timestamp": func(e *Event) *Event {
+			return e.Timestamp()
+		},
+		"IPAddr": func(e *Event) *Event {
+			return e.IPAddr("k", fixtures.IPAddrs[0])
+		},
+		"IPAddrs": func(e *Event) *Event {
+			return e.IPAddrs("k", fixtures.IPAddrs)
+		},
+		"IPPrefix": func(e *Event) *Event {
+			return e.IPPrefix("k", fixtures.IPPfxs[0])
+		},
+		"IPPrefixes": func(e *Event) *Event {
+			return e.IPPrefixes("k", fixtures.IPPfxs)
+		},
+		"MACAddr": func(e *Event) *Event {
+			return e.MACAddr("k", fixtures.MACAddr)
+		},
+		"Type": func(e *Event) *Event {
+			return e.Type("k", fixtures.Type)
 		},
 	}
-	logger := New(ioutil.Discard)
+
+	logger := New(io.Discard)
 	b.ResetTimer()
 	for name := range types {
 		f := types[name]
@@ -203,3 +232,141 @@ func BenchmarkLogFieldType(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkContextFieldType(b *testing.B) {
+	oldFormat := TimeFieldFormat
+	TimeFieldFormat = TimeFormatUnix
+	defer func() { TimeFieldFormat = oldFormat }()
+
+	fixtures := makeFieldFixtures()
+	types := map[string]func(c Context) Context{
+		"Any": func(c Context) Context {
+			return c.Any("k", fixtures.Interfaces[0])
+		},
+		"Bool": func(c Context) Context {
+			return c.Bool("k", fixtures.Bools[0])
+		},
+		"Bools": func(c Context) Context {
+			return c.Bools("k", fixtures.Bools)
+		},
+		"Bytes": func(c Context) Context {
+			return c.Bytes("k", fixtures.Bytes)
+		},
+		"Hex": func(c Context) Context {
+			return c.Hex("k", fixtures.Bytes)
+		},
+		"Int": func(c Context) Context {
+			return c.Int("k", fixtures.Ints[0])
+		},
+		"Ints": func(c Context) Context {
+			return c.Ints("k", fixtures.Ints)
+		},
+		"Float32": func(c Context) Context {
+			return c.Float32("k", fixtures.Floats32[0])
+		},
+		"Floats32": func(c Context) Context {
+			return c.Floats32("k", fixtures.Floats32)
+		},
+		"Float64": func(c Context) Context {
+			return c.Float64("k", fixtures.Floats64[0])
+		},
+		"Floats64": func(c Context) Context {
+			return c.Floats64("k", fixtures.Floats64)
+		},
+		"Str": func(c Context) Context {
+			return c.Str("k", fixtures.Strings[0])
+		},
+		"Strs": func(c Context) Context {
+			return c.Strs("k", fixtures.Strings)
+		},
+		"StrsV": func(c Context) Context {
+			return c.StrsV("k", fixtures.Strings...)
+		},
+		"Stringer": func(c Context) Context {
+			return c.Stringer("k", fixtures.Stringers[0])
+		},
+		"Stringers": func(c Context) Context {
+			return c.Stringers("k", fixtures.Stringers)
+		},
+		"StringersV": func(c Context) Context {
+			return c.StringersV("k", fixtures.Stringers...)
+		},
+		"Err": func(c Context) Context {
+			return c.Err(fixtures.Errs[0])
+		},
+		"Errs": func(c Context) Context {
+			return c.Errs("k", fixtures.Errs)
+		},
+		"Ctx": func(c Context) Context {
+			return c.Ctx(fixtures.Ctx)
+		},
+		"Time": func(c Context) Context {
+			return c.Time("k", fixtures.Times[0])
+		},
+		"Times": func(c Context) Context {
+			return c.Times("k", fixtures.Times)
+		},
+		"Dur": func(c Context) Context {
+			return c.Dur("k", fixtures.Durations[0])
+		},
+		"Durs": func(c Context) Context {
+			return c.Durs("k", fixtures.Durations)
+		},
+		"Interface": func(c Context) Context {
+			return c.Interface("k", fixtures.Interfaces[0])
+		},
+		"Interfaces": func(c Context) Context {
+			return c.Interface("k", fixtures.Interfaces)
+		},
+		"Interface(Object)": func(c Context) Context {
+			return c.Interface("k", fixtures.Objects[0])
+		},
+		"Interface(Objects)": func(c Context) Context {
+			return c.Interface("k", fixtures.Objects)
+		},
+		"Object": func(c Context) Context {
+			return c.Object("k", fixtures.Objects[0])
+		},
+		"Objects": func(c Context) Context {
+			return c.Objects("k", fixtures.Objects)
+		},
+		"ObjectsV": func(c Context) Context {
+			return c.ObjectsV("k", fixtures.Objects...)
+		},
+		"Timestamp": func(c Context) Context {
+			return c.Timestamp()
+		},
+		"IPAddr": func(c Context) Context {
+			return c.IPAddr("k", fixtures.IPAddrs[0])
+		},
+		"IPAddrs": func(c Context) Context {
+			return c.IPAddrs("k", fixtures.IPAddrs)
+		},
+		"IPPrefix": func(c Context) Context {
+			return c.IPPrefix("k", fixtures.IPPfxs[0])
+		},
+		"IPPrefixes": func(c Context) Context {
+			return c.IPPrefixes("k", fixtures.IPPfxs)
+		},
+		"MACAddr": func(c Context) Context {
+			return c.MACAddr("k", fixtures.MACAddr)
+		},
+		"Type": func(c Context) Context {
+			return c.Type("k", fixtures.Type)
+		},
+	}
+
+	logger := New(io.Discard)
+	b.ResetTimer()
+	for name := range types {
+		f := types[name]
+		b.Run(name, func(b *testing.B) {
+			b.RunParallel(func(pb *testing.PB) {
+				for pb.Next() {
+					l := f(logger.With()).Logger()
+					l.Info().Msg("")
+				}
+			})
+		})
+	}
+}

binary_test.go

@@ -0,0 +1,647 @@
+//go:build binary_log
+// +build binary_log
+
+package zerolog
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"net"
+
+	stdlog "log"
+	"time"
+)
+
+func ExampleLogger_With() {
+	dst := bytes.Buffer{}
+	log := New(&dst).
+		With().
+		Str("foo", "bar").
+		Logger()
+
+	log.Info().Msg("hello world")
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+
+	// Output: {"level":"info","foo":"bar","message":"hello world"}
+}
+
+func ExampleLogger_Level() {
+	dst := bytes.Buffer{}
+	log := New(&dst).Level(WarnLevel)
+
+	log.Info().Msg("filtered out message")
+	log.Error().Msg("kept message")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"error","message":"kept message"}
+}
+
+func ExampleLogger_Sample() {
+	dst := bytes.Buffer{}
+	log := New(&dst).Sample(&BasicSampler{N: 2})
+
+	log.Info().Msg("message 1")
+	log.Info().Msg("message 2")
+	log.Info().Msg("message 3")
+	log.Info().Msg("message 4")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","message":"message 1"}
+	// {"level":"info","message":"message 3"}
+}
+
+type LevelNameHook1 struct{}
+
+func (h LevelNameHook1) Run(e *Event, l Level, msg string) {
+	if l != NoLevel {
+		e.Str("level_name", l.String())
+	} else {
+		e.Str("level_name", "NoLevel")
+	}
+}
+
+type MessageHook string
+
+func (h MessageHook) Run(e *Event, l Level, msg string) {
+	e.Str("the_message", msg)
+}
+
+func ExampleLogger_Hook() {
+	var levelNameHook LevelNameHook1
+	var messageHook MessageHook = "The message"
+
+	dst := bytes.Buffer{}
+	log := New(&dst).Hook(levelNameHook).Hook(messageHook)
+
+	log.Info().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","level_name":"info","the_message":"hello world","message":"hello world"}
+}
+
+func ExampleLogger_Print() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Print("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Printf() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Printf("hello %s", "world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Trace() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Trace().
+		Str("foo", "bar").
+		Int("n", 123).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"trace","foo":"bar","n":123,"message":"hello world"}
+}
+
+func ExampleLogger_Debug() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Debug().
+		Str("foo", "bar").
+		Int("n", 123).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"debug","foo":"bar","n":123,"message":"hello world"}
+}
+
+func ExampleLogger_Info() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Info().
+		Str("foo", "bar").
+		Int("n", 123).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","foo":"bar","n":123,"message":"hello world"}
+}
+
+func ExampleLogger_Warn() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Warn().
+		Str("foo", "bar").
+		Msg("a warning message")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"warn","foo":"bar","message":"a warning message"}
+}
+
+func ExampleLogger_Error() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Error().
+		Err(errors.New("some error")).
+		Msg("error doing something")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"error","error":"some error","message":"error doing something"}
+}
+
+func ExampleLogger_WithLevel() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.WithLevel(InfoLevel).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","message":"hello world"}
+}
+
+func ExampleLogger_Write() {
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Logger()
+
+	stdlog.SetFlags(0)
+	stdlog.SetOutput(log)
+
+	stdlog.Print("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","message":"hello world"}
+}
+
+func ExampleLogger_Log() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Str("bar", "baz").
+		Msg("")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","bar":"baz"}
+}
+
+func ExampleEvent_Dict() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	e := log.Log().
+		Str("foo", "bar")
+
+	e.Dict("dict", e.CreateDict().
+		Str("bar", "baz").
+		Int("n", 1),
+	).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
+}
+
+type User struct {
+	Name    string
+	Age     int
+	Created time.Time
+}
+
+func (u User) MarshalZerologObject(e *Event) {
+	e.Str("name", u.Name).
+		Int("age", u.Age).
+		Time("created", u.Created)
+}
+
+type Users []User
+
+// User implements LogObjectMarshaler
+func (uu Users) MarshalZerologArray(a *Array) {
+	for _, u := range uu {
+		a.Object(u)
+	}
+}
+
+func ExampleEvent_Array() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	e := log.Log().
+		Str("foo", "bar")
+
+	e.Array("array", e.CreateArray().
+		Str("baz").
+		Int(1),
+	).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","array":["baz",1],"message":"hello world"}
+}
+
+func ExampleEvent_Array_object() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	// Users implements LogArrayMarshaler
+	u := Users{
+		User{"John", 35, time.Time{}},
+		User{"Bob", 55, time.Time{}},
+	}
+
+	log.Log().
+		Str("foo", "bar").
+		Array("users", u).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bob","age":55,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleEvent_Object() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	// User implements LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+
+	log.Log().
+		Str("foo", "bar").
+		Object("user", u).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","user":{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},"message":"hello world"}
+}
+
+func ExampleContext_Objects() {
+	// In go, arrays are type invariant so even if you have a variable u of type []User array and User implements
+	// the LogObjectMarshaler interface, you cannot pass that to func that takes an []LogObjectMarshaler array in the
+	// Objects call. In 1.24+ it allows passing the variadic covariant slice (e.g. u...) but the unit test needs to
+	// work in earlier versions so we'll declare the array as []LogObjectMarshaler here.
+	u := []LogObjectMarshaler{User{"John", 35, time.Time{}}, User{"Bob", 55, time.Time{}}}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Objects("users", u).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bob","age":55,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleEvent_EmbedObject() {
+	price := Price{val: 6449, prec: 2, unit: "$"}
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		EmbedObject(price).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","price":"$64.49","message":"hello world"}
+}
+
+func ExampleEvent_Interface() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	obj := struct {
+		Name string `json:"name"`
+	}{
+		Name: "john",
+	}
+
+	log.Log().
+		Str("foo", "bar").
+		Interface("obj", obj).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","obj":{"name":"john"},"message":"hello world"}
+}
+
+func ExampleEvent_Dur() {
+	d := time.Duration(10 * time.Second)
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Dur("dur", d).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dur":10000,"message":"hello world"}
+}
+
+func ExampleEvent_Durs() {
+	d := []time.Duration{
+		time.Duration(10 * time.Second),
+		time.Duration(20 * time.Second),
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Durs("durs", d).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","durs":[10000,20000],"message":"hello world"}
+}
+
+func ExampleEvent_Fields_map() {
+	fields := map[string]interface{}{
+		"bar": "baz",
+		"n":   1,
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Fields(fields).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleEvent_Fields_slice() {
+	fields := []interface{}{
+		"bar", "baz",
+		"n", 1,
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Fields(fields).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleContext_Dict() {
+	dst := bytes.Buffer{}
+	ctx := New(&dst).With().
+		Str("foo", "bar")
+
+	logger := ctx.Dict("dict", ctx.CreateDict().
+		Str("bar", "baz").
+		Int("n", 1),
+	).Logger()
+
+	logger.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
+}
+
+func ExampleContext_Array() {
+	dst := bytes.Buffer{}
+	ctx := New(&dst).With().
+		Str("foo", "bar")
+
+	logger := ctx.Array("array", ctx.CreateArray().
+		Str("baz").
+		Int(1),
+	).Logger()
+
+	logger.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","array":["baz",1],"message":"hello world"}
+}
+
+func ExampleContext_Array_object() {
+	// Users implements LogArrayMarshaler
+	u := Users{
+		User{"John", 35, time.Time{}},
+		User{"Bob", 55, time.Time{}},
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Array("users", u).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bob","age":55,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+type Price struct {
+	val  uint64
+	prec int
+	unit string
+}
+
+func (p Price) MarshalZerologObject(e *Event) {
+	denom := uint64(1)
+	for i := 0; i < p.prec; i++ {
+		denom *= 10
+	}
+	result := []byte(p.unit)
+	result = append(result, fmt.Sprintf("%d.%d", p.val/denom, p.val%denom)...)
+	e.Str("price", string(result))
+}
+
+func ExampleContext_EmbedObject() {
+	price := Price{val: 6449, prec: 2, unit: "$"}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		EmbedObject(price).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","price":"$64.49","message":"hello world"}
+}
+func ExampleContext_Object() {
+	// User implements LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Object("user", u).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","user":{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},"message":"hello world"}
+}
+
+func ExampleContext_Interface() {
+	obj := struct {
+		Name string `json:"name"`
+	}{
+		Name: "john",
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Interface("obj", obj).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","obj":{"name":"john"},"message":"hello world"}
+}
+
+func ExampleContext_Dur() {
+	d := time.Duration(10 * time.Second)
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Dur("dur", d).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dur":10000,"message":"hello world"}
+}
+
+func ExampleContext_Durs() {
+	d := []time.Duration{
+		time.Duration(10 * time.Second),
+		time.Duration(20 * time.Second),
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Durs("durs", d).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","durs":[10000,20000],"message":"hello world"}
+}
+
+func ExampleContext_Fields_map() {
+	fields := map[string]interface{}{
+		"bar": "baz",
+		"n":   1,
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Fields(fields).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleContext_Fields_slice() {
+	fields := []interface{}{
+		"bar", "baz",
+		"n", 1,
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Fields(fields).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleContext_IPAddr() {
+	ipV4 := net.IP{192, 168, 0, 1}
+	ipV6 := net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		IPAddr("v4", ipV4).
+		IPAddr("v6", ipV6).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","v4":"192.168.0.1","v6":"2001:db8:85a3::8a2e:370:7334","message":"hello world"}
+}
+func ExampleContext_IPPrefix() {
+	pfxV4 := net.IPNet{IP: net.IP{192, 168, 0, 100}, Mask: net.CIDRMask(24, 32)}
+	pfxV6 := net.IPNet{IP: net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x00}, Mask: net.CIDRMask(64, 128)}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		IPPrefix("v4", pfxV4).
+		IPPrefix("v6", pfxV6).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","v4":"192.168.0.100/24","v6":"2001:db8:85a3::8a2e:370:7300/64","message":"hello world"}
+}
+func ExampleContext_MACAddr() {
+	mac := net.HardwareAddr{0x12, 0x34, 0x56, 0x78, 0x90, 0xab}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		MACAddr("mac", mac).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","mac":"12:34:56:78:90:ab","message":"hello world"}
+}

cmd/lint/README.md

@@ -0,0 +1,39 @@
+# Zerolog Lint
+
+**DEPRECATED: In favor of https://github.com/ykadowak/zerologlint which is integrated with `go vet` and [golangci-lint](https://golangci-lint.run/).**
+
+This is a basic linter that checks for missing log event finishers. Finds errors like: `log.Error().Int64("userID": 5)` - missing the `Msg`/`Msgf` finishers.
+
+## Problem
+
+When using zerolog it's easy to forget to finish the log event chain by calling a finisher - the `Msg` or `Msgf` function that will schedule the event for writing. The problem with this is that it doesn't warn/panic during compilation and it's not easily found by grep or other general tools. It's even prominently mentioned in the project's readme, that:
+
+> It is very important to note that when using the **zerolog** chaining API, as shown above (`log.Info().Msg("hello world"`), the chain must have either the `Msg` or `Msgf` method call. If you forget to add either of these, the log will not occur and there is no compile time error to alert you of this.
+
+## Solution
+
+A basic linter like this one here that looks for method invocations on `zerolog.Event` can examine the last call in a method call chain and check if it is a finisher, thus pointing out these errors.
+
+## Usage
+
+Just compile this and then run it. Or just run it via `go run` command via something like `go run cmd/lint/lint.go`.
+
+The command accepts only one argument - the package to be inspected - and 4 optional flags, all of which can occur multiple times. The standard synopsis of the command is:
+
+`lint [-finisher value] [-ignoreFile value] [-ignorePkg value] [-ignorePkgRecursively value] package`
+
+#### Flags
+
+- finisher
+    - specify which finishers to accept, defaults to `Msg` and `Msgf`
+- ignoreFile
+    - which files to ignore, either by full path or by go path (package/file.go)
+- ignorePkg
+    - do not inspect the specified package if found in the dependency tree
+- ignorePkgRecursively
+    - do not inspect the specified package or its subpackages if found in the dependency tree
+
+## Drawbacks
+
+As it is, linter can generate a false positives in a specific case. These false positives come from the fact that if you have a method that returns a `zerolog.Event` the linter will flag it because you are obviously not finishing the event. This will be solved in later release.
+

cmd/lint/go.mod

@@ -0,0 +1,5 @@
+module github.com/rs/zerolog/cmd/lint
+
+go 1.15
+
+require golang.org/x/tools v0.1.8

cmd/lint/go.sum

@@ -0,0 +1,28 @@
+github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.5.1 h1:OJxoQ/rynoF0dcCdI7cLPktw/hR2cueqYfjm43oqK38=
+golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 h1:id054HUawV2/6IGm2IV8KZQjqtwAOo2CYlOToYqa0d0=
+golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.8 h1:P1HhGGuLW4aAclzjtmJdf0mJOjVUZUzOTqkAkWL+l6w=
+golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

cmd/lint/lint.go

@@ -0,0 +1,175 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/tools/go/loader"
+)
+
+var (
+	recursivelyIgnoredPkgs arrayFlag
+	ignoredPkgs            arrayFlag
+	ignoredFiles           arrayFlag
+	allowedFinishers       arrayFlag = []string{"Msg", "Msgf"}
+	rootPkg                string
+)
+
+// parse input flags and args
+func init() {
+	flag.Var(&recursivelyIgnoredPkgs, "ignorePkgRecursively", "ignore the specified package and all subpackages recursively")
+	flag.Var(&ignoredPkgs, "ignorePkg", "ignore the specified package")
+	flag.Var(&ignoredFiles, "ignoreFile", "ignore the specified file by its path and/or go path (package/file.go)")
+	flag.Var(&allowedFinishers, "finisher", "allowed finisher for the event chain")
+	flag.Parse()
+
+	// add zerolog to recursively ignored packages
+	recursivelyIgnoredPkgs = append(recursivelyIgnoredPkgs, "github.com/rs/zerolog")
+	args := flag.Args()
+	if len(args) != 1 {
+		fmt.Fprintln(os.Stderr, "you must provide exactly one package path")
+		os.Exit(1)
+	}
+	rootPkg = args[0]
+}
+
+func main() {
+	// load the package and all its dependencies
+	conf := loader.Config{}
+	conf.Import(rootPkg)
+	p, err := conf.Load()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: unable to load the root package. %s\n", err.Error())
+		os.Exit(1)
+	}
+
+	// get the github.com/rs/zerolog.Event type
+	event := getEvent(p)
+	if event == nil {
+		fmt.Fprintln(os.Stderr, "Error: github.com/rs/zerolog.Event declaration not found, maybe zerolog is not imported in the scanned package?")
+		os.Exit(1)
+	}
+
+	// get all selections (function calls) with the github.com/rs/zerolog.Event (or pointer) receiver
+	selections := getSelectionsWithReceiverType(p, event)
+
+	// print the violations (if any)
+	hasViolations := false
+	for _, s := range selections {
+		if hasBadFinisher(p, s) {
+			hasViolations = true
+			fmt.Printf("Error: missing or bad finisher for log chain, last call: %q at: %s:%v\n", s.fn.Name(), p.Fset.File(s.Pos()).Name(), p.Fset.Position(s.Pos()).Line)
+		}
+	}
+
+	// if no violations detected, return normally
+	if !hasViolations {
+		fmt.Println("No violations found")
+		return
+	}
+
+	// if violations were detected, return error code
+	os.Exit(1)
+}
+
+func getEvent(p *loader.Program) types.Type {
+	for _, pkg := range p.AllPackages {
+		if strings.HasSuffix(pkg.Pkg.Path(), "github.com/rs/zerolog") {
+			for _, d := range pkg.Defs {
+				if d != nil && d.Name() == "Event" {
+					return d.Type()
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+func getSelectionsWithReceiverType(p *loader.Program, targetType types.Type) map[token.Pos]selection {
+	selections := map[token.Pos]selection{}
+
+	for _, z := range p.AllPackages {
+		for i, t := range z.Selections {
+			switch o := t.Obj().(type) {
+			case *types.Func:
+				// this is not a bug, o.Type() is always *types.Signature, see docs
+				if vt := o.Type().(*types.Signature).Recv(); vt != nil {
+					typ := vt.Type()
+					if pointer, ok := typ.(*types.Pointer); ok {
+						typ = pointer.Elem()
+					}
+
+					if typ == targetType {
+						if s, ok := selections[i.Pos()]; !ok || i.End() > s.End() {
+							selections[i.Pos()] = selection{i, o, z.Pkg}
+						}
+					}
+				}
+			default:
+				// skip
+			}
+		}
+	}
+
+	return selections
+}
+
+func hasBadFinisher(p *loader.Program, s selection) bool {
+	pkgPath := strings.TrimPrefix(s.pkg.Path(), rootPkg+"/vendor/")
+	absoluteFilePath := strings.TrimPrefix(p.Fset.File(s.Pos()).Name(), rootPkg+"/vendor/")
+	goFilePath := pkgPath + "/" + filepath.Base(p.Fset.Position(s.Pos()).Filename)
+
+	for _, f := range allowedFinishers {
+		if f == s.fn.Name() {
+			return false
+		}
+	}
+
+	for _, ignoredPkg := range recursivelyIgnoredPkgs {
+		if strings.HasPrefix(pkgPath, ignoredPkg) {
+			return false
+		}
+	}
+
+	for _, ignoredPkg := range ignoredPkgs {
+		if pkgPath == ignoredPkg {
+			return false
+		}
+	}
+
+	for _, ignoredFile := range ignoredFiles {
+		if absoluteFilePath == ignoredFile {
+			return false
+		}
+
+		if goFilePath == ignoredFile {
+			return false
+		}
+	}
+
+	return true
+}
+
+type arrayFlag []string
+
+func (i *arrayFlag) String() string {
+	return fmt.Sprintf("%v", []string(*i))
+}
+
+func (i *arrayFlag) Set(value string) error {
+	*i = append(*i, value)
+	return nil
+}
+
+type selection struct {
+	*ast.SelectorExpr
+	fn  *types.Func
+	pkg *types.Package
+}

cmd/prettylog/README.md

@@ -0,0 +1,40 @@
+# Zerolog PrettyLog
+
+This is a basic CLI utility that will colorize and pretty print your structured JSON logs.
+
+## Usage
+
+You can compile it or run it directly. The only issue is that by default Zerolog does not output to `stdout`
+but rather to `stderr` so we must pipe `stderr` stream to this CLI tool.
+
+### Linux
+
+These commands will redirect `stderr` to our `prettylog` tool and `stdout` will remain unaffected.
+
+1. Compiled version
+
+```shell
+some_program_with_zerolog 2> >(prettylog)
+```
+
+2. Run it directly with `go run`
+
+```shell
+some_program_with_zerolog 2> >(go run cmd/prettylog/prettylog.go)
+```
+
+### Windows
+
+These commands will redirect `stderr` to `stdout` and then pipe it to our `prettylog` tool.
+
+1. Compiled version
+
+```shell
+some_program_with_zerolog 2>&1 | prettylog
+```
+
+2. Run it directly with `go run`
+
+```shell
+some_program_with_zerolog 2>&1 | go run cmd/prettylog/prettylog.go
+```

cmd/prettylog/prettylog.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/rs/zerolog"
+)
+
+func isInputFromPipe() bool {
+	fileInfo, _ := os.Stdin.Stat()
+	return fileInfo.Mode()&os.ModeCharDevice == 0
+}
+
+func processInput(reader io.Reader, writer io.Writer) error {
+	scanner := bufio.NewScanner(reader)
+	for scanner.Scan() {
+		bytesToWrite := scanner.Bytes()
+		_, err := writer.Write(bytesToWrite)
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+
+			fmt.Printf("%s\n", bytesToWrite)
+		}
+	}
+
+	return scanner.Err()
+}
+
+func main() {
+	timeFormats := map[string]string{
+		"default": time.Kitchen,
+		"full":    time.RFC1123,
+	}
+
+	timeFormatFlag := flag.String(
+		"time-format",
+		"default",
+		"Time format, either 'default' or 'full'",
+	)
+
+	flag.Parse()
+
+	timeFormat, ok := timeFormats[*timeFormatFlag]
+	if !ok {
+		panic("Invalid time-format provided")
+	}
+
+	writer := zerolog.NewConsoleWriter()
+	writer.TimeFormat = timeFormat
+
+	if isInputFromPipe() {
+		_ = processInput(os.Stdin, writer)
+	} else if flag.NArg() >= 1 {
+		for _, filename := range flag.Args() {
+			// Scan each line from filename and write it into writer
+			reader, err := os.Open(filename)
+			if err != nil {
+				fmt.Printf("%s open: %v", filename, err)
+				os.Exit(1)
+			}
+
+			if err := processInput(reader, writer); err != nil {
+				fmt.Printf("%s scan: %v", filename, err)
+				os.Exit(1)
+			}
+		}
+	} else {
+		fmt.Println("Usage:")
+		fmt.Println("  app_with_zerolog | 2> >(prettylog)")
+		fmt.Println("  prettylog zerolog_output.jsonl")
+		os.Exit(1)
+		return
+	}
+}

console.go

@@ -0,0 +1,535 @@
+package zerolog
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/mattn/go-colorable"
+)
+
+const (
+	colorBlack = iota + 30
+	colorRed
+	colorGreen
+	colorYellow
+	colorBlue
+	colorMagenta
+	colorCyan
+	colorWhite
+
+	colorBold     = 1
+	colorDarkGray = 90
+
+	unknownLevel = "???"
+)
+
+var (
+	consoleBufPool = sync.Pool{
+		New: func() interface{} {
+			return bytes.NewBuffer(make([]byte, 0, 100))
+		},
+	}
+)
+
+const (
+	consoleDefaultTimeFormat = time.Kitchen
+)
+
+// Formatter transforms the input into a formatted string.
+type Formatter func(interface{}) string
+
+// FormatterByFieldName transforms the input into a formatted string,
+// being able to differentiate formatting based on field name.
+type FormatterByFieldName func(interface{}, string) string
+
+// ConsoleWriter parses the JSON input and writes it in an
+// (optionally) colorized, human-friendly format to Out.
+type ConsoleWriter struct {
+	// Out is the output destination.
+	Out io.Writer
+
+	// NoColor disables the colorized output.
+	NoColor bool
+
+	// TimeFormat specifies the format for timestamp in output.
+	TimeFormat string
+
+	// TimeLocation tells ConsoleWriter’s default FormatTimestamp
+	// how to localize the time.
+	TimeLocation *time.Location
+
+	// PartsOrder defines the order of parts in output.
+	PartsOrder []string
+
+	// PartsExclude defines parts to not display in output.
+	PartsExclude []string
+
+	// FieldsOrder defines the order of contextual fields in output.
+	FieldsOrder []string
+
+	fieldIsOrdered map[string]int
+
+	// FieldsExclude defines contextual fields to not display in output.
+	FieldsExclude []string
+
+	FormatTimestamp     Formatter
+	FormatLevel         Formatter
+	FormatCaller        Formatter
+	FormatMessage       Formatter
+	FormatFieldName     Formatter
+	FormatFieldValue    Formatter
+	FormatErrFieldName  Formatter
+	FormatErrFieldValue Formatter
+	// If this is configured it is used for "part" values and
+	// has precedence on FormatFieldValue
+	FormatPartValueByName FormatterByFieldName
+
+	FormatExtra func(map[string]interface{}, *bytes.Buffer) error
+
+	FormatPrepare func(map[string]interface{}) error
+}
+
+// NewConsoleWriter creates and initializes a new ConsoleWriter.
+func NewConsoleWriter(options ...func(w *ConsoleWriter)) ConsoleWriter {
+	w := ConsoleWriter{
+		Out:        os.Stdout,
+		TimeFormat: consoleDefaultTimeFormat,
+		PartsOrder: consoleDefaultPartsOrder(),
+	}
+
+	for _, opt := range options {
+		opt(&w)
+	}
+
+	// Fix color on Windows
+	if w.Out == os.Stdout || w.Out == os.Stderr {
+		w.Out = colorable.NewColorable(w.Out.(*os.File))
+	}
+
+	return w
+}
+
+// Write transforms the JSON input with formatters and appends to w.Out.
+func (w ConsoleWriter) Write(p []byte) (n int, err error) {
+	// Fix color on Windows
+	if w.Out == os.Stdout || w.Out == os.Stderr {
+		w.Out = colorable.NewColorable(w.Out.(*os.File))
+	}
+
+	if w.PartsOrder == nil {
+		w.PartsOrder = consoleDefaultPartsOrder()
+	}
+
+	var buf = consoleBufPool.Get().(*bytes.Buffer)
+	defer func() {
+		buf.Reset()
+		consoleBufPool.Put(buf)
+	}()
+
+	var evt map[string]interface{}
+	p = decodeIfBinaryToBytes(p)
+	d := json.NewDecoder(bytes.NewReader(p))
+	d.UseNumber()
+	err = d.Decode(&evt)
+	if err != nil {
+		return n, fmt.Errorf("cannot decode event: %s", err)
+	}
+
+	if w.FormatPrepare != nil {
+		err = w.FormatPrepare(evt)
+		if err != nil {
+			return n, err
+		}
+	}
+
+	for _, p := range w.PartsOrder {
+		w.writePart(buf, evt, p)
+	}
+
+	w.writeFields(evt, buf)
+
+	if w.FormatExtra != nil {
+		err = w.FormatExtra(evt, buf)
+		if err != nil {
+			return n, err
+		}
+	}
+
+	err = buf.WriteByte('\n')
+	if err != nil {
+		return n, err
+	}
+
+	_, err = buf.WriteTo(w.Out)
+	return len(p), err
+}
+
+// Call the underlying writer's Close method if it is an io.Closer. Otherwise
+// does nothing.
+func (w ConsoleWriter) Close() error {
+	if closer, ok := w.Out.(io.Closer); ok {
+		return closer.Close()
+	}
+	return nil
+}
+
+// writeFields appends formatted key-value pairs to buf.
+func (w ConsoleWriter) writeFields(evt map[string]interface{}, buf *bytes.Buffer) {
+	var fields = make([]string, 0, len(evt))
+	for field := range evt {
+		var isExcluded bool
+		for _, excluded := range w.FieldsExclude {
+			if field == excluded {
+				isExcluded = true
+				break
+			}
+		}
+		if isExcluded {
+			continue
+		}
+
+		switch field {
+		case LevelFieldName, TimestampFieldName, MessageFieldName, CallerFieldName:
+			continue
+		}
+		fields = append(fields, field)
+	}
+
+	if len(w.FieldsOrder) > 0 {
+		w.orderFields(fields)
+	} else {
+		sort.Strings(fields)
+	}
+
+	// Write space only if something has already been written to the buffer, and if there are fields.
+	if buf.Len() > 0 && len(fields) > 0 {
+		buf.WriteByte(' ')
+	}
+
+	// Move the "error" field to the front
+	ei := sort.Search(len(fields), func(i int) bool { return fields[i] >= ErrorFieldName })
+	if ei < len(fields) && fields[ei] == ErrorFieldName {
+		fields[ei] = ""
+		fields = append([]string{ErrorFieldName}, fields...)
+		var xfields = make([]string, 0, len(fields))
+		for _, field := range fields {
+			if field == "" { // Skip empty fields
+				continue
+			}
+			xfields = append(xfields, field)
+		}
+		fields = xfields
+	}
+
+	for i, field := range fields {
+		var fn Formatter
+		var fv Formatter
+
+		if field == ErrorFieldName {
+			if w.FormatErrFieldName == nil {
+				fn = consoleDefaultFormatErrFieldName(w.NoColor)
+			} else {
+				fn = w.FormatErrFieldName
+			}
+
+			if w.FormatErrFieldValue == nil {
+				fv = consoleDefaultFormatErrFieldValue(w.NoColor)
+			} else {
+				fv = w.FormatErrFieldValue
+			}
+		} else {
+			if w.FormatFieldName == nil {
+				fn = consoleDefaultFormatFieldName(w.NoColor)
+			} else {
+				fn = w.FormatFieldName
+			}
+
+			if w.FormatFieldValue == nil {
+				fv = consoleDefaultFormatFieldValue
+			} else {
+				fv = w.FormatFieldValue
+			}
+		}
+
+		buf.WriteString(fn(field))
+
+		switch fValue := evt[field].(type) {
+		case string:
+			if needsQuote(fValue) {
+				buf.WriteString(fv(strconv.Quote(fValue)))
+			} else {
+				buf.WriteString(fv(fValue))
+			}
+		case json.Number:
+			buf.WriteString(fv(fValue))
+		default:
+			b, err := InterfaceMarshalFunc(fValue)
+			if err != nil {
+				fmt.Fprintf(buf, colorize("[error: %v]", colorRed, w.NoColor), err)
+			} else {
+				fmt.Fprint(buf, fv(b))
+			}
+		}
+
+		if i < len(fields)-1 { // Skip space for last field
+			buf.WriteByte(' ')
+		}
+	}
+}
+
+// writePart appends a formatted part to buf.
+func (w ConsoleWriter) writePart(buf *bytes.Buffer, evt map[string]interface{}, p string) {
+	var f Formatter
+	var fvn FormatterByFieldName
+
+	if len(w.PartsExclude) > 0 {
+		for _, exclude := range w.PartsExclude {
+			if exclude == p {
+				return
+			}
+		}
+	}
+
+	switch p {
+	case LevelFieldName:
+		if w.FormatLevel == nil {
+			f = consoleDefaultFormatLevel(w.NoColor)
+		} else {
+			f = w.FormatLevel
+		}
+	case TimestampFieldName:
+		if w.FormatTimestamp == nil {
+			f = consoleDefaultFormatTimestamp(w.TimeFormat, w.TimeLocation, w.NoColor)
+		} else {
+			f = w.FormatTimestamp
+		}
+	case MessageFieldName:
+		if w.FormatMessage == nil {
+			f = consoleDefaultFormatMessage(w.NoColor, evt[LevelFieldName])
+		} else {
+			f = w.FormatMessage
+		}
+	case CallerFieldName:
+		if w.FormatCaller == nil {
+			f = consoleDefaultFormatCaller(w.NoColor)
+		} else {
+			f = w.FormatCaller
+		}
+	default:
+		if w.FormatPartValueByName != nil {
+			fvn = w.FormatPartValueByName
+		} else if w.FormatFieldValue != nil {
+			f = w.FormatFieldValue
+		} else {
+			f = consoleDefaultFormatFieldValue
+		}
+	}
+
+	var s string
+	if f == nil {
+		s = fvn(evt[p], p)
+	} else {
+		s = f(evt[p])
+	}
+
+	if len(s) > 0 {
+		if buf.Len() > 0 {
+			buf.WriteByte(' ') // Write space only if not the first part
+		}
+		buf.WriteString(s)
+	}
+}
+
+// orderFields takes an array of field names and an array representing field order
+// and returns an array with any ordered fields at the beginning, in order,
+// and the remaining fields after in their original order.
+func (w ConsoleWriter) orderFields(fields []string) {
+	if w.fieldIsOrdered == nil {
+		w.fieldIsOrdered = make(map[string]int)
+		for i, fieldName := range w.FieldsOrder {
+			w.fieldIsOrdered[fieldName] = i
+		}
+	}
+	sort.Slice(fields, func(i, j int) bool {
+		ii, iOrdered := w.fieldIsOrdered[fields[i]]
+		jj, jOrdered := w.fieldIsOrdered[fields[j]]
+		if iOrdered && jOrdered {
+			return ii < jj
+		}
+		if iOrdered {
+			return true
+		}
+		if jOrdered {
+			return false
+		}
+		return fields[i] < fields[j]
+	})
+}
+
+// needsQuote returns true when the string s should be quoted in output.
+func needsQuote(s string) bool {
+	for i := range s {
+		if s[i] < 0x20 || s[i] > 0x7e || s[i] == ' ' || s[i] == '\\' || s[i] == '"' {
+			return true
+		}
+	}
+	return false
+}
+
+// colorize returns the string s wrapped in ANSI code c, unless disabled is true or c is 0.
+func colorize(s interface{}, c int, disabled bool) string {
+	e := os.Getenv("NO_COLOR")
+	if e != "" || c == 0 {
+		disabled = true
+	}
+
+	if disabled {
+		return fmt.Sprintf("%s", s)
+	}
+	return fmt.Sprintf("\x1b[%dm%v\x1b[0m", c, s)
+}
+
+// ----- DEFAULT FORMATTERS ---------------------------------------------------
+
+func consoleDefaultPartsOrder() []string {
+	return []string{
+		TimestampFieldName,
+		LevelFieldName,
+		CallerFieldName,
+		MessageFieldName,
+	}
+}
+
+func consoleDefaultFormatTimestamp(timeFormat string, location *time.Location, noColor bool) Formatter {
+	if timeFormat == "" {
+		timeFormat = consoleDefaultTimeFormat
+	}
+	if location == nil {
+		location = time.Local
+	}
+
+	return func(i interface{}) string {
+		t := "<nil>"
+		switch tt := i.(type) {
+		case string:
+			ts, err := time.ParseInLocation(TimeFieldFormat, tt, location)
+			if err != nil {
+				t = tt
+			} else {
+				t = ts.In(location).Format(timeFormat)
+			}
+		case json.Number:
+			i, err := tt.Int64()
+			if err != nil {
+				t = tt.String()
+			} else {
+				var sec, nsec int64
+
+				switch TimeFieldFormat {
+				case TimeFormatUnixNano:
+					sec, nsec = 0, i
+				case TimeFormatUnixMicro:
+					sec, nsec = 0, int64(time.Duration(i)*time.Microsecond)
+				case TimeFormatUnixMs:
+					sec, nsec = 0, int64(time.Duration(i)*time.Millisecond)
+				default:
+					sec, nsec = i, 0
+				}
+
+				ts := time.Unix(sec, nsec)
+				t = ts.In(location).Format(timeFormat)
+			}
+		}
+		return colorize(t, colorDarkGray, noColor)
+	}
+}
+
+func stripLevel(ll string) string {
+	if len(ll) == 0 {
+		return unknownLevel
+	}
+	if len(ll) > 3 {
+		ll = ll[:3]
+	}
+	return strings.ToUpper(ll)
+}
+
+func consoleDefaultFormatLevel(noColor bool) Formatter {
+	return func(i interface{}) string {
+		if ll, ok := i.(string); ok {
+			level, _ := ParseLevel(ll)
+			fl, ok := FormattedLevels[level]
+			if ok {
+				return colorize(fl, LevelColors[level], noColor)
+			}
+			return stripLevel(ll)
+		}
+		if i == nil {
+			return unknownLevel
+		}
+		return stripLevel(fmt.Sprintf("%s", i))
+	}
+}
+
+func consoleDefaultFormatCaller(noColor bool) Formatter {
+	return func(i interface{}) string {
+		var c string
+		if cc, ok := i.(string); ok {
+			c = cc
+		}
+		if len(c) > 0 {
+			if cwd, err := os.Getwd(); err == nil {
+				if rel, err := filepath.Rel(cwd, c); err == nil {
+					c = rel
+				}
+			}
+			c = colorize(c, colorBold, noColor) + colorize(" >", colorCyan, noColor)
+		}
+		return c
+	}
+}
+
+func consoleDefaultFormatMessage(noColor bool, level interface{}) Formatter {
+	return func(i interface{}) string {
+		if i == nil || i == "" {
+			return ""
+		}
+		switch level {
+		case LevelInfoValue, LevelWarnValue, LevelErrorValue, LevelFatalValue, LevelPanicValue:
+			return colorize(fmt.Sprintf("%s", i), colorBold, noColor)
+		default:
+			return fmt.Sprintf("%s", i)
+		}
+	}
+}
+
+func consoleDefaultFormatFieldName(noColor bool) Formatter {
+	return func(i interface{}) string {
+		return colorize(fmt.Sprintf("%s=", i), colorCyan, noColor)
+	}
+}
+
+func consoleDefaultFormatFieldValue(i interface{}) string {
+	return fmt.Sprintf("%s", i)
+}
+
+func consoleDefaultFormatErrFieldName(noColor bool) Formatter {
+	return func(i interface{}) string {
+		return colorize(fmt.Sprintf("%s=", i), colorCyan, noColor)
+	}
+}
+
+func consoleDefaultFormatErrFieldValue(noColor bool) Formatter {
+	return func(i interface{}) string {
+		return colorize(colorize(fmt.Sprintf("%s", i), colorBold, noColor), colorRed, noColor)
+	}
+}

console_test.go

@@ -0,0 +1,654 @@
+package zerolog_test
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/rs/zerolog"
+)
+
+func ExampleConsoleWriter() {
+	log := zerolog.New(zerolog.ConsoleWriter{Out: os.Stdout, NoColor: true})
+
+	log.Info().Str("foo", "bar").Msg("Hello World")
+	// Output: <nil> INF Hello World foo=bar
+}
+
+func ExampleConsoleWriter_customFormatters() {
+	out := zerolog.ConsoleWriter{Out: os.Stdout, NoColor: true}
+	out.FormatLevel = func(i interface{}) string { return strings.ToUpper(fmt.Sprintf("%-6s|", i)) }
+	out.FormatFieldName = func(i interface{}) string { return fmt.Sprintf("%s:", i) }
+	out.FormatFieldValue = func(i interface{}) string { return strings.ToUpper(fmt.Sprintf("%s", i)) }
+	log := zerolog.New(out)
+
+	log.Info().Str("foo", "bar").Msg("Hello World")
+	// Output: <nil> INFO  | Hello World foo:BAR
+}
+
+func ExampleConsoleWriter_partValueFormatter() {
+	out := zerolog.ConsoleWriter{Out: os.Stdout, NoColor: true,
+		PartsOrder:    []string{"level", "one", "two", "three", "message"},
+		FieldsExclude: []string{"one", "two", "three"}}
+	out.FormatLevel = func(i interface{}) string { return strings.ToUpper(fmt.Sprintf("%-6s", i)) }
+	out.FormatFieldName = func(i interface{}) string { return fmt.Sprintf("%s:", i) }
+	out.FormatPartValueByName = func(i interface{}, s string) string {
+		var ret string
+		switch s {
+		case "one":
+			ret = strings.ToUpper(fmt.Sprintf("%s", i))
+		case "two":
+			ret = strings.ToLower(fmt.Sprintf("%s", i))
+		case "three":
+			ret = strings.ToLower(fmt.Sprintf("(%s)", i))
+		}
+		return ret
+	}
+	log := zerolog.New(out)
+
+	log.Info().Str("foo", "bar").
+		Str("two", "TEST_TWO").
+		Str("one", "test_one").
+		Str("three", "test_three").
+		Msg("Hello World")
+	// Output: INFO   TEST_ONE test_two (test_three) Hello World foo:bar
+}
+
+func ExampleNewConsoleWriter() {
+	out := zerolog.NewConsoleWriter()
+	out.NoColor = true // For testing purposes only
+	log := zerolog.New(out)
+
+	log.Debug().Str("foo", "bar").Msg("Hello World")
+	// Output: <nil> DBG Hello World foo=bar
+}
+
+func ExampleNewConsoleWriter_customFormatters() {
+	out := zerolog.NewConsoleWriter(
+		func(w *zerolog.ConsoleWriter) {
+			// Customize time format
+			w.TimeFormat = time.RFC822
+			// Customize level formatting
+			w.FormatLevel = func(i interface{}) string { return strings.ToUpper(fmt.Sprintf("[%-5s]", i)) }
+		},
+	)
+	out.NoColor = true // For testing purposes only
+
+	log := zerolog.New(out)
+
+	log.Info().Str("foo", "bar").Msg("Hello World")
+	// Output: <nil> [INFO ] Hello World foo=bar
+}
+
+func TestConsoleLogger(t *testing.T) {
+	t.Run("Numbers", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		log := zerolog.New(zerolog.ConsoleWriter{Out: buf, NoColor: true})
+		log.Info().
+			Float64("float", 1.23).
+			Uint64("small", 123).
+			Uint64("big", 1152921504606846976).
+			Msg("msg")
+		if got, want := strings.TrimSpace(buf.String()), "<nil> INF msg big=1152921504606846976 float=1.23 small=123"; got != want {
+			t.Errorf("\ngot:\n%s\nwant:\n%s", got, want)
+		}
+	})
+}
+
+func TestConsoleWriter(t *testing.T) {
+	t.Run("Default field formatter", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, PartsOrder: []string{"foo"}}
+
+		_, err := w.Write([]byte(`{"foo": "DEFAULT"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "DEFAULT foo=DEFAULT\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Write colorized", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: false}
+
+		_, err := w.Write([]byte(`{"level": "warn", "message": "Foobar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "\x1b[90m<nil>\x1b[0m \x1b[33mWRN\x1b[0m \x1b[1mFoobar\x1b[0m\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("NO_COLOR = true", func(t *testing.T) {
+		os.Setenv("NO_COLOR", "anything")
+
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf}
+
+		_, err := w.Write([]byte(`{"level": "warn", "message": "Foobar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> WRN Foobar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+		os.Unsetenv("NO_COLOR")
+	})
+
+	t.Run("Write fields", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		ts := time.Unix(0, 0)
+		d := ts.UTC().Format(time.RFC3339)
+		_, err := w.Write([]byte(`{"time": "` + d + `", "level": "debug", "message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := ts.Format(time.Kitchen) + " DBG Foobar foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Unix timestamp input format", func(t *testing.T) {
+		of := zerolog.TimeFieldFormat
+		defer func() {
+			zerolog.TimeFieldFormat = of
+		}()
+		zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, TimeFormat: time.StampMilli, NoColor: true}
+
+		_, err := w.Write([]byte(`{"time": 1234, "level": "debug", "message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := time.Unix(1234, 0).Format(time.StampMilli) + " DBG Foobar foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Unix timestamp ms input format", func(t *testing.T) {
+		of := zerolog.TimeFieldFormat
+		defer func() {
+			zerolog.TimeFieldFormat = of
+		}()
+		zerolog.TimeFieldFormat = zerolog.TimeFormatUnixMs
+
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, TimeFormat: time.StampMilli, NoColor: true}
+
+		_, err := w.Write([]byte(`{"time": 1234567, "level": "debug", "message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := time.Unix(1234, 567000000).Format(time.StampMilli) + " DBG Foobar foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Unix timestamp us input format", func(t *testing.T) {
+		of := zerolog.TimeFieldFormat
+		defer func() {
+			zerolog.TimeFieldFormat = of
+		}()
+		zerolog.TimeFieldFormat = zerolog.TimeFormatUnixMicro
+
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, TimeFormat: time.StampMicro, NoColor: true}
+
+		_, err := w.Write([]byte(`{"time": 1234567891, "level": "debug", "message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := time.Unix(1234, 567891000).Format(time.StampMicro) + " DBG Foobar foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("No message field", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		_, err := w.Write([]byte(`{"level": "debug", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> DBG foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("No level field", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		_, err := w.Write([]byte(`{"message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> ??? Foobar foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Write colorized fields", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: false}
+
+		_, err := w.Write([]byte(`{"level": "warn", "message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "\x1b[90m<nil>\x1b[0m \x1b[33mWRN\x1b[0m \x1b[1mFoobar\x1b[0m \x1b[36mfoo=\x1b[0mbar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Write error field", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		ts := time.Unix(0, 0)
+		d := ts.UTC().Format(time.RFC3339)
+		evt := `{"time": "` + d + `", "level": "error", "message": "Foobar", "aaa": "bbb", "error": "Error"}`
+		// t.Log(evt)
+
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := ts.Format(time.Kitchen) + " ERR Foobar error=Error aaa=bbb\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Write caller field", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		cwd, err := os.Getwd()
+		if err != nil {
+			t.Fatalf("Cannot get working directory: %s", err)
+		}
+
+		ts := time.Unix(0, 0)
+		d := ts.UTC().Format(time.RFC3339)
+
+		fields := map[string]interface{}{
+			"time":    d,
+			"level":   "debug",
+			"message": "Foobar",
+			"foo":     "bar",
+			"caller":  filepath.Join(cwd, "foo", "bar.go"),
+		}
+
+		evt, err := json.Marshal(fields)
+		if err != nil {
+			t.Fatalf("Cannot marshal fields: %s", err)
+		}
+
+		_, err = w.Write(evt)
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		// Define the expected output with forward slashes
+		expectedOutput := ts.Format(time.Kitchen) + " DBG foo/bar.go > Foobar foo=bar\n"
+
+		// Get the actual output and normalize path separators to forward slashes
+		actualOutput := buf.String()
+		actualOutput = strings.ReplaceAll(actualOutput, string(os.PathSeparator), "/")
+
+		// Compare the normalized actual output to the expected output
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Write JSON field", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		evt := `{"level": "debug", "message": "Foobar", "foo": [1, 2, 3], "bar": true}`
+		// t.Log(evt)
+
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> DBG Foobar bar=true foo=[1,2,3]\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("With an extra 'level' field", func(t *testing.T) {
+		t.Run("malformed string", func(t *testing.T) {
+			cases := []struct {
+				field  string
+				output string
+			}{
+				{"", "<nil> ??? Hello World foo=bar\n"},
+				{"-", "<nil> - Hello World foo=bar\n"},
+				{"1", "<nil> " + zerolog.FormattedLevels[1] + " Hello World foo=bar\n"},
+				{"a", "<nil> A Hello World foo=bar\n"},
+				{"12", "<nil> 12 Hello World foo=bar\n"},
+				{"a2", "<nil> A2 Hello World foo=bar\n"},
+				{"2a", "<nil> 2A Hello World foo=bar\n"},
+				{"ab", "<nil> AB Hello World foo=bar\n"},
+				{"12a", "<nil> 12A Hello World foo=bar\n"},
+				{"a12", "<nil> A12 Hello World foo=bar\n"},
+				{"abc", "<nil> ABC Hello World foo=bar\n"},
+				{"123", "<nil> 123 Hello World foo=bar\n"},
+				{"abcd", "<nil> ABC Hello World foo=bar\n"},
+				{"1234", "<nil> 123 Hello World foo=bar\n"},
+				{"123d", "<nil> 123 Hello World foo=bar\n"},
+				{"01", "<nil> " + zerolog.FormattedLevels[1] + " Hello World foo=bar\n"},
+				{"001", "<nil> " + zerolog.FormattedLevels[1] + " Hello World foo=bar\n"},
+				{"0001", "<nil> " + zerolog.FormattedLevels[1] + " Hello World foo=bar\n"},
+			}
+			for i, c := range cases {
+				c := c
+				t.Run(fmt.Sprintf("case %d", i), func(t *testing.T) {
+					buf := &bytes.Buffer{}
+					out := zerolog.NewConsoleWriter()
+					out.NoColor = true
+					out.Out = buf
+					log := zerolog.New(out)
+
+					log.Debug().Str("level", c.field).Str("foo", "bar").Msg("Hello World")
+
+					actualOutput := buf.String()
+					if actualOutput != c.output {
+						t.Errorf("Unexpected output %q, want: %q", actualOutput, c.output)
+					}
+				})
+			}
+		})
+
+		t.Run("weird value", func(t *testing.T) {
+			cases := []struct {
+				field  interface{}
+				output string
+			}{
+				{0, "<nil> 0 Hello World foo=bar\n"},
+				{1, "<nil> 1 Hello World foo=bar\n"},
+				{-1, "<nil> -1 Hello World foo=bar\n"},
+				{-3, "<nil> -3 Hello World foo=bar\n"},
+				{-32, "<nil> -32 Hello World foo=bar\n"},
+				{-321, "<nil> -32 Hello World foo=bar\n"},
+				{12, "<nil> 12 Hello World foo=bar\n"},
+				{123, "<nil> 123 Hello World foo=bar\n"},
+				{1234, "<nil> 123 Hello World foo=bar\n"},
+			}
+			for i, c := range cases {
+				c := c
+				t.Run(fmt.Sprintf("case %d", i), func(t *testing.T) {
+					buf := &bytes.Buffer{}
+					out := zerolog.NewConsoleWriter()
+					out.NoColor = true
+					out.Out = buf
+					log := zerolog.New(out)
+
+					log.Debug().Interface("level", c.field).Str("foo", "bar").Msg("Hello World")
+
+					actualOutput := buf.String()
+					if actualOutput != c.output {
+						t.Errorf("Unexpected output %q, want: %q", actualOutput, c.output)
+					}
+				})
+			}
+		})
+	})
+}
+
+func TestConsoleWriterConfiguration(t *testing.T) {
+	t.Run("Sets TimeFormat", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, TimeFormat: time.RFC3339}
+
+		ts := time.Unix(0, 0)
+		d := ts.UTC().Format(time.RFC3339)
+		evt := `{"time": "` + d + `", "level": "info", "message": "Foobar"}`
+
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := ts.Format(time.RFC3339) + " INF Foobar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Sets TimeFormat and TimeLocation", func(t *testing.T) {
+		locs := []*time.Location{time.Local, time.UTC}
+
+		for _, location := range locs {
+			buf := &bytes.Buffer{}
+			w := zerolog.ConsoleWriter{
+				Out:          buf,
+				NoColor:      true,
+				TimeFormat:   time.RFC3339,
+				TimeLocation: location,
+			}
+
+			ts := time.Unix(0, 0)
+			d := ts.UTC().Format(time.RFC3339)
+			evt := `{"time": "` + d + `", "level": "info", "message": "Foobar"}`
+
+			_, err := w.Write([]byte(evt))
+			if err != nil {
+				t.Errorf("Unexpected error when writing output: %s", err)
+			}
+
+			expectedOutput := ts.In(location).Format(time.RFC3339) + " INF Foobar\n"
+			actualOutput := buf.String()
+			if actualOutput != expectedOutput {
+				t.Errorf("Unexpected output %q, want: %q (location=%s)", actualOutput, expectedOutput, location)
+			}
+		}
+	})
+
+	t.Run("Sets PartsOrder", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, PartsOrder: []string{"message", "level"}}
+
+		evt := `{"level": "info", "message": "Foobar"}`
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "Foobar INF\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Sets PartsExclude", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, PartsExclude: []string{"time"}}
+
+		d := time.Unix(0, 0).UTC().Format(time.RFC3339)
+		evt := `{"time": "` + d + `", "level": "info", "message": "Foobar"}`
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "INF Foobar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Sets FieldsOrder", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, FieldsOrder: []string{"zebra", "aardvark"}}
+
+		evt := `{"level": "info", "message": "Zoo", "aardvark": "Able", "mussel": "Mountain", "zebra": "Zulu"}`
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> INF Zoo zebra=Zulu aardvark=Able mussel=Mountain\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Sets FieldsExclude", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, FieldsExclude: []string{"foo"}}
+
+		evt := `{"level": "info", "message": "Foobar", "foo":"bar", "baz":"quux"}`
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> INF Foobar baz=quux\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Sets FormatExtra", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{
+			Out: buf, NoColor: true, PartsOrder: []string{"level", "message"},
+			FormatExtra: func(evt map[string]interface{}, buf *bytes.Buffer) error {
+				buf.WriteString("\nAdditional stacktrace")
+				return nil
+			},
+		}
+
+		evt := `{"level": "info", "message": "Foobar"}`
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "INF Foobar\nAdditional stacktrace\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Sets FormatPrepare", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{
+			Out: buf, NoColor: true, PartsOrder: []string{"level", "message"},
+			FormatPrepare: func(evt map[string]interface{}) error {
+				evt["message"] = fmt.Sprintf("msg=%s", evt["message"])
+				return nil
+			},
+		}
+
+		evt := `{"level": "info", "message": "Foobar"}`
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "INF msg=Foobar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
+	t.Run("Uses local time for console writer without time zone", func(t *testing.T) {
+		// Regression test for issue #483 (check there for more details)
+
+		timeFormat := "2006-01-02 15:04:05"
+		expectedOutput := "2022-10-20 20:24:50 INF Foobar\n"
+		evt := `{"time": "2022-10-20 20:24:50", "level": "info", "message": "Foobar"}`
+
+		of := zerolog.TimeFieldFormat
+		defer func() {
+			zerolog.TimeFieldFormat = of
+		}()
+		zerolog.TimeFieldFormat = timeFormat
+
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, TimeFormat: timeFormat}
+		_, err := w.Write([]byte(evt))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+}
+
+func BenchmarkConsoleWriter(b *testing.B) {
+	b.ResetTimer()
+	b.ReportAllocs()
+
+	var msg = []byte(`{"level": "info", "foo": "bar", "message": "HELLO", "time": "1990-01-01"}`)
+
+	w := zerolog.ConsoleWriter{Out: io.Discard, NoColor: false}
+
+	for i := 0; i < b.N; i++ {
+		w.Write(msg)
+	}
+}

context.go

@@ -1,10 +1,11 @@
 package zerolog
 
 import (
-	"io/ioutil"
+	"context"
+	"fmt"
+	"math"
+	"net"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 // Context configures a new sub-logger with contextual fields.
@@ -17,284 +18,518 @@ func (c Context) Logger() Logger {
 	return c.l
 }
 
-// Fields is a helper function to use a map to set fields using type assertion.
-func (c Context) Fields(fields map[string]interface{}) Context {
-	c.l.context = appendFields(c.l.context, fields)
+// Fields is a helper function to use a map or slice to set fields using type assertion.
+// Only map[string]interface{} and []interface{} are accepted. []interface{} must
+// alternate string keys and arbitrary values, and extraneous ones are ignored.
+func (c Context) Fields(fields interface{}) Context {
+	c.l.context = appendFields(c.l.context, fields, c.l.stack, c.l.ctx, c.l.hooks)
 	return c
 }
 
 // Dict adds the field key with the dict to the logger context.
 func (c Context) Dict(key string, dict *Event) Context {
-	dict.buf = append(dict.buf, '}')
-	c.l.context = append(json.AppendKey(c.l.context, key), dict.buf...)
-	eventPool.Put(dict)
+	dict.buf = enc.AppendEndMarker(dict.buf)
+	c.l.context = append(enc.AppendKey(c.l.context, key), dict.buf...)
+	putEvent(dict)
 	return c
 }
 
+// CreateDict creates an Event to be used with the Context.Dict method.
+// It preserves the stack, hooks, and context from the logger.
+// Call usual field methods like Str, Int etc to add fields to this
+// event and give it as argument the Context.Dict method.
+func (c Context) CreateDict() *Event {
+	return newEvent(nil, DebugLevel, c.l.stack, c.l.ctx, c.l.hooks)
+}
+
+// CreateArray creates an Array to be used with the Context.Array method.
+// It preserves the stack, hooks, and context from the logger.
+// Call usual field methods like Str, Int etc to add elements to this
+// array and give it as argument the Context.Array method.
+func (c Context) CreateArray() *Array {
+	a := Arr()
+	a.stack = c.l.stack
+	a.ctx = c.l.ctx
+	a.ch = c.l.hooks
+	return a
+}
+
 // Array adds the field key with an array to the event context.
-// Use zerolog.Arr() to create the array or pass a type that
+// Use c.CreateArray() to create the array or pass a type that
 // implement the LogArrayMarshaler interface.
 func (c Context) Array(key string, arr LogArrayMarshaler) Context {
-	c.l.context = json.AppendKey(c.l.context, key)
+	c.l.context = enc.AppendKey(c.l.context, key)
 	if arr, ok := arr.(*Array); ok {
 		c.l.context = arr.write(c.l.context)
 		return c
 	}
-	var a *Array
-	if aa, ok := arr.(*Array); ok {
-		a = aa
-	} else {
-		a = Arr()
-		arr.MarshalZerologArray(a)
-	}
+	a := c.CreateArray()
+	arr.MarshalZerologArray(a)
 	c.l.context = a.write(c.l.context)
 	return c
 }
 
 // Object marshals an object that implement the LogObjectMarshaler interface.
 func (c Context) Object(key string, obj LogObjectMarshaler) Context {
-	e := newEvent(levelWriterAdapter{ioutil.Discard}, 0, true)
+	e := c.l.scratchEvent()
 	e.Object(key, obj)
-	e.buf[0] = ',' // A new event starts as an object, we want to embed it.
-	c.l.context = append(c.l.context, e.buf...)
-	eventPool.Put(e)
+	c.l.context = enc.AppendObjectData(c.l.context, e.buf)
+	putEvent(e)
+	return c
+}
+
+// Objects adds the field key with objs to the logger context as an array of
+// objects that implement the LogObjectMarshaler interface.
+//
+// This is the array version that accepts a slice of LogObjectMarshaler objects.
+func (c Context) Objects(key string, objs []LogObjectMarshaler) Context {
+	e := c.l.scratchEvent()
+	e.Objects(key, objs)
+	c.l.context = enc.AppendObjectData(c.l.context, e.buf)
+	putEvent(e)
+	return c
+}
+
+// ObjectsV adds the field key with objs to the logger context as an array of
+// objects that implement the LogObjectMarshaler interface.
+//
+// This is a variadic version that accepts a list of individual LogObjectMarshaler objects.
+func (c Context) ObjectsV(key string, objs ...LogObjectMarshaler) Context {
+	return c.Objects(key, objs)
+}
+
+// EmbedObject marshals and Embeds an object that implement the LogObjectMarshaler interface.
+func (c Context) EmbedObject(obj LogObjectMarshaler) Context {
+	e := c.l.scratchEvent()
+	e.EmbedObject(obj)
+	c.l.context = enc.AppendObjectData(c.l.context, e.buf)
+	putEvent(e)
 	return c
 }
 
 // Str adds the field key with val as a string to the logger context.
 func (c Context) Str(key, val string) Context {
-	c.l.context = json.AppendString(json.AppendKey(c.l.context, key), val)
+	c.l.context = enc.AppendString(enc.AppendKey(c.l.context, key), val)
 	return c
 }
 
 // Strs adds the field key with val as a string to the logger context.
+//
+// This is the array version that accepts a slice of string values.
 func (c Context) Strs(key string, vals []string) Context {
-	c.l.context = json.AppendStrings(json.AppendKey(c.l.context, key), vals)
+	c.l.context = enc.AppendStrings(enc.AppendKey(c.l.context, key), vals)
 	return c
 }
 
+// StrsV adds the field key with vals as a []string to the logger context.
+//
+// This is a variadic version that accepts a list of individual strings.
+func (c Context) StrsV(key string, vals ...string) Context {
+	return c.Strs(key, vals)
+}
+
+// Stringer adds the field key with val.String() (or null if val is nil) to the logger context.
+func (c Context) Stringer(key string, val fmt.Stringer) Context {
+	if val != nil {
+		c.l.context = enc.AppendString(enc.AppendKey(c.l.context, key), val.String())
+		return c
+	}
+
+	c.l.context = enc.AppendInterface(enc.AppendKey(c.l.context, key), nil)
+	return c
+}
+
+// Stringers adds the field key with vals to the logger context where each
+// individual val is added by calling val.String().
+//
+// This is the array version that accepts a slice of fmt.Stringer values.
+func (c Context) Stringers(key string, vals []fmt.Stringer) Context {
+	c.l.context = enc.AppendStringers(enc.AppendKey(c.l.context, key), vals)
+	return c
+}
+
+// StringersV adds the field key with vals  to the logger context where each
+// individual val is added by calling val.String().
+//
+// This is a variadic version that accepts a list of individual
+// fmt.Stringer values.
+func (c Context) StringersV(key string, vals ...fmt.Stringer) Context {
+	return c.Stringers(key, vals)
+}
+
 // Bytes adds the field key with val as a []byte to the logger context.
 func (c Context) Bytes(key string, val []byte) Context {
-	c.l.context = json.AppendBytes(json.AppendKey(c.l.context, key), val)
+	c.l.context = enc.AppendBytes(enc.AppendKey(c.l.context, key), val)
 	return c
 }
 
-// AnErr adds the field key with err as a string to the logger context.
+// Hex adds the field key with val as a hex string to the logger context.
+func (c Context) Hex(key string, val []byte) Context {
+	c.l.context = enc.AppendHex(enc.AppendKey(c.l.context, key), val)
+	return c
+}
+
+// RawJSON adds already encoded JSON to context.
+//
+// No sanity check is performed on b; it must not contain carriage returns and
+// be valid JSON.
+func (c Context) RawJSON(key string, b []byte) Context {
+	c.l.context = appendJSON(enc.AppendKey(c.l.context, key), b)
+	return c
+}
+
+// AnErr adds the field key with serialized err to the logger context.
+// If err is nil, no field is added.
 func (c Context) AnErr(key string, err error) Context {
-	if err != nil {
-		c.l.context = json.AppendError(json.AppendKey(c.l.context, key), err)
+	switch m := ErrorMarshalFunc(err).(type) {
+	case nil:
+		return c
+	case LogObjectMarshaler:
+		return c.Object(key, m)
+	case error:
+		if isNilValue(m) {
+			return c
+		}
+		return c.Str(key, m.Error())
+	case string:
+		return c.Str(key, m)
+	default:
+		return c.Interface(key, m)
 	}
-	return c
 }
 
-// Errs adds the field key with errs as an array of strings to the logger context.
+// Errs adds the field key with errs as an array of serialized errors to the
+// logger context.
 func (c Context) Errs(key string, errs []error) Context {
-	c.l.context = json.AppendErrors(json.AppendKey(c.l.context, key), errs)
-	return c
+	arr := c.CreateArray().Errs(errs)
+	return c.Array(key, arr)
 }
 
-// Err adds the field "error" with err as a string to the logger context.
-// To customize the key name, change zerolog.ErrorFieldName.
+// Err adds the field "error" with serialized err to the logger context.
 func (c Context) Err(err error) Context {
-	if err != nil {
-		c.l.context = json.AppendError(json.AppendKey(c.l.context, ErrorFieldName), err)
+	if c.l.stack && ErrorStackMarshaler != nil {
+		switch m := ErrorStackMarshaler(err).(type) {
+		case nil:
+			return c // do nothing with nil errors
+		case LogObjectMarshaler:
+			c = c.Object(ErrorStackFieldName, m)
+		case error:
+			c = c.Str(ErrorStackFieldName, m.Error())
+		case string:
+			c = c.Str(ErrorStackFieldName, m)
+		default:
+			c = c.Interface(ErrorStackFieldName, m)
+		}
 	}
+
+	return c.AnErr(ErrorFieldName, err)
+}
+
+// Ctx adds the context.Context to the logger context. The context.Context is
+// not rendered in the error message, but is made available for hooks to use.
+// A typical use case is to extract tracing information from the
+// context.Context.
+func (c Context) Ctx(ctx context.Context) Context {
+	c.l.ctx = ctx
 	return c
 }
 
 // Bool adds the field key with val as a bool to the logger context.
 func (c Context) Bool(key string, b bool) Context {
-	c.l.context = json.AppendBool(json.AppendKey(c.l.context, key), b)
+	c.l.context = enc.AppendBool(enc.AppendKey(c.l.context, key), b)
 	return c
 }
 
 // Bools adds the field key with val as a []bool to the logger context.
 func (c Context) Bools(key string, b []bool) Context {
-	c.l.context = json.AppendBools(json.AppendKey(c.l.context, key), b)
+	c.l.context = enc.AppendBools(enc.AppendKey(c.l.context, key), b)
 	return c
 }
 
 // Int adds the field key with i as a int to the logger context.
 func (c Context) Int(key string, i int) Context {
-	c.l.context = json.AppendInt(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInt(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints adds the field key with i as a []int to the logger context.
 func (c Context) Ints(key string, i []int) Context {
-	c.l.context = json.AppendInts(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInts(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Int8 adds the field key with i as a int8 to the logger context.
 func (c Context) Int8(key string, i int8) Context {
-	c.l.context = json.AppendInt8(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInt8(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints8 adds the field key with i as a []int8 to the logger context.
 func (c Context) Ints8(key string, i []int8) Context {
-	c.l.context = json.AppendInts8(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInts8(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Int16 adds the field key with i as a int16 to the logger context.
 func (c Context) Int16(key string, i int16) Context {
-	c.l.context = json.AppendInt16(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInt16(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints16 adds the field key with i as a []int16 to the logger context.
 func (c Context) Ints16(key string, i []int16) Context {
-	c.l.context = json.AppendInts16(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInts16(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Int32 adds the field key with i as a int32 to the logger context.
 func (c Context) Int32(key string, i int32) Context {
-	c.l.context = json.AppendInt32(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInt32(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints32 adds the field key with i as a []int32 to the logger context.
 func (c Context) Ints32(key string, i []int32) Context {
-	c.l.context = json.AppendInts32(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInts32(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Int64 adds the field key with i as a int64 to the logger context.
 func (c Context) Int64(key string, i int64) Context {
-	c.l.context = json.AppendInt64(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInt64(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints64 adds the field key with i as a []int64 to the logger context.
 func (c Context) Ints64(key string, i []int64) Context {
-	c.l.context = json.AppendInts64(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendInts64(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint adds the field key with i as a uint to the logger context.
 func (c Context) Uint(key string, i uint) Context {
-	c.l.context = json.AppendUint(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUint(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints adds the field key with i as a []uint to the logger context.
 func (c Context) Uints(key string, i []uint) Context {
-	c.l.context = json.AppendUints(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUints(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint8 adds the field key with i as a uint8 to the logger context.
 func (c Context) Uint8(key string, i uint8) Context {
-	c.l.context = json.AppendUint8(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUint8(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints8 adds the field key with i as a []uint8 to the logger context.
 func (c Context) Uints8(key string, i []uint8) Context {
-	c.l.context = json.AppendUints8(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUints8(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint16 adds the field key with i as a uint16 to the logger context.
 func (c Context) Uint16(key string, i uint16) Context {
-	c.l.context = json.AppendUint16(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUint16(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints16 adds the field key with i as a []uint16 to the logger context.
 func (c Context) Uints16(key string, i []uint16) Context {
-	c.l.context = json.AppendUints16(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUints16(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint32 adds the field key with i as a uint32 to the logger context.
 func (c Context) Uint32(key string, i uint32) Context {
-	c.l.context = json.AppendUint32(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUint32(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints32 adds the field key with i as a []uint32 to the logger context.
 func (c Context) Uints32(key string, i []uint32) Context {
-	c.l.context = json.AppendUints32(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUints32(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint64 adds the field key with i as a uint64 to the logger context.
 func (c Context) Uint64(key string, i uint64) Context {
-	c.l.context = json.AppendUint64(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUint64(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints64 adds the field key with i as a []uint64 to the logger context.
 func (c Context) Uints64(key string, i []uint64) Context {
-	c.l.context = json.AppendUints64(json.AppendKey(c.l.context, key), i)
+	c.l.context = enc.AppendUints64(enc.AppendKey(c.l.context, key), i)
 	return c
 }
 
 // Float32 adds the field key with f as a float32 to the logger context.
 func (c Context) Float32(key string, f float32) Context {
-	c.l.context = json.AppendFloat32(json.AppendKey(c.l.context, key), f)
+	c.l.context = enc.AppendFloat32(enc.AppendKey(c.l.context, key), f, FloatingPointPrecision)
 	return c
 }
 
 // Floats32 adds the field key with f as a []float32 to the logger context.
 func (c Context) Floats32(key string, f []float32) Context {
-	c.l.context = json.AppendFloats32(json.AppendKey(c.l.context, key), f)
+	c.l.context = enc.AppendFloats32(enc.AppendKey(c.l.context, key), f, FloatingPointPrecision)
 	return c
 }
 
 // Float64 adds the field key with f as a float64 to the logger context.
 func (c Context) Float64(key string, f float64) Context {
-	c.l.context = json.AppendFloat64(json.AppendKey(c.l.context, key), f)
+	c.l.context = enc.AppendFloat64(enc.AppendKey(c.l.context, key), f, FloatingPointPrecision)
 	return c
 }
 
 // Floats64 adds the field key with f as a []float64 to the logger context.
 func (c Context) Floats64(key string, f []float64) Context {
-	c.l.context = json.AppendFloats64(json.AppendKey(c.l.context, key), f)
+	c.l.context = enc.AppendFloats64(enc.AppendKey(c.l.context, key), f, FloatingPointPrecision)
 	return c
 }
 
-// Timestamp adds the current local time as UNIX timestamp to the logger context with the "time" key.
+type timestampHook struct{}
+
+func (ts timestampHook) Run(e *Event, level Level, msg string) {
+	e.Timestamp()
+}
+
+var th = timestampHook{}
+
+// Timestamp adds the current local time to the logger context with the "time" key, formatted using zerolog.TimeFieldFormat.
 // To customize the key name, change zerolog.TimestampFieldName.
+// To customize the time format, change zerolog.TimeFieldFormat.
+//
+// NOTE: It won't dedupe the "time" key if the *Context has one already.
 func (c Context) Timestamp() Context {
-	if len(c.l.context) > 0 {
-		c.l.context[0] = 1
-	} else {
-		c.l.context = append(c.l.context, 1)
-	}
+	c.l = c.l.Hook(th)
 	return c
 }
 
-// Time adds the field key with t formated as string using zerolog.TimeFieldFormat.
+// Time adds the field key with t formatted as string using zerolog.TimeFieldFormat.
 func (c Context) Time(key string, t time.Time) Context {
-	c.l.context = json.AppendTime(json.AppendKey(c.l.context, key), t, TimeFieldFormat)
+	c.l.context = enc.AppendTime(enc.AppendKey(c.l.context, key), t, TimeFieldFormat)
 	return c
 }
 
-// Times adds the field key with t formated as string using zerolog.TimeFieldFormat.
+// Times adds the field key with t formatted as string using zerolog.TimeFieldFormat.
 func (c Context) Times(key string, t []time.Time) Context {
-	c.l.context = json.AppendTimes(json.AppendKey(c.l.context, key), t, TimeFieldFormat)
+	c.l.context = enc.AppendTimes(enc.AppendKey(c.l.context, key), t, TimeFieldFormat)
 	return c
 }
 
-// Dur adds the fields key with d divided by unit and stored as a float.
+// Dur adds the field key with d divided by unit and stored as a float.
 func (c Context) Dur(key string, d time.Duration) Context {
-	c.l.context = json.AppendDuration(json.AppendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldInteger)
+	c.l.context = enc.AppendDuration(enc.AppendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldFormat, DurationFieldInteger, FloatingPointPrecision)
 	return c
 }
 
-// Durs adds the fields key with d divided by unit and stored as a float.
+// Durs adds the field key with d divided by unit and stored as a float.
 func (c Context) Durs(key string, d []time.Duration) Context {
-	c.l.context = json.AppendDurations(json.AppendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldInteger)
+	c.l.context = enc.AppendDurations(enc.AppendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldFormat, DurationFieldInteger, FloatingPointPrecision)
 	return c
 }
 
 // Interface adds the field key with obj marshaled using reflection.
 func (c Context) Interface(key string, i interface{}) Context {
-	c.l.context = json.AppendInterface(json.AppendKey(c.l.context, key), i)
+	if obj, ok := i.(LogObjectMarshaler); ok {
+		return c.Object(key, obj)
+	}
+	c.l.context = enc.AppendInterface(enc.AppendKey(c.l.context, key), i)
+	return c
+}
+
+// Type adds the field key with val's type using reflection.
+func (c Context) Type(key string, val interface{}) Context {
+	c.l.context = enc.AppendType(enc.AppendKey(c.l.context, key), val)
+	return c
+}
+
+// Any is a wrapper around Context.Interface.
+func (c Context) Any(key string, i interface{}) Context {
+	return c.Interface(key, i)
+}
+
+// Reset removes all the context fields.
+func (c Context) Reset() Context {
+	c.l.context = enc.AppendBeginMarker(make([]byte, 0, 500))
+	return c
+}
+
+type callerHook struct {
+	callerSkipFrameCount int
+}
+
+func newCallerHook(skipFrameCount int) callerHook {
+	return callerHook{callerSkipFrameCount: skipFrameCount}
+}
+
+func (ch callerHook) Run(e *Event, level Level, msg string) {
+	switch ch.callerSkipFrameCount {
+	case useGlobalSkipFrameCount:
+		// Extra frames to skip (added by hook infra).
+		e.caller(CallerSkipFrameCount + contextCallerSkipFrameCount)
+	default:
+		// Extra frames to skip (added by hook infra).
+		e.caller(ch.callerSkipFrameCount + contextCallerSkipFrameCount)
+	}
+}
+
+// useGlobalSkipFrameCount acts as a flag to informat callerHook.Run
+// to use the global CallerSkipFrameCount.
+const useGlobalSkipFrameCount = math.MinInt32
+
+// ch is the default caller hook using the global CallerSkipFrameCount.
+var ch = newCallerHook(useGlobalSkipFrameCount)
+
+// Caller adds the file:line of the caller with the zerolog.CallerFieldName key.
+func (c Context) Caller() Context {
+	c.l = c.l.Hook(ch)
+	return c
+}
+
+// CallerWithSkipFrameCount adds the file:line of the caller with the zerolog.CallerFieldName key.
+// The specified skipFrameCount int will override the global CallerSkipFrameCount for this context's respective logger.
+// If set to -1 the global CallerSkipFrameCount will be used.
+func (c Context) CallerWithSkipFrameCount(skipFrameCount int) Context {
+	c.l = c.l.Hook(newCallerHook(skipFrameCount))
+	return c
+}
+
+// Stack enables stack trace printing for the error passed to Err().
+func (c Context) Stack() Context {
+	c.l.stack = true
+	return c
+}
+
+// IPAddr adds adds the field key with ip as a net.IP IPv4 or IPv6 Address to the context
+func (c Context) IPAddr(key string, ip net.IP) Context {
+	c.l.context = enc.AppendIPAddr(enc.AppendKey(c.l.context, key), ip)
+	return c
+}
+
+// IPAddrs adds the field key with ip as a []net.IP array of IPv4 or IPv6 Address to the context
+func (c Context) IPAddrs(key string, ip []net.IP) Context {
+	c.l.context = enc.AppendIPAddrs(enc.AppendKey(c.l.context, key), ip)
+	return c
+}
+
+// IPPrefix adds adds the field key with pfx as a []net.IPNet IPv4 or IPv6 Prefix (address and mask) to the context
+func (c Context) IPPrefix(key string, pfx net.IPNet) Context {
+	c.l.context = enc.AppendIPPrefix(enc.AppendKey(c.l.context, key), pfx)
+	return c
+}
+
+// IPPrefix adds adds the field key with pfx as a []net.IPNet array of IPv4 or IPv6 Prefix (address and mask) to the context
+func (c Context) IPPrefixes(key string, pfx []net.IPNet) Context {
+	c.l.context = enc.AppendIPPrefixes(enc.AppendKey(c.l.context, key), pfx)
+	return c
+}
+
+// MACAddr adds adds the field key with ha as a net.HardwareAddr MAC address to the context
+func (c Context) MACAddr(key string, ha net.HardwareAddr) Context {
+	c.l.context = enc.AppendMACAddr(enc.AppendKey(c.l.context, key), ha)
 	return c
 }

context_test.go

@@ -0,0 +1,143 @@
+package zerolog
+
+import (
+	"bytes"
+	"errors"
+	"testing"
+)
+
+type myError struct{}
+
+func (e *myError) Error() string { return "test" }
+
+func TestContext_ErrWithStackMarshaler(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler
+	ErrorStackMarshaler = func(err error) interface{} {
+		return "stack-trace"
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf).With().Stack().Err(errors.New("test error")).Logger()
+
+	log.Info().Msg("test message")
+
+	got := decodeIfBinaryToString(buf.Bytes())
+	want := `{"level":"info","stack":"stack-trace","error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Context.Err() with stack marshaler = %q, want %q", got, want)
+	}
+}
+
+func TestContext_AnErrWithNilErrorMarshal(t *testing.T) {
+	// Save original
+	original := ErrorMarshalFunc
+	defer func() { ErrorMarshalFunc = original }()
+
+	// Set marshaler to return a nil error pointer
+	ErrorMarshalFunc = func(err error) interface{} {
+		return (*myError)(nil) // nil pointer of error type
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf).With().AnErr("test", errors.New("some error")).Logger()
+
+	log.Info().Msg("test message")
+
+	got := decodeIfBinaryToString(buf.Bytes())
+	want := `{"level":"info","message":"test message"}` + "\n" // No "test" field because isNilValue returned true
+	if got != want {
+		t.Errorf("Context.AnErr() with nil error marshal = %q, want %q", got, want)
+	}
+}
+
+func TestContext_ErrWithNilStackMarshaler(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set marshaler to return nil
+	ErrorStackMarshaler = func(err error) interface{} {
+		return nil
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf).With().Stack().Err(errors.New("test error")).Logger()
+
+	log.Info().Msg("test message")
+
+	got := decodeIfBinaryToString(buf.Bytes())
+	want := `{"level":"info","message":"test message"}` + "\n" // No stack or error field because stack marshaler returned nil
+	if got != want {
+		t.Errorf("Context.Err() with nil stack marshaler = %q, want %q", got, want)
+	}
+}
+
+func TestContext_ErrWithStackMarshalerObject(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns LogObjectMarshaler
+	ErrorStackMarshaler = func(err error) interface{} {
+		return logObjectMarshalerImpl{name: "user", age: 30}
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf).With().Stack().Err(errors.New("test error")).Logger()
+
+	log.Info().Msg("test message")
+
+	got := decodeIfBinaryToString(buf.Bytes())
+	want := `{"level":"info","stack":{"name":"user","age":-30},"error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Context.Err() with stack marshaler object = %q, want %q", got, want)
+	}
+}
+
+func TestContext_ErrWithStackMarshalerError(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns an error
+	ErrorStackMarshaler = func(err error) interface{} {
+		return errors.New("stack error")
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf).With().Stack().Err(errors.New("test error")).Logger()
+
+	log.Info().Msg("test message")
+
+	got := decodeIfBinaryToString(buf.Bytes())
+	want := `{"level":"info","stack":"stack error","error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Context.Err() with stack marshaler error = %q, want %q", got, want)
+	}
+}
+
+func TestContext_ErrWithStackMarshalerInterface(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns an int
+	ErrorStackMarshaler = func(err error) interface{} {
+		return 42
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf).With().Stack().Err(errors.New("test error")).Logger()
+
+	log.Info().Msg("test message")
+
+	got := decodeIfBinaryToString(buf.Bytes())
+	want := `{"level":"info","stack":42,"error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Context.Err() with stack marshaler interface = %q, want %q", got, want)
+	}
+}

ctx.go

@@ -2,28 +2,50 @@ package zerolog
 
 import (
 	"context"
-	"io/ioutil"
 )
 
-var disabledLogger = New(ioutil.Discard).Level(Disabled)
+var disabledLogger *Logger
+
+func init() {
+	SetGlobalLevel(TraceLevel)
+	l := Nop()
+	disabledLogger = &l
+}
 
 type ctxKey struct{}
 
-// WithContext returns a copy of ctx with l associated.
+// WithContext returns a copy of ctx with the receiver attached. The Logger
+// attached to the provided Context (if any) will not be effected.  If the
+// receiver's log level is Disabled it will only be attached to the returned
+// Context if the provided Context has a previously attached Logger. If the
+// provided Context has no attached Logger, a Disabled Logger will not be
+// attached.
+//
+// Note: to modify the existing Logger attached to a Context (instead of
+// replacing it in a new Context), use UpdateContext with the following
+// notation:
+//
+//	ctx := r.Context()
+//	l := zerolog.Ctx(ctx)
+//	l.UpdateContext(func(c Context) Context {
+//	    return c.Str("bar", "baz")
+//	})
 func (l Logger) WithContext(ctx context.Context) context.Context {
-	if lp, ok := ctx.Value(ctxKey{}).(*Logger); ok {
-		// Update existing pointer.
-		*lp = l
+	if _, ok := ctx.Value(ctxKey{}).(*Logger); !ok && l.level == Disabled {
+		// Do not store disabled logger.
 		return ctx
 	}
 	return context.WithValue(ctx, ctxKey{}, &l)
 }
 
 // Ctx returns the Logger associated with the ctx. If no logger
-// is associated, a disabled logger is returned.
-func Ctx(ctx context.Context) Logger {
+// is associated, DefaultContextLogger is returned, unless DefaultContextLogger
+// is nil, in which case a disabled logger is returned.
+func Ctx(ctx context.Context) *Logger {
 	if l, ok := ctx.Value(ctxKey{}).(*Logger); ok {
-		return *l
+		return l
+	} else if l = DefaultContextLogger; l != nil {
+		return l
 	}
 	return disabledLogger
 }

ctx_test.go

@@ -1,17 +1,21 @@
 package zerolog
 
 import (
+	"bytes"
 	"context"
-	"io/ioutil"
+	"io"
 	"reflect"
+	"strings"
 	"testing"
+
+	"github.com/rs/zerolog/internal/cbor"
 )
 
 func TestCtx(t *testing.T) {
-	log := New(ioutil.Discard)
+	log := New(io.Discard)
 	ctx := log.WithContext(context.Background())
 	log2 := Ctx(ctx)
-	if !reflect.DeepEqual(log, log2) {
+	if !reflect.DeepEqual(log, *log2) {
 		t.Error("Ctx did not return the expected logger")
 	}
 
@@ -19,12 +23,80 @@ func TestCtx(t *testing.T) {
 	log = log.Level(InfoLevel)
 	ctx = log.WithContext(ctx)
 	log2 = Ctx(ctx)
-	if !reflect.DeepEqual(log, log2) {
+	if !reflect.DeepEqual(log, *log2) {
 		t.Error("Ctx did not return the expected logger")
 	}
 
 	log2 = Ctx(context.Background())
-	if !reflect.DeepEqual(log2, disabledLogger) {
+	if log2 != disabledLogger {
+		t.Error("Ctx did not return the expected logger")
+	}
+
+	DefaultContextLogger = &log
+	t.Cleanup(func() { DefaultContextLogger = nil })
+	log2 = Ctx(context.Background())
+	if log2 != &log {
 		t.Error("Ctx did not return the expected logger")
 	}
 }
+
+func TestCtxDisabled(t *testing.T) {
+	dl := New(io.Discard).Level(Disabled)
+	ctx := dl.WithContext(context.Background())
+	if ctx != context.Background() {
+		t.Error("WithContext stored a disabled logger")
+	}
+
+	l := New(io.Discard).With().Str("foo", "bar").Logger()
+	ctx = l.WithContext(ctx)
+	if !reflect.DeepEqual(Ctx(ctx), &l) {
+		t.Error("WithContext did not store logger")
+	}
+
+	l.UpdateContext(func(c Context) Context {
+		return c.Str("bar", "baz")
+	})
+	ctx = l.WithContext(ctx)
+	if !reflect.DeepEqual(Ctx(ctx), &l) {
+		t.Error("WithContext did not store updated logger")
+	}
+
+	l = l.Level(DebugLevel)
+	ctx = l.WithContext(ctx)
+	if !reflect.DeepEqual(Ctx(ctx), &l) {
+		t.Error("WithContext did not store copied logger")
+	}
+
+	ctx = dl.WithContext(ctx)
+	if !reflect.DeepEqual(Ctx(ctx), &dl) {
+		t.Error("WithContext did not override logger with a disabled logger")
+	}
+}
+
+type logObjectMarshalerImpl struct {
+	name string
+	age  int
+}
+
+func (t logObjectMarshalerImpl) MarshalZerologObject(e *Event) {
+	e.Str("name", strings.ToLower(t.name)).Int("age", -t.age)
+}
+
+func Test_InterfaceLogObjectMarshaler(t *testing.T) {
+	var buf bytes.Buffer
+	log := New(&buf)
+	ctx := log.WithContext(context.Background())
+
+	log2 := Ctx(ctx)
+
+	withLog := log2.With().Interface("obj", &logObjectMarshalerImpl{
+		name: "FOO",
+		age:  29,
+	}).Logger()
+
+	withLog.Info().Msg("test")
+
+	if got, want := cbor.DecodeIfBinaryToString(buf.Bytes()), `{"level":"info","obj":{"name":"foo","age":-29},"message":"test"}`+"\n"; got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}

diode/diode.go

@@ -0,0 +1,114 @@
+// Package diode provides a thread-safe, lock-free, non-blocking io.Writer
+// wrapper.
+package diode
+
+import (
+	"context"
+	"io"
+	"sync"
+	"time"
+
+	"github.com/rs/zerolog/diode/internal/diodes"
+)
+
+var bufPool = &sync.Pool{
+	New: func() interface{} {
+		return make([]byte, 0, 500)
+	},
+}
+
+type Alerter func(missed int)
+
+type diodeFetcher interface {
+	diodes.Diode
+	Next() diodes.GenericDataType
+}
+
+// Writer is a io.Writer wrapper that uses a diode to make Write lock-free,
+// non-blocking and thread safe.
+type Writer struct {
+	w    io.Writer
+	d    diodeFetcher
+	c    context.CancelFunc
+	done chan struct{}
+}
+
+// NewWriter creates a writer wrapping w with a many-to-one diode in order to
+// never block log producers and drop events if the writer can't keep up with
+// the flow of data.
+//
+// Use a diode.Writer when
+//
+//     wr := diode.NewWriter(w, 1000, 0, func(missed int) {
+//         log.Printf("Dropped %d messages", missed)
+//     })
+//     log := zerolog.New(wr)
+//
+// If pollInterval is greater than 0, a poller is used otherwise a waiter is
+// used.
+//
+// See code.cloudfoundry.org/go-diodes for more info on diode.
+func NewWriter(w io.Writer, size int, pollInterval time.Duration, f Alerter) Writer {
+	ctx, cancel := context.WithCancel(context.Background())
+	dw := Writer{
+		w:    w,
+		c:    cancel,
+		done: make(chan struct{}),
+	}
+	if f == nil {
+		f = func(int) {}
+	}
+	d := diodes.NewManyToOne(size, diodes.AlertFunc(f))
+	if pollInterval > 0 {
+		dw.d = diodes.NewPoller(d,
+			diodes.WithPollingInterval(pollInterval),
+			diodes.WithPollingContext(ctx))
+	} else {
+		dw.d = diodes.NewWaiter(d,
+			diodes.WithWaiterContext(ctx))
+	}
+	go dw.poll()
+	return dw
+}
+
+func (dw Writer) Write(p []byte) (n int, err error) {
+	// p is pooled in zerolog so we can't hold it passed this call, hence the
+	// copy.
+	p = append(bufPool.Get().([]byte), p...)
+	dw.d.Set(diodes.GenericDataType(&p))
+	return len(p), nil
+}
+
+// Close releases the diode poller and call Close on the wrapped writer if
+// io.Closer is implemented.
+func (dw Writer) Close() error {
+	dw.c()
+	<-dw.done
+	if w, ok := dw.w.(io.Closer); ok {
+		return w.Close()
+	}
+	return nil
+}
+
+func (dw Writer) poll() {
+	defer close(dw.done)
+	for {
+		d := dw.d.Next()
+		if d == nil {
+			return
+		}
+		p := *(*[]byte)(d)
+		dw.w.Write(p)
+
+		// Proper usage of a sync.Pool requires each entry to have approximately
+		// the same memory cost. To obtain this property when the stored type
+		// contains a variably-sized buffer, we add a hard limit on the maximum buffer
+		// to place back in the pool.
+		//
+		// See https://golang.org/issue/23199
+		const maxSize = 1 << 16 // 64KiB
+		if cap(p) <= maxSize {
+			bufPool.Put(p[:0])
+		}
+	}
+}

diode/diode_example_test.go

@@ -0,0 +1,23 @@
+// +build !binary_log
+
+package diode_test
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/diode"
+)
+
+func ExampleNewWriter() {
+	w := diode.NewWriter(os.Stdout, 1000, 0, func(missed int) {
+		fmt.Printf("Dropped %d messages\n", missed)
+	})
+	log := zerolog.New(w)
+	log.Print("test")
+
+	w.Close()
+
+	// Output: {"level":"debug","message":"test"}
+}

diode/diode_test.go

@@ -0,0 +1,171 @@
+package diode_test
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/diode"
+	"github.com/rs/zerolog/internal/cbor"
+)
+
+func TestNewWriter(t *testing.T) {
+	buf := bytes.Buffer{}
+	w := diode.NewWriter(&buf, 1000, 0, func(missed int) {
+		fmt.Printf("Dropped %d messages\n", missed)
+	})
+	log := zerolog.New(w)
+	log.Print("test")
+
+	w.Close()
+	want := "{\"level\":\"debug\",\"message\":\"test\"}\n"
+	got := cbor.DecodeIfBinaryToString(buf.Bytes())
+	if got != want {
+		t.Errorf("Diode New Writer Test failed. got:%s, want:%s!", got, want)
+	}
+}
+
+func TestClose(t *testing.T) {
+	buf := bytes.Buffer{}
+	w := diode.NewWriter(&buf, 1000, 0, func(missed int) {})
+	log := zerolog.New(w)
+	log.Print("test")
+	w.Close()
+}
+
+func TestFatal(t *testing.T) {
+	if os.Getenv("TEST_FATAL") == "1" {
+		w := diode.NewWriter(os.Stderr, 1000, 0, func(missed int) {
+			fmt.Printf("Dropped %d messages\n", missed)
+		})
+		defer w.Close()
+		log := zerolog.New(w)
+		log.Fatal().Msg("test")
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestFatal")
+	cmd.Env = append(os.Environ(), "TEST_FATAL=1")
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = cmd.Start()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var stderrBuf bytes.Buffer
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		if _, err := io.Copy(&stderrBuf, stderr); err != nil {
+			t.Errorf("failed to copy stderr: %v", err)
+		}
+	}()
+
+	err = cmd.Wait()
+	if err == nil {
+		t.Error("Expected log.Fatal to exit with non-zero status")
+	}
+
+	wg.Wait() // Wait for the goroutine to finish copying
+	slurp := stderrBuf.Bytes()
+
+	want := "{\"level\":\"fatal\",\"message\":\"test\"}\n"
+	got := cbor.DecodeIfBinaryToString(slurp)
+	if got != want {
+		t.Errorf("Diode Fatal Test failed. got:%s, want:%s!", got, want)
+	}
+}
+
+type SlowWriter struct{}
+
+func (rw *SlowWriter) Write(p []byte) (n int, err error) {
+	time.Sleep(200 * time.Millisecond)
+	fmt.Print(string(p))
+	return len(p), nil
+}
+
+func TestFatalWithFilteredLevelWriter(t *testing.T) {
+	if os.Getenv("TEST_FATAL_SLOW") == "1" {
+		slowWriter := SlowWriter{}
+		diodeWriter := diode.NewWriter(&slowWriter, 500, 0, func(missed int) {
+			fmt.Printf("Missed %d logs\n", missed)
+		})
+		leveledDiodeWriter := zerolog.LevelWriterAdapter{
+			Writer: &diodeWriter,
+		}
+		filteredDiodeWriter := zerolog.FilteredLevelWriter{
+			Writer: &leveledDiodeWriter,
+			Level:  zerolog.InfoLevel,
+		}
+		logger := zerolog.New(&filteredDiodeWriter)
+		logger.Fatal().Msg("test")
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestFatalWithFilteredLevelWriter")
+	cmd.Env = append(os.Environ(), "TEST_FATAL_SLOW=1")
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = cmd.Start()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var stdoutBuf bytes.Buffer
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		_, _ = io.Copy(&stdoutBuf, stdout)
+	}()
+
+	err = cmd.Wait()
+	if err == nil {
+		t.Error("Expected log.Fatal to exit with non-zero status")
+	}
+
+	wg.Wait() // Wait for the goroutine to finish copying
+	slurp := stdoutBuf.Bytes()
+
+	got := cbor.DecodeIfBinaryToString(slurp)
+	want := "{\"level\":\"fatal\",\"message\":\"test\"}\n"
+	if got != want {
+		t.Errorf("Expected output %q, got: %q", want, got)
+	}
+}
+
+func Benchmark(b *testing.B) {
+	log.SetOutput(io.Discard)
+	defer log.SetOutput(os.Stderr)
+	benchs := map[string]time.Duration{
+		"Waiter": 0,
+		"Pooler": 10 * time.Millisecond,
+	}
+	for name, interval := range benchs {
+		b.Run(name, func(b *testing.B) {
+			w := diode.NewWriter(io.Discard, 100000, interval, nil)
+			log := zerolog.New(w)
+			defer w.Close()
+
+			b.SetParallelism(1000)
+			b.RunParallel(func(pb *testing.PB) {
+				for pb.Next() {
+					log.Print("test")
+				}
+			})
+		})
+	}
+}

diode/internal/diodes/README

@@ -0,0 +1 @@
+Copied from https://github.com/cloudfoundry/go-diodes to avoid test dependencies.

diode/internal/diodes/many_to_one.go

@@ -0,0 +1,130 @@
+package diodes
+
+import (
+	"log"
+	"sync/atomic"
+	"unsafe"
+)
+
+// ManyToOne diode is optimal for many writers (go-routines B-n) and a single
+// reader (go-routine A). It is not thread safe for multiple readers.
+type ManyToOne struct {
+	writeIndex uint64
+	readIndex  uint64
+	buffer     []unsafe.Pointer
+	alerter    Alerter
+}
+
+// NewManyToOne creates a new diode (ring buffer). The ManyToOne diode
+// is optimized for many writers (on go-routines B-n) and a single reader
+// (on go-routine A). The alerter is invoked on the read's go-routine. It is
+// called when it notices that the writer go-routine has passed it and wrote
+// over data. A nil can be used to ignore alerts.
+func NewManyToOne(size int, alerter Alerter) *ManyToOne {
+	if alerter == nil {
+		alerter = AlertFunc(func(int) {})
+	}
+
+	d := &ManyToOne{
+		buffer:  make([]unsafe.Pointer, size),
+		alerter: alerter,
+	}
+
+	// Start write index at the value before 0
+	// to allow the first write to use AddUint64
+	// and still have a beginning index of 0
+	d.writeIndex = ^d.writeIndex
+	return d
+}
+
+// Set sets the data in the next slot of the ring buffer.
+func (d *ManyToOne) Set(data GenericDataType) {
+	for {
+		writeIndex := atomic.AddUint64(&d.writeIndex, 1)
+		idx := writeIndex % uint64(len(d.buffer))
+		old := atomic.LoadPointer(&d.buffer[idx])
+
+		if old != nil &&
+			(*bucket)(old) != nil &&
+			(*bucket)(old).seq > writeIndex-uint64(len(d.buffer)) {
+			log.Println("Diode set collision: consider using a larger diode")
+			continue
+		}
+
+		newBucket := &bucket{
+			data: data,
+			seq:  writeIndex,
+		}
+
+		if !atomic.CompareAndSwapPointer(&d.buffer[idx], old, unsafe.Pointer(newBucket)) {
+			log.Println("Diode set collision: consider using a larger diode")
+			continue
+		}
+
+		return
+	}
+}
+
+// TryNext will attempt to read from the next slot of the ring buffer.
+// If there is no data available, it will return (nil, false).
+func (d *ManyToOne) TryNext() (data GenericDataType, ok bool) {
+	// Read a value from the ring buffer based on the readIndex.
+	idx := d.readIndex % uint64(len(d.buffer))
+	result := (*bucket)(atomic.SwapPointer(&d.buffer[idx], nil))
+
+	// When the result is nil that means the writer has not had the
+	// opportunity to write a value into the diode. This value must be ignored
+	// and the read head must not increment.
+	if result == nil {
+		return nil, false
+	}
+
+	// When the seq value is less than the current read index that means a
+	// value was read from idx that was previously written but since has
+	// been dropped. This value must be ignored and the read head must not
+	// increment.
+	//
+	// The simulation for this scenario assumes the fast forward occurred as
+	// detailed below.
+	//
+	// 5. The reader reads again getting seq 5. It then reads again expecting
+	//    seq 6 but gets seq 2. This is a read of a stale value that was
+	//    effectively "dropped" so the read fails and the read head stays put.
+	//    `| 4 | 5 | 2 | 3 |` r: 7, w: 6
+	//
+	if result.seq < d.readIndex {
+		return nil, false
+	}
+
+	// When the seq value is greater than the current read index that means a
+	// value was read from idx that overwrote the value that was expected to
+	// be at this idx. This happens when the writer has lapped the reader. The
+	// reader needs to catch up to the writer so it moves its write head to
+	// the new seq, effectively dropping the messages that were not read in
+	// between the two values.
+	//
+	// Here is a simulation of this scenario:
+	//
+	// 1. Both the read and write heads start at 0.
+	//    `| nil | nil | nil | nil |` r: 0, w: 0
+	// 2. The writer fills the buffer.
+	//    `| 0 | 1 | 2 | 3 |` r: 0, w: 4
+	// 3. The writer laps the read head.
+	//    `| 4 | 5 | 2 | 3 |` r: 0, w: 6
+	// 4. The reader reads the first value, expecting a seq of 0 but reads 4,
+	//    this forces the reader to fast forward to 5.
+	//    `| 4 | 5 | 2 | 3 |` r: 5, w: 6
+	//
+	if result.seq > d.readIndex {
+		dropped := result.seq - d.readIndex
+		d.readIndex = result.seq
+		d.alerter.Alert(int(dropped))
+	}
+
+	// Only increment read index if a regular read occurred (where seq was
+	// equal to readIndex) or a value was read that caused a fast forward
+	// (where seq was greater than readIndex).
+	//
+	d.readIndex++
+	return result.data, true
+}

diode/internal/diodes/one_to_one.go

@@ -0,0 +1,129 @@
+package diodes
+
+import (
+	"sync/atomic"
+	"unsafe"
+)
+
+// GenericDataType is the data type the diodes operate on.
+type GenericDataType unsafe.Pointer
+
+// Alerter is used to report how many values were overwritten since the
+// last write.
+type Alerter interface {
+	Alert(missed int)
+}
+
+// AlertFunc type is an adapter to allow the use of ordinary functions as
+// Alert handlers.
+type AlertFunc func(missed int)
+
+// Alert calls f(missed)
+func (f AlertFunc) Alert(missed int) {
+	f(missed)
+}
+
+type bucket struct {
+	data GenericDataType
+	seq  uint64 // seq is the recorded write index at the time of writing
+}
+
+// OneToOne diode is meant to be used by a single reader and a single writer.
+// It is not thread safe if used otherwise.
+type OneToOne struct {
+	writeIndex uint64
+	readIndex  uint64
+	buffer     []unsafe.Pointer
+	alerter    Alerter
+}
+
+// NewOneToOne creates a new diode is meant to be used by a single reader and
+// a single writer. The alerter is invoked on the read's go-routine. It is
+// called when it notices that the writer go-routine has passed it and wrote
+// over data. A nil can be used to ignore alerts.
+func NewOneToOne(size int, alerter Alerter) *OneToOne {
+	if alerter == nil {
+		alerter = AlertFunc(func(int) {})
+	}
+
+	return &OneToOne{
+		buffer:  make([]unsafe.Pointer, size),
+		alerter: alerter,
+	}
+}
+
+// Set sets the data in the next slot of the ring buffer.
+func (d *OneToOne) Set(data GenericDataType) {
+	idx := d.writeIndex % uint64(len(d.buffer))
+
+	newBucket := &bucket{
+		data: data,
+		seq:  d.writeIndex,
+	}
+	d.writeIndex++
+
+	atomic.StorePointer(&d.buffer[idx], unsafe.Pointer(newBucket))
+}
+
+// TryNext will attempt to read from the next slot of the ring buffer.
+// If there is no data available, it will return (nil, false).
+func (d *OneToOne) TryNext() (data GenericDataType, ok bool) {
+	// Read a value from the ring buffer based on the readIndex.
+	idx := d.readIndex % uint64(len(d.buffer))
+	result := (*bucket)(atomic.SwapPointer(&d.buffer[idx], nil))
+
+	// When the result is nil that means the writer has not had the
+	// opportunity to write a value into the diode. This value must be ignored
+	// and the read head must not increment.
+	if result == nil {
+		return nil, false
+	}
+
+	// When the seq value is less than the current read index that means a
+	// value was read from idx that was previously written but since has
+	// been dropped. This value must be ignored and the read head must not
+	// increment.
+	//
+	// The simulation for this scenario assumes the fast forward occurred as
+	// detailed below.
+	//
+	// 5. The reader reads again getting seq 5. It then reads again expecting
+	//    seq 6 but gets seq 2. This is a read of a stale value that was
+	//    effectively "dropped" so the read fails and the read head stays put.
+	//    `| 4 | 5 | 2 | 3 |` r: 7, w: 6
+	//
+	if result.seq < d.readIndex {
+		return nil, false
+	}
+
+	// When the seq value is greater than the current read index that means a
+	// value was read from idx that overwrote the value that was expected to
+	// be at this idx. This happens when the writer has lapped the reader. The
+	// reader needs to catch up to the writer so it moves its write head to
+	// the new seq, effectively dropping the messages that were not read in
+	// between the two values.
+	//
+	// Here is a simulation of this scenario:
+	//
+	// 1. Both the read and write heads start at 0.
+	//    `| nil | nil | nil | nil |` r: 0, w: 0
+	// 2. The writer fills the buffer.
+	//    `| 0 | 1 | 2 | 3 |` r: 0, w: 4
+	// 3. The writer laps the read head.
+	//    `| 4 | 5 | 2 | 3 |` r: 0, w: 6
+	// 4. The reader reads the first value, expecting a seq of 0 but reads 4,
+	//    this forces the reader to fast forward to 5.
+	//    `| 4 | 5 | 2 | 3 |` r: 5, w: 6
+	//
+	if result.seq > d.readIndex {
+		dropped := result.seq - d.readIndex
+		d.readIndex = result.seq
+		d.alerter.Alert(int(dropped))
+	}
+
+	// Only increment read index if a regular read occurred (where seq was
+	// equal to readIndex) or a value was read that caused a fast forward
+	// (where seq was greater than readIndex).
+	d.readIndex++
+	return result.data, true
+}

diode/internal/diodes/poller.go

@@ -0,0 +1,80 @@
+package diodes
+
+import (
+	"context"
+	"time"
+)
+
+// Diode is any implementation of a diode.
+type Diode interface {
+	Set(GenericDataType)
+	TryNext() (GenericDataType, bool)
+}
+
+// Poller will poll a diode until a value is available.
+type Poller struct {
+	Diode
+	interval time.Duration
+	ctx      context.Context
+}
+
+// PollerConfigOption can be used to setup the poller.
+type PollerConfigOption func(*Poller)
+
+// WithPollingInterval sets the interval at which the diode is queried
+// for new data. The default is 10ms.
+func WithPollingInterval(interval time.Duration) PollerConfigOption {
+	return func(c *Poller) {
+		c.interval = interval
+	}
+}
+
+// WithPollingContext sets the context to cancel any retrieval (Next()). It
+// will not change any results for adding data (Set()). Default is
+// context.Background().
+func WithPollingContext(ctx context.Context) PollerConfigOption {
+	return func(c *Poller) {
+		c.ctx = ctx
+	}
+}
+
+// NewPoller returns a new Poller that wraps the given diode.
+func NewPoller(d Diode, opts ...PollerConfigOption) *Poller {
+	p := &Poller{
+		Diode:    d,
+		interval: 10 * time.Millisecond,
+		ctx:      context.Background(),
+	}
+
+	for _, o := range opts {
+		o(p)
+	}
+
+	return p
+}
+
+// Next polls the diode until data is available or until the context is done.
+// If the context is done, then nil will be returned.
+func (p *Poller) Next() GenericDataType {
+	for {
+		data, ok := p.Diode.TryNext()
+		if !ok {
+			if p.isDone() {
+				return nil
+			}
+
+			time.Sleep(p.interval)
+			continue
+		}
+		return data
+	}
+}
+
+func (p *Poller) isDone() bool {
+	select {
+	case <-p.ctx.Done():
+		return true
+	default:
+		return false
+	}
+}

diode/internal/diodes/waiter.go

@@ -0,0 +1,88 @@
+package diodes
+
+import (
+	"context"
+	"sync"
+)
+
+// Waiter will use a conditional mutex to alert the reader to when data is
+// available.
+type Waiter struct {
+	Diode
+	mu  sync.Mutex
+	c   *sync.Cond
+	ctx context.Context
+}
+
+// WaiterConfigOption can be used to setup the waiter.
+type WaiterConfigOption func(*Waiter)
+
+// WithWaiterContext sets the context to cancel any retrieval (Next()). It
+// will not change any results for adding data (Set()). Default is
+// context.Background().
+func WithWaiterContext(ctx context.Context) WaiterConfigOption {
+	return func(c *Waiter) {
+		c.ctx = ctx
+	}
+}
+
+// NewWaiter returns a new Waiter that wraps the given diode.
+func NewWaiter(d Diode, opts ...WaiterConfigOption) *Waiter {
+	w := new(Waiter)
+	w.Diode = d
+	w.c = sync.NewCond(&w.mu)
+	w.ctx = context.Background()
+
+	for _, opt := range opts {
+		opt(w)
+	}
+
+	go func() {
+		<-w.ctx.Done()
+
+		// Mutex is strictly necessary here to avoid a race in Next() (between
+		// w.isDone() and w.c.Wait()) and w.c.Broadcast() here.
+		w.mu.Lock()
+		w.c.Broadcast()
+		w.mu.Unlock()
+	}()
+
+	return w
+}
+
+// Set invokes the wrapped diode's Set with the given data and uses Broadcast
+// to wake up any readers.
+func (w *Waiter) Set(data GenericDataType) {
+	w.Diode.Set(data)
+	w.c.Broadcast()
+}
+
+// Next returns the next data point on the wrapped diode. If there is not any
+// new data, it will Wait for set to be called or the context to be done.
+// If the context is done, then nil will be returned.
+func (w *Waiter) Next() GenericDataType {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	for {
+		data, ok := w.Diode.TryNext()
+		if !ok {
+			if w.isDone() {
+				return nil
+			}
+
+			w.c.Wait()
+			continue
+		}
+		return data
+	}
+}
+
+func (w *Waiter) isDone() bool {
+	select {
+	case <-w.ctx.Done():
+		return true
+	default:
+		return false
+	}
+}

encoder.go

@@ -0,0 +1,56 @@
+package zerolog
+
+import (
+	"net"
+	"time"
+)
+
+type encoder interface {
+	AppendArrayDelim(dst []byte) []byte
+	AppendArrayEnd(dst []byte) []byte
+	AppendArrayStart(dst []byte) []byte
+	AppendBeginMarker(dst []byte) []byte
+	AppendBool(dst []byte, val bool) []byte
+	AppendBools(dst []byte, vals []bool) []byte
+	AppendBytes(dst, s []byte) []byte
+	AppendDuration(dst []byte, d time.Duration, unit time.Duration, format string, useInt bool, precision int) []byte
+	AppendDurations(dst []byte, vals []time.Duration, unit time.Duration, format string, useInt bool, precision int) []byte
+	AppendEndMarker(dst []byte) []byte
+	AppendFloat32(dst []byte, val float32, precision int) []byte
+	AppendFloat64(dst []byte, val float64, precision int) []byte
+	AppendFloats32(dst []byte, vals []float32, precision int) []byte
+	AppendFloats64(dst []byte, vals []float64, precision int) []byte
+	AppendHex(dst, s []byte) []byte
+	AppendIPAddr(dst []byte, ip net.IP) []byte
+	AppendIPPrefix(dst []byte, pfx net.IPNet) []byte
+	AppendInt(dst []byte, val int) []byte
+	AppendInt16(dst []byte, val int16) []byte
+	AppendInt32(dst []byte, val int32) []byte
+	AppendInt64(dst []byte, val int64) []byte
+	AppendInt8(dst []byte, val int8) []byte
+	AppendInterface(dst []byte, i interface{}) []byte
+	AppendInts(dst []byte, vals []int) []byte
+	AppendInts16(dst []byte, vals []int16) []byte
+	AppendInts32(dst []byte, vals []int32) []byte
+	AppendInts64(dst []byte, vals []int64) []byte
+	AppendInts8(dst []byte, vals []int8) []byte
+	AppendKey(dst []byte, key string) []byte
+	AppendLineBreak(dst []byte) []byte
+	AppendMACAddr(dst []byte, ha net.HardwareAddr) []byte
+	AppendNil(dst []byte) []byte
+	AppendObjectData(dst []byte, o []byte) []byte
+	AppendString(dst []byte, s string) []byte
+	AppendStrings(dst []byte, vals []string) []byte
+	AppendTime(dst []byte, t time.Time, format string) []byte
+	AppendTimes(dst []byte, vals []time.Time, format string) []byte
+	AppendUint(dst []byte, val uint) []byte
+	AppendUint16(dst []byte, val uint16) []byte
+	AppendUint32(dst []byte, val uint32) []byte
+	AppendUint64(dst []byte, val uint64) []byte
+	AppendUint8(dst []byte, val uint8) []byte
+	AppendUints(dst []byte, vals []uint) []byte
+	AppendUints16(dst []byte, vals []uint16) []byte
+	AppendUints32(dst []byte, vals []uint32) []byte
+	AppendUints64(dst []byte, vals []uint64) []byte
+	AppendUints8(dst []byte, vals []uint8) []byte
+}

encoder_cbor.go

@@ -0,0 +1,45 @@
+// +build binary_log
+
+package zerolog
+
+// This file contains bindings to do binary encoding.
+
+import (
+	"github.com/rs/zerolog/internal/cbor"
+)
+
+var (
+	_ encoder = (*cbor.Encoder)(nil)
+
+	enc = cbor.Encoder{}
+)
+
+func init() {
+	// using closure to reflect the changes at runtime.
+	cbor.JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return InterfaceMarshalFunc(v)
+	}
+}
+
+func appendJSON(dst []byte, j []byte) []byte {
+	return cbor.AppendEmbeddedJSON(dst, j)
+}
+func appendCBOR(dst []byte, c []byte) []byte {
+	return cbor.AppendEmbeddedCBOR(dst, c)
+}
+
+// decodeIfBinaryToString - converts a binary formatted log msg to a
+// JSON formatted String Log message.
+func decodeIfBinaryToString(in []byte) string {
+	return cbor.DecodeIfBinaryToString(in)
+}
+
+func decodeObjectToStr(in []byte) string {
+	return cbor.DecodeObjectToStr(in)
+}
+
+// decodeIfBinaryToBytes - converts a binary formatted log msg to a
+// JSON formatted Bytes Log message.
+func decodeIfBinaryToBytes(in []byte) []byte {
+	return cbor.DecodeIfBinaryToBytes(in)
+}

encoder_json.go

@@ -0,0 +1,51 @@
+// +build !binary_log
+
+package zerolog
+
+// encoder_json.go file contains bindings to generate
+// JSON encoded byte stream.
+
+import (
+	"encoding/base64"
+	"github.com/rs/zerolog/internal/json"
+)
+
+var (
+	_ encoder = (*json.Encoder)(nil)
+
+	enc = json.Encoder{}
+)
+
+func init() {
+	// using closure to reflect the changes at runtime.
+	json.JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return InterfaceMarshalFunc(v)
+	}
+}
+
+func appendJSON(dst []byte, j []byte) []byte {
+	return append(dst, j...)
+}
+func appendCBOR(dst []byte, cbor []byte) []byte {
+	dst = append(dst, []byte("\"data:application/cbor;base64,")...)
+	l := len(dst)
+	enc := base64.StdEncoding
+	n := enc.EncodedLen(len(cbor))
+	for i := 0; i < n; i++ {
+		dst = append(dst, '.')
+	}
+	enc.Encode(dst[l:], cbor)
+	return append(dst, '"')
+}
+
+func decodeIfBinaryToString(in []byte) string {
+	return string(in)
+}
+
+func decodeObjectToStr(in []byte) string {
+	return string(in)
+}
+
+func decodeIfBinaryToBytes(in []byte) []byte {
+	return in
+}

error_marshal_test.go

@@ -0,0 +1,224 @@
+package zerolog
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+type loggableError struct {
+	error
+}
+
+func (l loggableError) MarshalZerologObject(e *Event) {
+	if l.error == nil {
+		return
+	}
+	e.Str("l", strings.ToUpper(l.error.Error()))
+}
+
+type nonLoggableError struct {
+	error
+	line int
+}
+
+type wrappedError struct {
+	error
+	msg string
+}
+
+func (w wrappedError) Error() string {
+	if w.error == nil {
+		return w.msg
+	}
+	return w.error.Error() + ": " + w.msg
+}
+
+type interfaceError struct {
+	val string
+}
+
+func TestArrayErrorMarshalFunc(t *testing.T) {
+	prefixed := func(s, prefix string) string {
+		if s == "null" {
+			return ""
+		}
+		return prefix + s + `,`
+	}
+	errs := []error{
+		nil,
+		fmt.Errorf("failure"),
+		loggableError{fmt.Errorf("whoops")},
+		nonLoggableError{fmt.Errorf("oops"), 402},
+	}
+	type testCase struct {
+		name    string
+		marshal func(err error) interface{}
+		want    []string
+	}
+	testCases := []testCase{
+		{
+			name:    "default",
+			marshal: nil,
+			want:    []string{`null`, `"failure"`, `{"l":"WHOOPS"}`, `"oops"`},
+		},
+		{
+			name: "string",
+			marshal: func(err error) interface{} {
+				if err == nil {
+					return nil
+				}
+				return err.Error()
+			},
+			want: []string{`null`, `"failure"`, `"whoops"`, `"oops"`},
+		},
+		{
+			name: "loggable",
+			marshal: func(err error) interface{} {
+				if err == nil {
+					return nil
+				}
+				return loggableError{err}
+			},
+			want: []string{`null`, `{"l":"FAILURE"}`, `{"l":"WHOOPS"}`, `{"l":"OOPS"}`},
+		},
+		{
+			name: "non-loggable",
+			marshal: func(err error) interface{} {
+				if err == nil {
+					return nil
+				}
+				return nonLoggableError{err, 404}
+			},
+			want: []string{`null`, `"failure"`, `"whoops"`, `"oops"`},
+		},
+		{
+			name: "interface",
+			marshal: func(err error) interface{} {
+				var some interfaceError
+				if err != nil {
+					some.val = err.Error()
+				}
+				var interfaceErr interface{} = some
+				return interfaceErr
+			},
+			want: []string{`{}`, `{}`, `{}`, `{}`},
+		},
+		{
+			name: "nilError",
+			marshal: func(err error) interface{} {
+				var errNil error = nil
+				return errNil
+			},
+			want: []string{`null`, `null`, `null`, `null`},
+		},
+		{
+			name: "wrapped error",
+			marshal: func(err error) interface{} {
+				if err == nil {
+					return nil
+				} else if we, ok := err.(wrappedError); ok {
+					return we
+				} else {
+					return wrappedError{err, "addendum"}
+				}
+			},
+			want: []string{`null`, `"failure: addendum"`, `"whoops: addendum"`, `"oops: addendum"`},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			originalErrorMarshalFunc := ErrorMarshalFunc
+			defer func() {
+				ErrorMarshalFunc = originalErrorMarshalFunc
+			}()
+
+			if tc.marshal != nil {
+				ErrorMarshalFunc = tc.marshal
+			}
+
+			t.Run("Err", func(t *testing.T) {
+				for i, err := range errs {
+					want := tc.want[i]
+					t.Run("Arr", func(t *testing.T) {
+						wants := `[` + want + `]`
+						a := Arr().Err(err)
+						if got := decodeObjectToStr(a.write([]byte{})); got != wants {
+							t.Errorf("%s %d Array.Err(%v)\ngot:  %s\nwant: %s", tc.name, i, err, got, wants)
+						}
+					})
+					t.Run("Ctx", func(t *testing.T) {
+						wants := `{` + prefixed(want, `"error":`) + `"message":"msg"}` + "\n"
+						out := &bytes.Buffer{}
+						logger := New(out).With().Err(err).Logger()
+						logger.Log().Msg("msg")
+						if got := decodeIfBinaryToString(out.Bytes()); got != wants {
+							t.Errorf("%s %d Ctx.Err(%v)\ngot:  %v\nwant: %v", tc.name, i, err, got, wants)
+						}
+					})
+					t.Run("Event", func(t *testing.T) {
+						wants := `{` + prefixed(want, `"error":`) + `"message":"msg"}` + "\n"
+						out := &bytes.Buffer{}
+						logger := New(out)
+						logger.Log().Err(err).Msg("msg")
+						if got := decodeIfBinaryToString(out.Bytes()); got != wants {
+							t.Errorf("%s %d Event.Err(%v)\ngot:  %v\nwant: %v", tc.name, i, err, got, wants)
+						}
+					})
+					t.Run("Fields", func(t *testing.T) {
+						if i == 0 && tc.want[i] == "{}" {
+							want = `null`
+						}
+						wants := `{"err":` + want + `,"message":"msg"}` + "\n"
+						out := &bytes.Buffer{}
+						logger := New(out)
+						logger.Log().Fields(map[string]interface{}{"err": err}).Msg("msg")
+						if got := decodeIfBinaryToString(out.Bytes()); got != wants {
+							t.Errorf("%s %d Event.Fields(%v)\ngot:  %v\nwant: %v", tc.name, i, err, got, wants)
+						}
+					})
+				}
+			})
+
+			t.Run("Errs", func(t *testing.T) {
+				want := `[` + strings.Join(tc.want, ",") + `]`
+				t.Run("Arr", func(t *testing.T) {
+					a := Arr().Errs(errs)
+					if got := decodeObjectToStr(a.write([]byte{})); got != want {
+						t.Errorf("%s Array.Errs()\ngot:  %s\nwant: %s", tc.name, got, want)
+					}
+				})
+
+				t.Run("Ctx", func(t *testing.T) {
+					wants := `{"e":` + want + `,"message":"msg"}` + "\n"
+					out := &bytes.Buffer{}
+					logger := New(out).With().Errs("e", errs).Logger()
+					logger.Log().Msg("msg")
+					if got := decodeIfBinaryToString(out.Bytes()); got != wants {
+						t.Errorf("%s Ctx.Errs()\ngot:  %v\nwant: %v", tc.name, got, wants)
+					}
+				})
+				t.Run("Event", func(t *testing.T) {
+					wants := `{"e":` + want + `,"message":"msg"}` + "\n"
+					out := &bytes.Buffer{}
+					logger := New(out)
+					logger.Log().Errs("e", errs).Msg("msg")
+					if got := decodeIfBinaryToString(out.Bytes()); got != wants {
+						t.Errorf("%s Ctx.Errs()\ngot:  %v\nwant: %v", tc.name, got, wants)
+					}
+				})
+				t.Run("Fields", func(t *testing.T) {
+					wants := `{"e":` + want + `,"message":"msg"}` + "\n"
+					out := &bytes.Buffer{}
+					logger := New(out)
+					logger.Log().Fields(map[string]interface{}{"e": errs}).Msg("msg")
+					if got := decodeIfBinaryToString(out.Bytes()); got != wants {
+						t.Errorf("%s Ctx.Errs()\ngot:  %v\nwant: %v", tc.name, got, wants)
+					}
+				})
+			})
+		})
+	}
+}

event_test.go

@@ -0,0 +1,733 @@
+//go:build !binary_log
+// +build !binary_log
+
+package zerolog
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"os"
+	"strings"
+	"testing"
+)
+
+type nilError struct{}
+
+func (nilError) Error() string {
+	return "nope"
+}
+
+func TestEvent_AnErr(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+		want string
+	}{
+		{"nil", nil, `{}`},
+		{"error", errors.New("test"), `{"err":"test"}`},
+		{"nil interface", func() *nilError { return nil }(), `{}`},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, false, nil, nil)
+			e = e.AnErr("err", tt.err)
+			err := e.write()
+			if err != nil {
+				t.Errorf("Event.AnErr() error: %v", err)
+			}
+
+			if got, want := strings.TrimSpace(buf.String()), tt.want; got != want {
+				t.Errorf("Event.AnErr() = %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+func TestEvent_writeWithNil(t *testing.T) {
+	var e *Event = nil
+	got := e.write()
+
+	var want *Event = nil
+	if got != nil {
+		t.Errorf("Event.write() = %v, want %v", got, want)
+	}
+}
+
+type loggableObject struct {
+	member string
+}
+
+func (o loggableObject) MarshalZerologObject(e *Event) {
+	e.Str("member", o.member)
+}
+
+func TestEvent_Object(t *testing.T) {
+	t.Run("ObjectWithNil", func(t *testing.T) {
+		var buf bytes.Buffer
+		e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, false, nil, nil)
+		e = e.Object("obj", nil)
+		err := e.write()
+		if err != nil {
+			t.Errorf("Event.Object() error: %v", err)
+		}
+
+		want := `{"obj":null}`
+		got := strings.TrimSpace(buf.String())
+		if got != want {
+			t.Errorf("Event.Object()\ngot:  %s\nwant: %s", got, want)
+		}
+	})
+
+	t.Run("EmbedObjectWithNil", func(t *testing.T) {
+		var buf bytes.Buffer
+		e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, false, nil, nil)
+		e = e.EmbedObject(nil)
+		err := e.write()
+		if err != nil {
+			t.Errorf("Event.EmbedObject() error: %v", err)
+		}
+
+		want := "{}"
+		got := strings.TrimSpace(buf.String())
+		if got != want {
+			t.Errorf("Event.EmbedObject()\ngot:  %s\nwant: %s", got, want)
+		}
+	})
+
+	type contextKeyType struct{}
+	var contextKey = contextKeyType{}
+
+	called := false
+	ctxHook := HookFunc(func(e *Event, level Level, message string) {
+		called = true
+		ctx := e.GetCtx()
+		if ctx == nil {
+			t.Errorf("expected context to be set in Event")
+		}
+		val := ctx.Value(contextKey)
+		if val == nil {
+			t.Errorf("expected context value, got %v", val)
+		}
+		e.Str("ctxValue", val.(string))
+		e.Bool("stackValue", e.stack)
+	})
+
+	t.Run("ObjectWithFullContext", func(t *testing.T) {
+		called = false
+		ctx := context.WithValue(context.Background(), contextKey, "ctx-object")
+
+		var buf bytes.Buffer
+		e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, true, ctx, []Hook{ctxHook})
+		e = e.Object("obj", loggableObject{member: "object-value"})
+		e.Msg("hello")
+
+		if !called {
+			t.Errorf("hook was not called")
+		}
+
+		want := `{"obj":{"member":"object-value"},"ctxValue":"ctx-object","stackValue":true,"message":"hello"}`
+		got := strings.TrimSpace(buf.String())
+		if got != want {
+			t.Errorf("Event.EmbedObject()\ngot:  %s\nwant: %s", got, want)
+		}
+	})
+
+	t.Run("EmbedObjectWithFullContext", func(t *testing.T) {
+		called = false
+		ctx := context.WithValue(context.Background(), contextKey, "ctx-embed")
+
+		var buf bytes.Buffer
+		e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, false, ctx, []Hook{ctxHook})
+		e = e.EmbedObject(loggableObject{member: "embedded-value"})
+		e.Msg("hello")
+
+		if !called {
+			t.Errorf("hook was not called")
+		}
+
+		want := `{"member":"embedded-value","ctxValue":"ctx-embed","stackValue":false,"message":"hello"}`
+		got := strings.TrimSpace(buf.String())
+		if got != want {
+			t.Errorf("Event.EmbedObject()\ngot:  %s\nwant: %s", got, want)
+		}
+	})
+}
+
+func TestEvent_WithNilEvent(t *testing.T) {
+	// coverage for nil Event receiver for all types
+	var e *Event = nil
+
+	fixtures := makeFieldFixtures()
+	types := map[string]func() *Event{
+		"Array": func() *Event {
+			arr := e.CreateArray()
+			return e.Array("k", arr)
+		},
+		"Bool": func() *Event {
+			return e.Bool("k", fixtures.Bools[0])
+		},
+		"Bools": func() *Event {
+			return e.Bools("k", fixtures.Bools)
+		},
+		"Fields": func() *Event {
+			return e.Fields(fixtures)
+		},
+		"Int": func() *Event {
+			return e.Int("k", fixtures.Ints[0])
+		},
+		"Ints": func() *Event {
+			return e.Ints("k", fixtures.Ints)
+		},
+		"Int8": func() *Event {
+			return e.Int8("k", fixtures.Ints8[0])
+		},
+		"Ints8": func() *Event {
+			return e.Ints8("k", fixtures.Ints8)
+		},
+		"Int16": func() *Event {
+			return e.Int16("k", fixtures.Ints16[0])
+		},
+		"Ints16": func() *Event {
+			return e.Ints16("k", fixtures.Ints16)
+		},
+		"Int32": func() *Event {
+			return e.Int32("k", fixtures.Ints32[0])
+		},
+		"Ints32": func() *Event {
+			return e.Ints32("k", fixtures.Ints32)
+		},
+		"Int64": func() *Event {
+			return e.Int64("k", fixtures.Ints64[0])
+		},
+		"Ints64": func() *Event {
+			return e.Ints64("k", fixtures.Ints64)
+		},
+		"Uint": func() *Event {
+			return e.Uint("k", fixtures.Uints[0])
+		},
+		"Uints": func() *Event {
+			return e.Uints("k", fixtures.Uints)
+		},
+		"Uint8": func() *Event {
+			return e.Uint8("k", fixtures.Uints8[0])
+		},
+		"Uints8": func() *Event {
+			return e.Uints8("k", fixtures.Uints8)
+		},
+		"Uint16": func() *Event {
+			return e.Uint16("k", fixtures.Uints16[0])
+		},
+		"Uints16": func() *Event {
+			return e.Uints16("k", fixtures.Uints16)
+		},
+		"Uint32": func() *Event {
+			return e.Uint32("k", fixtures.Uints32[0])
+		},
+		"Uints32": func() *Event {
+			return e.Uints32("k", fixtures.Uints32)
+		},
+		"Uint64": func() *Event {
+			return e.Uint64("k", fixtures.Uints64[0])
+		},
+		"Uints64": func() *Event {
+			return e.Uints64("k", fixtures.Uints64)
+		},
+		"Float64": func() *Event {
+			return e.Float64("k", fixtures.Floats64[0])
+		},
+		"Floats64": func() *Event {
+			return e.Floats64("k", fixtures.Floats64)
+		},
+		"Float32": func() *Event {
+			return e.Float32("k", fixtures.Floats32[0])
+		},
+		"Floats32": func() *Event {
+			return e.Floats32("k", fixtures.Floats32)
+		},
+		"RawCBOR": func() *Event {
+			return e.RawCBOR("k", fixtures.RawCBOR)
+		},
+		"RawJSON": func() *Event {
+			return e.RawJSON("k", fixtures.RawJSONs[0])
+		},
+		"Str": func() *Event {
+			return e.Str("k", fixtures.Strings[0])
+		},
+		"Strs": func() *Event {
+			return e.Strs("k", fixtures.Strings)
+		},
+		"StrsV": func() *Event {
+			return e.StrsV("k", fixtures.Strings...)
+		},
+		"Stringers": func() *Event {
+			return e.Stringers("k", fixtures.Stringers)
+		},
+		"StringersV": func() *Event {
+			return e.StringersV("k", fixtures.Stringers...)
+		},
+		"Err": func() *Event {
+			return e.Err(fixtures.Errs[0])
+		},
+		"Errs": func() *Event {
+			return e.Errs("k", fixtures.Errs)
+		},
+		"Ctx": func() *Event {
+			return e.Ctx(fixtures.Ctx)
+		},
+		"Time": func() *Event {
+			return e.Time("k", fixtures.Times[0])
+		},
+		"Times": func() *Event {
+			return e.Times("k", fixtures.Times)
+		},
+		"Dict": func() *Event {
+			d := e.CreateDict()
+			d.Str("greeting", "hello")
+			return e.Dict("k", d)
+		},
+		"Dur": func() *Event {
+			return e.Dur("k", fixtures.Durations[0])
+		},
+		"Durs": func() *Event {
+			return e.Durs("k", fixtures.Durations)
+		},
+		"Interface": func() *Event {
+			return e.Interface("k", fixtures.Interfaces[0])
+		},
+		"Interfaces": func() *Event {
+			return e.Interface("k", fixtures.Interfaces)
+		},
+		"Interface(Object)": func() *Event {
+			return e.Interface("k", fixtures.Objects[0])
+		},
+		"Interface(Objects)": func() *Event {
+			return e.Interface("k", fixtures.Objects)
+		},
+		"Object": func() *Event {
+			return e.Object("k", fixtures.Objects[0])
+		},
+		"Objects": func() *Event {
+			return e.Objects("k", fixtures.Objects)
+		},
+		"ObjectsV": func() *Event {
+			return e.ObjectsV("k", fixtures.Objects...)
+		},
+		"EmbedObject": func() *Event {
+			return e.EmbedObject(fixtures.Objects[0])
+		},
+		"Timestamp": func() *Event {
+			return e.Timestamp()
+		},
+		"IPAddr": func() *Event {
+			return e.IPAddr("k", fixtures.IPAddrs[0])
+		},
+		"IPAddrs": func() *Event {
+			return e.IPAddrs("k", fixtures.IPAddrs)
+		},
+		"IPPrefix": func() *Event {
+			return e.IPPrefix("k", fixtures.IPPfxs[0])
+		},
+		"IPPrefixes": func() *Event {
+			return e.IPPrefixes("k", fixtures.IPPfxs)
+		},
+		"MACAddr": func() *Event {
+			return e.MACAddr("k", fixtures.MACAddr)
+		},
+		"Type": func() *Event {
+			return e.Type("k", fixtures.Type)
+		},
+		"Caller": func() *Event {
+			return e.Caller(1)
+		},
+		"CallerSkip": func() *Event {
+			return e.CallerSkipFrame(2)
+		},
+		"Stack": func() *Event {
+			return e.Stack()
+		},
+	}
+
+	for name := range types {
+		f := types[name]
+		if got := f(); got != nil {
+			t.Errorf("Event.Bool() = %v, want %v", got, nil)
+		}
+	}
+
+	e.Send()
+	e.Msg("nothing")
+	e.Msgf("what %s", "nothing")
+
+	got := e.write()
+	if got != nil {
+		t.Errorf("Event.write() = %v, want %v", got, e)
+	}
+
+	called := false
+	e.MsgFunc(func() string {
+		called = true
+		return "called"
+	})
+	if called {
+		t.Errorf("Event.MsgFunc() should not be called on nil Event")
+	}
+}
+
+func TestEvent_MsgFunc(t *testing.T) {
+	var buf bytes.Buffer
+	e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, false, nil, nil)
+
+	called := false
+	e.MsgFunc(func() string {
+		called = true
+		return "called"
+	})
+	if !called {
+		t.Errorf("Event.MsgFunc() was not called on non-nil Event")
+	}
+
+	want := `{"message":"called"}`
+	got := strings.TrimSpace(buf.String())
+	if got != want {
+		t.Errorf("Event.MsgFunc() = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_CallerRuntimeFail(t *testing.T) {
+	var buf bytes.Buffer
+	e := newEvent(LevelWriterAdapter{&buf}, DebugLevel, false, nil, nil)
+
+	// Set a very large skipFrame to make runtime.Caller fail
+	e.CallerSkipFrame(1000)
+	e.Caller()
+
+	e.Msg("test")
+
+	got := strings.TrimSpace(buf.String())
+	want := `{"message":"test"}` // No caller field because runtime.Caller failed
+	if got != want {
+		t.Errorf("Event.Caller() with failed runtime.Caller = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_DoneHandler(t *testing.T) {
+	e := newEvent(nil, InfoLevel, false, nil, nil)
+
+	// Set up a done handler to capture calls
+	var called bool
+	var capturedMsg string
+	e.done = func(msg string) {
+		called = true
+		capturedMsg = msg
+	}
+
+	// Trigger msg via Msg
+	e.Msg("test message")
+
+	// Assert the handler was called with the correct message
+	if !called {
+		t.Error("Done handler was not called")
+	}
+	if capturedMsg != "test message" {
+		t.Errorf("Expected message 'test message', got '%s'", capturedMsg)
+	}
+}
+
+type badLevelWriter struct {
+	err error
+}
+
+func (w *badLevelWriter) WriteLevel(level Level, p []byte) (n int, err error) {
+	return 0, w.err
+}
+
+func (w *badLevelWriter) Write(p []byte) (n int, err error) {
+	return 0, w.err
+}
+
+func TestEvent_Msg_ErrorHandlerNil(t *testing.T) {
+	// Save original ErrorHandler and restore after test
+	originalErrorHandler := ErrorHandler
+	ErrorHandler = nil
+	defer func() { ErrorHandler = originalErrorHandler }()
+
+	// Create a LevelWriter that always returns an error
+	mockWriter := &badLevelWriter{err: errors.New("write error")}
+
+	e := newEvent(mockWriter, InfoLevel, false, nil, nil)
+	if e == nil {
+		t.Fatal("Event should not be nil")
+	}
+
+	// Capture stderr
+	oldStderr := os.Stderr
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	os.Stderr = w
+
+	// Call Msg to trigger write error
+	e.Msg("test message")
+
+	// Restore stderr and read captured output
+	w.Close()
+	os.Stderr = oldStderr
+	captured, err := io.ReadAll(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Assert the error message was printed to stderr
+	expected := "zerolog: could not write event: write error\n"
+	if string(captured) != expected {
+		t.Errorf("Expected stderr output %q, got %q", expected, string(captured))
+	}
+}
+
+type mockLogObjectMarshaler struct {
+	data string
+}
+
+func (m mockLogObjectMarshaler) MarshalZerologObject(e *Event) {
+	e.Str("stack_func", m.data)
+}
+
+func TestEvent_ErrWithStackMarshaler(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler
+	ErrorStackMarshaler = func(err error) interface{} {
+		return "stack-trace"
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Err(err).Msg("test message")
+
+	got := buf.String()
+	want := `{"stack":"stack-trace","error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Err() with stack marshaler = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_FieldsWithErrorAndStackMarshaler(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler
+	ErrorStackMarshaler = func(err error) interface{} {
+		return "stack-trace"
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Fields([]interface{}{"error", err}).Msg("test message")
+
+	got := buf.String()
+	want := `{"error":"test error","stack":"stack-trace","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Fields() with error and stack marshaler = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_FieldsWithErrorAndStackMarshalerObject(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns LogObjectMarshaler
+	ErrorStackMarshaler = func(err error) interface{} {
+		return mockLogObjectMarshaler{data: "stack-data"}
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Fields([]interface{}{"error", err}).Msg("test message")
+
+	got := buf.String()
+	want := `{"error":"test error","stack":{"stack_func":"stack-data"},"message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Fields() with error and stack marshaler object = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_FieldsWithErrorAndStackMarshalerError(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns an error
+	ErrorStackMarshaler = func(err error) interface{} {
+		return errors.New("stack error")
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Fields([]interface{}{"error", err}).Msg("test message")
+
+	got := buf.String()
+	want := `{"error":"test error","stack":"stack error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Fields() with error and stack marshaler error = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_FieldsWithErrorAndStackMarshalerInterface(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns an int
+	ErrorStackMarshaler = func(err error) interface{} {
+		return 42
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Fields([]interface{}{"error", err}).Msg("test message")
+
+	got := buf.String()
+	want := `{"error":"test error","stack":42,"message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Fields() with error and stack marshaler interface = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_FieldsWithErrorAndStackMarshalerNil(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set marshaler to return nil
+	ErrorStackMarshaler = func(err error) interface{} {
+		return nil
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Fields([]interface{}{"error", err}).Msg("test message")
+
+	got := buf.String()
+	want := `{"error":"test error","message":"test message"}` + "\n" // No stack field because marshaler returned nil
+	if got != want {
+		t.Errorf("Event.Fields() with error and nil stack marshaler = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_ErrWithStackMarshalerObject(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns LogObjectMarshaler
+	ErrorStackMarshaler = func(err error) interface{} {
+		return mockLogObjectMarshaler{data: "stack-data"}
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Err(err).Msg("test message")
+
+	got := buf.String()
+	want := `{"stack":{"stack_func":"stack-data"},"error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Err() with stack marshaler object = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_ErrWithStackMarshalerError(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns an error
+	ErrorStackMarshaler = func(err error) interface{} {
+		return errors.New("stack error")
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Err(err).Msg("test message")
+
+	got := buf.String()
+	want := `{"stack":"stack error","error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Err() with stack marshaler error = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_ErrWithStackMarshalerInterface(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set a mock marshaler that returns an int
+	ErrorStackMarshaler = func(err error) interface{} {
+		return 42
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Err(err).Msg("test message")
+
+	got := buf.String()
+	want := `{"stack":42,"error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Err() with stack marshaler interface = %q, want %q", got, want)
+	}
+}
+
+func TestEvent_ErrWithStackMarshalerNil(t *testing.T) {
+	// Save original
+	original := ErrorStackMarshaler
+	defer func() { ErrorStackMarshaler = original }()
+
+	// Set marshaler to return nil
+	ErrorStackMarshaler = func(err error) interface{} {
+		return nil
+	}
+
+	var buf bytes.Buffer
+	log := New(&buf)
+
+	err := errors.New("test error")
+	log.Log().Stack().Err(err).Msg("test message")
+
+	got := buf.String()
+	// When ErrorStackMarshaler returns nil (no stack trace available for this
+	// error), Err() must still log the error value via AnErr.  Without a stack
+	// field, the output is the same as if Stack() had not been called.
+	// Regression test for https://github.com/rs/zerolog/issues/762:
+	// commit f6fbd33 introduced a `case nil: return e` branch that silently
+	// swallowed the error instead of falling through to AnErr.
+	want := `{"error":"test error","message":"test message"}` + "\n"
+	if got != want {
+		t.Errorf("Event.Err() with nil stack marshaler = %q, want %q", got, want)
+	}
+}

example.jsonl

@@ -0,0 +1,7 @@
+{"time":"5:41PM","level":"info","message":"Starting listener","listen":":8080","pid":37556}
+{"time":"5:41PM","level":"debug","message":"Access","database":"myapp","host":"localhost:4962","pid":37556}
+{"time":"5:41PM","level":"info","message":"Access","method":"GET","path":"/users","pid":37556,"resp_time":23}
+{"time":"5:41PM","level":"info","message":"Access","method":"POST","path":"/posts","pid":37556,"resp_time":532}
+{"time":"5:41PM","level":"warn","message":"Slow request","method":"POST","path":"/posts","pid":37556,"resp_time":532}
+{"time":"5:41PM","level":"info","message":"Access","method":"GET","path":"/users","pid":37556,"resp_time":10}
+{"time":"5:41PM","level":"error","message":"Database connection lost","database":"myapp","pid":37556,"error":"connection reset by peer"}

fields.go

@@ -1,95 +1,311 @@
 package zerolog
 
 import (
+	"context"
+	"encoding/json"
+	"io"
+	"net"
+	"reflect"
 	"sort"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
-func appendFields(dst []byte, fields map[string]interface{}) []byte {
-	keys := make([]string, 0, len(fields))
-	for key := range fields {
-		keys = append(keys, key)
+func isNilValue(e error) bool {
+	switch reflect.TypeOf(e).Kind() {
+	case reflect.Ptr:
+		return reflect.ValueOf(e).IsNil()
+	default:
+		return false
 	}
-	sort.Strings(keys)
-	for _, key := range keys {
-		dst = json.AppendKey(dst, key)
-		switch val := fields[key].(type) {
-		case string:
-			dst = json.AppendString(dst, val)
-		case []byte:
-			dst = json.AppendBytes(dst, val)
-		case error:
-			dst = json.AppendError(dst, val)
-		case []error:
-			dst = json.AppendErrors(dst, val)
-		case bool:
-			dst = json.AppendBool(dst, val)
-		case int:
-			dst = json.AppendInt(dst, val)
-		case int8:
-			dst = json.AppendInt8(dst, val)
-		case int16:
-			dst = json.AppendInt16(dst, val)
-		case int32:
-			dst = json.AppendInt32(dst, val)
-		case int64:
-			dst = json.AppendInt64(dst, val)
-		case uint:
-			dst = json.AppendUint(dst, val)
-		case uint8:
-			dst = json.AppendUint8(dst, val)
-		case uint16:
-			dst = json.AppendUint16(dst, val)
-		case uint32:
-			dst = json.AppendUint32(dst, val)
-		case uint64:
-			dst = json.AppendUint64(dst, val)
-		case float32:
-			dst = json.AppendFloat32(dst, val)
-		case float64:
-			dst = json.AppendFloat64(dst, val)
-		case time.Time:
-			dst = json.AppendTime(dst, val, TimeFieldFormat)
-		case time.Duration:
-			dst = json.AppendDuration(dst, val, DurationFieldUnit, DurationFieldInteger)
-		case []string:
-			dst = json.AppendStrings(dst, val)
-		case []bool:
-			dst = json.AppendBools(dst, val)
-		case []int:
-			dst = json.AppendInts(dst, val)
-		case []int8:
-			dst = json.AppendInts8(dst, val)
-		case []int16:
-			dst = json.AppendInts16(dst, val)
-		case []int32:
-			dst = json.AppendInts32(dst, val)
-		case []int64:
-			dst = json.AppendInts64(dst, val)
-		case []uint:
-			dst = json.AppendUints(dst, val)
-		// case []uint8:
-		// 	dst = appendUints8(dst, val)
-		case []uint16:
-			dst = json.AppendUints16(dst, val)
-		case []uint32:
-			dst = json.AppendUints32(dst, val)
-		case []uint64:
-			dst = json.AppendUints64(dst, val)
-		case []float32:
-			dst = json.AppendFloats32(dst, val)
-		case []float64:
-			dst = json.AppendFloats64(dst, val)
-		case []time.Time:
-			dst = json.AppendTimes(dst, val, TimeFieldFormat)
-		case []time.Duration:
-			dst = json.AppendDurations(dst, val, DurationFieldUnit, DurationFieldInteger)
-		case nil:
-			dst = append(dst, "null"...)
-		default:
-			dst = json.AppendInterface(dst, val)
+}
+
+func appendFields(dst []byte, fields interface{}, stack bool, ctx context.Context, hooks []Hook) []byte {
+	switch fields := fields.(type) {
+	case []interface{}:
+		if n := len(fields); n&0x1 == 1 { // odd number
+			fields = fields[:n-1]
+		}
+		dst = appendFieldList(dst, fields, stack, ctx, hooks)
+	case map[string]interface{}:
+		keys := make([]string, 0, len(fields))
+		for key := range fields {
+			keys = append(keys, key)
+		}
+		sort.Strings(keys)
+		kv := make([]interface{}, 2)
+		for _, key := range keys {
+			kv[0], kv[1] = key, fields[key]
+			dst = appendFieldList(dst, kv, stack, ctx, hooks)
+		}
+	}
+	return dst
+}
+
+func appendObject(dst []byte, obj LogObjectMarshaler, stack bool, ctx context.Context, hooks []Hook) []byte {
+	e := newEvent(LevelWriterAdapter{io.Discard}, DebugLevel, stack, ctx, hooks)
+	e.buf = e.buf[:0] // discard the beginning marker added by newEvent
+	e.appendObject(obj)
+	dst = append(dst, e.buf...)
+	putEvent(e)
+	return dst
+}
+
+func appendFieldList(dst []byte, kvList []interface{}, stack bool, ctx context.Context, hooks []Hook) []byte {
+	for i, n := 0, len(kvList); i < n; i += 2 {
+		key, val := kvList[i], kvList[i+1]
+		if key, ok := key.(string); ok {
+			dst = enc.AppendKey(dst, key)
+		} else {
+			continue
+		}
+		switch val := val.(type) {
+		case string:
+			dst = enc.AppendString(dst, val)
+		case []byte:
+			dst = enc.AppendBytes(dst, val)
+		case error:
+			switch m := ErrorMarshalFunc(val).(type) {
+			case nil:
+				dst = enc.AppendNil(dst)
+			case LogObjectMarshaler:
+				dst = appendObject(dst, m, stack, ctx, hooks)
+			case error:
+				if !isNilValue(m) {
+					dst = enc.AppendString(dst, m.Error())
+				}
+			case string:
+				dst = enc.AppendString(dst, m)
+			default:
+				dst = enc.AppendInterface(dst, m)
+			}
+
+			if stack && ErrorStackMarshaler != nil {
+				switch m := ErrorStackMarshaler(val).(type) {
+				case nil:
+					return dst // do nothing with nil errors
+				case LogObjectMarshaler:
+					dst = enc.AppendKey(dst, ErrorStackFieldName)
+					dst = appendObject(dst, m, stack, ctx, hooks)
+				case error:
+					dst = enc.AppendKey(dst, ErrorStackFieldName)
+					dst = enc.AppendString(dst, m.Error())
+				case string:
+					dst = enc.AppendKey(dst, ErrorStackFieldName)
+					dst = enc.AppendString(dst, m)
+				default:
+					dst = enc.AppendKey(dst, ErrorStackFieldName)
+					dst = enc.AppendInterface(dst, m)
+				}
+			}
+		case []error:
+			dst = enc.AppendArrayStart(dst)
+			for i, err := range val {
+				switch m := ErrorMarshalFunc(err).(type) {
+				case nil:
+					dst = enc.AppendNil(dst)
+				case LogObjectMarshaler:
+					dst = appendObject(dst, m, stack, ctx, hooks)
+				case error:
+					if !isNilValue(m) {
+						dst = enc.AppendString(dst, m.Error())
+					}
+				case string:
+					dst = enc.AppendString(dst, m)
+				default:
+					dst = enc.AppendInterface(dst, m)
+				}
+
+				if i < (len(val) - 1) {
+					dst = enc.AppendArrayDelim(dst)
+				}
+			}
+			dst = enc.AppendArrayEnd(dst)
+		case []LogObjectMarshaler:
+			dst = enc.AppendArrayStart(dst)
+			for i, obj := range val {
+				dst = appendObject(dst, obj, stack, ctx, hooks)
+				if i < (len(val) - 1) {
+					dst = enc.AppendArrayDelim(dst)
+				}
+			}
+			dst = enc.AppendArrayEnd(dst)
+		case bool:
+			dst = enc.AppendBool(dst, val)
+		case int:
+			dst = enc.AppendInt(dst, val)
+		case int8:
+			dst = enc.AppendInt8(dst, val)
+		case int16:
+			dst = enc.AppendInt16(dst, val)
+		case int32:
+			dst = enc.AppendInt32(dst, val)
+		case int64:
+			dst = enc.AppendInt64(dst, val)
+		case uint:
+			dst = enc.AppendUint(dst, val)
+		case uint8:
+			dst = enc.AppendUint8(dst, val)
+		case uint16:
+			dst = enc.AppendUint16(dst, val)
+		case uint32:
+			dst = enc.AppendUint32(dst, val)
+		case uint64:
+			dst = enc.AppendUint64(dst, val)
+		case float32:
+			dst = enc.AppendFloat32(dst, val, FloatingPointPrecision)
+		case float64:
+			dst = enc.AppendFloat64(dst, val, FloatingPointPrecision)
+		case time.Time:
+			dst = enc.AppendTime(dst, val, TimeFieldFormat)
+		case time.Duration:
+			dst = enc.AppendDuration(dst, val, DurationFieldUnit, DurationFieldFormat, DurationFieldInteger, FloatingPointPrecision)
+		case *string:
+			if val != nil {
+				dst = enc.AppendString(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *bool:
+			if val != nil {
+				dst = enc.AppendBool(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *int:
+			if val != nil {
+				dst = enc.AppendInt(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *int8:
+			if val != nil {
+				dst = enc.AppendInt8(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *int16:
+			if val != nil {
+				dst = enc.AppendInt16(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *int32:
+			if val != nil {
+				dst = enc.AppendInt32(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *int64:
+			if val != nil {
+				dst = enc.AppendInt64(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *uint:
+			if val != nil {
+				dst = enc.AppendUint(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *uint8:
+			if val != nil {
+				dst = enc.AppendUint8(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *uint16:
+			if val != nil {
+				dst = enc.AppendUint16(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *uint32:
+			if val != nil {
+				dst = enc.AppendUint32(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *uint64:
+			if val != nil {
+				dst = enc.AppendUint64(dst, *val)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *float32:
+			if val != nil {
+				dst = enc.AppendFloat32(dst, *val, FloatingPointPrecision)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *float64:
+			if val != nil {
+				dst = enc.AppendFloat64(dst, *val, FloatingPointPrecision)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *time.Time:
+			if val != nil {
+				dst = enc.AppendTime(dst, *val, TimeFieldFormat)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case *time.Duration:
+			if val != nil {
+				dst = enc.AppendDuration(dst, *val, DurationFieldUnit, DurationFieldFormat, DurationFieldInteger, FloatingPointPrecision)
+			} else {
+				dst = enc.AppendNil(dst)
+			}
+		case []string:
+			dst = enc.AppendStrings(dst, val)
+		case []bool:
+			dst = enc.AppendBools(dst, val)
+		case []int:
+			dst = enc.AppendInts(dst, val)
+		case []int8:
+			dst = enc.AppendInts8(dst, val)
+		case []int16:
+			dst = enc.AppendInts16(dst, val)
+		case []int32:
+			dst = enc.AppendInts32(dst, val)
+		case []int64:
+			dst = enc.AppendInts64(dst, val)
+		case []uint:
+			dst = enc.AppendUints(dst, val)
+		// case []uint8: is handled as []byte above
+		case []uint16:
+			dst = enc.AppendUints16(dst, val)
+		case []uint32:
+			dst = enc.AppendUints32(dst, val)
+		case []uint64:
+			dst = enc.AppendUints64(dst, val)
+		case []float32:
+			dst = enc.AppendFloats32(dst, val, FloatingPointPrecision)
+		case []float64:
+			dst = enc.AppendFloats64(dst, val, FloatingPointPrecision)
+		case []time.Time:
+			dst = enc.AppendTimes(dst, val, TimeFieldFormat)
+		case []time.Duration:
+			dst = enc.AppendDurations(dst, val, DurationFieldUnit, DurationFieldFormat, DurationFieldInteger, FloatingPointPrecision)
+		case nil:
+			dst = enc.AppendNil(dst)
+		case net.IP:
+			dst = enc.AppendIPAddr(dst, val)
+		case []net.IP:
+			dst = enc.AppendIPAddrs(dst, val)
+		case net.IPNet:
+			dst = enc.AppendIPPrefix(dst, val)
+		case []net.IPNet:
+			dst = enc.AppendIPPrefixes(dst, val)
+		case net.HardwareAddr:
+			dst = enc.AppendMACAddr(dst, val)
+		case json.RawMessage:
+			dst = appendJSON(dst, val)
+		default:
+			if lom, ok := val.(LogObjectMarshaler); ok {
+				dst = appendObject(dst, lom, stack, ctx, hooks)
+			} else {
+				dst = enc.AppendInterface(dst, val)
+			}
 		}
 	}
 	return dst

fixtures_test.go

@@ -0,0 +1,159 @@
+package zerolog
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"reflect"
+	"time"
+)
+
+type fixtureObj struct {
+	Pub  string
+	Tag  string `json:"tag"`
+	priv int
+}
+
+func (o fixtureObj) MarshalZerologObject(e *Event) {
+	e.Str("Pub", o.Pub).
+		Str("Tag", o.Tag).
+		Int("priv", o.priv)
+}
+
+type fieldFixtures struct {
+	Bools      []bool
+	Bytes      []byte
+	Ctx        context.Context
+	Durations  []time.Duration
+	Errs       []error
+	Floats32   []float32
+	Floats64   []float64
+	Interfaces []struct {
+		Pub  string
+		Tag  string `json:"tag"`
+		priv int
+	}
+	Ints      []int
+	Ints8     []int8
+	Ints16    []int16
+	Ints32    []int32
+	Ints64    []int64
+	Uints     []uint
+	Uints8    []uint8
+	Uints16   []uint16
+	Uints32   []uint32
+	Uints64   []uint64
+	IPAddrs   []net.IP
+	IPPfxs    []net.IPNet
+	MACAddr   net.HardwareAddr
+	Objects   []LogObjectMarshaler
+	RawCBOR   []byte
+	RawJSONs  [][]byte
+	Stringers []fmt.Stringer
+	Strings   []string
+	Times     []time.Time
+	Type      reflect.Type
+}
+
+func makeFieldFixtures() *fieldFixtures {
+	bools := []bool{true, false, true, false, true, false, true, false, true, false}
+	bytes := []byte(`abcdef`)
+	ints := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	ints8 := []int8{-8, 8}
+	ints16 := []int16{-16, 16}
+	ints32 := []int32{-32, 32}
+	ints64 := []int64{-64, 64}
+	uints := []uint{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	uints8 := []uint8{8, uint8(^uint8(0))}
+	uints16 := []uint16{16, uint16(^uint16(0))}
+	uints32 := []uint32{32, uint32(^uint32(0))}
+	uints64 := []uint64{64, uint64(^uint64(0))}
+	floats32 := []float32{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	floats64 := []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	strings := []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j"}
+	durations := []time.Duration{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	times := []time.Time{
+		time.Unix(0, 0),
+		time.Unix(1, 0),
+		time.Unix(2, 0),
+		time.Unix(3, 0),
+		time.Unix(4, 0),
+		time.Unix(5, 0),
+		time.Unix(6, 0),
+		time.Unix(7, 0),
+		time.Unix(8, 0),
+		time.Unix(9, 0),
+	}
+	interfaces := []struct {
+		Pub  string
+		Tag  string `json:"tag"`
+		priv int
+	}{
+		{"A", "j", -5},
+		{"B", "i", -4},
+		{"C", "h", -3},
+		{"D", "g", -2},
+		{"E", "f", -1},
+		{"F", "e", 0},
+		{"G", "d", 1},
+		{"H", "c", 2},
+		{"I", "b", 3},
+		{"J", "a", 4},
+	}
+	objects := []LogObjectMarshaler{
+		fixtureObj{"a", "z", 1},
+		fixtureObj{"b", "y", 2},
+		fixtureObj{"c", "x", 3},
+		fixtureObj{"d", "w", 4},
+		fixtureObj{"e", "v", 5},
+		fixtureObj{"f", "u", 6},
+		fixtureObj{"g", "t", 7},
+		fixtureObj{"h", "s", 8},
+		fixtureObj{"i", "r", 9},
+		fixtureObj{"j", "q", 10},
+	}
+	ipAddrV4 := net.IP{192, 168, 0, 1}
+	ipAddrV6 := net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34}
+	ipAddrs := []net.IP{ipAddrV4, ipAddrV6, ipAddrV4, ipAddrV6, ipAddrV4, ipAddrV6, ipAddrV4, ipAddrV6, ipAddrV4, ipAddrV6}
+	ipPfxV4 := net.IPNet{IP: net.IP{192, 168, 0, 0}, Mask: net.CIDRMask(24, 32)}
+	ipPfxV6 := net.IPNet{IP: net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x00}, Mask: net.CIDRMask(64, 128)}
+	ipPfxs := []net.IPNet{ipPfxV4, ipPfxV6, ipPfxV4, ipPfxV6, ipPfxV4, ipPfxV6, ipPfxV4, ipPfxV6, ipPfxV4, ipPfxV6}
+	macAddr := net.HardwareAddr{0x00, 0x1A, 0x2B, 0x3C, 0x4D, 0x5E}
+	errs := []error{errors.New("a"), errors.New("b"), errors.New("c"), errors.New("d"), errors.New("e"), nil, loggableError{fmt.Errorf("oops")}}
+	ctx := context.Background()
+	stringers := []fmt.Stringer{ipAddrs[0], durations[0]}
+	rawJSONs := [][]byte{[]byte(`{"some":"json"}`), []byte(`{"longer":[1111,2222,3333,4444,5555]}`)}
+	rawCBOR := []byte{0xA1, 0x64, 0x73, 0x6F, 0x6D, 0x65, 0x64, 0x61, 0x74, 0x61} // {"some":"data"}
+
+	return &fieldFixtures{
+		Bools:      bools,
+		Bytes:      bytes,
+		Ctx:        ctx,
+		Durations:  durations,
+		Errs:       errs,
+		Floats32:   floats32,
+		Floats64:   floats64,
+		Interfaces: interfaces,
+		Ints:       ints,
+		Ints8:      ints8,
+		Ints16:     ints16,
+		Ints32:     ints32,
+		Ints64:     ints64,
+		Uints:      uints,
+		Uints8:     uints8,
+		Uints16:    uints16,
+		Uints32:    uints32,
+		Uints64:    uints64,
+		IPAddrs:    ipAddrs,
+		IPPfxs:     ipPfxs,
+		MACAddr:    macAddr,
+		Objects:    objects,
+		RawCBOR:    rawCBOR,
+		RawJSONs:   rawJSONs,
+		Stringers:  stringers,
+		Strings:    strings,
+		Times:      times,
+		Type:       reflect.TypeOf(12345),
+	}
+}

globals.go

@@ -1,7 +1,40 @@
 package zerolog
 
-import "time"
-import "sync/atomic"
+import (
+	"bytes"
+	"encoding/json"
+	"strconv"
+	"sync/atomic"
+	"time"
+)
+
+const (
+	// TimeFormatUnix defines a time format that makes time fields to be
+	// serialized as Unix timestamp integers.
+	TimeFormatUnix = ""
+
+	// TimeFormatUnixMs defines a time format that makes time fields to be
+	// serialized as Unix timestamp integers in milliseconds.
+	TimeFormatUnixMs = "UNIXMS"
+
+	// TimeFormatUnixMicro defines a time format that makes time fields to be
+	// serialized as Unix timestamp integers in microseconds.
+	TimeFormatUnixMicro = "UNIXMICRO"
+
+	// TimeFormatUnixNano defines a time format that makes time fields to be
+	// serialized as Unix timestamp integers in nanoseconds.
+	TimeFormatUnixNano = "UNIXNANO"
+
+	// DurationFormatFloat defines a format for Duration fields that makes duration fields to be
+	// serialized as floating point numbers.
+	DurationFormatFloat = "float"
+	// DurationFormatInt defines a format for Duration fields that makes duration fields to be
+	// serialized as integers.
+	DurationFormatInt = "int"
+	// DurationFormatString defines a format for Duration fields that makes duration fields to be
+	// serialized as string.
+	DurationFormatString = "string"
+)
 
 var (
 	// TimestampFieldName is the field name used for the timestamp field.
@@ -10,35 +43,142 @@ var (
 	// LevelFieldName is the field name used for the level field.
 	LevelFieldName = "level"
 
+	// LevelTraceValue is the value used for the trace level field.
+	LevelTraceValue = "trace"
+	// LevelDebugValue is the value used for the debug level field.
+	LevelDebugValue = "debug"
+	// LevelInfoValue is the value used for the info level field.
+	LevelInfoValue = "info"
+	// LevelWarnValue is the value used for the warn level field.
+	LevelWarnValue = "warn"
+	// LevelErrorValue is the value used for the error level field.
+	LevelErrorValue = "error"
+	// LevelFatalValue is the value used for the fatal level field.
+	LevelFatalValue = "fatal"
+	// LevelPanicValue is the value used for the panic level field.
+	LevelPanicValue = "panic"
+
+	// LevelFieldMarshalFunc allows customization of global level field marshaling.
+	LevelFieldMarshalFunc = func(l Level) string {
+		return l.String()
+	}
+
 	// MessageFieldName is the field name used for the message field.
 	MessageFieldName = "message"
 
 	// ErrorFieldName is the field name used for error fields.
 	ErrorFieldName = "error"
 
-	// SampleFieldName is the name of the field used to report sampling.
-	SampleFieldName = "sample"
+	// CallerFieldName is the field name used for caller field.
+	CallerFieldName = "caller"
 
-	// TimeFieldFormat defines the time format of the Time field type.
-	// If set to an empty string, the time is formatted as an UNIX timestamp
-	// as integer.
+	// CallerSkipFrameCount is the number of stack frames to skip to find the caller.
+	CallerSkipFrameCount = 2
+
+	// CallerMarshalFunc allows customization of global caller marshaling
+	CallerMarshalFunc = func(pc uintptr, file string, line int) string {
+		return file + ":" + strconv.Itoa(line)
+	}
+
+	// ErrorStackFieldName is the field name used for error stacks.
+	ErrorStackFieldName = "stack"
+
+	// ErrorStackMarshaler extract the stack from err if any.
+	ErrorStackMarshaler func(err error) interface{}
+
+	// ErrorMarshalFunc allows customization of global error marshaling
+	ErrorMarshalFunc = func(err error) interface{} {
+		return err
+	}
+
+	// InterfaceMarshalFunc allows customization of interface marshaling.
+	// Default: "encoding/json.Marshal" with disabled HTML escaping
+	InterfaceMarshalFunc = func(v interface{}) ([]byte, error) {
+		var buf bytes.Buffer
+		encoder := json.NewEncoder(&buf)
+		encoder.SetEscapeHTML(false)
+		err := encoder.Encode(v)
+		if err != nil {
+			return nil, err
+		}
+		b := buf.Bytes()
+		if len(b) > 0 {
+			// Remove trailing \n which is added by Encode.
+			return b[:len(b)-1], nil
+		}
+		return b, nil
+	}
+
+	// TimeFieldFormat defines the time format of the Time field type. If set to
+	// TimeFormatUnix, TimeFormatUnixMs, TimeFormatUnixMicro or TimeFormatUnixNano, the time is formatted as a UNIX
+	// timestamp as integer.
 	TimeFieldFormat = time.RFC3339
 
 	// TimestampFunc defines the function called to generate a timestamp.
 	TimestampFunc = time.Now
 
+	// DurationFieldFormat defines the format of the Duration field type.
+	DurationFieldFormat = DurationFormatFloat
+
 	// DurationFieldUnit defines the unit for time.Duration type fields added
 	// using the Dur method.
 	DurationFieldUnit = time.Millisecond
 
 	// DurationFieldInteger renders Dur fields as integer instead of float if
 	// set to true.
+	// Deprecated: use DurationFieldFormat with DurationFormatInt instead.
 	DurationFieldInteger = false
+
+	// ErrorHandler is called whenever zerolog fails to write an event on its
+	// output. If not set, an error is printed on the stderr. This handler must
+	// be thread safe and non-blocking.
+	ErrorHandler func(err error)
+
+	// FatalExitFunc is called by log.Fatal() instead of os.Exit(1). If not set,
+	// os.Exit(1) is called.
+	FatalExitFunc func()
+
+	// DefaultContextLogger is returned from Ctx() if there is no logger associated
+	// with the context.
+	DefaultContextLogger *Logger
+
+	// LevelColors are used by ConsoleWriter's consoleDefaultFormatLevel to color
+	// log levels.
+	LevelColors = map[Level]int{
+		TraceLevel: colorBlue,
+		DebugLevel: 0,
+		InfoLevel:  colorGreen,
+		WarnLevel:  colorYellow,
+		ErrorLevel: colorRed,
+		FatalLevel: colorRed,
+		PanicLevel: colorRed,
+	}
+
+	// FormattedLevels are used by ConsoleWriter's consoleDefaultFormatLevel
+	// for a short level name.
+	FormattedLevels = map[Level]string{
+		TraceLevel: "TRC",
+		DebugLevel: "DBG",
+		InfoLevel:  "INF",
+		WarnLevel:  "WRN",
+		ErrorLevel: "ERR",
+		FatalLevel: "FTL",
+		PanicLevel: "PNC",
+	}
+
+	// TriggerLevelWriterBufferReuseLimit is a limit in bytes that a buffer is dropped
+	// from the TriggerLevelWriter buffer pool if the buffer grows above the limit.
+	TriggerLevelWriterBufferReuseLimit = 64 * 1024
+
+	// FloatingPointPrecision, if set to a value other than -1, controls the number
+	// of digits when formatting float numbers in JSON. See strconv.FormatFloat for
+	// more details.
+	FloatingPointPrecision = -1
 )
 
 var (
-	gLevel          = new(uint32)
-	disableSampling = new(uint32)
+	gLevel          = new(int32)
+	disableSampling = new(int32)
 )
 
 // SetGlobalLevel sets the global override for log level. If this
@@ -46,22 +186,23 @@ var (
 //
 // To globally disable logs, set GlobalLevel to Disabled.
 func SetGlobalLevel(l Level) {
-	atomic.StoreUint32(gLevel, uint32(l))
+	atomic.StoreInt32(gLevel, int32(l))
 }
 
-func globalLevel() Level {
-	return Level(atomic.LoadUint32(gLevel))
+// GlobalLevel returns the current global log level
+func GlobalLevel() Level {
+	return Level(atomic.LoadInt32(gLevel))
 }
 
 // DisableSampling will disable sampling in all Loggers if true.
 func DisableSampling(v bool) {
-	var i uint32
+	var i int32
 	if v {
 		i = 1
 	}
-	atomic.StoreUint32(disableSampling, i)
+	atomic.StoreInt32(disableSampling, i)
 }
 
 func samplingDisabled() bool {
-	return atomic.LoadUint32(disableSampling) == 1
+	return atomic.LoadInt32(disableSampling) == 1
 }

globals_118.go

@@ -0,0 +1,30 @@
+//go:build go1.18
+// +build go1.18
+
+package zerolog
+
+import (
+	"fmt"
+)
+
+func AsLogObjectMarshalers[T LogObjectMarshaler](objs []T) []LogObjectMarshaler {
+	if objs == nil {
+		return nil
+	}
+	s := make([]LogObjectMarshaler, len(objs))
+	for i, v := range objs {
+		s[i] = v
+	}
+	return s
+}
+
+func AsStringers[T fmt.Stringer](objs []T) []fmt.Stringer {
+	if objs == nil {
+		return nil
+	}
+	s := make([]fmt.Stringer, len(objs))
+	for i, v := range objs {
+		s[i] = v
+	}
+	return s
+}

go.mod

@@ -0,0 +1,15 @@
+module github.com/rs/zerolog
+
+go 1.23
+
+require (
+	github.com/coreos/go-systemd/v22 v22.7.0
+	github.com/mattn/go-colorable v0.1.14
+	github.com/pkg/errors v0.9.1
+	github.com/rs/xid v1.6.0
+)
+
+require (
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	golang.org/x/sys v0.29.0 // indirect
+)

go.sum

@@ -0,0 +1,13 @@
+github.com/coreos/go-systemd/v22 v22.7.0 h1:LAEzFkke61DFROc7zNLX/WA2i5J8gYqe0rSj9KI28KA=
+github.com/coreos/go-systemd/v22 v22.7.0/go.mod h1:xNUYtjHu2EDXbsxz1i41wouACIwT7Ybq9o0BQhMwD0w=
+github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
+github.com/mattn/go-colorable v0.1.14/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/rs/xid v1.6.0 h1:fV591PaemRlL6JfRxGDEPl69wICngIQ3shQtzfy2gxU=
+github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

go112.go

@@ -0,0 +1,7 @@
+// +build go1.12
+
+package zerolog
+
+// Since go 1.12, some auto generated init functions are hidden from
+// runtime.Caller.
+const contextCallerSkipFrameCount = 2

hlog/hlog.go

@@ -5,17 +5,18 @@ import (
 	"context"
 	"net"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/rs/xid"
 	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/hlog/internal/mutil"
 	"github.com/rs/zerolog/log"
-	"github.com/zenazn/goji/web/mutil"
 )
 
 // FromRequest gets the logger in the request's context.
 // This is a shortcut for log.Ctx(r.Context())
-func FromRequest(r *http.Request) zerolog.Logger {
+func FromRequest(r *http.Request) *zerolog.Logger {
 	return log.Ctx(r.Context())
 }
 
@@ -23,7 +24,10 @@ func FromRequest(r *http.Request) zerolog.Logger {
 func NewHandler(log zerolog.Logger) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			r = r.WithContext(log.WithContext(r.Context()))
+			// Create a copy of the logger (including internal context slice)
+			// to prevent data race when using UpdateContext.
+			l := log.With().Logger()
+			r = r.WithContext(l.WithContext(r.Context()))
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -35,8 +39,9 @@ func URLHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			log := zerolog.Ctx(r.Context())
-			log = log.With().Str(fieldKey, r.URL.String()).Logger()
-			r = r.WithContext(log.WithContext(r.Context()))
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.URL.String())
+			})
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -48,8 +53,9 @@ func MethodHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			log := zerolog.Ctx(r.Context())
-			log = log.With().Str(fieldKey, r.Method).Logger()
-			r = r.WithContext(log.WithContext(r.Context()))
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.Method)
+			})
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -61,8 +67,9 @@ func RequestHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			log := zerolog.Ctx(r.Context())
-			log = log.With().Str(fieldKey, r.Method+" "+r.URL.String()).Logger()
-			r = r.WithContext(log.WithContext(r.Context()))
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.Method+" "+r.URL.String())
+			})
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -73,10 +80,40 @@ func RequestHandler(fieldKey string) func(next http.Handler) http.Handler {
 func RemoteAddrHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
+			if r.RemoteAddr != "" {
 				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, host).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, r.RemoteAddr)
+				})
+			}
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+func getHost(hostPort string) string {
+	if hostPort == "" {
+		return ""
+	}
+
+	host, _, err := net.SplitHostPort(hostPort)
+	if err != nil {
+		return hostPort
+	}
+	return host
+}
+
+// RemoteIPHandler is similar to RemoteAddrHandler, but logs only
+// an IP, not a port.
+func RemoteIPHandler(fieldKey string) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ip := getHost(r.RemoteAddr)
+			if ip != "" {
+				log := zerolog.Ctx(r.Context())
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, ip)
+				})
 			}
 			next.ServeHTTP(w, r)
 		})
@@ -90,8 +127,9 @@ func UserAgentHandler(fieldKey string) func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if ua := r.Header.Get("User-Agent"); ua != "" {
 				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, ua).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, ua)
+				})
 			}
 			next.ServeHTTP(w, r)
 		})
@@ -105,25 +143,65 @@ func RefererHandler(fieldKey string) func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if ref := r.Header.Get("Referer"); ref != "" {
 				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, ref).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, ref)
+				})
 			}
 			next.ServeHTTP(w, r)
 		})
 	}
 }
 
+// ProtoHandler adds the requests protocol version as a field to the context logger
+// using fieldKey as field Key.
+func ProtoHandler(fieldKey string) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			log := zerolog.Ctx(r.Context())
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.Proto)
+			})
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+// HTTPVersionHandler is similar to ProtoHandler, but it does not store the "HTTP/"
+// prefix in the protocol name.
+func HTTPVersionHandler(fieldKey string) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			proto := strings.TrimPrefix(r.Proto, "HTTP/")
+			log := zerolog.Ctx(r.Context())
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, proto)
+			})
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
 type idKey struct{}
 
-// IDFromRequest returns the unique id accociated to the request if any.
+// IDFromRequest returns the unique id associated to the request if any.
 func IDFromRequest(r *http.Request) (id xid.ID, ok bool) {
 	if r == nil {
 		return
 	}
-	id, ok = r.Context().Value(idKey{}).(xid.ID)
+	return IDFromCtx(r.Context())
+}
+
+// IDFromCtx returns the unique id associated to the context if any.
+func IDFromCtx(ctx context.Context) (id xid.ID, ok bool) {
+	id, ok = ctx.Value(idKey{}).(xid.ID)
 	return
 }
 
+// CtxWithID adds the given xid.ID to the context
+func CtxWithID(ctx context.Context, id xid.ID) context.Context {
+	return context.WithValue(ctx, idKey{}, id)
+}
+
 // RequestIDHandler returns a handler setting a unique id to the request which can
 // be gathered using IDFromRequest(req). This generated id is added as a field to the
 // logger using the passed fieldKey as field name. The id is also added as a response
@@ -136,16 +214,18 @@ func IDFromRequest(r *http.Request) (id xid.ID, ok bool) {
 func RequestIDHandler(fieldKey, headerName string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ctx := r.Context()
 			id, ok := IDFromRequest(r)
 			if !ok {
 				id = xid.New()
-				ctx := context.WithValue(r.Context(), idKey{}, id)
+				ctx = CtxWithID(ctx, id)
 				r = r.WithContext(ctx)
 			}
 			if fieldKey != "" {
-				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, id.String()).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log := zerolog.Ctx(ctx)
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, id.String())
+				})
 			}
 			if headerName != "" {
 				w.Header().Set(headerName, id.String())
@@ -155,14 +235,92 @@ func RequestIDHandler(fieldKey, headerName string) func(next http.Handler) http.
 	}
 }
 
+// CustomHeaderHandler adds given header from request's header as a field to
+// the context's logger using fieldKey as field key.
+func CustomHeaderHandler(fieldKey, header string) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if val := r.Header.Get(header); val != "" {
+				log := zerolog.Ctx(r.Context())
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, val)
+				})
+			}
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+// EtagHandler adds Etag header from response's header as a field to
+// the context's logger using fieldKey as field key.
+func EtagHandler(fieldKey string) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			defer func() {
+				etag := w.Header().Get("Etag")
+				if etag != "" {
+					etag = strings.ReplaceAll(etag, `"`, "")
+					log := zerolog.Ctx(r.Context())
+					log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+						return c.Str(fieldKey, etag)
+					})
+				}
+			}()
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+func ResponseHeaderHandler(fieldKey, headerName string) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			defer func() {
+				value := w.Header().Get(headerName)
+				if value != "" {
+					log := zerolog.Ctx(r.Context())
+					log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+						return c.Str(fieldKey, value)
+					})
+				}
+			}()
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
 // AccessHandler returns a handler that call f after each request.
 func AccessHandler(f func(r *http.Request, status, size int, duration time.Duration)) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			start := time.Now()
 			lw := mutil.WrapWriter(w)
+			defer func() {
+				f(r, lw.Status(), lw.BytesWritten(), time.Since(start))
+			}()
 			next.ServeHTTP(lw, r)
-			f(r, lw.Status(), lw.BytesWritten(), time.Since(start))
+		})
+	}
+}
+
+// HostHandler adds the request's host as a field to the context's logger
+// using fieldKey as field key. If trimPort is set to true, then port is
+// removed from the host.
+func HostHandler(fieldKey string, trimPort ...bool) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			var host string
+			if len(trimPort) > 0 && trimPort[0] {
+				host = getHost(r.Host)
+			} else {
+				host = r.Host
+			}
+			if host != "" {
+				log := zerolog.Ctx(r.Context())
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, host)
+				})
+			}
+			next.ServeHTTP(w, r)
 		})
 	}
 }

hlog/hlog_example_test.go

@@ -1,3 +1,5 @@
+// +build !binary_log
+
 package hlog_test
 
 import (
@@ -46,8 +48,8 @@ func Example_handler() {
 	// Install the logger handler with default output on the console
 	c = c.Append(hlog.NewHandler(log))
 
-	// Install some provided extra handler to set some request's context fields.
-	// Thanks to those handler, all our logs will come with some pre-populated fields.
+	// Install some provided extra handlers to set some request's context fields.
+	// Thanks to those handlers, all our logs will come with some pre-populated fields.
 	c = c.Append(hlog.RemoteAddrHandler("ip"))
 	c = c.Append(hlog.UserAgentHandler("user_agent"))
 	c = c.Append(hlog.RefererHandler("referer"))
@@ -61,11 +63,11 @@ func Example_handler() {
 		hlog.FromRequest(r).Info().
 			Str("user", "current user").
 			Str("status", "ok").
-			Msg("Something happend")
+			Msg("Something happened")
 	}))
 	http.Handle("/", h)
 
 	h.ServeHTTP(httptest.NewRecorder(), &http.Request{})
 
-	// Output: {"time":"2001-02-03T04:05:06Z","level":"info","role":"my-service","host":"local-hostname","user":"current user","status":"ok","message":"Something happend"}
+	// Output: {"level":"info","role":"my-service","host":"local-hostname","user":"current user","status":"ok","time":"2001-02-03T04:05:06Z","message":"Something happened"}
 }

hlog/hlog_test.go

@@ -1,21 +1,32 @@
+//go:build go1.7
 // +build go1.7
 
 package hlog
 
 import (
 	"bytes"
+	"context"
 	"fmt"
+	"io"
 	"net/http"
+	"net/http/httptest"
 	"net/url"
+	"reflect"
 	"testing"
 
-	"reflect"
-
-	"net/http/httptest"
-
+	"github.com/rs/xid"
 	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/internal/cbor"
 )
 
+func decodeIfBinary(out *bytes.Buffer) string {
+	p := out.Bytes()
+	if len(p) == 0 || p[0] < 0x7F {
+		return out.String()
+	}
+	return cbor.DecodeObjectToStr(p) + "\n"
+}
+
 func TestNewHandler(t *testing.T) {
 	log := zerolog.New(nil).With().
 		Str("foo", "bar").
@@ -23,7 +34,7 @@ func TestNewHandler(t *testing.T) {
 	lh := NewHandler(log)
 	h := lh(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
-		if !reflect.DeepEqual(l, log) {
+		if !reflect.DeepEqual(*l, log) {
 			t.Fail()
 		}
 	}))
@@ -38,12 +49,12 @@ func TestURLHandler(t *testing.T) {
 	h := URLHandler("url")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"url":"/path?foo=bar"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"url":"/path?foo=bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestMethodHandler(t *testing.T) {
@@ -54,12 +65,12 @@ func TestMethodHandler(t *testing.T) {
 	h := MethodHandler("method")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"method":"POST"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"method":"POST"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRequestHandler(t *testing.T) {
@@ -71,12 +82,12 @@ func TestRequestHandler(t *testing.T) {
 	h := RequestHandler("request")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"request":"POST /path?foo=bar"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"request":"POST /path?foo=bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRemoteAddrHandler(t *testing.T) {
@@ -87,12 +98,12 @@ func TestRemoteAddrHandler(t *testing.T) {
 	h := RemoteAddrHandler("ip")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"ip":"1.2.3.4"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"ip":"1.2.3.4:1234"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRemoteAddrHandlerIPv6(t *testing.T) {
@@ -103,12 +114,44 @@ func TestRemoteAddrHandlerIPv6(t *testing.T) {
 	h := RemoteAddrHandler("ip")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"ip":"2001:db8:a0b:12f0::1"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"ip":"[2001:db8:a0b:12f0::1]:1234"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestRemoteIPHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		RemoteAddr: "1.2.3.4:1234",
+	}
+	h := RemoteIPHandler("ip")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"ip":"1.2.3.4"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestRemoteIPHandlerIPv6(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		RemoteAddr: "[2001:db8:a0b:12f0::1]:1234",
+	}
+	h := RemoteIPHandler("ip")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"ip":"2001:db8:a0b:12f0::1"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestUserAgentHandler(t *testing.T) {
@@ -121,12 +164,12 @@ func TestUserAgentHandler(t *testing.T) {
 	h := UserAgentHandler("ua")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"ua":"some user agent string"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"ua":"some user agent string"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRefererHandler(t *testing.T) {
@@ -139,12 +182,12 @@ func TestRefererHandler(t *testing.T) {
 	h := RefererHandler("referer")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"referer":"http://foo.com/bar"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"referer":"http://foo.com/bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRequestIDHandler(t *testing.T) {
@@ -164,10 +207,229 @@ func TestRequestIDHandler(t *testing.T) {
 		}
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := fmt.Sprintf(`{"id":"%s"}`+"\n", id), out.String(); want != got {
+		if want, got := fmt.Sprintf(`{"id":"%s"}`+"\n", id), decodeIfBinary(out); want != got {
 			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
 		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(httptest.NewRecorder(), r)
 }
+
+func TestCustomHeaderHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		Header: http.Header{
+			"X-Request-Id": []string{"514bbe5bb5251c92bd07a9846f4a1ab6"},
+		},
+	}
+	h := CustomHeaderHandler("reqID", "X-Request-Id")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"reqID":"514bbe5bb5251c92bd07a9846f4a1ab6"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestEtagHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	w := httptest.NewRecorder()
+	r := &http.Request{}
+	h := EtagHandler("etag")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Etag", `"abcdef"`)
+		w.WriteHeader(http.StatusOK)
+	}))
+	h2 := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		h.ServeHTTP(w, r)
+		l := FromRequest(r)
+		l.Log().Msg("")
+	})
+	h3 := NewHandler(zerolog.New(out))(h2)
+	h3.ServeHTTP(w, r)
+	if want, got := `{"etag":"abcdef"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestResponseHeaderHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	w := httptest.NewRecorder()
+	r := &http.Request{}
+	h := ResponseHeaderHandler("encoding", "Content-Encoding")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Encoding", `gzip`)
+		w.WriteHeader(http.StatusOK)
+	}))
+	h2 := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		h.ServeHTTP(w, r)
+		l := FromRequest(r)
+		l.Log().Msg("")
+	})
+	h3 := NewHandler(zerolog.New(out))(h2)
+	h3.ServeHTTP(w, r)
+	if want, got := `{"encoding":"gzip"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestProtoHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		Proto: "test",
+	}
+	h := ProtoHandler("proto")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"proto":"test"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestHTTPVersionHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		Proto: "HTTP/1.1",
+	}
+	h := HTTPVersionHandler("proto")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"proto":"1.1"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestCombinedHandlers(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		Method: "POST",
+		URL:    &url.URL{Path: "/path", RawQuery: "foo=bar"},
+	}
+	h := MethodHandler("method")(RequestHandler("request")(URLHandler("url")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"method":"POST","request":"POST /path?foo=bar","url":"/path?foo=bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func BenchmarkHandlers(b *testing.B) {
+	r := &http.Request{
+		Method: "POST",
+		URL:    &url.URL{Path: "/path", RawQuery: "foo=bar"},
+	}
+	h1 := URLHandler("url")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h2 := MethodHandler("method")(RequestHandler("request")(h1))
+	handlers := map[string]http.Handler{
+		"Single":           NewHandler(zerolog.New(io.Discard))(h1),
+		"Combined":         NewHandler(zerolog.New(io.Discard))(h2),
+		"SingleDisabled":   NewHandler(zerolog.New(io.Discard).Level(zerolog.Disabled))(h1),
+		"CombinedDisabled": NewHandler(zerolog.New(io.Discard).Level(zerolog.Disabled))(h2),
+	}
+	for name := range handlers {
+		h := handlers[name]
+		b.Run(name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				h.ServeHTTP(nil, r)
+			}
+		})
+	}
+}
+
+func BenchmarkDataRace(b *testing.B) {
+	log := zerolog.New(nil).With().
+		Str("foo", "bar").
+		Logger()
+	lh := NewHandler(log)
+	h := lh(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.UpdateContext(func(c zerolog.Context) zerolog.Context {
+			return c.Str("bar", "baz")
+		})
+		l.Log().Msg("")
+	}))
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			h.ServeHTTP(nil, &http.Request{})
+		}
+	})
+}
+
+func TestCtxWithID(t *testing.T) {
+	ctx := context.Background()
+
+	id, _ := xid.FromString(`c0umremcie6smuu506pg`)
+
+	want := context.Background()
+	want = context.WithValue(want, idKey{}, id)
+
+	if got := CtxWithID(ctx, id); !reflect.DeepEqual(got, want) {
+		t.Errorf("CtxWithID() = %v, want %v", got, want)
+	}
+}
+
+func TestHostHandler(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{Host: "example.com:8080"}
+	h := HostHandler("host")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"host":"example.com:8080"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestHostHandlerWithoutPort(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{Host: "example.com:8080"}
+	h := HostHandler("host", true)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"host":"example.com"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func TestGetHost(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"", ""},
+		{"example.com:8080", "example.com"},
+		{"example.com", "example.com"},
+		{"invalid", "invalid"},
+		{"192.168.0.1:8080", "192.168.0.1"},
+		{"[2001:0db8:85a3:0000:0000:8a2e:0370:7334]:8080", "2001:0db8:85a3:0000:0000:8a2e:0370:7334"},
+		{"こんにちは.com:8080", "こんにちは.com"},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.input, func(t *testing.T) {
+			result := getHost(tt.input)
+			if tt.expected != result {
+				t.Errorf("Invalid log output, got: %s, want: %s", result, tt.expected)
+			}
+		})
+	}
+}

hlog/internal/mutil/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2014, 2015, 2016 Carl Jackson (carl@avtok.com)
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

hlog/internal/mutil/mutil.go

@@ -0,0 +1,6 @@
+// Package mutil contains various functions that are helpful when writing http
+// middleware.
+//
+// It has been vendored from Goji v1.0, with the exception of the code for Go 1.8:
+// https://github.com/zenazn/goji/
+package mutil

hlog/internal/mutil/writer_proxy.go

@@ -0,0 +1,154 @@
+package mutil
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"net/http"
+)
+
+// WriterProxy is a proxy around an http.ResponseWriter that allows you to hook
+// into various parts of the response process.
+type WriterProxy interface {
+	http.ResponseWriter
+	// Status returns the HTTP status of the request, or 0 if one has not
+	// yet been sent.
+	Status() int
+	// BytesWritten returns the total number of bytes sent to the client.
+	BytesWritten() int
+	// Tee causes the response body to be written to the given io.Writer in
+	// addition to proxying the writes through. Only one io.Writer can be
+	// tee'd to at once: setting a second one will overwrite the first.
+	// Writes will be sent to the proxy before being written to this
+	// io.Writer. It is illegal for the tee'd writer to be modified
+	// concurrently with writes.
+	Tee(io.Writer)
+	// Unwrap returns the original proxied target.
+	Unwrap() http.ResponseWriter
+}
+
+// WrapWriter wraps an http.ResponseWriter, returning a proxy that allows you to
+// hook into various parts of the response process.
+func WrapWriter(w http.ResponseWriter) WriterProxy {
+	_, cn := w.(http.CloseNotifier)
+	_, fl := w.(http.Flusher)
+	_, hj := w.(http.Hijacker)
+	_, rf := w.(io.ReaderFrom)
+
+	bw := basicWriter{ResponseWriter: w}
+	if cn && fl && hj && rf {
+		return &fancyWriter{bw}
+	}
+	if fl {
+		return &flushWriter{bw}
+	}
+	return &bw
+}
+
+// basicWriter wraps a http.ResponseWriter that implements the minimal
+// http.ResponseWriter interface.
+type basicWriter struct {
+	http.ResponseWriter
+	wroteHeader bool
+	code        int
+	bytes       int
+	tee         io.Writer
+}
+
+func (b *basicWriter) WriteHeader(code int) {
+	if !b.wroteHeader {
+		b.code = code
+		b.wroteHeader = true
+		b.ResponseWriter.WriteHeader(code)
+	}
+}
+
+func (b *basicWriter) Write(buf []byte) (int, error) {
+	b.WriteHeader(http.StatusOK)
+	n, err := b.ResponseWriter.Write(buf)
+	if b.tee != nil {
+		_, err2 := b.tee.Write(buf[:n])
+		// Prefer errors generated by the proxied writer.
+		if err == nil {
+			err = err2
+		}
+	}
+	b.bytes += n
+	return n, err
+}
+
+func (b *basicWriter) maybeWriteHeader() {
+	if !b.wroteHeader {
+		b.WriteHeader(http.StatusOK)
+	}
+}
+
+func (b *basicWriter) Status() int {
+	return b.code
+}
+
+func (b *basicWriter) BytesWritten() int {
+	return b.bytes
+}
+
+func (b *basicWriter) Tee(w io.Writer) {
+	b.tee = w
+}
+
+func (b *basicWriter) Unwrap() http.ResponseWriter {
+	return b.ResponseWriter
+}
+
+// fancyWriter is a writer that additionally satisfies http.CloseNotifier,
+// http.Flusher, http.Hijacker, and io.ReaderFrom. It exists for the common case
+// of wrapping the http.ResponseWriter that package http gives you, in order to
+// make the proxied object support the full method set of the proxied object.
+type fancyWriter struct {
+	basicWriter
+}
+
+func (f *fancyWriter) CloseNotify() <-chan bool {
+	cn := f.basicWriter.ResponseWriter.(http.CloseNotifier)
+	return cn.CloseNotify()
+}
+
+func (f *fancyWriter) Flush() {
+	fl := f.basicWriter.ResponseWriter.(http.Flusher)
+	fl.Flush()
+}
+
+func (f *fancyWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	hj := f.basicWriter.ResponseWriter.(http.Hijacker)
+	return hj.Hijack()
+}
+
+func (f *fancyWriter) ReadFrom(r io.Reader) (int64, error) {
+	if f.basicWriter.tee != nil {
+		n, err := io.Copy(&f.basicWriter, r)
+		f.bytes += int(n)
+		return n, err
+	}
+	rf := f.basicWriter.ResponseWriter.(io.ReaderFrom)
+	f.basicWriter.maybeWriteHeader()
+
+	n, err := rf.ReadFrom(r)
+	f.bytes += int(n)
+	return n, err
+}
+
+type flushWriter struct {
+	basicWriter
+}
+
+func (f *flushWriter) Flush() {
+	fl := f.basicWriter.ResponseWriter.(http.Flusher)
+	fl.Flush()
+}
+
+var (
+	_ http.CloseNotifier = &fancyWriter{}
+	_ http.Flusher       = &fancyWriter{}
+	_ http.Hijacker      = &fancyWriter{}
+	_ io.ReaderFrom      = &fancyWriter{}
+	_ http.Flusher       = &flushWriter{}
+)

hook.go

@@ -0,0 +1,64 @@
+package zerolog
+
+// Hook defines an interface to a log hook.
+type Hook interface {
+	// Run runs the hook with the event.
+	Run(e *Event, level Level, message string)
+}
+
+// HookFunc is an adaptor to allow the use of an ordinary function
+// as a Hook.
+type HookFunc func(e *Event, level Level, message string)
+
+// Run implements the Hook interface.
+func (h HookFunc) Run(e *Event, level Level, message string) {
+	h(e, level, message)
+}
+
+// LevelHook applies a different hook for each level.
+type LevelHook struct {
+	NoLevelHook, TraceHook, DebugHook, InfoHook, WarnHook, ErrorHook, FatalHook, PanicHook Hook
+}
+
+// Run implements the Hook interface.
+func (h LevelHook) Run(e *Event, level Level, message string) {
+	switch level {
+	case TraceLevel:
+		if h.TraceHook != nil {
+			h.TraceHook.Run(e, level, message)
+		}
+	case DebugLevel:
+		if h.DebugHook != nil {
+			h.DebugHook.Run(e, level, message)
+		}
+	case InfoLevel:
+		if h.InfoHook != nil {
+			h.InfoHook.Run(e, level, message)
+		}
+	case WarnLevel:
+		if h.WarnHook != nil {
+			h.WarnHook.Run(e, level, message)
+		}
+	case ErrorLevel:
+		if h.ErrorHook != nil {
+			h.ErrorHook.Run(e, level, message)
+		}
+	case FatalLevel:
+		if h.FatalHook != nil {
+			h.FatalHook.Run(e, level, message)
+		}
+	case PanicLevel:
+		if h.PanicHook != nil {
+			h.PanicHook.Run(e, level, message)
+		}
+	case NoLevel:
+		if h.NoLevelHook != nil {
+			h.NoLevelHook.Run(e, level, message)
+		}
+	}
+}
+
+// NewLevelHook returns a new LevelHook.
+func NewLevelHook() LevelHook {
+	return LevelHook{}
+}

hook_test.go

@@ -0,0 +1,298 @@
+package zerolog
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"testing"
+)
+
+type contextKeyType int
+
+var contextKey contextKeyType
+
+var (
+	levelNameHook = HookFunc(func(e *Event, level Level, msg string) {
+		levelName := level.String()
+		if level == NoLevel {
+			levelName = "nolevel"
+		}
+		e.Str("level_name", levelName)
+	})
+	simpleHook = HookFunc(func(e *Event, level Level, msg string) {
+		e.Bool("has_level", level != NoLevel)
+		e.Str("test", "logged")
+	})
+	copyHook = HookFunc(func(e *Event, level Level, msg string) {
+		hasLevel := level != NoLevel
+		e.Bool("copy_has_level", hasLevel)
+		if hasLevel {
+			e.Str("copy_level", level.String())
+		}
+		e.Str("copy_msg", msg)
+	})
+	nopHook = HookFunc(func(e *Event, level Level, message string) {
+	})
+	discardHook = HookFunc(func(e *Event, level Level, message string) {
+		e.Discard()
+	})
+	contextHook = HookFunc(func(e *Event, level Level, message string) {
+		contextData, ok := e.GetCtx().Value(contextKey).(string)
+		if ok {
+			e.Str("context-data", contextData)
+		}
+	})
+)
+
+func TestHook(t *testing.T) {
+	tests := []struct {
+		name string
+		want string
+		test func(log Logger)
+	}{
+		{"Message", `{"message":"test message"}` + "\n", func(log Logger) {
+			log = log.Hook()
+			log.Log().Msg("test message")
+		}},
+		{"Message", `{"level_name":"nolevel","message":"test message"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook)
+			log.Log().Msg("test message")
+		}},
+		{"NoLevel", `{"level_name":"nolevel"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook)
+			log.Log().Msg("")
+		}},
+		{"Print", `{"level":"debug","level_name":"debug"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook)
+			log.Print("")
+		}},
+		{"Error", `{"level":"error","level_name":"error"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook)
+			log.Error().Msg("")
+		}},
+		{"Copy/1", `{"copy_has_level":false,"copy_msg":""}` + "\n", func(log Logger) {
+			log = log.Hook(copyHook)
+			log.Log().Msg("")
+		}},
+		{"Copy/2", `{"level":"info","copy_has_level":true,"copy_level":"info","copy_msg":"a message","message":"a message"}` + "\n", func(log Logger) {
+			log = log.Hook(copyHook)
+			log.Info().Msg("a message")
+		}},
+		{"Multi", `{"level":"error","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook).Hook(simpleHook)
+			log.Error().Msg("")
+		}},
+		{"Multi/Message", `{"level":"error","level_name":"error","has_level":true,"test":"logged","message":"a message"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook).Hook(simpleHook)
+			log.Error().Msg("a message")
+		}},
+		{"Output/single/pre", `{"level":"error","level_name":"error"}` + "\n", func(log Logger) {
+			ignored := &bytes.Buffer{}
+			log = New(ignored).Hook(levelNameHook).Output(log.w)
+			log.Error().Msg("")
+		}},
+		{"Output/single/post", `{"level":"error","level_name":"error"}` + "\n", func(log Logger) {
+			ignored := &bytes.Buffer{}
+			log = New(ignored).Output(log.w).Hook(levelNameHook)
+			log.Error().Msg("")
+		}},
+		{"Output/multi/pre", `{"level":"error","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			ignored := &bytes.Buffer{}
+			log = New(ignored).Hook(levelNameHook).Hook(simpleHook).Output(log.w)
+			log.Error().Msg("")
+		}},
+		{"Output/multi/post", `{"level":"error","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			ignored := &bytes.Buffer{}
+			log = New(ignored).Output(log.w).Hook(levelNameHook).Hook(simpleHook)
+			log.Error().Msg("")
+		}},
+		{"Output/mixed", `{"level":"error","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			ignored := &bytes.Buffer{}
+			log = New(ignored).Hook(levelNameHook).Output(log.w).Hook(simpleHook)
+			log.Error().Msg("")
+		}},
+		{"With/single/pre", `{"level":"error","with":"pre","level_name":"error"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook).With().Str("with", "pre").Logger()
+			log.Error().Msg("")
+		}},
+		{"With/single/post", `{"level":"error","with":"post","level_name":"error"}` + "\n", func(log Logger) {
+			log = log.With().Str("with", "post").Logger().Hook(levelNameHook)
+			log.Error().Msg("")
+		}},
+		{"With/multi/pre", `{"level":"error","with":"pre","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook).Hook(simpleHook).With().Str("with", "pre").Logger()
+			log.Error().Msg("")
+		}},
+		{"With/multi/post", `{"level":"error","with":"post","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			log = log.With().Str("with", "post").Logger().Hook(levelNameHook).Hook(simpleHook)
+			log.Error().Msg("")
+		}},
+		{"With/mixed", `{"level":"error","with":"mixed","level_name":"error","has_level":true,"test":"logged"}` + "\n", func(log Logger) {
+			log = log.Hook(levelNameHook).With().Str("with", "mixed").Logger().Hook(simpleHook)
+			log.Error().Msg("")
+		}},
+		{"Discard", "", func(log Logger) {
+			log = log.Hook(discardHook)
+			log.Log().Msg("test message")
+		}},
+		{"Context/Background", `{"level":"info","message":"test message"}` + "\n", func(log Logger) {
+			log = log.Hook(contextHook)
+			log.Info().Ctx(context.Background()).Msg("test message")
+		}},
+		{"Context/nil", `{"level":"info","message":"test message"}` + "\n", func(log Logger) {
+			// passing `nil` where a context is wanted is against
+			// the rules, but people still do it.
+			log = log.Hook(contextHook)
+			log.Info().Ctx(nil).Msg("test message") // nolint
+		}},
+		{"Context/valid", `{"level":"info","context-data":"12345abcdef","message":"test message"}` + "\n", func(log Logger) {
+			ctx := context.Background()
+			ctx = context.WithValue(ctx, contextKey, "12345abcdef")
+			log = log.Hook(contextHook)
+			log.Info().Ctx(ctx).Msg("test message")
+		}},
+		{"Context/With/valid", `{"level":"info","context-data":"12345abcdef","message":"test message"}` + "\n", func(log Logger) {
+			ctx := context.Background()
+			ctx = context.WithValue(ctx, contextKey, "12345abcdef")
+			log = log.Hook(contextHook)
+			log = log.With().Ctx(ctx).Logger()
+			log.Info().Msg("test message")
+		}},
+		{"None", `{"level":"error"}` + "\n", func(log Logger) {
+			log.Error().Msg("")
+		}},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			out := &bytes.Buffer{}
+			log := New(out)
+			tt.test(log)
+			if got, want := decodeIfBinaryToString(out.Bytes()), tt.want; got != want {
+				t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+			}
+		})
+	}
+}
+
+func TestLevelHook(t *testing.T) {
+	var called []string
+
+	traceHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "trace")
+	})
+	debugHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "debug")
+	})
+	infoHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "info")
+	})
+	warnHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "warn")
+	})
+	errorHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "error")
+	})
+	fatalHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "fatal")
+	})
+	panicHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "panic")
+	})
+	noLevelHook := HookFunc(func(e *Event, level Level, msg string) {
+		called = append(called, "nolevel")
+	})
+
+	hook := LevelHook{
+		TraceHook:   traceHook,
+		DebugHook:   debugHook,
+		InfoHook:    infoHook,
+		WarnHook:    warnHook,
+		ErrorHook:   errorHook,
+		FatalHook:   fatalHook,
+		PanicHook:   panicHook,
+		NoLevelHook: noLevelHook,
+	}
+
+	e := &Event{}
+
+	// Test each level
+	hook.Run(e, TraceLevel, "")
+	if len(called) != 1 || called[0] != "trace" {
+		t.Errorf("TraceLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, DebugLevel, "")
+	if len(called) != 1 || called[0] != "debug" {
+		t.Errorf("DebugLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, InfoLevel, "")
+	if len(called) != 1 || called[0] != "info" {
+		t.Errorf("InfoLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, WarnLevel, "")
+	if len(called) != 1 || called[0] != "warn" {
+		t.Errorf("WarnLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, ErrorLevel, "")
+	if len(called) != 1 || called[0] != "error" {
+		t.Errorf("ErrorLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, FatalLevel, "")
+	if len(called) != 1 || called[0] != "fatal" {
+		t.Errorf("FatalLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, PanicLevel, "")
+	if len(called) != 1 || called[0] != "panic" {
+		t.Errorf("PanicLevel hook not called correctly: %v", called)
+	}
+
+	called = nil
+	hook.Run(e, NoLevel, "")
+	if len(called) != 1 || called[0] != "nolevel" {
+		t.Errorf("NoLevel hook not called correctly: %v", called)
+	}
+
+	// Test NewLevelHook
+	_ = NewLevelHook()
+}
+
+func BenchmarkHooks(b *testing.B) {
+	logger := New(io.Discard)
+	b.ResetTimer()
+	b.Run("Nop/Single", func(b *testing.B) {
+		log := logger.Hook(nopHook)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				log.Log().Msg("")
+			}
+		})
+	})
+	b.Run("Nop/Multi", func(b *testing.B) {
+		log := logger.Hook(nopHook).Hook(nopHook)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				log.Log().Msg("")
+			}
+		})
+	})
+	b.Run("Simple", func(b *testing.B) {
+		log := logger.Hook(simpleHook)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				log.Log().Msg("")
+			}
+		})
+	})
+}

internal/cbor/README.md

@@ -0,0 +1,56 @@
+## Reference:
+   CBOR Encoding is described in [RFC7049](https://tools.ietf.org/html/rfc7049)
+
+## Comparison of JSON vs CBOR
+
+Two main areas of reduction are:
+
+1. CPU usage to write a log msg 
+2. Size (in bytes) of log messages.
+
+
+CPU Usage savings are below:
+```
+name                                    JSON time/op    CBOR time/op   delta
+Info-32                                   15.3ns ± 1%    11.7ns ± 3%  -23.78%  (p=0.000 n=9+10)      
+ContextFields-32                          16.2ns ± 2%    12.3ns ± 3%  -23.97%  (p=0.000 n=9+9)       
+ContextAppend-32                          6.70ns ± 0%    6.20ns ± 0%   -7.44%  (p=0.000 n=9+9)       
+LogFields-32                              66.4ns ± 0%    24.6ns ± 2%  -62.89%  (p=0.000 n=10+9)      
+LogArrayObject-32                          911ns ±11%     768ns ± 6%  -15.64%  (p=0.000 n=10+10)     
+LogFieldType/Floats-32                    70.3ns ± 2%    29.5ns ± 1%  -57.98%  (p=0.000 n=10+10)     
+LogFieldType/Err-32                       14.0ns ± 3%    12.1ns ± 8%  -13.20%  (p=0.000 n=8+10)      
+LogFieldType/Dur-32                       17.2ns ± 2%    13.1ns ± 1%  -24.27%  (p=0.000 n=10+9)      
+LogFieldType/Object-32                    54.3ns ±11%    52.3ns ± 7%     ~     (p=0.239 n=10+10)     
+LogFieldType/Ints-32                      20.3ns ± 2%    15.1ns ± 2%  -25.50%  (p=0.000 n=9+10)      
+LogFieldType/Interfaces-32                 642ns ±11%     621ns ± 9%     ~     (p=0.118 n=10+10)     
+LogFieldType/Interface(Objects)-32         635ns ±13%     632ns ± 9%     ~     (p=0.592 n=10+10)     
+LogFieldType/Times-32                      294ns ± 0%      27ns ± 1%  -90.71%  (p=0.000 n=10+9)      
+LogFieldType/Durs-32                       121ns ± 0%      33ns ± 2%  -72.44%  (p=0.000 n=9+9)       
+LogFieldType/Interface(Object)-32         56.6ns ± 8%    52.3ns ± 8%   -7.54%  (p=0.007 n=10+10)     
+LogFieldType/Errs-32                      17.8ns ± 3%    16.1ns ± 2%   -9.71%  (p=0.000 n=10+9)      
+LogFieldType/Time-32                      40.5ns ± 1%    12.7ns ± 6%  -68.66%  (p=0.000 n=8+9)       
+LogFieldType/Bool-32                      12.0ns ± 5%    10.2ns ± 2%  -15.18%  (p=0.000 n=10+8)      
+LogFieldType/Bools-32                     17.2ns ± 2%    12.6ns ± 4%  -26.63%  (p=0.000 n=10+10)     
+LogFieldType/Int-32                       12.3ns ± 2%    11.2ns ± 4%   -9.27%  (p=0.000 n=9+10)      
+LogFieldType/Float-32                     16.7ns ± 1%    12.6ns ± 2%  -24.42%  (p=0.000 n=7+9)       
+LogFieldType/Str-32                       12.7ns ± 7%    11.3ns ± 7%  -10.88%  (p=0.000 n=10+9)      
+LogFieldType/Strs-32                      20.3ns ± 3%    18.2ns ± 3%  -10.25%  (p=0.000 n=9+10)      
+LogFieldType/Interface-32                  183ns ±12%     175ns ± 9%     ~     (p=0.078 n=10+10)     
+```
+
+Log message size savings is greatly dependent on the number and type of fields in the log message.
+Assuming this log message (with an Integer, timestamp and string, in addition to level).
+
+`{"level":"error","Fault":41650,"time":"2018-04-01T15:18:19-07:00","message":"Some Message"}`
+
+Two measurements were done for the log file sizes - one without any compression, second
+using [compress/zlib](https://golang.org/pkg/compress/zlib/). 
+
+Results for 10,000 log messages:
+
+| Log Format |  Plain File Size (in KB) | Compressed File Size (in KB) |
+| :--- | :---: | :---: |
+| JSON | 920 | 28 |
+| CBOR | 550 | 28 |
+
+The example used to calculate the above data is available in [Examples](examples).

internal/cbor/base.go

@@ -0,0 +1,19 @@
+package cbor
+
+// JSONMarshalFunc is used to marshal interface to JSON encoded byte slice.
+// Making it package level instead of embedded in Encoder brings
+// some extra efforts at importing, but avoids value copy when the functions
+// of Encoder being invoked.
+// DO REMEMBER to set this variable at importing, or
+// you might get a nil pointer dereference panic at runtime.
+var JSONMarshalFunc func(v interface{}) ([]byte, error)
+
+type Encoder struct{}
+
+// AppendKey adds a key (string) to the binary encoded log message
+func (e Encoder) AppendKey(dst []byte, key string) []byte {
+	if len(dst) < 1 {
+		dst = e.AppendBeginMarker(dst)
+	}
+	return e.AppendString(dst, key)
+}

internal/cbor/base_test.go

@@ -0,0 +1,22 @@
+package cbor
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+)
+
+func TestAppendKey(t *testing.T) {
+	want := make([]byte, 0)
+	want = append(want, 0xbf) // start string
+	want = append(want, 0x63) // length 3
+	want = append(want, []byte("key")...)
+
+	got := enc.AppendKey([]byte{}, "key")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendKey(%v)\ngot:  0x%s\nwant: 0x%s",
+			"key",
+			hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+}

internal/cbor/cbor.go

@@ -0,0 +1,102 @@
+// Package cbor provides primitives for storing different data
+// in the CBOR (binary) format. CBOR is defined in RFC7049.
+package cbor
+
+import "time"
+
+const (
+	majorOffset   = 5
+	additionalMax = 23
+
+	// Non Values.
+	additionalTypeBoolFalse byte = 20
+	additionalTypeBoolTrue  byte = 21
+	additionalTypeNull      byte = 22
+
+	// Integer (+ve and -ve) Sub-types.
+	additionalTypeIntUint8  byte = 24
+	additionalTypeIntUint16 byte = 25
+	additionalTypeIntUint32 byte = 26
+	additionalTypeIntUint64 byte = 27
+
+	// Float Sub-types.
+	additionalTypeFloat16 byte = 25
+	additionalTypeFloat32 byte = 26
+	additionalTypeFloat64 byte = 27
+	additionalTypeBreak   byte = 31
+
+	// Tag Sub-types.
+	additionalTypeTimestamp    byte = 01
+	additionalTypeEmbeddedCBOR byte = 63
+
+	// Extended Tags - from https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml
+	additionalTypeTagNetworkAddr   uint16 = 260
+	additionalTypeTagNetworkPrefix uint16 = 261
+	additionalTypeEmbeddedJSON     uint16 = 262
+	additionalTypeTagHexString     uint16 = 263
+
+	// Unspecified number of elements.
+	additionalTypeInfiniteCount byte = 31
+)
+const (
+	majorTypeUnsignedInt    byte = iota << majorOffset // Major type 0
+	majorTypeNegativeInt                               // Major type 1
+	majorTypeByteString                                // Major type 2
+	majorTypeUtf8String                                // Major type 3
+	majorTypeArray                                     // Major type 4
+	majorTypeMap                                       // Major type 5
+	majorTypeTags                                      // Major type 6
+	majorTypeSimpleAndFloat                            // Major type 7
+)
+
+const (
+	maskOutAdditionalType byte = (7 << majorOffset)
+	maskOutMajorType      byte = 31
+)
+
+const (
+	float32Nan         = "\x7f\xc0\x00\x00"
+	float32PosInfinity = "\x7f\x80\x00\x00"
+	float32NegInfinity = "\xff\x80\x00\x00"
+	float64Nan         = "\x7f\xf8\x00\x00\x00\x00\x00\x00"
+	float64PosInfinity = "\x7f\xf0\x00\x00\x00\x00\x00\x00"
+	float64NegInfinity = "\xff\xf0\x00\x00\x00\x00\x00\x00"
+)
+
+// IntegerTimeFieldFormat indicates the format of timestamp decoded
+// from an integer (time in seconds).
+var IntegerTimeFieldFormat = time.RFC3339
+
+// NanoTimeFieldFormat indicates the format of timestamp decoded
+// from a float value (time in seconds and nanoseconds).
+var NanoTimeFieldFormat = time.RFC3339Nano
+
+func appendCborTypePrefix(dst []byte, major byte, number uint64) []byte {
+	var byteCount int
+	var minor byte
+	switch {
+	case number < 256:
+		byteCount = 1
+		minor = additionalTypeIntUint8
+
+	case number < 65536:
+		byteCount = 2
+		minor = additionalTypeIntUint16
+
+	case number < 4294967296:
+		byteCount = 4
+		minor = additionalTypeIntUint32
+
+	default:
+		byteCount = 8
+		minor = additionalTypeIntUint64
+
+	}
+
+	dst = append(dst, major|minor)
+	byteCount--
+	for ; byteCount >= 0; byteCount-- {
+		dst = append(dst, byte(number>>(uint(byteCount)*8)))
+	}
+	return dst
+}

internal/cbor/decode_stream.go

@@ -0,0 +1,654 @@
+package cbor
+
+// This file contains code to decode a stream of CBOR Data into JSON.
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"math"
+	"net"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+var decodeTimeZone *time.Location
+
+const hexTable = "0123456789abcdef"
+
+const isFloat32 = 4
+const isFloat64 = 8
+
+func readNBytes(src *bufio.Reader, n int) []byte {
+	ret := make([]byte, n)
+	for i := 0; i < n; i++ {
+		ch, e := src.ReadByte()
+		if e != nil {
+			panic(fmt.Errorf("Tried to Read %d Bytes.. But hit end of file", n))
+		}
+		ret[i] = ch
+	}
+	return ret
+}
+
+func readByte(src *bufio.Reader) byte {
+	b, e := src.ReadByte()
+	if e != nil {
+		panic(fmt.Errorf("Tried to Read 1 Byte.. But hit end of file"))
+	}
+	return b
+}
+
+func decodeIntAdditionalType(src *bufio.Reader, minor byte) int64 {
+	val := int64(0)
+	if minor <= 23 {
+		val = int64(minor)
+	} else {
+		bytesToRead := 0
+		switch minor {
+		case additionalTypeIntUint8:
+			bytesToRead = 1
+		case additionalTypeIntUint16:
+			bytesToRead = 2
+		case additionalTypeIntUint32:
+			bytesToRead = 4
+		case additionalTypeIntUint64:
+			bytesToRead = 8
+		default:
+			panic(fmt.Errorf("Invalid Additional Type: %d in decodeInteger (expected <28)", minor))
+		}
+		pb := readNBytes(src, bytesToRead)
+		for i := 0; i < bytesToRead; i++ {
+			val = val * 256
+			val += int64(pb[i])
+		}
+	}
+	return val
+}
+
+func decodeInteger(src *bufio.Reader) int64 {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeUnsignedInt && major != majorTypeNegativeInt {
+		panic(fmt.Errorf("Major type is: %d in decodeInteger!! (expected 0 or 1)", major))
+	}
+	val := decodeIntAdditionalType(src, minor)
+	if major == 0 {
+		return val
+	}
+	return (-1 - val)
+}
+
+func decodeFloat(src *bufio.Reader) (float64, int) {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeSimpleAndFloat {
+		panic(fmt.Errorf("Incorrect Major type is: %d in decodeFloat", major))
+	}
+
+	switch minor {
+	case additionalTypeFloat16:
+		panic(fmt.Errorf("float16 is not supported in decodeFloat"))
+
+	case additionalTypeFloat32:
+		pb := readNBytes(src, 4)
+		switch string(pb) {
+		case float32Nan:
+			return math.NaN(), isFloat32
+		case float32PosInfinity:
+			return math.Inf(0), isFloat32
+		case float32NegInfinity:
+			return math.Inf(-1), isFloat32
+		}
+		n := uint32(0)
+		for i := 0; i < 4; i++ {
+			n = n * 256
+			n += uint32(pb[i])
+		}
+		val := math.Float32frombits(n)
+		return float64(val), isFloat32
+	case additionalTypeFloat64:
+		pb := readNBytes(src, 8)
+		switch string(pb) {
+		case float64Nan:
+			return math.NaN(), isFloat64
+		case float64PosInfinity:
+			return math.Inf(0), isFloat64
+		case float64NegInfinity:
+			return math.Inf(-1), isFloat64
+		}
+		n := uint64(0)
+		for i := 0; i < 8; i++ {
+			n = n * 256
+			n += uint64(pb[i])
+		}
+		val := math.Float64frombits(n)
+		return val, isFloat64
+	}
+	panic(fmt.Errorf("Invalid Additional Type: %d in decodeFloat", minor))
+}
+
+func decodeStringComplex(dst []byte, s string, pos uint) []byte {
+	i := int(pos)
+	start := 0
+
+	for i < len(s) {
+		b := s[i]
+		if b >= utf8.RuneSelf {
+			r, size := utf8.DecodeRuneInString(s[i:])
+			if r == utf8.RuneError && size == 1 {
+				// In case of error, first append previous simple characters to
+				// the byte slice if any and append a replacement character code
+				// in place of the invalid sequence.
+				if start < i {
+					dst = append(dst, s[start:i]...)
+				}
+				dst = append(dst, `\ufffd`...)
+				i += size
+				start = i
+				continue
+			}
+			i += size
+			continue
+		}
+		if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
+			i++
+			continue
+		}
+		// We encountered a character that needs to be encoded.
+		// Let's append the previous simple characters to the byte slice
+		// and switch our operation to read and encode the remainder
+		// characters byte-by-byte.
+		if start < i {
+			dst = append(dst, s[start:i]...)
+		}
+		switch b {
+		case '"', '\\':
+			dst = append(dst, '\\', b)
+		case '\b':
+			dst = append(dst, '\\', 'b')
+		case '\f':
+			dst = append(dst, '\\', 'f')
+		case '\n':
+			dst = append(dst, '\\', 'n')
+		case '\r':
+			dst = append(dst, '\\', 'r')
+		case '\t':
+			dst = append(dst, '\\', 't')
+		default:
+			dst = append(dst, '\\', 'u', '0', '0', hexTable[b>>4], hexTable[b&0xF])
+		}
+		i++
+		start = i
+	}
+	if start < len(s) {
+		dst = append(dst, s[start:]...)
+	}
+	return dst
+}
+
+func decodeString(src *bufio.Reader, noQuotes bool) []byte {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeByteString {
+		panic(fmt.Errorf("Major type is: %d in decodeString", major))
+	}
+	result := []byte{}
+	if !noQuotes {
+		result = append(result, '"')
+	}
+	length := decodeIntAdditionalType(src, minor)
+	len := int(length)
+	pbs := readNBytes(src, len)
+	result = append(result, pbs...)
+	if noQuotes {
+		return result
+	}
+	return append(result, '"')
+}
+func decodeStringToDataUrl(src *bufio.Reader, mimeType string) []byte {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeByteString {
+		panic(fmt.Errorf("Major type is: %d in decodeString", major))
+	}
+	length := decodeIntAdditionalType(src, minor)
+	l := int(length)
+	enc := base64.StdEncoding
+	lEnc := enc.EncodedLen(l)
+	result := make([]byte, len("\"data:;base64,\"")+len(mimeType)+lEnc)
+	dest := result
+	u := copy(dest, "\"data:")
+	dest = dest[u:]
+	u = copy(dest, mimeType)
+	dest = dest[u:]
+	u = copy(dest, ";base64,")
+	dest = dest[u:]
+	pbs := readNBytes(src, l)
+	enc.Encode(dest, pbs)
+	dest = dest[lEnc:]
+	dest[0] = '"'
+	return result
+}
+
+func decodeUTF8String(src *bufio.Reader) []byte {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeUtf8String {
+		panic(fmt.Errorf("Major type is: %d in decodeUTF8String", major))
+	}
+	result := []byte{'"'}
+	length := decodeIntAdditionalType(src, minor)
+	len := int(length)
+	pbs := readNBytes(src, len)
+
+	for i := 0; i < len; i++ {
+		// Check if the character needs encoding. Control characters, slashes,
+		// and the double quote need json encoding. Bytes above the ascii
+		// boundary needs utf8 encoding.
+		if pbs[i] < 0x20 || pbs[i] > 0x7e || pbs[i] == '\\' || pbs[i] == '"' {
+			// We encountered a character that needs to be encoded. Switch
+			// to complex version of the algorithm.
+			dst := []byte{'"'}
+			dst = decodeStringComplex(dst, string(pbs), uint(i))
+			return append(dst, '"')
+		}
+	}
+	// The string has no need for encoding and therefore is directly
+	// appended to the byte slice.
+	result = append(result, pbs...)
+	return append(result, '"')
+}
+
+func array2Json(src *bufio.Reader, dst io.Writer) {
+	dst.Write([]byte{'['})
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeArray {
+		panic(fmt.Errorf("Major type is: %d in array2Json", major))
+	}
+	len := 0
+	unSpecifiedCount := false
+	if minor == additionalTypeInfiniteCount {
+		unSpecifiedCount = true
+	} else {
+		length := decodeIntAdditionalType(src, minor)
+		len = int(length)
+	}
+	for i := 0; unSpecifiedCount || i < len; i++ {
+		if unSpecifiedCount {
+			pb, e := src.Peek(1)
+			if e != nil {
+				panic(e)
+			}
+			if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
+				readByte(src)
+				break
+			}
+		}
+		cbor2JsonOneObject(src, dst)
+		if unSpecifiedCount {
+			pb, e := src.Peek(1)
+			if e != nil {
+				panic(e)
+			}
+			if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
+				readByte(src)
+				break
+			}
+			dst.Write([]byte{','})
+		} else if i+1 < len {
+			dst.Write([]byte{','})
+		}
+	}
+	dst.Write([]byte{']'})
+}
+
+func map2Json(src *bufio.Reader, dst io.Writer) {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeMap {
+		panic(fmt.Errorf("Major type is: %d in map2Json", major))
+	}
+	len := 0
+	unSpecifiedCount := false
+	if minor == additionalTypeInfiniteCount {
+		unSpecifiedCount = true
+	} else {
+		length := decodeIntAdditionalType(src, minor)
+		len = int(length)
+	}
+	dst.Write([]byte{'{'})
+	for i := 0; unSpecifiedCount || i < len; i++ {
+		if unSpecifiedCount {
+			pb, e := src.Peek(1)
+			if e != nil {
+				panic(e)
+			}
+			if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
+				readByte(src)
+				break
+			}
+		}
+		cbor2JsonOneObject(src, dst)
+		if i%2 == 0 {
+			// Even position values are keys.
+			dst.Write([]byte{':'})
+		} else {
+			if unSpecifiedCount {
+				pb, e := src.Peek(1)
+				if e != nil {
+					panic(e)
+				}
+				if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
+					readByte(src)
+					break
+				}
+				dst.Write([]byte{','})
+			} else if i+1 < len {
+				dst.Write([]byte{','})
+			}
+		}
+	}
+	dst.Write([]byte{'}'})
+}
+
+func decodeTagData(src *bufio.Reader) []byte {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeTags {
+		panic(fmt.Errorf("Major type is: %d in decodeTagData", major))
+	}
+	switch minor {
+	case additionalTypeTimestamp:
+		return decodeTimeStamp(src)
+	case additionalTypeIntUint8:
+		val := decodeIntAdditionalType(src, minor)
+		switch byte(val) {
+		case additionalTypeEmbeddedCBOR:
+			pb := readByte(src)
+			dataMajor := pb & maskOutAdditionalType
+			if dataMajor != majorTypeByteString {
+				panic(fmt.Errorf("Unsupported embedded Type: %d in decodeEmbeddedCBOR", dataMajor))
+			}
+			src.UnreadByte()
+			return decodeStringToDataUrl(src, "application/cbor")
+		default:
+			panic(fmt.Errorf("Unsupported Additional Tag Type: %d in decodeTagData", val))
+		}
+
+	// Tag value is larger than 256 (so uint16).
+	case additionalTypeIntUint16:
+		val := decodeIntAdditionalType(src, minor)
+
+		switch uint16(val) {
+		case additionalTypeEmbeddedJSON:
+			pb := readByte(src)
+			dataMajor := pb & maskOutAdditionalType
+			if dataMajor != majorTypeByteString {
+				panic(fmt.Errorf("Unsupported embedded Type: %d in decodeEmbeddedJSON", dataMajor))
+			}
+			src.UnreadByte()
+			return decodeString(src, true)
+
+		case additionalTypeTagNetworkAddr:
+			octets := decodeString(src, true)
+			ss := []byte{'"'}
+			switch len(octets) {
+			case 6: // MAC address.
+				ha := net.HardwareAddr(octets)
+				ss = append(append(ss, ha.String()...), '"')
+			case 4: // IPv4 address.
+				fallthrough
+			case 16: // IPv6 address.
+				ip := net.IP(octets)
+				ss = append(append(ss, ip.String()...), '"')
+			default:
+				panic(fmt.Errorf("Unexpected Network Address length: %d (expected 4,6,16)", len(octets)))
+			}
+			return ss
+
+		case additionalTypeTagNetworkPrefix:
+			pb := readByte(src)
+			if pb != majorTypeMap|0x1 {
+				panic(fmt.Errorf("IP Prefix is NOT of MAP of 1 elements as expected"))
+			}
+			octets := decodeString(src, true)
+			val := decodeInteger(src)
+			ip := net.IP(octets)
+			var mask net.IPMask
+			pfxLen := int(val)
+			if len(octets) == 4 {
+				mask = net.CIDRMask(pfxLen, 32)
+			} else {
+				mask = net.CIDRMask(pfxLen, 128)
+			}
+			ipPfx := net.IPNet{IP: ip, Mask: mask}
+			ss := []byte{'"'}
+			ss = append(append(ss, ipPfx.String()...), '"')
+			return ss
+
+		case additionalTypeTagHexString:
+			octets := decodeString(src, true)
+			ss := []byte{'"'}
+			for _, v := range octets {
+				ss = append(ss, hexTable[v>>4], hexTable[v&0x0f])
+			}
+			return append(ss, '"')
+
+		default:
+			panic(fmt.Errorf("Unsupported Additional Tag Type: %d in decodeTagData", val))
+		}
+	}
+	panic(fmt.Errorf("Unsupported Additional Type: %d in decodeTagData", minor))
+}
+
+func decodeTimeStamp(src *bufio.Reader) []byte {
+	pb := readByte(src)
+	src.UnreadByte()
+	tsMajor := pb & maskOutAdditionalType
+	if tsMajor == majorTypeUnsignedInt || tsMajor == majorTypeNegativeInt {
+		n := decodeInteger(src)
+		t := time.Unix(n, 0)
+		if decodeTimeZone != nil {
+			t = t.In(decodeTimeZone)
+		} else {
+			t = t.In(time.UTC)
+		}
+		tsb := []byte{}
+		tsb = append(tsb, '"')
+		tsb = t.AppendFormat(tsb, IntegerTimeFieldFormat)
+		tsb = append(tsb, '"')
+		return tsb
+	} else if tsMajor == majorTypeSimpleAndFloat {
+		n, _ := decodeFloat(src)
+		secs := int64(n)
+		n -= float64(secs)
+		n *= float64(1e9)
+		t := time.Unix(secs, int64(n))
+		if decodeTimeZone != nil {
+			t = t.In(decodeTimeZone)
+		} else {
+			t = t.In(time.UTC)
+		}
+		tsb := []byte{}
+		tsb = append(tsb, '"')
+		tsb = t.AppendFormat(tsb, NanoTimeFieldFormat)
+		tsb = append(tsb, '"')
+		return tsb
+	}
+	panic(fmt.Errorf("TS format is neither int nor float: %d", tsMajor))
+}
+
+func decodeSimpleFloat(src *bufio.Reader) []byte {
+	pb := readByte(src)
+	major := pb & maskOutAdditionalType
+	minor := pb & maskOutMajorType
+	if major != majorTypeSimpleAndFloat {
+		panic(fmt.Errorf("Major type is: %d in decodeSimpleFloat", major))
+	}
+	switch minor {
+	case additionalTypeBoolTrue:
+		return []byte("true")
+	case additionalTypeBoolFalse:
+		return []byte("false")
+	case additionalTypeNull:
+		return []byte("null")
+	case additionalTypeFloat16:
+		fallthrough
+	case additionalTypeFloat32:
+		fallthrough
+	case additionalTypeFloat64:
+		src.UnreadByte()
+		v, bc := decodeFloat(src)
+		ba := []byte{}
+		switch {
+		case math.IsNaN(v):
+			return []byte("\"NaN\"")
+		case math.IsInf(v, 1):
+			return []byte("\"+Inf\"")
+		case math.IsInf(v, -1):
+			return []byte("\"-Inf\"")
+		}
+		if bc == isFloat32 {
+			ba = strconv.AppendFloat(ba, v, 'f', -1, 32)
+		} else if bc == isFloat64 {
+			ba = strconv.AppendFloat(ba, v, 'f', -1, 64)
+		} else {
+			panic(fmt.Errorf("Invalid Float precision from decodeFloat: %d", bc))
+		}
+		return ba
+	default:
+		panic(fmt.Errorf("Invalid Additional Type: %d in decodeSimpleFloat", minor))
+	}
+}
+
+func cbor2JsonOneObject(src *bufio.Reader, dst io.Writer) {
+	pb, e := src.Peek(1)
+	if e != nil {
+		panic(e)
+	}
+	major := (pb[0] & maskOutAdditionalType)
+
+	switch major {
+	case majorTypeUnsignedInt:
+		fallthrough
+	case majorTypeNegativeInt:
+		n := decodeInteger(src)
+		dst.Write([]byte(strconv.Itoa(int(n))))
+
+	case majorTypeByteString:
+		s := decodeString(src, false)
+		dst.Write(s)
+
+	case majorTypeUtf8String:
+		s := decodeUTF8String(src)
+		dst.Write(s)
+
+	case majorTypeArray:
+		array2Json(src, dst)
+
+	case majorTypeMap:
+		map2Json(src, dst)
+
+	case majorTypeTags:
+		s := decodeTagData(src)
+		dst.Write(s)
+
+	case majorTypeSimpleAndFloat:
+		s := decodeSimpleFloat(src)
+		dst.Write(s)
+	}
+}
+
+func moreBytesToRead(src *bufio.Reader) bool {
+	_, e := src.ReadByte()
+	if e == nil {
+		src.UnreadByte()
+		return true
+	}
+	return false
+}
+
+// Cbor2JsonManyObjects decodes all the CBOR Objects read from src
+// reader. It keeps on decoding until reader returns EOF (error when reading).
+// Decoded string is written to the dst. At the end of every CBOR Object
+// newline is written to the output stream.
+//
+// Returns error (if any) that was encountered during decode.
+// The child functions will generate a panic when error is encountered and
+// this function will recover non-runtime Errors and return the reason as error.
+func Cbor2JsonManyObjects(src io.Reader, dst io.Writer) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if _, ok := r.(runtime.Error); ok {
+				panic(r)
+			}
+			err = r.(error)
+		}
+	}()
+	bufRdr := bufio.NewReader(src)
+	for moreBytesToRead(bufRdr) {
+		cbor2JsonOneObject(bufRdr, dst)
+		dst.Write([]byte("\n"))
+	}
+	return nil
+}
+
+// Detect if the bytes to be printed is Binary or not.
+func binaryFmt(p []byte) bool {
+	if len(p) > 0 && p[0] > 0x7F {
+		return true
+	}
+	return false
+}
+
+func getReader(str string) *bufio.Reader {
+	return bufio.NewReader(strings.NewReader(str))
+}
+
+// DecodeIfBinaryToString converts a binary formatted log msg to a
+// JSON formatted String Log message - suitable for printing to Console/Syslog.
+func DecodeIfBinaryToString(in []byte) string {
+	if binaryFmt(in) {
+		var b bytes.Buffer
+		Cbor2JsonManyObjects(strings.NewReader(string(in)), &b)
+		return b.String()
+	}
+	return string(in)
+}
+
+// DecodeObjectToStr checks if the input is a binary format, if so,
+// it will decode a single Object and return the decoded string.
+func DecodeObjectToStr(in []byte) string {
+	if binaryFmt(in) {
+		var b bytes.Buffer
+		cbor2JsonOneObject(getReader(string(in)), &b)
+		return b.String()
+	}
+	return string(in)
+}
+
+// DecodeIfBinaryToBytes checks if the input is a binary format, if so,
+// it will decode all Objects and return the decoded string as byte array.
+func DecodeIfBinaryToBytes(in []byte) []byte {
+	if binaryFmt(in) {
+		var b bytes.Buffer
+		Cbor2JsonManyObjects(bytes.NewReader(in), &b)
+		return b.Bytes()
+	}
+	return in
+}

internal/cbor/decoder_test.go

@@ -0,0 +1,489 @@
+package cbor
+
+import (
+	"bytes"
+	"encoding/hex"
+	"math"
+	"testing"
+	"time"
+
+	"github.com/rs/zerolog/internal"
+)
+
+func TestDecodeInteger(t *testing.T) {
+	for _, tc := range internal.IntegerTestCases {
+		gotv := decodeInteger(getReader(tc.Binary))
+		if gotv != int64(tc.Val) {
+			t.Errorf("decodeInteger(0x%s)=0x%d, want: 0x%d",
+				hex.EncodeToString([]byte(tc.Binary)), gotv, tc.Val)
+		}
+	}
+}
+
+func TestDecodeString(t *testing.T) {
+	for _, tt := range encodeStringTests {
+		got := decodeUTF8String(getReader(tt.binary))
+		if string(got) != "\""+tt.json+"\"" {
+			t.Errorf("DecodeString(0x%s)=%s, want:\"%s\"\n", hex.EncodeToString([]byte(tt.binary)), string(got),
+				hex.EncodeToString([]byte(tt.json)))
+		}
+	}
+}
+
+func TestDecodeArray(t *testing.T) {
+	for _, tc := range internal.IntegerArrayTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		array2Json(getReader(tc.Binary), buf)
+		if buf.String() != tc.Json {
+			t.Errorf("array2Json(0x%s)=%s, want: %s", hex.EncodeToString([]byte(tc.Binary)), buf.String(), tc.Json)
+		}
+	}
+	//Unspecified Length Array
+	var infiniteArrayTestCases = []struct {
+		in  string
+		out string
+	}{
+		{"\x9f\x20\x00\x18\xc8\x14\xff", "[-1,0,200,20]"},
+		{"\x9f\x38\xc7\x29\x18\xc8\x19\x01\x90\xff", "[-200,-10,200,400]"},
+		{"\x9f\x01\x02\x03\xff", "[1,2,3]"},
+		{"\x9f\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x18\x18\x19\xff",
+			"[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]"},
+	}
+	for _, tc := range infiniteArrayTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		array2Json(getReader(tc.in), buf)
+		if buf.String() != tc.out {
+			t.Errorf("array2Json(0x%s)=%s, want: %s", hex.EncodeToString([]byte(tc.out)), buf.String(), tc.out)
+		}
+	}
+	for _, tc := range internal.BooleanArrayTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		array2Json(getReader(tc.Binary), buf)
+		if buf.String() != tc.Json {
+			t.Errorf("array2Json(0x%s)=%s, want: %s", hex.EncodeToString([]byte(tc.Binary)), buf.String(), tc.Json)
+		}
+	}
+	//TODO add cases for arrays of other types
+}
+
+var infiniteMapDecodeTestCases = []struct {
+	Bin  []byte
+	Json string
+}{
+	{[]byte("\xbf\x64IETF\x20\xff"), "{\"IETF\":-1}"},
+	{[]byte("\xbf\x65Array\x84\x20\x00\x18\xc8\x14\xff"), "{\"Array\":[-1,0,200,20]}"},
+}
+
+var mapDecodeTestCases = []struct {
+	Bin  []byte
+	Json string
+}{
+	{[]byte("\xa2\x64IETF\x20"), "{\"IETF\":-1}"},
+	{[]byte("\xa2\x65Array\x84\x20\x00\x18\xc8\x14"), "{\"Array\":[-1,0,200,20]}"},
+	{[]byte("\xa6\x61\x61\x01\x61\x62\x02\x61\x63\x03"), "{\"a\":1,\"b\":2,\"c\":3}"},
+	{[]byte("\xbf\x61a\x01\x61b\x02\xff"), "{\"a\":1,\"b\":2}"},
+}
+
+func TestDecodeMap(t *testing.T) {
+	for _, tc := range mapDecodeTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		map2Json(getReader(string(tc.Bin)), buf)
+		if buf.String() != tc.Json {
+			t.Errorf("map2Json(0x%s)=%s, want: %s", hex.EncodeToString(tc.Bin), buf.String(), tc.Json)
+		}
+	}
+	for _, tc := range infiniteMapDecodeTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		map2Json(getReader(string(tc.Bin)), buf)
+		if buf.String() != tc.Json {
+			t.Errorf("map2Json(0x%s)=%s, want: %s", hex.EncodeToString(tc.Bin), buf.String(), tc.Json)
+		}
+	}
+}
+
+func TestDecodeBool(t *testing.T) {
+	for _, tc := range internal.BooleanTestCases {
+		got := decodeSimpleFloat(getReader(tc.Binary))
+		if string(got) != tc.Json {
+			t.Errorf("decodeSimpleFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Binary)), string(got), tc.Json)
+		}
+	}
+}
+
+func TestDecodeFloat(t *testing.T) {
+	for _, tc := range internal.Float32TestCases {
+		got, _ := decodeFloat(getReader(tc.Binary))
+		if got != float64(tc.Val) && math.IsNaN(got) != math.IsNaN(float64(tc.Val)) {
+			t.Errorf("decodeFloat(0x%s)=%f, want:%f", hex.EncodeToString([]byte(tc.Binary)), got, tc.Val)
+		}
+	}
+	for _, tc := range internal.Float64TestCases {
+		got, _ := decodeFloat(getReader(tc.Binary))
+		if got != tc.Val && math.IsNaN(got) != math.IsNaN(tc.Val) {
+			t.Errorf("decodeFloat(0x%s)=%f, want:%f", hex.EncodeToString([]byte(tc.Binary)), got, tc.Val)
+		}
+	}
+
+	// Test float64 special values with correct CBOR encoding
+	float64Tests := []struct {
+		name  string
+		input string
+		want  float64
+	}{
+		{"float64 NaN", "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00", math.NaN()},
+		{"float64 +Inf", "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00", math.Inf(0)},
+		{"float64 -Inf", "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00", math.Inf(-1)},
+		{"float64 1.0", "\xfb\x3f\xf0\x00\x00\x00\x00\x00\x00", 1.0},
+	}
+
+	for _, tt := range float64Tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, _ := decodeFloat(getReader(tt.input))
+			if math.IsNaN(tt.want) {
+				if !math.IsNaN(got) {
+					t.Errorf("decodeFloat(%q) = %f, want NaN", tt.input, got)
+				}
+			} else if math.IsInf(tt.want, 0) {
+				if !math.IsInf(got, 0) {
+					t.Errorf("decodeFloat(%q) = %f, want +Inf", tt.input, got)
+				}
+			} else if math.IsInf(tt.want, -1) {
+				if !math.IsInf(got, -1) {
+					t.Errorf("decodeFloat(%q) = %f, want -Inf", tt.input, got)
+				}
+			} else if got != tt.want {
+				t.Errorf("decodeFloat(%q) = %f, want %f", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDecodeTimestamp(t *testing.T) {
+	decodeTimeZone, _ = time.LoadLocation("UTC")
+	for _, tc := range internal.TimeIntegerTestcases {
+		tm := decodeTagData(getReader(tc.Binary))
+		if string(tm) != "\""+tc.RfcStr+"\"" {
+			t.Errorf("decodeFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Binary)), tm, tc.RfcStr)
+		}
+	}
+	for _, tc := range internal.TimeFloatTestcases {
+		tm := decodeTagData(getReader(tc.Out))
+		//Since we convert to float and back - it may be slightly off - so
+		//we cannot check for exact equality instead, we'll check it is
+		//very close to each other Less than a Microsecond (lets not yet do nanosec)
+
+		got, _ := time.Parse(string(tm), string(tm))
+		want, _ := time.Parse(tc.RfcStr, tc.RfcStr)
+		if got.Sub(want) > time.Microsecond {
+			t.Errorf("decodeFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Out)), tm, tc.RfcStr)
+		}
+	}
+
+	// Test with decodeTimeZone = nil to cover the else branches
+	oldTimeZone := decodeTimeZone
+	decodeTimeZone = nil
+	defer func() { decodeTimeZone = oldTimeZone }()
+
+	for _, tc := range internal.TimeIntegerTestcases {
+		tm := decodeTagData(getReader(tc.Binary))
+		if string(tm) != "\""+tc.RfcStr+"\"" {
+			t.Errorf("decodeFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Binary)), tm, tc.RfcStr)
+		}
+	}
+	for _, tc := range internal.TimeFloatTestcases {
+		tm := decodeTagData(getReader(tc.Out))
+		got, _ := time.Parse(string(tm), string(tm))
+		want, _ := time.Parse(tc.RfcStr, tc.RfcStr)
+		if got.Sub(want) > time.Microsecond {
+			t.Errorf("decodeFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Out)), tm, tc.RfcStr)
+		}
+	}
+}
+
+func TestDecodeNetworkAddr(t *testing.T) {
+	for _, tc := range internal.IpAddrTestCases {
+		d1 := decodeTagData(getReader(tc.Binary))
+		if string(d1) != tc.Text {
+			t.Errorf("decodeNetworkAddr(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Binary)), d1, tc.Text)
+		}
+	}
+}
+
+func TestDecodeMACAddr(t *testing.T) {
+	for _, tc := range internal.MacAddrTestCases {
+		d1 := decodeTagData(getReader(tc.Binary))
+		if string(d1) != tc.Text {
+			t.Errorf("decodeNetworkAddr(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Binary)), d1, tc.Text)
+		}
+	}
+}
+
+func TestDecodeIPPrefix(t *testing.T) {
+	for _, tc := range internal.IPPrefixTestCases {
+		d1 := decodeTagData(getReader(tc.Binary))
+		if string(d1) != tc.Text {
+			t.Errorf("decodeIPPrefix(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.Binary)), d1, tc.Text)
+		}
+	}
+}
+
+var compositeCborTestCases = []struct {
+	Binary []byte
+	Json   string
+}{
+	{[]byte("\xbf\x64IETF\x20\x65Array\x9f\x20\x00\x18\xc8\x14\xff\xff"), "{\"IETF\":-1,\"Array\":[-1,0,200,20]}\n"},
+	{[]byte("\xbf\x64IETF\x64YES!\x65Array\x9f\x20\x00\x18\xc8\x14\xff\xff"), "{\"IETF\":\"YES!\",\"Array\":[-1,0,200,20]}\n"},
+	{[]byte("\xbf\x61a\x01\x61b\x02\x61c\x03\xff"), "{\"a\":1,\"b\":2,\"c\":3}\n"},
+	{[]byte("\xc1\x1a\x51\x0f\x30\xd8"), "\"2013-02-04T03:54:00Z\"\n"},
+}
+
+func TestDecodeCbor2Json(t *testing.T) {
+	for _, tc := range compositeCborTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		err := Cbor2JsonManyObjects(getReader(string(tc.Binary)), buf)
+		if buf.String() != tc.Json || err != nil {
+			t.Errorf("cbor2JsonManyObjects(0x%s)=%s, want: %s, err:%s", hex.EncodeToString(tc.Binary), buf.String(), tc.Json, err.Error())
+		}
+	}
+}
+
+var negativeCborTestCases = []struct {
+	Binary []byte
+	errStr string
+}{
+	{[]byte("\xb9\x64IETF\x20\x65Array\x9f\x20\x00\x18\xc8\x14"), "Tried to Read 18 Bytes.. But hit end of file"},
+	{[]byte("\xbf\x64IETF\x20\x65Array\x9f\x20\x00\x18\xc8\x14"), "EOF"},
+	{[]byte("\xbf\x14IETF\x20\x65Array\x9f\x20\x00\x18\xc8\x14"), "Tried to Read 40736 Bytes.. But hit end of file"},
+	{[]byte("\xbf\x64IETF"), "EOF"},
+	{[]byte("\xbf\x64IETF\x20\x65Array\x9f\x20\x00\x18\xc8\xff\xff\xff"), "Invalid Additional Type: 31 in decodeSimpleFloat"},
+	{[]byte("\xbf\x64IETF\x20\x65Array"), "EOF"},
+	{[]byte("\xbf\x64"), "Tried to Read 4 Bytes.. But hit end of file"},
+}
+
+func TestDecodeNegativeCbor2Json(t *testing.T) {
+	for _, tc := range negativeCborTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		err := Cbor2JsonManyObjects(getReader(string(tc.Binary)), buf)
+		if err == nil || err.Error() != tc.errStr {
+			t.Errorf("Expected error got:%s, want:%s", err, tc.errStr)
+		}
+	}
+}
+
+func TestBinaryFmt(t *testing.T) {
+	tests := []struct {
+		input []byte
+		want  bool
+	}{
+		{[]byte{}, false},
+		{[]byte{0x00}, false},
+		{[]byte{0x7F}, false},
+		{[]byte{0x80}, true},
+		{[]byte{0xFF}, true},
+		{[]byte{0x00, 0x80}, false}, // Only checks first byte
+	}
+
+	for _, tt := range tests {
+		got := binaryFmt(tt.input)
+		if got != tt.want {
+			t.Errorf("binaryFmt(%v) = %v, want %v", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestDecodeIfBinaryToString(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []byte
+		want  string
+	}{
+		{
+			name:  "non-binary input",
+			input: []byte(`{"key":"value"}`),
+			want:  `{"key":"value"}`,
+		},
+		{
+			name:  "binary input - simple object",
+			input: []byte("\xbf\x64IETF\x20\xff"), // {"IETF": -1} in indefinite length CBOR
+			want:  "{\"IETF\":-1}\n",
+		},
+		{
+			name:  "binary input - multiple objects",
+			input: []byte("\xbf\x64IETF\x20\xff\xbf\x65Array\x84\x20\x00\x18\xc8\x14\xff"), // Two objects
+			want:  "{\"IETF\":-1}\n{\"Array\":[-1,0,200,20]}\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DecodeIfBinaryToString(tt.input)
+			if got != tt.want {
+				t.Errorf("DecodeIfBinaryToString() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDecodeObjectToStr(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []byte
+		want  string
+	}{
+		{
+			name:  "non-binary input",
+			input: []byte(`{"key":"value"}`),
+			want:  `{"key":"value"}`,
+		},
+		{
+			name:  "binary input - simple object",
+			input: []byte("\xbf\x64IETF\x20\xff"), // {"IETF": -1} in indefinite length CBOR
+			want:  "{\"IETF\":-1}",
+		},
+		{
+			name:  "binary input - array",
+			input: []byte("\x84\x20\x00\x18\xc8\x14"), // [-1, 0, 200, 20]
+			want:  "[-1,0,200,20]",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DecodeObjectToStr(tt.input)
+			if got != tt.want {
+				t.Errorf("DecodeObjectToStr() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDecodeIfBinaryToBytes(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []byte
+		want  []byte
+	}{
+		{
+			name:  "non-binary input",
+			input: []byte(`{"key":"value"}`),
+			want:  []byte(`{"key":"value"}`),
+		},
+		{
+			name:  "binary input - simple object",
+			input: []byte("\xbf\x64IETF\x20\xff"), // {"IETF": -1} in indefinite length CBOR
+			want:  []byte("{\"IETF\":-1}\n"),
+		},
+		{
+			name:  "binary input - multiple objects",
+			input: []byte("\xbf\x64IETF\x20\xff\xbf\x65Array\x84\x20\x00\x18\xc8\x14\xff"), // Two objects
+			want:  []byte("{\"IETF\":-1}\n{\"Array\":[-1,0,200,20]}\n"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DecodeIfBinaryToBytes(tt.input)
+			if !bytes.Equal(got, tt.want) {
+				t.Errorf("DecodeIfBinaryToBytes() = %q, want %q", string(got), string(tt.want))
+			}
+		})
+	}
+}
+
+func TestDecodeEmbeddedCBOR(t *testing.T) {
+	// Test embedded CBOR tag: 0xD8 0x3F (tag 63) followed by byte string
+	// 0xD8 = major type 6 (tags) + additional type 24 (uint8 follows)
+	// 0x3F = 63 (additionalTypeEmbeddedCBOR)
+	// 0x43 = major type 2 (byte string) + length 3
+	// 0x01 0x02 0x03 = the embedded CBOR data
+
+	embeddedCBOR := []byte("\xd8\x3f\x43\x01\x02\x03")
+	expected := "\"data:application/cbor;base64,AQID\""
+
+	got := decodeTagData(getReader(string(embeddedCBOR)))
+	if string(got) != expected {
+		t.Errorf("decodeTagData(embedded CBOR) = %q, want %q", string(got), expected)
+	}
+}
+
+func TestDecodeEmbeddedJSON(t *testing.T) {
+	t.Run("valid embedded JSON", func(t *testing.T) {
+		// Test embedded JSON tag: 0xD9 0x01 0x06 (tag 262) followed by byte string.
+		// 0xD9 = major type 6 (tags) + additional type 25 (uint16 follows)
+		// 0x01 0x06 = 262 (additionalTypeEmbeddedJSON)
+		// 0x47 = major type 2 (byte string) + length 7
+		// {"a":1} = embedded JSON payload (no surrounding quotes expected)
+		embeddedJSON := []byte("\xd9\x01\x06\x47{\"a\":1}")
+		expected := "{\"a\":1}"
+
+		got := decodeTagData(getReader(string(embeddedJSON)))
+		if string(got) != expected {
+			t.Errorf("decodeTagData(embedded JSON) = %q, want %q", string(got), expected)
+		}
+	})
+
+	t.Run("unsupported embedded type panics", func(t *testing.T) {
+		// Same embedded JSON tag, but followed by a UTF-8 string instead of a byte string.
+		// This should hit the "Unsupported embedded Type" panic branch.
+		bad := []byte("\xd9\x01\x06\x61x")
+
+		defer func() {
+			if r := recover(); r == nil {
+				t.Fatalf("expected panic, got none")
+			}
+		}()
+
+		_ = decodeTagData(getReader(string(bad)))
+	})
+}
+
+func TestDecodeHexString(t *testing.T) {
+	// Test hex string tag: 0xD9 0x01 0x07 (tag 263) followed by byte string
+	// 0xD9 = major type 6 (tags) + additional type 25 (uint16 follows)
+	// 0x01 0x07 = 263 (additionalTypeTagHexString)
+	// 0x43 = major type 2 (byte string) + length 3
+	// 0x01 0x02 0x03 = the byte data to hex encode
+
+	hexString := []byte("\xd9\x01\x07\x43\x01\x02\x03")
+	expected := "\"010203\""
+
+	got := decodeTagData(getReader(string(hexString)))
+	if string(got) != expected {
+		t.Errorf("decodeTagData(hex string) = %q, want %q", string(got), expected)
+	}
+}
+
+func TestDecodeSimpleFloat(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		// Boolean and null cases (already covered)
+		{"true", "\xf5", "true"},
+		{"false", "\xf4", "false"},
+		{"null", "\xf6", "null"},
+
+		// Float32 cases
+		{"float32 1.0", "\xfa\x3f\x80\x00\x00", "1"},
+		{"float32 1.5", "\xfa\x3f\xc0\x00\x00", "1.5"},
+		{"float32 +Inf", "\xfa\x7f\x80\x00\x00", "\"+Inf\""},
+		{"float32 -Inf", "\xfa\xff\x80\x00\x00", "\"-Inf\""},
+		{"float32 NaN", "\xfa\x7f\xc0\x00\x00", "\"NaN\""},
+
+		// Float64 cases
+		{"float64 1.0", "\xfb\x3f\xf0\x00\x00\x00\x00\x00\x00", "1"},
+		{"float64 +Inf", "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00", "\"+Inf\""},
+		{"float64 -Inf", "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00", "\"-Inf\""},
+		{"float64 NaN", "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00", "\"NaN\""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := decodeSimpleFloat(getReader(tt.input))
+			if string(got) != tt.want {
+				t.Errorf("decodeSimpleFloat(%q) = %q, want %q", tt.input, string(got), tt.want)
+			}
+		})
+	}
+}

internal/cbor/examples/genLog.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"compress/zlib"
+	"flag"
+	"io"
+	"log"
+	"os"
+	"time"
+
+	"github.com/rs/zerolog"
+)
+
+func writeLog(fname string, count int, useCompress bool) {
+	opFile := os.Stdout
+	if fname != "<stdout>" {
+		fil, _ := os.Create(fname)
+		opFile = fil
+		defer func() {
+			if err := fil.Close(); err != nil {
+				log.Fatal(err)
+			}
+		}()
+	}
+
+	var f io.WriteCloser = opFile
+	if useCompress {
+		f = zlib.NewWriter(f)
+		defer func() {
+			if err := f.Close(); err != nil {
+				log.Fatal(err)
+			}
+		}()
+
+	}
+
+	zerolog.TimestampFunc = func() time.Time { return time.Now().Round(time.Second) }
+	log := zerolog.New(f).With().
+		Timestamp().
+		Logger()
+	for i := 0; i < count; i++ {
+		log.Error().
+			Int("Fault", 41650+i).Msg("Some Message")
+	}
+}
+
+func main() {
+	outFile := flag.String("out", "<stdout>", "Output File to which logs will be written to (WILL overwrite if already present).")
+	numLogs := flag.Int("num", 10, "Number of log messages to generate.")
+	doCompress := flag.Bool("compress", false, "Enable inline compressed writer")
+
+	flag.Parse()
+
+	writeLog(*outFile, *numLogs, *doCompress)
+}

internal/cbor/examples/makefile

@@ -0,0 +1,10 @@
+all: genLogJSON genLogCBOR
+
+genLogJSON: genLog.go
+	go build -o genLogJSON genLog.go 
+
+genLogCBOR: genLog.go
+	go build -tags binary_log -o genLogCBOR genLog.go 
+
+clean:
+	rm -f genLogJSON genLogCBOR

internal/cbor/string.go

@@ -0,0 +1,117 @@
+package cbor
+
+import "fmt"
+
+// AppendStrings encodes and adds an array of strings to the dst byte array.
+func (e Encoder) AppendStrings(dst []byte, vals []string) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendString(dst, v)
+	}
+	return dst
+}
+
+// AppendString encodes and adds a string to the dst byte array.
+func (Encoder) AppendString(dst []byte, s string) []byte {
+	major := majorTypeUtf8String
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, majorTypeUtf8String, uint64(l))
+	}
+	return append(dst, s...)
+}
+
+// AppendStringers encodes and adds an array of Stringer values
+// to the dst byte array.
+func (e Encoder) AppendStringers(dst []byte, vals []fmt.Stringer) []byte {
+	if vals == nil || len(vals) == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	dst = e.AppendArrayStart(dst)
+	dst = e.AppendStringer(dst, vals[0])
+	if len(vals) > 1 {
+		for _, val := range vals[1:] {
+			dst = e.AppendStringer(dst, val)
+		}
+	}
+	return e.AppendArrayEnd(dst)
+}
+
+// AppendStringer encodes and adds the Stringer value to the dst
+// byte array.
+func (e Encoder) AppendStringer(dst []byte, val fmt.Stringer) []byte {
+	if val == nil {
+		return e.AppendNil(dst)
+	}
+	return e.AppendString(dst, val.String())
+}
+
+// AppendBytes encodes and adds an array of bytes to the dst byte array.
+func (Encoder) AppendBytes(dst, s []byte) []byte {
+	major := majorTypeByteString
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	return append(dst, s...)
+}
+
+// AppendEmbeddedJSON adds a tag and embeds input JSON as such.
+func AppendEmbeddedJSON(dst, s []byte) []byte {
+	major := majorTypeTags
+	minor := additionalTypeEmbeddedJSON
+
+	// Append the TAG to indicate this is Embedded JSON.
+	dst = append(dst, major|additionalTypeIntUint16)
+	dst = append(dst, byte(minor>>8))
+	dst = append(dst, byte(minor&0xff))
+
+	// Append the JSON Object as Byte String.
+	major = majorTypeByteString
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	return append(dst, s...)
+}
+
+// AppendEmbeddedCBOR adds a tag and embeds input CBOR as such.
+func AppendEmbeddedCBOR(dst, s []byte) []byte {
+	major := majorTypeTags
+	minor := additionalTypeEmbeddedCBOR
+
+	// Append the TAG to indicate this is Embedded JSON.
+	dst = append(dst, major|additionalTypeIntUint8)
+	dst = append(dst, minor)
+
+	// Append the CBOR Object as Byte String.
+	major = majorTypeByteString
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	return append(dst, s...)
+}

internal/cbor/string_test.go

@@ -0,0 +1,283 @@
+package cbor
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+
+	"github.com/rs/zerolog/internal"
+)
+
+var encodeStringTests = []struct {
+	plain  string
+	binary string
+	json   string //begin and end quotes are implied
+}{
+	{"", "\x60", ""},
+	{"\\", "\x61\x5c", "\\\\"},
+	{"\"", "\x61\x22", "\\\""},
+	{"\b", "\x61\x08", "\\b"},
+	{"\f", "\x61\x0c", "\\f"},
+	{"\n", "\x61\x0a", "\\n"},
+	{"\r", "\x61\x0d", "\\r"},
+	{"\t", "\x61\x09", "\\t"},
+	{"Hi\t", "\x63Hi\x09", "Hi\\t"},
+	{"\x00", "\x61\x00", "\\u0000"},
+	{"\x01", "\x61\x01", "\\u0001"},
+	{"\x02", "\x61\x02", "\\u0002"},
+	{"\x03", "\x61\x03", "\\u0003"},
+	{"\x04", "\x61\x04", "\\u0004"},
+	{"*", "\x61*", "*"},
+	{"a", "\x61a", "a"},
+	{"IETF", "\x64IETF", "IETF"},
+	{"abcdefghijklmnopqrstuvwxyzABCD", "\x78\x1eabcdefghijklmnopqrstuvwxyzABCD", "abcdefghijklmnopqrstuvwxyzABCD"},
+	{"<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->",
+		"\x79\x01\x2c<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->",
+		"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->"},
+	{"emoji \u2764\ufe0f!", "\x6demoji ❤️!", "emoji \u2764\ufe0f!"},
+	{"invalid utf8 \xff", "\x6einvalid utf8 \xff", "invalid utf8 \\ufffd"},
+}
+
+var encodeByteTests = []struct {
+	plain  []byte
+	binary string
+}{
+	{[]byte{}, "\x40"},
+	{[]byte("\\"), "\x41\x5c"},
+	{[]byte("\x00"), "\x41\x00"},
+	{[]byte("\x01"), "\x41\x01"},
+	{[]byte("\x02"), "\x41\x02"},
+	{[]byte("\x03"), "\x41\x03"},
+	{[]byte("\x04"), "\x41\x04"},
+	{[]byte("\f"), "\x41\x0C"},
+	{[]byte("\n"), "\x41\x0A"},
+	{[]byte("\r"), "\x41\x0D"},
+	{[]byte("*"), "\x41*"},
+	{[]byte("a"), "\x41a"},
+	{[]byte("IETF"), "\x44IETF"},
+	{[]byte("abcdefghijklmnopqrstuvwxyzABCD"), "\x58\x1eabcdefghijklmnopqrstuvwxyzABCD"},
+	{[]byte("<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->"),
+		"\x59\x01\x2c<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->"},
+	{[]byte("emoji \u2764\ufe0f!"), "\x4demoji ❤️!"},
+}
+
+func TestAppendString(t *testing.T) {
+	for _, tt := range encodeStringTests {
+		b := enc.AppendString([]byte{}, tt.plain)
+		if got, want := string(b), tt.binary; got != want {
+			t.Errorf("appendString(%q) = %#q, want %#q", tt.plain, got, want)
+		}
+	}
+	//Test a large string > 65535 length
+
+	var buffer bytes.Buffer
+	for i := 0; i < 0x00011170; i++ { //70,000 character string
+		buffer.WriteString("a")
+	}
+	inp := buffer.String()
+	want := "\x7a\x00\x01\x11\x70" + inp
+	b := enc.AppendString([]byte{}, inp)
+	if got := string(b); got != want {
+		t.Errorf("appendString(%q) = %#q, want %#q", inp, got, want)
+	}
+}
+func TestAppendStrings(t *testing.T) {
+	array := []string{}
+	for _, tt := range encodeStringTests {
+		array = append(array, tt.plain)
+	}
+	want := make([]byte, 0)
+	want = append(want, 0x95) // start array
+	for _, tt := range encodeStringTests {
+		want = append(want, []byte(tt.binary)...)
+	}
+
+	got := enc.AppendStrings([]byte{}, array)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendStrings(%v)\ngot:  0x%s\nwant: 0x%s",
+			array,
+			hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now empty array case
+	array = make([]string, 0)
+	want = make([]byte, 0)
+	want = append(want, 0x80) // start an empty string array
+	got = enc.AppendStrings([]byte{}, array)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendStrings(%v)\ngot:  0x%s\nwant: 0x%s",
+			array, hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now large array case
+	array = make([]string, 24)
+	want = make([]byte, 0)
+	want = append(want, 0x98) // start a large array
+	want = append(want, 0x18) // of length 24
+	for i := 0; i < len(array); i++ {
+		array[i] = "test"
+		want = append(want, []byte("\x64test")...)
+	}
+	got = enc.AppendStrings([]byte{}, array)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendStrings(%v)\ngot:  %s\nwant: %s",
+			array,
+			hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+}
+
+func TestAppendStringer(t *testing.T) {
+	oldJSONMarshalFunc := JSONMarshalFunc
+	defer func() {
+		JSONMarshalFunc = oldJSONMarshalFunc
+	}()
+
+	JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return internal.InterfaceMarshalFunc(v)
+	}
+
+	for _, tt := range internal.EncodeStringerTests {
+		got := enc.AppendStringer([]byte{}, tt.In)
+		want := []byte(tt.Binary)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendStrings(%v)\ngot:  %s\nwant: %s",
+				tt.In,
+				hex.EncodeToString(got),
+				hex.EncodeToString(want))
+		}
+	}
+}
+
+func TestAppendStringers(t *testing.T) {
+	for _, tt := range internal.EncodeStringersTests {
+		want := make([]byte, 0)
+		want = append(want, []byte(tt.Binary)...)
+
+		got := enc.AppendStringers([]byte{}, tt.In)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendStrings(%v)\ngot:  %s\nwant: %s",
+				tt,
+				hex.EncodeToString(got),
+				hex.EncodeToString(want))
+		}
+	}
+}
+
+func TestAppendBytes(t *testing.T) {
+	for _, tt := range encodeByteTests {
+		b := enc.AppendBytes([]byte{}, tt.plain)
+		if got, want := string(b), tt.binary; got != want {
+			t.Errorf("appendString(%q) = %#q, want %#q", tt.plain, got, want)
+		}
+	}
+	//Test a large string > 65535 length
+
+	inp := []byte{}
+	for i := 0; i < 0x00011170; i++ { //70,000 character string
+		inp = append(inp, byte('a'))
+	}
+	want := "\x5a\x00\x01\x11\x70" + string(inp)
+	b := enc.AppendBytes([]byte{}, inp)
+	if got := string(b); got != want {
+		t.Errorf("appendString(%q) = %#q, want %#q", inp, got, want)
+	}
+}
+
+func BenchmarkAppendString(b *testing.B) {
+	tests := map[string]string{
+		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingMiddle":   `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingLast":     `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
+		"MultiBytesFirst":  `❤️aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤️aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesLast":   `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤️`,
+	}
+	for name, str := range tests {
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 120)
+			for i := 0; i < b.N; i++ {
+				_ = enc.AppendString(buf, str)
+			}
+		})
+	}
+}
+
+func TestAppendEmbeddedJSON(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []byte
+		want  string
+	}{
+		{
+			name:  "empty JSON",
+			input: []byte{},
+			want:  "\xd9\x01\x06@", // tag 0xd9 + empty byte string
+		},
+		{
+			name:  "small JSON",
+			input: []byte(`{"key":"value"}`),
+			want:  "\xd9\x01\x06O{\"key\":\"value\"}", // tag 0xd9 + byte string with content
+		},
+		{
+			name:  "large JSON (>23 bytes)",
+			input: []byte(`{"key":"this is a very long value that exceeds the 23 byte limit for direct encoding"}`),
+			want:  "\xd9\x01\x06XV{\"key\":\"this is a very long value that exceeds the 23 byte limit for direct encoding\"}",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := AppendEmbeddedJSON([]byte{}, tt.input)
+			if string(got) != tt.want {
+				t.Errorf("AppendEmbeddedJSON() = %q, want %q", string(got), tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendEmbeddedCBOR(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []byte
+		want  string
+	}{
+		{
+			name:  "empty CBOR",
+			input: []byte{},
+			want:  "\xd8?@", // tag 0xd8 + empty byte string
+		},
+		{
+			name:  "small CBOR",
+			input: []byte{0x01, 0x02, 0x03},
+			want:  "\xd8?C\x01\x02\x03", // tag 0xd8 + byte string with 3 bytes
+		},
+		{
+			name:  "large CBOR (>23 bytes)",
+			input: make([]byte, 30),                        // 30 bytes of zeros
+			want:  "\xd8?X\x1e" + string(make([]byte, 30)), // tag 0xd8 + byte string with length prefix
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := AppendEmbeddedCBOR([]byte{}, tt.input)
+			if string(got) != tt.want {
+				t.Errorf("AppendEmbeddedCBOR() = %q, want %q", string(got), tt.want)
+			}
+		})
+	}
+}

internal/cbor/time.go

@@ -0,0 +1,111 @@
+package cbor
+
+import (
+	"time"
+)
+
+const (
+	// Import from zerolog/global.go
+	timeFormatUnix       = ""
+	timeFormatUnixMs     = "UNIXMS"
+	timeFormatUnixMicro  = "UNIXMICRO"
+	timeFormatUnixNano   = "UNIXNANO"
+	durationFormatFloat  = "float"
+	durationFormatInt    = "int"
+	durationFormatString = "string"
+)
+
+func appendIntegerTimestamp(dst []byte, t time.Time) []byte {
+	major := majorTypeTags
+	minor := additionalTypeTimestamp
+	dst = append(dst, major|minor)
+	secs := t.Unix()
+	var val uint64
+	if secs < 0 {
+		major = majorTypeNegativeInt
+		val = uint64(-secs - 1)
+	} else {
+		major = majorTypeUnsignedInt
+		val = uint64(secs)
+	}
+	dst = appendCborTypePrefix(dst, major, val)
+	return dst
+}
+
+func (e Encoder) appendFloatTimestamp(dst []byte, t time.Time) []byte {
+	major := majorTypeTags
+	minor := additionalTypeTimestamp
+	dst = append(dst, major|minor)
+	secs := t.Unix()
+	nanos := t.Nanosecond()
+	val := float64(secs)*1.0 + float64(nanos)*1e-9
+	return e.AppendFloat64(dst, val, -1)
+}
+
+// AppendTime encodes and adds a timestamp to the dst byte array.
+func (e Encoder) AppendTime(dst []byte, t time.Time, unused string) []byte {
+	utc := t.UTC()
+	if utc.Nanosecond() == 0 {
+		return appendIntegerTimestamp(dst, utc)
+	}
+	return e.appendFloatTimestamp(dst, utc)
+}
+
+// AppendTimes encodes and adds an array of timestamps to the dst byte array.
+func (e Encoder) AppendTimes(dst []byte, vals []time.Time, unused string) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+
+	for _, t := range vals {
+		dst = e.AppendTime(dst, t, unused)
+	}
+	return dst
+}
+
+// AppendDuration encodes and adds a duration to the dst byte array.
+// useInt field indicates whether to store the duration as seconds (integer) or
+// as seconds+nanoseconds (float).
+func (e Encoder) AppendDuration(dst []byte, d time.Duration, unit time.Duration, format string, useInt bool, unused int) []byte {
+	if useInt {
+		return e.AppendInt64(dst, int64(d/unit))
+	}
+	switch format {
+	case durationFormatFloat:
+		return e.AppendFloat64(dst, float64(d)/float64(unit), unused)
+	case durationFormatInt:
+		return e.AppendInt64(dst, int64(d/unit))
+	case durationFormatString:
+		return e.AppendString(dst, d.String())
+	}
+	return e.AppendFloat64(dst, float64(d)/float64(unit), unused)
+}
+
+// AppendDurations encodes and adds an array of durations to the dst byte array.
+// useInt field indicates whether to store the duration as seconds (integer) or
+// as seconds+nanoseconds (float).
+func (e Encoder) AppendDurations(dst []byte, vals []time.Duration, unit time.Duration, format string, useInt bool, unused int) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, d := range vals {
+		dst = e.AppendDuration(dst, d, unit, format, useInt, unused)
+	}
+	return dst
+}

internal/cbor/time_test.go

@@ -0,0 +1,348 @@
+package cbor
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"math"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/rs/zerolog/internal"
+)
+
+func TestEncoder_AppendDuration(t *testing.T) {
+	type args struct {
+		dst    []byte
+		d      time.Duration
+		unit   time.Duration
+		format string
+		useInt bool
+		unused int
+	}
+	tests := []struct {
+		name string
+		args args
+		want []byte
+	}{
+		{
+			name: "useInt",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				useInt: true,
+			},
+			want: []byte{1},
+		},
+		{
+			name: "formatFloat",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				format: durationFormatFloat,
+			},
+			want: []byte{251, 63, 243, 192, 202, 66, 131, 222, 27},
+		},
+		{
+			name: "formatInt",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				format: durationFormatInt,
+			},
+			want: []byte{1},
+		},
+		{
+			name: "formatString",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				format: durationFormatString,
+			},
+			want: []byte{107, 49, 46, 50, 51, 52, 53, 54, 55, 56, 57, 115},
+		},
+		{
+			name: "formatBlank",
+			args: args{
+				d:    1234567890,
+				unit: time.Second,
+			},
+			want: []byte{251, 63, 243, 192, 202, 66, 131, 222, 27},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := Encoder{}
+			if got := e.AppendDuration(tt.args.dst, tt.args.d, tt.args.unit, tt.args.format, tt.args.useInt, tt.args.unused); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("AppendDuration() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestEncoder_AppendDurations(t *testing.T) {
+	type args struct {
+		dst    []byte
+		vals   []time.Duration
+		unit   time.Duration
+		format string
+		useInt bool
+		unused int
+	}
+	tests := []struct {
+		name string
+		args args
+		want []byte
+	}{
+		{
+			name: "useInt",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				useInt: true,
+			},
+			want: []byte{129, 1},
+		},
+		{
+			name: "formatFloat",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				format: durationFormatFloat,
+			},
+			want: []byte{129, 251, 63, 243, 192, 202, 66, 131, 222, 27},
+		},
+		{
+			name: "formatInt",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				format: durationFormatInt,
+			},
+			want: []byte{129, 1},
+		},
+		{
+			name: "formatString",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				format: durationFormatString,
+			},
+			want: []byte{129, 107, 49, 46, 50, 51, 52, 53, 54, 55, 56, 57, 115},
+		},
+		{
+			name: "formatBlank",
+			args: args{
+				vals: []time.Duration{1234567890},
+				unit: time.Second,
+			},
+			want: []byte{129, 251, 63, 243, 192, 202, 66, 131, 222, 27},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := Encoder{}
+			if got := e.AppendDurations(tt.args.dst, tt.args.vals, tt.args.unit, tt.args.format, tt.args.useInt, tt.args.unused); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("AppendDurations() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendTimeNow(t *testing.T) {
+	tm := time.Now()
+	s := enc.AppendTime([]byte{}, tm, "unused")
+	got := string(s)
+
+	tm1 := float64(tm.Unix()) + float64(tm.Nanosecond())*1e-9
+	tm2 := math.Float64bits(tm1)
+	var tm3 [8]byte
+	for i := uint(0); i < 8; i++ {
+		tm3[i] = byte(tm2 >> ((8 - i - 1) * 8))
+	}
+	want := append([]byte{0xc1, 0xfb}, tm3[:]...)
+	if got != string(want) {
+		t.Errorf("Appendtime(%s)=0x%s, want: 0x%s",
+			"time.Now()", hex.EncodeToString(s),
+			hex.EncodeToString(want))
+	}
+}
+
+func TestAppendTimePastPresentInteger(t *testing.T) {
+	for _, tt := range internal.TimeIntegerTestcases {
+		tin, err := time.Parse(time.RFC3339, tt.Txt)
+		if err != nil {
+			fmt.Println("Cannot parse input", tt.Txt, ".. Skipping!", err)
+			continue
+		}
+		b := enc.AppendTime([]byte{}, tin, "unused")
+		if got, want := string(b), tt.Binary; got != want {
+			t.Errorf("appendString(%s) = 0x%s, want 0x%s", tt.Txt,
+				hex.EncodeToString(b),
+				hex.EncodeToString([]byte(want)))
+		}
+	}
+}
+
+func TestAppendTimePastPresentFloat(t *testing.T) {
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+	for _, tt := range internal.TimeFloatTestcases {
+		tin, err := time.Parse(timeFloatFmt, tt.RfcStr)
+		if err != nil {
+			fmt.Println("Cannot parse input", tt.RfcStr, ".. Skipping!")
+			continue
+		}
+		b := enc.AppendTime([]byte{}, tin, "unused")
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("appendString(%s) = 0x%s, want 0x%s", tt.RfcStr,
+				hex.EncodeToString(b),
+				hex.EncodeToString([]byte(want)))
+		}
+	}
+}
+func TestAppendTimes(t *testing.T) {
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+	array := make([]time.Time, len(internal.TimeFloatTestcases))
+	want := make([]byte, 0)
+	want = append(want, 0x82) // start small array
+	for i, tt := range internal.TimeFloatTestcases {
+		array[i], _ = time.Parse(timeFloatFmt, tt.RfcStr)
+		want = append(want, []byte(tt.Out)...)
+	}
+
+	got := enc.AppendTimes([]byte{}, array, "unused")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendTimes(%v)\ngot:  0x%s\nwant: 0x%s",
+			array, hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now empty array case
+	array = make([]time.Time, 0)
+	want = make([]byte, 0)
+	want = append(want, 0x9f) // start and end array
+	want = append(want, 0xff) // for empty array
+	got = enc.AppendTimes([]byte{}, array, "unused")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendTimes(%v)\ngot:  0x%s\nwant: 0x%s",
+			array, hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now large array case
+	testtime, _ := time.Parse(timeFloatFmt, internal.TimeFloatTestcases[0].RfcStr)
+	outbytes := internal.TimeFloatTestcases[0].Out
+	array = make([]time.Time, 24)
+	want = make([]byte, 0)
+	want = append(want, 0x98) // start a large array
+	want = append(want, 0x18) // of length 24
+	for i := 0; i < len(array); i++ {
+		array[i] = testtime
+		want = append(want, []byte(outbytes)...)
+	}
+	got = enc.AppendTimes([]byte{}, array, "unused")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendTimes(%v)\ngot:  0x%s\nwant: 0x%s",
+			array,
+			hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+}
+
+func TestAppendDurationFloat(t *testing.T) {
+	for _, tt := range internal.DurTestcases {
+		dur := tt.Duration
+		want := []byte{}
+		want = append(want, []byte(tt.FloatOut)...)
+		got := enc.AppendDuration([]byte{}, dur, time.Microsecond, "", false, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendDuration(%v)=\ngot:  0x%s\nwant: 0x%s",
+				dur,
+				hex.EncodeToString(got),
+				hex.EncodeToString(want))
+		}
+	}
+}
+func TestAppendDurationInteger(t *testing.T) {
+	for _, tt := range internal.DurTestcases {
+		dur := tt.Duration
+		want := []byte{}
+		want = append(want, []byte(tt.IntegerOut)...)
+		got := enc.AppendDuration([]byte{}, dur, time.Microsecond, "", true, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendDuration(%v)=\ngot:  0x%s\nwant: 0x%s",
+				dur,
+				hex.EncodeToString(got),
+				hex.EncodeToString(want))
+		}
+	}
+}
+func TestAppendDurations(t *testing.T) {
+	array := make([]time.Duration, len(internal.DurTestcases))
+	want := make([]byte, 0)
+	want = append(want, 0x83) // start 3 element array
+	for i, tt := range internal.DurTestcases {
+		array[i] = tt.Duration
+		want = append(want, []byte(tt.FloatOut)...)
+	}
+
+	got := enc.AppendDurations([]byte{}, array, time.Microsecond, "", false, -1)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendDurations(%v)\ngot:  0x%s\nwant: 0x%s",
+			array, hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now empty array case
+	array = make([]time.Duration, 0)
+	want = make([]byte, 0)
+	want = append(want, 0x9f) // start and end array
+	want = append(want, 0xff) // for empty array
+	got = enc.AppendDurations([]byte{}, array, time.Microsecond, "", false, -1)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendDurations(%v)\ngot:  0x%s\nwant: 0x%s",
+			array, hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now large array case
+	testtime := internal.DurTestcases[0].Duration
+	outbytes := internal.DurTestcases[0].FloatOut
+	array = make([]time.Duration, 24)
+	want = make([]byte, 0)
+	want = append(want, 0x98) // start a large array
+	want = append(want, 0x18) // of length 24
+	for i := 0; i < len(array); i++ {
+		array[i] = testtime
+		want = append(want, []byte(outbytes)...)
+	}
+	got = enc.AppendDurations([]byte{}, array, time.Microsecond, "", false, -1)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendDurations(%v)\ngot:  0x%s\nwant: 0x%s",
+			array,
+			hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+}
+
+func BenchmarkAppendTime(b *testing.B) {
+	tests := map[string]string{
+		"Integer": "Feb 3, 2013 at 7:54pm (PST)",
+		"Float":   "2006-01-02T15:04:05.999999-08:00",
+	}
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+
+	for name, str := range tests {
+		t, err := time.Parse(time.RFC3339, str)
+		if err != nil {
+			t, _ = time.Parse(timeFloatFmt, str)
+		}
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				_ = enc.AppendTime(buf, t, "unused")
+			}
+		})
+	}
+}

internal/cbor/types.go

@@ -0,0 +1,524 @@
+package cbor
+
+import (
+	"fmt"
+	"math"
+	"net"
+	"reflect"
+)
+
+// AppendNil inserts a 'Nil' object into the dst byte array.
+func (Encoder) AppendNil(dst []byte) []byte {
+	return append(dst, majorTypeSimpleAndFloat|additionalTypeNull)
+}
+
+// AppendBeginMarker inserts a map start into the dst byte array.
+func (Encoder) AppendBeginMarker(dst []byte) []byte {
+	return append(dst, majorTypeMap|additionalTypeInfiniteCount)
+}
+
+// AppendEndMarker inserts a map end into the dst byte array.
+func (Encoder) AppendEndMarker(dst []byte) []byte {
+	return append(dst, majorTypeSimpleAndFloat|additionalTypeBreak)
+}
+
+// AppendObjectData takes an object in form of a byte array and appends to dst.
+func (Encoder) AppendObjectData(dst []byte, o []byte) []byte {
+	// BeginMarker is present in the dst, which
+	// should not be copied when appending to existing data.
+	return append(dst, o[1:]...)
+}
+
+// AppendArrayStart adds markers to indicate the start of an array.
+func (Encoder) AppendArrayStart(dst []byte) []byte {
+	return append(dst, majorTypeArray|additionalTypeInfiniteCount)
+}
+
+// AppendArrayEnd adds markers to indicate the end of an array.
+func (Encoder) AppendArrayEnd(dst []byte) []byte {
+	return append(dst, majorTypeSimpleAndFloat|additionalTypeBreak)
+}
+
+// AppendArrayDelim adds markers to indicate end of a particular array element.
+func (Encoder) AppendArrayDelim(dst []byte) []byte {
+	//No delimiters needed in cbor
+	return dst
+}
+
+// AppendLineBreak is a noop that keep API compat with json encoder.
+func (Encoder) AppendLineBreak(dst []byte) []byte {
+	// No line breaks needed in binary format.
+	return dst
+}
+
+// AppendBool encodes and inserts a boolean value into the dst byte array.
+func (Encoder) AppendBool(dst []byte, val bool) []byte {
+	b := additionalTypeBoolFalse
+	if val {
+		b = additionalTypeBoolTrue
+	}
+	return append(dst, majorTypeSimpleAndFloat|b)
+}
+
+// AppendBools encodes and inserts an array of boolean values into the dst byte array.
+func (e Encoder) AppendBools(dst []byte, vals []bool) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendBool(dst, v)
+	}
+	return dst
+}
+
+// AppendInt encodes and inserts an integer value into the dst byte array.
+func (Encoder) AppendInt(dst []byte, val int) []byte {
+	major := majorTypeUnsignedInt
+	contentVal := val
+	if val < 0 {
+		major = majorTypeNegativeInt
+		contentVal = -val - 1
+	}
+	if contentVal <= additionalMax {
+		lb := byte(contentVal)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
+	}
+	return dst
+}
+
+// AppendInts encodes and inserts an array of integer values into the dst byte array.
+func (e Encoder) AppendInts(dst []byte, vals []int) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendInt(dst, v)
+	}
+	return dst
+}
+
+// AppendInt8 encodes and inserts an int8 value into the dst byte array.
+func (e Encoder) AppendInt8(dst []byte, val int8) []byte {
+	return e.AppendInt(dst, int(val))
+}
+
+// AppendInts8 encodes and inserts an array of integer values into the dst byte array.
+func (e Encoder) AppendInts8(dst []byte, vals []int8) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendInt(dst, int(v))
+	}
+	return dst
+}
+
+// AppendInt16 encodes and inserts a int16 value into the dst byte array.
+func (e Encoder) AppendInt16(dst []byte, val int16) []byte {
+	return e.AppendInt(dst, int(val))
+}
+
+// AppendInts16 encodes and inserts an array of int16 values into the dst byte array.
+func (e Encoder) AppendInts16(dst []byte, vals []int16) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendInt(dst, int(v))
+	}
+	return dst
+}
+
+// AppendInt32 encodes and inserts a int32 value into the dst byte array.
+func (e Encoder) AppendInt32(dst []byte, val int32) []byte {
+	return e.AppendInt(dst, int(val))
+}
+
+// AppendInts32 encodes and inserts an array of int32 values into the dst byte array.
+func (e Encoder) AppendInts32(dst []byte, vals []int32) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendInt(dst, int(v))
+	}
+	return dst
+}
+
+// AppendInt64 encodes and inserts a int64 value into the dst byte array.
+func (Encoder) AppendInt64(dst []byte, val int64) []byte {
+	major := majorTypeUnsignedInt
+	contentVal := val
+	if val < 0 {
+		major = majorTypeNegativeInt
+		contentVal = -val - 1
+	}
+	if contentVal <= additionalMax {
+		lb := byte(contentVal)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
+	}
+	return dst
+}
+
+// AppendInts64 encodes and inserts an array of int64 values into the dst byte array.
+func (e Encoder) AppendInts64(dst []byte, vals []int64) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendInt64(dst, v)
+	}
+	return dst
+}
+
+// AppendUint encodes and inserts an unsigned integer value into the dst byte array.
+func (e Encoder) AppendUint(dst []byte, val uint) []byte {
+	return e.AppendInt64(dst, int64(val))
+}
+
+// AppendUints encodes and inserts an array of unsigned integer values into the dst byte array.
+func (e Encoder) AppendUints(dst []byte, vals []uint) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendUint(dst, v)
+	}
+	return dst
+}
+
+// AppendUint8 encodes and inserts a unsigned int8 value into the dst byte array.
+func (e Encoder) AppendUint8(dst []byte, val uint8) []byte {
+	return e.AppendUint(dst, uint(val))
+}
+
+// AppendUints8 encodes and inserts an array of uint8 values into the dst byte array.
+func (e Encoder) AppendUints8(dst []byte, vals []uint8) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendUint8(dst, v)
+	}
+	return dst
+}
+
+// AppendUint16 encodes and inserts a uint16 value into the dst byte array.
+func (e Encoder) AppendUint16(dst []byte, val uint16) []byte {
+	return e.AppendUint(dst, uint(val))
+}
+
+// AppendUints16 encodes and inserts an array of uint16 values into the dst byte array.
+func (e Encoder) AppendUints16(dst []byte, vals []uint16) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendUint16(dst, v)
+	}
+	return dst
+}
+
+// AppendUint32 encodes and inserts a uint32 value into the dst byte array.
+func (e Encoder) AppendUint32(dst []byte, val uint32) []byte {
+	return e.AppendUint(dst, uint(val))
+}
+
+// AppendUints32 encodes and inserts an array of uint32 values into the dst byte array.
+func (e Encoder) AppendUints32(dst []byte, vals []uint32) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendUint32(dst, v)
+	}
+	return dst
+}
+
+// AppendUint64 encodes and inserts a uint64 value into the dst byte array.
+func (Encoder) AppendUint64(dst []byte, val uint64) []byte {
+	major := majorTypeUnsignedInt
+	contentVal := val
+	if contentVal <= additionalMax {
+		lb := byte(contentVal)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, contentVal)
+	}
+	return dst
+}
+
+// AppendUints64 encodes and inserts an array of uint64 values into the dst byte array.
+func (e Encoder) AppendUints64(dst []byte, vals []uint64) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendUint64(dst, v)
+	}
+	return dst
+}
+
+// AppendFloat32 encodes and inserts a single precision float value into the dst byte array.
+func (Encoder) AppendFloat32(dst []byte, val float32, unused int) []byte {
+	switch {
+	case math.IsNaN(float64(val)):
+		return append(dst, "\xfa\x7f\xc0\x00\x00"...)
+	case math.IsInf(float64(val), 1):
+		return append(dst, "\xfa\x7f\x80\x00\x00"...)
+	case math.IsInf(float64(val), -1):
+		return append(dst, "\xfa\xff\x80\x00\x00"...)
+	}
+	major := majorTypeSimpleAndFloat
+	subType := additionalTypeFloat32
+	n := math.Float32bits(val)
+	var buf [4]byte
+	for i := uint(0); i < 4; i++ {
+		buf[i] = byte(n >> ((3 - i) * 8))
+	}
+	return append(append(dst, major|subType), buf[0], buf[1], buf[2], buf[3])
+}
+
+// AppendFloats32 encodes and inserts an array of single precision float value into the dst byte array.
+func (e Encoder) AppendFloats32(dst []byte, vals []float32, unused int) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendFloat32(dst, v, unused)
+	}
+	return dst
+}
+
+// AppendFloat64 encodes and inserts a double precision float value into the dst byte array.
+func (Encoder) AppendFloat64(dst []byte, val float64, unused int) []byte {
+	switch {
+	case math.IsNaN(val):
+		return append(dst, "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00"...)
+	case math.IsInf(val, 1):
+		return append(dst, "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00"...)
+	case math.IsInf(val, -1):
+		return append(dst, "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00"...)
+	}
+	major := majorTypeSimpleAndFloat
+	subType := additionalTypeFloat64
+	n := math.Float64bits(val)
+	dst = append(dst, major|subType)
+	for i := uint(1); i <= 8; i++ {
+		b := byte(n >> ((8 - i) * 8))
+		dst = append(dst, b)
+	}
+	return dst
+}
+
+// AppendFloats64 encodes and inserts an array of double precision float values into the dst byte array.
+func (e Encoder) AppendFloats64(dst []byte, vals []float64, unused int) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = e.AppendFloat64(dst, v, unused)
+	}
+	return dst
+}
+
+// AppendInterface takes an arbitrary object and converts it to JSON and embeds it dst.
+func (e Encoder) AppendInterface(dst []byte, i interface{}) []byte {
+	marshaled, err := JSONMarshalFunc(i)
+	if err != nil {
+		return e.AppendString(dst, fmt.Sprintf("marshaling error: %v", err))
+	}
+	return AppendEmbeddedJSON(dst, marshaled)
+}
+
+// AppendType appends the parameter type (as a string) to the input byte slice.
+func (e Encoder) AppendType(dst []byte, i interface{}) []byte {
+	if i == nil {
+		return e.AppendString(dst, "<nil>")
+	}
+	return e.AppendString(dst, reflect.TypeOf(i).String())
+}
+
+// AppendIPAddr adds a net.IP IPv4 or IPv6 address into the dst byte array.
+func (e Encoder) AppendIPAddr(dst []byte, ip net.IP) []byte {
+	dst = append(dst, majorTypeTags|additionalTypeIntUint16)
+	dst = append(dst, byte(additionalTypeTagNetworkAddr>>8))
+	dst = append(dst, byte(additionalTypeTagNetworkAddr&0xff))
+	return e.AppendBytes(dst, ip)
+}
+
+// AppendIPAddrs adds a []net.IP array of IPv4 or IPv6 address into the dst byte array.
+func (e Encoder) AppendIPAddrs(dst []byte, ips []net.IP) []byte {
+	major := majorTypeArray
+	l := len(ips)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range ips {
+		dst = e.AppendIPAddr(dst, v)
+	}
+	return dst
+}
+
+// AppendIPPrefix adds a net.IPNet IPv4 or IPv6 Prefix (address & mask) into the dst byte array.
+func (e Encoder) AppendIPPrefix(dst []byte, pfx net.IPNet) []byte {
+	dst = append(dst, majorTypeTags|additionalTypeIntUint16)
+	dst = append(dst, byte(additionalTypeTagNetworkPrefix>>8))
+	dst = append(dst, byte(additionalTypeTagNetworkPrefix&0xff))
+
+	// Prefix is a tuple (aka MAP of 1 pair of elements) -
+	// first element is prefix, second is mask length.
+	dst = append(dst, majorTypeMap|0x1)
+	dst = e.AppendBytes(dst, pfx.IP)
+	maskLen, _ := pfx.Mask.Size()
+	return e.AppendUint8(dst, uint8(maskLen))
+}
+
+// AppendIPPrefixes adds a []net.IPNet array of IPv4 or IPv6 Prefix (address & mask) into the dst byte array.
+func (e Encoder) AppendIPPrefixes(dst []byte, pfxs []net.IPNet) []byte {
+	major := majorTypeArray
+	l := len(pfxs)
+	if l == 0 {
+		return e.AppendArrayEnd(e.AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, major|lb)
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range pfxs {
+		dst = e.AppendIPPrefix(dst, v)
+	}
+	return dst
+}
+
+// AppendMACAddr encodes and inserts a Hardware (MAC) address.
+func (e Encoder) AppendMACAddr(dst []byte, ha net.HardwareAddr) []byte {
+	dst = append(dst, majorTypeTags|additionalTypeIntUint16)
+	dst = append(dst, byte(additionalTypeTagNetworkAddr>>8))
+	dst = append(dst, byte(additionalTypeTagNetworkAddr&0xff))
+	return e.AppendBytes(dst, ha)
+}
+
+// AppendHex adds a TAG and inserts a hex bytes as a string.
+func (e Encoder) AppendHex(dst []byte, val []byte) []byte {
+	dst = append(dst, majorTypeTags|additionalTypeIntUint16)
+	dst = append(dst, byte(additionalTypeTagHexString>>8))
+	dst = append(dst, byte(additionalTypeTagHexString&0xff))
+	return e.AppendBytes(dst, val)
+}

internal/cbor/types_64_test.go

@@ -0,0 +1,34 @@
+// +build !386
+
+package cbor
+
+import (
+	"encoding/hex"
+	"testing"
+)
+
+var enc2 = Encoder{}
+
+var integerTestCases_64bit = []struct {
+	val    int
+	binary string
+}{
+	// Value in 8 bytes.
+	{0xabcd100000000, "\x1b\x00\x0a\xbc\xd1\x00\x00\x00\x00"},
+	{1000000000000, "\x1b\x00\x00\x00\xe8\xd4\xa5\x10\x00"},
+	// Value in 8 bytes.
+	{-0xabcd100000001, "\x3b\x00\x0a\xbc\xd1\x00\x00\x00\x00"},
+	{-1000000000001, "\x3b\x00\x00\x00\xe8\xd4\xa5\x10\x00"},
+}
+
+func TestAppendInt_64bit(t *testing.T) {
+	for _, tc := range integerTestCases_64bit {
+		s := enc2.AppendInt([]byte{}, tc.val)
+		got := string(s)
+		if got != tc.binary {
+			t.Errorf("AppendInt(0x%x)=0x%s, want: 0x%s",
+				tc.val, hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.binary)))
+		}
+	}
+}

internal/json/base.go

@@ -1,39 +1,19 @@
 package json
 
-func AppendKey(dst []byte, key string) []byte {
-	if len(dst) > 1 {
+// JSONMarshalFunc is used to marshal interface to JSON encoded byte slice.
+// Making it package level instead of embedded in Encoder brings
+// some extra efforts at importing, but avoids value copy when the functions
+// of Encoder being invoked.
+// DO REMEMBER to set this variable at importing, or
+// you might get a nil pointer dereference panic at runtime.
+var JSONMarshalFunc func(v interface{}) ([]byte, error)
+
+type Encoder struct{}
+
+// AppendKey appends a new key to the output JSON.
+func (e Encoder) AppendKey(dst []byte, key string) []byte {
+	if dst[len(dst)-1] != '{' {
 		dst = append(dst, ',')
 	}
-	dst = AppendString(dst, key)
-	return append(dst, ':')
-}
-
-func AppendError(dst []byte, err error) []byte {
-	if err == nil {
-		return append(dst, `null`...)
-	}
-	return AppendString(dst, err.Error())
-}
-
-func AppendErrors(dst []byte, errs []error) []byte {
-	if len(errs) == 0 {
-		return append(dst, '[', ']')
-	}
-	dst = append(dst, '[')
-	if errs[0] != nil {
-		dst = AppendString(dst, errs[0].Error())
-	} else {
-		dst = append(dst, "null"...)
-	}
-	if len(errs) > 1 {
-		for _, err := range errs[1:] {
-			if err == nil {
-				dst = append(dst, ",null"...)
-				continue
-			}
-			dst = AppendString(append(dst, ','), err.Error())
-		}
-	}
-	dst = append(dst, ']')
-	return dst
+	return append(e.AppendString(dst, key), ':')
 }

internal/json/base_test.go

@@ -0,0 +1,30 @@
+package json
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestAppendKey(t *testing.T) {
+	want := make([]byte, 0)
+	want = append(want, []byte("{\"key\":")...)
+
+	got := enc.AppendKey([]byte("{"), "key") // test with empty object
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendKey(%v)\ngot:  %s\nwant: %s",
+			"key",
+			string(got),
+			string(want))
+	}
+
+	want = make([]byte, 0)
+	want = append(want, []byte("},\"key\":")...) // test with non-empty object
+
+	got = enc.AppendKey([]byte("}"), "key")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendKey(%v)\ngot:  %s\nwant: %s",
+			"key",
+			string(got),
+			string(want))
+	}
+}

internal/json/bytes.go

@@ -0,0 +1,85 @@
+package json
+
+import "unicode/utf8"
+
+// AppendBytes is a mirror of appendString with []byte arg
+func (Encoder) AppendBytes(dst, s []byte) []byte {
+	dst = append(dst, '"')
+	for i := 0; i < len(s); i++ {
+		if !noEscapeTable[s[i]] {
+			dst = appendBytesComplex(dst, s, i)
+			return append(dst, '"')
+		}
+	}
+	dst = append(dst, s...)
+	return append(dst, '"')
+}
+
+// AppendHex encodes the input bytes to a hex string and appends
+// the encoded string to the input byte slice.
+//
+// The operation loops though each byte and encodes it as hex using
+// the hex lookup table.
+func (Encoder) AppendHex(dst, s []byte) []byte {
+	dst = append(dst, '"')
+	for _, v := range s {
+		dst = append(dst, hexCharacters[v>>4], hexCharacters[v&0x0f])
+	}
+	return append(dst, '"')
+}
+
+// appendBytesComplex is a mirror of the appendStringComplex
+// with []byte arg
+func appendBytesComplex(dst, s []byte, i int) []byte {
+	start := 0
+	for i < len(s) {
+		b := s[i]
+		if b >= utf8.RuneSelf {
+			r, size := utf8.DecodeRune(s[i:])
+			if r == utf8.RuneError && size == 1 {
+				if start < i {
+					dst = append(dst, s[start:i]...)
+				}
+				dst = append(dst, `\ufffd`...)
+				i += size
+				start = i
+				continue
+			}
+			i += size
+			continue
+		}
+		if noEscapeTable[b] {
+			i++
+			continue
+		}
+		// We encountered a character that needs to be encoded.
+		// Let's append the previous simple characters to the byte slice
+		// and switch our operation to read and encode the remainder
+		// characters byte-by-byte.
+		if start < i {
+			dst = append(dst, s[start:i]...)
+		}
+		switch b {
+		case '"', '\\':
+			dst = append(dst, '\\', b)
+		case '\b':
+			dst = append(dst, '\\', 'b')
+		case '\f':
+			dst = append(dst, '\\', 'f')
+		case '\n':
+			dst = append(dst, '\\', 'n')
+		case '\r':
+			dst = append(dst, '\\', 'r')
+		case '\t':
+			dst = append(dst, '\\', 't')
+		default:
+			dst = append(dst, '\\', 'u', '0', '0', hexCharacters[b>>4], hexCharacters[b&0xF])
+		}
+		i++
+		start = i
+	}
+	if start < len(s) {
+		dst = append(dst, s[start:]...)
+	}
+	return dst
+}

internal/json/bytes_test.go

@@ -0,0 +1,86 @@
+package json
+
+import (
+	"testing"
+	"unicode"
+
+	"github.com/rs/zerolog/internal"
+)
+
+var enc = Encoder{}
+
+func TestAppendBytes(t *testing.T) {
+	for _, tt := range internal.EncodeStringTests {
+		b := enc.AppendBytes([]byte{}, []byte(tt.In))
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("appendBytes(%q) = %#q, want %#q", tt.In, got, want)
+		}
+	}
+}
+
+func TestAppendHex(t *testing.T) {
+	for _, tt := range internal.EncodeHexTests {
+		b := enc.AppendHex([]byte{}, []byte{tt.In})
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("appendHex(%x) = %s, want %s", tt.In, got, want)
+		}
+	}
+}
+
+func TestStringBytes(t *testing.T) {
+	t.Parallel()
+	// Test that encodeState.stringBytes and encodeState.string use the same encoding.
+	var r []rune
+	for i := '\u0000'; i <= unicode.MaxRune; i++ {
+		r = append(r, i)
+	}
+	s := string(r) + "\xff\xff\xffhello" // some invalid UTF-8 too
+
+	encStr := string(enc.AppendString([]byte{}, s))
+	encBytes := string(enc.AppendBytes([]byte{}, []byte(s)))
+
+	if encStr != encBytes {
+		i := 0
+		for i < len(encStr) && i < len(encBytes) && encStr[i] == encBytes[i] {
+			i++
+		}
+		encStr = encStr[i:]
+		encBytes = encBytes[i:]
+		i = 0
+		for i < len(encStr) && i < len(encBytes) && encStr[len(encStr)-i-1] == encBytes[len(encBytes)-i-1] {
+			i++
+		}
+		encStr = encStr[:len(encStr)-i]
+		encBytes = encBytes[:len(encBytes)-i]
+
+		if len(encStr) > 20 {
+			encStr = encStr[:20] + "..."
+		}
+		if len(encBytes) > 20 {
+			encBytes = encBytes[:20] + "..."
+		}
+
+		t.Errorf("encodings differ at %#q vs %#q", encStr, encBytes)
+	}
+}
+
+func BenchmarkAppendBytes(b *testing.B) {
+	tests := map[string]string{
+		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingMiddle":   `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingLast":     `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
+		"MultiBytesFirst":  `❤️aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤️aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesLast":   `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤️`,
+	}
+	for name, str := range tests {
+		byt := []byte(str)
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				_ = enc.AppendBytes(buf, byt)
+			}
+		})
+	}
+}

internal/json/float_test.go

@@ -0,0 +1,433 @@
+package json
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"math"
+	"math/rand"
+	"testing"
+
+	"github.com/rs/zerolog/internal"
+)
+
+var float64Tests = []struct {
+	Name string
+	Val  float64
+	Want string
+}{
+	{
+		Name: "Positive integer",
+		Val:  1234.0,
+		Want: "1234",
+	},
+	{
+		Name: "Negative integer",
+		Val:  -5678.0,
+		Want: "-5678",
+	},
+	{
+		Name: "Positive decimal",
+		Val:  12.3456,
+		Want: "12.3456",
+	},
+	{
+		Name: "Negative decimal",
+		Val:  -78.9012,
+		Want: "-78.9012",
+	},
+	{
+		Name: "Large positive number",
+		Val:  123456789.0,
+		Want: "123456789",
+	},
+	{
+		Name: "Large negative number",
+		Val:  -987654321.0,
+		Want: "-987654321",
+	},
+	{
+		Name: "Zero",
+		Val:  0.0,
+		Want: "0",
+	},
+	{
+		Name: "Smallest positive value",
+		Val:  math.SmallestNonzeroFloat64,
+		Want: "5e-324",
+	},
+	{
+		Name: "Largest positive value",
+		Val:  math.MaxFloat64,
+		Want: "1.7976931348623157e+308",
+	},
+	{
+		Name: "Smallest negative value",
+		Val:  -math.SmallestNonzeroFloat64,
+		Want: "-5e-324",
+	},
+	{
+		Name: "Largest negative value",
+		Val:  -math.MaxFloat64,
+		Want: "-1.7976931348623157e+308",
+	},
+	{
+		Name: "NaN",
+		Val:  math.NaN(),
+		Want: `"NaN"`,
+	},
+	{
+		Name: "+Inf",
+		Val:  math.Inf(1),
+		Want: `"+Inf"`,
+	},
+	{
+		Name: "-Inf",
+		Val:  math.Inf(-1),
+		Want: `"-Inf"`,
+	},
+	{
+		Name: "Clean up e-09 to e-9 case 1",
+		Val:  1e-9,
+		Want: "1e-9",
+	},
+	{
+		Name: "Clean up e-09 to e-9 case 2",
+		Val:  -2.236734e-9,
+		Want: "-2.236734e-9",
+	},
+}
+
+func TestEncoder_AppendFloat64(t *testing.T) {
+	for _, tc := range float64Tests {
+		t.Run(tc.Name, func(t *testing.T) {
+			var b []byte
+			b = (Encoder{}).AppendFloat64(b, tc.Val, -1)
+			if s := string(b); tc.Want != s {
+				t.Errorf("%q", s)
+			}
+		})
+	}
+}
+
+func FuzzEncoder_AppendFloat64(f *testing.F) {
+	for _, tc := range float64Tests {
+		f.Add(tc.Val)
+	}
+	f.Fuzz(func(t *testing.T, val float64) {
+		actual := (Encoder{}).AppendFloat64(nil, val, -1)
+		if len(actual) == 0 {
+			t.Fatal("empty buffer")
+		}
+
+		if actual[0] == '"' {
+			switch string(actual) {
+			case `"NaN"`:
+				if !math.IsNaN(val) {
+					t.Fatalf("expected %v got NaN", val)
+				}
+			case `"+Inf"`:
+				if !math.IsInf(val, 1) {
+					t.Fatalf("expected %v got +Inf", val)
+				}
+			case `"-Inf"`:
+				if !math.IsInf(val, -1) {
+					t.Fatalf("expected %v got -Inf", val)
+				}
+			default:
+				t.Fatalf("unexpected string: %s", actual)
+			}
+			return
+		}
+
+		if expected, err := json.Marshal(val); err != nil {
+			t.Error(err)
+		} else if string(actual) != string(expected) {
+			t.Errorf("expected %s, got %s", expected, actual)
+		}
+
+		var parsed float64
+		if err := json.Unmarshal(actual, &parsed); err != nil {
+			t.Fatal(err)
+		}
+
+		if parsed != val {
+			t.Fatalf("expected %v, got %v", val, parsed)
+		}
+	})
+}
+
+var float32Tests = []struct {
+	Name string
+	Val  float32
+	Want string
+}{
+	{
+		Name: "Positive integer",
+		Val:  1234.0,
+		Want: "1234",
+	},
+	{
+		Name: "Negative integer",
+		Val:  -5678.0,
+		Want: "-5678",
+	},
+	{
+		Name: "Positive decimal",
+		Val:  12.3456,
+		Want: "12.3456",
+	},
+	{
+		Name: "Negative decimal",
+		Val:  -78.9012,
+		Want: "-78.9012",
+	},
+	{
+		Name: "Large positive number",
+		Val:  123456789.0,
+		Want: "123456790",
+	},
+	{
+		Name: "Large negative number",
+		Val:  -987654321.0,
+		Want: "-987654340",
+	},
+	{
+		Name: "Zero",
+		Val:  0.0,
+		Want: "0",
+	},
+	{
+		Name: "Smallest positive value",
+		Val:  math.SmallestNonzeroFloat32,
+		Want: "1e-45",
+	},
+	{
+		Name: "Largest positive value",
+		Val:  math.MaxFloat32,
+		Want: "3.4028235e+38",
+	},
+	{
+		Name: "Smallest negative value",
+		Val:  -math.SmallestNonzeroFloat32,
+		Want: "-1e-45",
+	},
+	{
+		Name: "Largest negative value",
+		Val:  -math.MaxFloat32,
+		Want: "-3.4028235e+38",
+	},
+	{
+		Name: "NaN",
+		Val:  float32(math.NaN()),
+		Want: `"NaN"`,
+	},
+	{
+		Name: "+Inf",
+		Val:  float32(math.Inf(1)),
+		Want: `"+Inf"`,
+	},
+	{
+		Name: "-Inf",
+		Val:  float32(math.Inf(-1)),
+		Want: `"-Inf"`,
+	},
+	{
+		Name: "Clean up e-09 to e-9 case 1",
+		Val:  1e-9,
+		Want: "1e-9",
+	},
+	{
+		Name: "Clean up e-09 to e-9 case 2",
+		Val:  -2.236734e-9,
+		Want: "-2.236734e-9",
+	},
+}
+
+func TestEncoder_AppendFloat32(t *testing.T) {
+	for _, tc := range float32Tests {
+		t.Run(tc.Name, func(t *testing.T) {
+			var b []byte
+			b = (Encoder{}).AppendFloat32(b, tc.Val, -1)
+			if s := string(b); tc.Want != s {
+				t.Errorf("%q", s)
+			}
+		})
+	}
+}
+
+func FuzzEncoder_AppendFloat32(f *testing.F) {
+	for _, tc := range float32Tests {
+		f.Add(tc.Val)
+	}
+	f.Fuzz(func(t *testing.T, val float32) {
+		actual := (Encoder{}).AppendFloat32(nil, val, -1)
+		if len(actual) == 0 {
+			t.Fatal("empty buffer")
+		}
+
+		if actual[0] == '"' {
+			val := float64(val)
+			switch string(actual) {
+			case `"NaN"`:
+				if !math.IsNaN(val) {
+					t.Fatalf("expected %v got NaN", val)
+				}
+			case `"+Inf"`:
+				if !math.IsInf(val, 1) {
+					t.Fatalf("expected %v got +Inf", val)
+				}
+			case `"-Inf"`:
+				if !math.IsInf(val, -1) {
+					t.Fatalf("expected %v got -Inf", val)
+				}
+			default:
+				t.Fatalf("unexpected string: %s", actual)
+			}
+			return
+		}
+
+		if expected, err := json.Marshal(val); err != nil {
+			t.Error(err)
+		} else if string(actual) != string(expected) {
+			t.Errorf("expected %s, got %s", expected, actual)
+		}
+
+		var parsed float32
+		if err := json.Unmarshal(actual, &parsed); err != nil {
+			t.Fatal(err)
+		}
+
+		if parsed != val {
+			t.Fatalf("expected %v, got %v", val, parsed)
+		}
+	})
+}
+
+func generateFloat32s(n int) []float32 {
+	floats := make([]float32, n)
+	for i := 0; i < n; i++ {
+		floats[i] = rand.Float32()
+	}
+	return floats
+}
+
+func generateFloat64s(n int) []float64 {
+	floats := make([]float64, n)
+	for i := 0; i < n; i++ {
+		floats[i] = rand.Float64()
+	}
+	return floats
+}
+
+func TestAppendFloats32(t *testing.T) {
+	doOne := func(vals []float32) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			if math.IsNaN(float64(val)) {
+				want = append(want, []byte(`"NaN"`)...)
+			} else if math.IsInf(float64(val), 1) {
+				want = append(want, []byte(`"+Inf"`)...)
+			} else if math.IsInf(float64(val), -1) {
+				want = append(want, []byte(`"-Inf"`)...)
+			} else {
+				want = append(want, []byte(fmt.Sprintf("%v", float32(val)))...)
+			}
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendFloats32([]byte{}, vals, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendFloats32(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]float32, 0)
+	for _, tc := range internal.Float32TestCases {
+		if tc.Val > 0 && tc.Val < 1e-4 {
+			continue // we want to ignore very small numbers for this test
+		}
+		array = append(array, float32(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+
+func TestAppendFloats64(t *testing.T) {
+	doOne := func(vals []float64) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			if math.IsNaN(val) {
+				want = append(want, []byte(`"NaN"`)...)
+			} else if math.IsInf(val, 1) {
+				want = append(want, []byte(`"+Inf"`)...)
+			} else if math.IsInf(val, -1) {
+				want = append(want, []byte(`"-Inf"`)...)
+			} else {
+				want = append(want, []byte(fmt.Sprintf("%v", val))...)
+			}
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendFloats64([]byte{}, vals, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendFloats64(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]float64, 0)
+	for _, tc := range internal.Float64TestCases {
+		if tc.Val > 0 && tc.Val < 1e-4 {
+			continue // we want to ignore very small numbers for this test
+		}
+		array = append(array, tc.Val)
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+
+// this is really just for the memory allocation characteristics
+func BenchmarkEncoder_AppendFloat32(b *testing.B) {
+	floats := append(generateFloat32s(5000), float32(math.NaN()), float32(math.Inf(1)), float32(math.Inf(-1)))
+	dst := make([]byte, 0, 128)
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		for _, f := range floats {
+			dst = (Encoder{}).AppendFloat32(dst[:0], f, -1)
+		}
+	}
+}
+
+// this is really just for the memory allocation characteristics
+func BenchmarkEncoder_AppendFloat64(b *testing.B) {
+	floats := append(generateFloat64s(5000), math.NaN(), math.Inf(1), math.Inf(-1))
+	dst := make([]byte, 0, 128)
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		for _, f := range floats {
+			dst = (Encoder{}).AppendFloat64(dst[:0], f, -1)
+		}
+	}
+}

internal/json/int_test.go

@@ -0,0 +1,356 @@
+package json
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"testing"
+
+	"github.com/rs/zerolog/internal"
+)
+
+func TestAppendInts8(t *testing.T) {
+	doOne := func(vals []int8) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", int8(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendInts8([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendInts8(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]int8, 0)
+	for _, tc := range internal.IntegerTestCases {
+		if (tc.Val < math.MinInt8) || (tc.Val > math.MaxInt8) {
+			continue
+		}
+		array = append(array, int8(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendUints8(t *testing.T) {
+	doOne := func(vals []uint8) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%v", uint8(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendUints8([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendUints8(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]uint8, 0)
+	for _, tc := range internal.UnsignedIntegerTestCases {
+		if tc.Val > math.MaxUint8 {
+			continue
+		}
+		array = append(array, uint8(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendInts16(t *testing.T) {
+	doOne := func(vals []int16) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", int16(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendInts16([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendInts16(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]int16, 0)
+	for _, tc := range internal.IntegerTestCases {
+		if (tc.Val < math.MinInt16) || (tc.Val > math.MaxInt16) {
+			continue
+		}
+		array = append(array, int16(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendUints16(t *testing.T) {
+	doOne := func(vals []uint16) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", uint16(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendUints16([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendUints16(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]uint16, 0)
+	for _, tc := range internal.UnsignedIntegerTestCases {
+		if tc.Val > math.MaxUint16 {
+			continue
+		}
+		array = append(array, uint16(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendInts32(t *testing.T) {
+	doOne := func(vals []int32) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", int32(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendInts32([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendInts32(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]int32, 0)
+	for _, tc := range internal.IntegerTestCases {
+		if (tc.Val < math.MinInt32) || (tc.Val > math.MaxInt32) {
+			continue
+		}
+		array = append(array, int32(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendUints32(t *testing.T) {
+	doOne := func(vals []uint32) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", uint32(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendUints32([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendUints32(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]uint32, 0)
+	for _, tc := range internal.UnsignedIntegerTestCases {
+		if tc.Val > math.MaxUint32 {
+			continue
+		}
+		array = append(array, uint32(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+
+func TestAppendInt64(t *testing.T) {
+	doOne := func(vals []int64) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", int64(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendInts64([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendInts64(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]int64, 0)
+	for _, tc := range internal.IntegerTestCases {
+		array = append(array, int64(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendUints64(t *testing.T) {
+	doOne := func(vals []uint64) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", uint64(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendUints64([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendUints64(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]uint64, 0)
+	for _, tc := range internal.UnsignedIntegerTestCases {
+		array = append(array, uint64(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+
+func TestAppendInt(t *testing.T) {
+	for _, tc := range internal.IntegerTestCases {
+		want := []byte(fmt.Sprintf("%d", tc.Val))
+		got := enc.AppendInt([]byte{}, tc.Val)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendInt(0x%x)\ngot:  %s\nwant: %s",
+				tc.Val,
+				string(got),
+				string(want))
+		}
+	}
+}
+func TestAppendUint(t *testing.T) {
+	for _, tc := range internal.UnsignedIntegerTestCases {
+		want := []byte(fmt.Sprintf("%d", tc.Val))
+		got := enc.AppendUint([]byte{}, tc.Val)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendUint(0x%x)\ngot:  %s\nwant: %s",
+				tc.Val,
+				string(got),
+				string(want))
+		}
+	}
+}
+
+func TestAppendInts(t *testing.T) {
+	doOne := func(vals []int) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", int(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendInts([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendInts(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]int, 0)
+	for _, tc := range internal.IntegerTestCases {
+		array = append(array, int(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}
+func TestAppendUints(t *testing.T) {
+	doOne := func(vals []uint) {
+		want := make([]byte, 0)
+		want = append(want, '[')
+		for i, val := range vals {
+			want = append(want, []byte(fmt.Sprintf("%d", uint(val)))...)
+			if i < len(vals)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got := enc.AppendUints([]byte{}, vals)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendUints(%v)\ngot:  %s\nwant: %s",
+				vals,
+				string(got),
+				string(want))
+		}
+	}
+
+	array := make([]uint, 0)
+	for _, tc := range internal.UnsignedIntegerTestCases {
+		array = append(array, uint(tc.Val))
+	}
+
+	doOne(array)
+	doOne(array[:1]) // single element
+	doOne(array[:0]) // edge case of zero length
+}

internal/json/string.go

@@ -1,18 +1,31 @@
 package json
 
-import "unicode/utf8"
+import (
+	"fmt"
+	"unicode/utf8"
+)
 
-const hex = "0123456789abcdef"
+const hexCharacters = "0123456789abcdef"
 
-func AppendStrings(dst []byte, vals []string) []byte {
+var noEscapeTable = [256]bool{}
+
+func init() {
+	for i := 0; i <= 0x7e; i++ {
+		noEscapeTable[i] = i >= 0x20 && i != '\\' && i != '"'
+	}
+}
+
+// AppendStrings encodes the input strings to json and
+// appends the encoded string list to the input byte slice.
+func (e Encoder) AppendStrings(dst []byte, vals []string) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
 	dst = append(dst, '[')
-	dst = AppendString(dst, vals[0])
+	dst = e.AppendString(dst, vals[0])
 	if len(vals) > 1 {
 		for _, val := range vals[1:] {
-			dst = AppendString(append(dst, ','), val)
+			dst = e.AppendString(append(dst, ','), val)
 		}
 	}
 	dst = append(dst, ']')
@@ -24,11 +37,11 @@ func AppendStrings(dst []byte, vals []string) []byte {
 //
 // The operation loops though each byte in the string looking
 // for characters that need json or utf8 encoding. If the string
-// does not need encoding, then the string is appended in it's
+// does not need encoding, then the string is appended in its
 // entirety to the byte slice.
 // If we encounter a byte that does need encoding, switch up
 // the operation and perform a byte-by-byte read-encode-append.
-func AppendString(dst []byte, s string) []byte {
+func (Encoder) AppendString(dst []byte, s string) []byte {
 	// Start with a double quote.
 	dst = append(dst, '"')
 	// Loop through each character in the string.
@@ -36,20 +49,45 @@ func AppendString(dst []byte, s string) []byte {
 		// Check if the character needs encoding. Control characters, slashes,
 		// and the double quote need json encoding. Bytes above the ascii
 		// boundary needs utf8 encoding.
-		if s[i] < 0x20 || s[i] > 0x7e || s[i] == '\\' || s[i] == '"' {
+		if !noEscapeTable[s[i]] {
 			// We encountered a character that needs to be encoded. Switch
 			// to complex version of the algorithm.
 			dst = appendStringComplex(dst, s, i)
 			return append(dst, '"')
 		}
 	}
-	// The string has no need for encoding an therefore is directly
+	// The string has no need for encoding and therefore is directly
 	// appended to the byte slice.
 	dst = append(dst, s...)
 	// End with a double quote
 	return append(dst, '"')
 }
 
+// AppendStringers encodes the provided Stringer list to json and
+// appends the encoded Stringer list to the input byte slice.
+func (e Encoder) AppendStringers(dst []byte, vals []fmt.Stringer) []byte {
+	if vals == nil || len(vals) == 0 {
+		return append(dst, '[', ']')
+	}
+	dst = append(dst, '[')
+	dst = e.AppendStringer(dst, vals[0])
+	if len(vals) > 1 {
+		for _, val := range vals[1:] {
+			dst = e.AppendStringer(append(dst, ','), val)
+		}
+	}
+	return append(dst, ']')
+}
+
+// AppendStringer encodes the input Stringer to json and appends the
+// encoded Stringer value to the input byte slice.
+func (e Encoder) AppendStringer(dst []byte, val fmt.Stringer) []byte {
+	if val == nil {
+		return e.AppendInterface(dst, nil)
+	}
+	return e.AppendString(dst, val.String())
+}
+
 // appendStringComplex is used by appendString to take over an in
 // progress JSON string encoding that encountered a character that needs
 // to be encoded.
@@ -61,7 +99,7 @@ func appendStringComplex(dst []byte, s string, i int) []byte {
 			r, size := utf8.DecodeRuneInString(s[i:])
 			if r == utf8.RuneError && size == 1 {
 				// In case of error, first append previous simple characters to
-				// the byte slice if any and append a remplacement character code
+				// the byte slice if any and append a replacement character code
 				// in place of the invalid sequence.
 				if start < i {
 					dst = append(dst, s[start:i]...)
@@ -74,7 +112,7 @@ func appendStringComplex(dst []byte, s string, i int) []byte {
 			i += size
 			continue
 		}
-		if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
+		if noEscapeTable[b] {
 			i++
 			continue
 		}
@@ -99,76 +137,7 @@ func appendStringComplex(dst []byte, s string, i int) []byte {
 		case '\t':
 			dst = append(dst, '\\', 't')
 		default:
-			dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF])
-		}
-		i++
-		start = i
-	}
-	if start < len(s) {
-		dst = append(dst, s[start:]...)
-	}
-	return dst
-}
-
-// AppendBytes is a mirror of appendString with []byte arg
-func AppendBytes(dst, s []byte) []byte {
-	dst = append(dst, '"')
-	for i := 0; i < len(s); i++ {
-		if s[i] < 0x20 || s[i] > 0x7e || s[i] == '\\' || s[i] == '"' {
-			dst = appendBytesComplex(dst, s, i)
-			return append(dst, '"')
-		}
-	}
-	dst = append(dst, s...)
-	return append(dst, '"')
-}
-
-// appendBytesComplex is a mirror of the appendStringComplex
-// with []byte arg
-func appendBytesComplex(dst, s []byte, i int) []byte {
-	start := 0
-	for i < len(s) {
-		b := s[i]
-		if b >= utf8.RuneSelf {
-			r, size := utf8.DecodeRune(s[i:])
-			if r == utf8.RuneError && size == 1 {
-				if start < i {
-					dst = append(dst, s[start:i]...)
-				}
-				dst = append(dst, `\ufffd`...)
-				i += size
-				start = i
-				continue
-			}
-			i += size
-			continue
-		}
-		if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
-			i++
-			continue
-		}
-		// We encountered a character that needs to be encoded.
-		// Let's append the previous simple characters to the byte slice
-		// and switch our operation to read and encode the remainder
-		// characters byte-by-byte.
-		if start < i {
-			dst = append(dst, s[start:i]...)
-		}
-		switch b {
-		case '"', '\\':
-			dst = append(dst, '\\', b)
-		case '\b':
-			dst = append(dst, '\\', 'b')
-		case '\f':
-			dst = append(dst, '\\', 'f')
-		case '\n':
-			dst = append(dst, '\\', 'n')
-		case '\r':
-			dst = append(dst, '\\', 'r')
-		case '\t':
-			dst = append(dst, '\\', 't')
-		default:
-			dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF])
+			dst = append(dst, '\\', 'u', '0', '0', hexCharacters[b>>4], hexCharacters[b&0xF])
 		}
 		i++
 		start = i

internal/json/string_test.go

@@ -2,113 +2,56 @@ package json
 
 import (
 	"testing"
-	"unicode"
+
+	"github.com/rs/zerolog/internal"
 )
 
-var encodeStringTests = []struct {
-	in  string
-	out string
-}{
-	{"", `""`},
-	{"\\", `"\\"`},
-	{"\x00", `"\u0000"`},
-	{"\x01", `"\u0001"`},
-	{"\x02", `"\u0002"`},
-	{"\x03", `"\u0003"`},
-	{"\x04", `"\u0004"`},
-	{"\x05", `"\u0005"`},
-	{"\x06", `"\u0006"`},
-	{"\x07", `"\u0007"`},
-	{"\x08", `"\b"`},
-	{"\x09", `"\t"`},
-	{"\x0a", `"\n"`},
-	{"\x0b", `"\u000b"`},
-	{"\x0c", `"\f"`},
-	{"\x0d", `"\r"`},
-	{"\x0e", `"\u000e"`},
-	{"\x0f", `"\u000f"`},
-	{"\x10", `"\u0010"`},
-	{"\x11", `"\u0011"`},
-	{"\x12", `"\u0012"`},
-	{"\x13", `"\u0013"`},
-	{"\x14", `"\u0014"`},
-	{"\x15", `"\u0015"`},
-	{"\x16", `"\u0016"`},
-	{"\x17", `"\u0017"`},
-	{"\x18", `"\u0018"`},
-	{"\x19", `"\u0019"`},
-	{"\x1a", `"\u001a"`},
-	{"\x1b", `"\u001b"`},
-	{"\x1c", `"\u001c"`},
-	{"\x1d", `"\u001d"`},
-	{"\x1e", `"\u001e"`},
-	{"\x1f", `"\u001f"`},
-	{"✭", `"✭"`},
-	{"foo\xc2\x7fbar", `"foo\ufffd\u007fbar"`}, // invalid sequence
-	{"ascii", `"ascii"`},
-	{"\"a", `"\"a"`},
-	{"\x1fa", `"\u001fa"`},
-	{"foo\"bar\"baz", `"foo\"bar\"baz"`},
-	{"\x1ffoo\x1fbar\x1fbaz", `"\u001ffoo\u001fbar\u001fbaz"`},
-	{"emoji \u2764\ufe0f!", `"emoji ❤️!"`},
-}
-
-func TestappendString(t *testing.T) {
-	for _, tt := range encodeStringTests {
-		b := AppendString([]byte{}, tt.in)
-		if got, want := string(b), tt.out; got != want {
-			t.Errorf("appendString(%q) = %#q, want %#q", tt.in, got, want)
+func TestAppendString(t *testing.T) {
+	for _, tt := range internal.EncodeStringTests {
+		b := enc.AppendString([]byte{}, tt.In)
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("appendString(%q) = %#q, want %#q", tt.In, got, want)
 		}
 	}
 }
 
-func TestappendBytes(t *testing.T) {
-	for _, tt := range encodeStringTests {
-		b := AppendBytes([]byte{}, []byte(tt.in))
-		if got, want := string(b), tt.out; got != want {
-			t.Errorf("appendBytes(%q) = %#q, want %#q", tt.in, got, want)
+func TestAppendStrings(t *testing.T) {
+	for _, tt := range internal.EncodeStringsTests {
+		b := enc.AppendStrings([]byte{}, tt.In)
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("appendStrings(%q) = %#q, want %#q", tt.In, got, want)
 		}
 	}
 }
 
-func TestStringBytes(t *testing.T) {
-	t.Parallel()
-	// Test that encodeState.stringBytes and encodeState.string use the same encoding.
-	var r []rune
-	for i := '\u0000'; i <= unicode.MaxRune; i++ {
-		r = append(r, i)
+func TestAppendStringer(t *testing.T) {
+	oldJSONMarshalFunc := JSONMarshalFunc
+	defer func() {
+		JSONMarshalFunc = oldJSONMarshalFunc
+	}()
+
+	JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return internal.InterfaceMarshalFunc(v)
 	}
-	s := string(r) + "\xff\xff\xffhello" // some invalid UTF-8 too
 
-	enc := string(AppendString([]byte{}, s))
-	encBytes := string(AppendBytes([]byte{}, []byte(s)))
-
-	if enc != encBytes {
-		i := 0
-		for i < len(enc) && i < len(encBytes) && enc[i] == encBytes[i] {
-			i++
+	for _, tt := range internal.EncodeStringerTests {
+		b := enc.AppendStringer([]byte{}, tt.In)
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("AppendStringer(%q)\ngot:  %#q, want: %#q", tt.In, got, want)
 		}
-		enc = enc[i:]
-		encBytes = encBytes[i:]
-		i = 0
-		for i < len(enc) && i < len(encBytes) && enc[len(enc)-i-1] == encBytes[len(encBytes)-i-1] {
-			i++
-		}
-		enc = enc[:len(enc)-i]
-		encBytes = encBytes[:len(encBytes)-i]
-
-		if len(enc) > 20 {
-			enc = enc[:20] + "..."
-		}
-		if len(encBytes) > 20 {
-			encBytes = encBytes[:20] + "..."
-		}
-
-		t.Errorf("encodings differ at %#q vs %#q", enc, encBytes)
 	}
 }
 
-func BenchmarkappendString(b *testing.B) {
+func TestAppendStringers(t *testing.T) {
+	for _, tt := range internal.EncodeStringersTests {
+		b := enc.AppendStringers([]byte{}, tt.In)
+		if got, want := string(b), tt.Out; got != want {
+			t.Errorf("appendStrings(%q) = %#q, want %#q", tt.In, got, want)
+		}
+	}
+}
+
+func BenchmarkAppendString(b *testing.B) {
 	tests := map[string]string{
 		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
 		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
@@ -122,28 +65,7 @@ func BenchmarkappendString(b *testing.B) {
 		b.Run(name, func(b *testing.B) {
 			buf := make([]byte, 0, 100)
 			for i := 0; i < b.N; i++ {
-				_ = AppendString(buf, str)
-			}
-		})
-	}
-}
-
-func BenchmarkappendBytes(b *testing.B) {
-	tests := map[string]string{
-		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
-		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
-		"EncodingMiddle":   `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
-		"EncodingLast":     `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
-		"MultiBytesFirst":  `❤️aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
-		"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤️aaaaaaaaaaaaaaaaaaaaaaaa`,
-		"MultiBytesLast":   `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤️`,
-	}
-	for name, str := range tests {
-		byt := []byte(str)
-		b.Run(name, func(b *testing.B) {
-			buf := make([]byte, 0, 100)
-			for i := 0; i < b.N; i++ {
-				_ = AppendBytes(buf, byt)
+				_ = enc.AppendString(buf, str)
 			}
 		})
 	}

internal/json/time.go

@@ -5,16 +5,45 @@ import (
 	"time"
 )
 
-func AppendTime(dst []byte, t time.Time, format string) []byte {
-	if format == "" {
-		return AppendInt64(dst, t.Unix())
+const (
+	// Import from zerolog/global.go
+	timeFormatUnix       = ""
+	timeFormatUnixMs     = "UNIXMS"
+	timeFormatUnixMicro  = "UNIXMICRO"
+	timeFormatUnixNano   = "UNIXNANO"
+	durationFormatFloat  = "float"
+	durationFormatInt    = "int"
+	durationFormatString = "string"
+)
+
+// AppendTime formats the input time with the given format
+// and appends the encoded string to the input byte slice.
+func (e Encoder) AppendTime(dst []byte, t time.Time, format string) []byte {
+	switch format {
+	case timeFormatUnix:
+		return e.AppendInt64(dst, t.Unix())
+	case timeFormatUnixMs:
+		return e.AppendInt64(dst, t.UnixNano()/1000000)
+	case timeFormatUnixMicro:
+		return e.AppendInt64(dst, t.UnixNano()/1000)
+	case timeFormatUnixNano:
+		return e.AppendInt64(dst, t.UnixNano())
 	}
 	return append(t.AppendFormat(append(dst, '"'), format), '"')
 }
 
-func AppendTimes(dst []byte, vals []time.Time, format string) []byte {
-	if format == "" {
+// AppendTimes converts the input times with the given format
+// and appends the encoded string list to the input byte slice.
+func (Encoder) AppendTimes(dst []byte, vals []time.Time, format string) []byte {
+	switch format {
+	case timeFormatUnix:
 		return appendUnixTimes(dst, vals)
+	case timeFormatUnixMs:
+		return appendUnixNanoTimes(dst, vals, 1000000)
+	case timeFormatUnixMicro:
+		return appendUnixNanoTimes(dst, vals, 1000)
+	case timeFormatUnixNano:
+		return appendUnixNanoTimes(dst, vals, 1)
 	}
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -38,29 +67,56 @@ func appendUnixTimes(dst []byte, vals []time.Time) []byte {
 	dst = strconv.AppendInt(dst, vals[0].Unix(), 10)
 	if len(vals) > 1 {
 		for _, t := range vals[1:] {
-			dst = strconv.AppendInt(dst, t.Unix(), 10)
+			dst = strconv.AppendInt(append(dst, ','), t.Unix(), 10)
 		}
 	}
 	dst = append(dst, ']')
 	return dst
 }
 
-func AppendDuration(dst []byte, d time.Duration, unit time.Duration, useInt bool) []byte {
-	if useInt {
-		return strconv.AppendInt(dst, int64(d/unit), 10)
-	}
-	return AppendFloat64(dst, float64(d)/float64(unit))
-}
-
-func AppendDurations(dst []byte, vals []time.Duration, unit time.Duration, useInt bool) []byte {
+func appendUnixNanoTimes(dst []byte, vals []time.Time, div int64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
 	dst = append(dst, '[')
-	dst = AppendDuration(dst, vals[0], unit, useInt)
+	dst = strconv.AppendInt(dst, vals[0].UnixNano()/div, 10)
 	if len(vals) > 1 {
-		for _, d := range vals[1:] {
-			dst = AppendDuration(append(dst, ','), d, unit, useInt)
+		for _, t := range vals[1:] {
+			dst = strconv.AppendInt(append(dst, ','), t.UnixNano()/div, 10)
+		}
+	}
+	dst = append(dst, ']')
+	return dst
+}
+
+// AppendDuration formats the input duration with the given unit & format
+// and appends the encoded string to the input byte slice.
+func (e Encoder) AppendDuration(dst []byte, d time.Duration, unit time.Duration, format string, useInt bool, precision int) []byte {
+	if useInt {
+		return strconv.AppendInt(dst, int64(d/unit), 10)
+	}
+	switch format {
+	case durationFormatFloat:
+		return e.AppendFloat64(dst, float64(d)/float64(unit), precision)
+	case durationFormatInt:
+		return e.AppendInt64(dst, int64(d/unit))
+	case durationFormatString:
+		return e.AppendString(dst, d.String())
+	}
+	return e.AppendFloat64(dst, float64(d)/float64(unit), precision)
+}
+
+// AppendDurations formats the input durations with the given unit & format
+// and appends the encoded string list to the input byte slice.
+func (e Encoder) AppendDurations(dst []byte, vals []time.Duration, unit time.Duration, format string, useInt bool, precision int) []byte {
+	if len(vals) == 0 {
+		return append(dst, '[', ']')
+	}
+	dst = append(dst, '[')
+	dst = e.AppendDuration(dst, vals[0], unit, format, useInt, precision)
+	if len(vals) > 1 {
+		for _, d := range vals[1:] {
+			dst = e.AppendDuration(append(dst, ','), d, unit, format, useInt, precision)
 		}
 	}
 	dst = append(dst, ']')

internal/json/time_test.go

@@ -0,0 +1,373 @@
+package json
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/rs/zerolog/internal"
+)
+
+func TestEncoder_AppendDuration(t *testing.T) {
+	type args struct {
+		dst    []byte
+		d      time.Duration
+		unit   time.Duration
+		format string
+		useInt bool
+		unused int
+	}
+	tests := []struct {
+		name string
+		args args
+		want []byte
+	}{
+		{
+			name: "useInt",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				useInt: true,
+			},
+			want: []byte{49},
+		},
+		{
+			name: "formatFloat",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				format: durationFormatFloat,
+			},
+			want: []byte{49},
+		},
+		{
+			name: "formatInt",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				format: durationFormatInt,
+			},
+			want: []byte{49},
+		},
+		{
+			name: "formatString",
+			args: args{
+				d:      1234567890,
+				unit:   time.Second,
+				format: durationFormatString,
+			},
+			want: []byte{34, 49, 46, 50, 51, 52, 53, 54, 55, 56, 57, 115, 34},
+		},
+		{
+			name: "formatBlank",
+			args: args{
+				d:    1234567890,
+				unit: time.Second,
+			},
+			want: []byte{49},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := Encoder{}
+			if got := e.AppendDuration(tt.args.dst, tt.args.d, tt.args.unit, tt.args.format, tt.args.useInt, tt.args.unused); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("AppendDuration() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestEncoder_AppendDurations(t *testing.T) {
+	type args struct {
+		dst    []byte
+		vals   []time.Duration
+		unit   time.Duration
+		format string
+		useInt bool
+		unused int
+	}
+	tests := []struct {
+		name string
+		args args
+		want []byte
+	}{
+		{
+			name: "useInt",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				useInt: true,
+			},
+			want: []byte{91, 49, 93},
+		},
+		{
+			name: "formatFloat",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				format: durationFormatFloat,
+			},
+			want: []byte{91, 49, 93},
+		},
+		{
+			name: "formatInt",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				format: durationFormatInt,
+			},
+			want: []byte{91, 49, 93},
+		},
+		{
+			name: "formatString",
+			args: args{
+				vals:   []time.Duration{1234567890},
+				unit:   time.Second,
+				format: durationFormatString,
+			},
+			want: []byte{91, 34, 49, 46, 50, 51, 52, 53, 54, 55, 56, 57, 115, 34, 93},
+		},
+		{
+			name: "formatBlank",
+			args: args{
+				vals: []time.Duration{1234567890},
+				unit: time.Second,
+			},
+			want: []byte{91, 49, 93},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := Encoder{}
+			if got := e.AppendDurations(tt.args.dst, tt.args.vals, tt.args.unit, tt.args.format, tt.args.useInt, tt.args.unused); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("AppendDurations() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendTimeNow(t *testing.T) {
+	tm := time.Now()
+	got := enc.AppendTime([]byte{}, tm, time.RFC3339)
+	want := tm.AppendFormat([]byte{'"'}, time.RFC3339)
+	want = append(want, '"')
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendTime(%s)\ngot:  %s\nwant: %s",
+			"time.Now()",
+			string(got),
+			string(want))
+	}
+}
+
+func TestAppendTimePastPresentInteger(t *testing.T) {
+	for _, tt := range internal.TimeIntegerTestcases {
+		tin, err := time.Parse(time.RFC3339, tt.Txt)
+		if err != nil {
+			fmt.Println("Cannot parse input", tt.Txt, ".. Skipping!", err)
+			continue
+		}
+
+		got := enc.AppendTime([]byte{}, tin, timeFormatUnix)
+		want := []byte(fmt.Sprintf("%d", tt.UnixInt))
+		if !bytes.Equal(got, want) {
+			t.Errorf("appendString(%s)\ngot:  %s\nwant: %s",
+				tt.Txt,
+				string(got),
+				string(want))
+		}
+		got = enc.AppendTime([]byte{}, tin, timeFormatUnixMs)
+		want = []byte(fmt.Sprintf("%d", tt.UnixInt*1000))
+		if !bytes.Equal(got, want) {
+			t.Errorf("appendString(%s)\ngot:  %s\nwant: %s",
+				tt.Txt,
+				string(got),
+				string(want))
+		}
+		got = enc.AppendTime([]byte{}, tin, timeFormatUnixMicro)
+		want = []byte(fmt.Sprintf("%d", tt.UnixInt*1000000))
+		if !bytes.Equal(got, want) {
+			t.Errorf("appendString(%s)\ngot:  %s\nwant: %s",
+				tt.Txt,
+				string(got),
+				string(want))
+		}
+		got = enc.AppendTime([]byte{}, tin, timeFormatUnixNano)
+		want = []byte(fmt.Sprintf("%d", tt.UnixInt*1000000000))
+		if !bytes.Equal(got, want) {
+			t.Errorf("appendString(%s)\ngot:  %s\nwant: %s",
+				tt.Txt,
+				string(got),
+				string(want))
+		}
+	}
+}
+
+func TestAppendTimePastPresentFloat(t *testing.T) {
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+	for _, tt := range internal.TimeFloatTestcases {
+		tin, err := time.Parse(timeFloatFmt, tt.RfcStr)
+		if err != nil {
+			fmt.Println("Cannot parse input", tt.RfcStr, ".. Skipping!")
+			continue
+		}
+		got := enc.AppendTime([]byte{}, tin, timeFormatUnix)
+		want := []byte(fmt.Sprintf("%d", tt.UnixInt))
+		if !bytes.Equal(got, want) {
+			t.Errorf("appendString(%s)\ngot:  %s\nwant: %s",
+				tt.RfcStr,
+				string(got),
+				string(want))
+		}
+	}
+}
+func TestAppendTimes(t *testing.T) {
+	doOne := func(multiplier int, format string) {
+		array := make([]time.Time, 0)
+		want := append([]byte{}, '[')
+		want = append(want, ']')
+		got := enc.AppendTimes([]byte{}, array, format)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendTimes(%v)\ngot:  %s\nwant: %s",
+				array,
+				string(got),
+				string(want))
+		}
+
+		array = make([]time.Time, len(internal.TimeIntegerTestcases))
+		want = append([]byte{}, '[')
+		for i, tt := range internal.TimeIntegerTestcases {
+			if tin, err := time.Parse(time.RFC3339, tt.RfcStr); err != nil {
+				fmt.Println("Cannot parse input", tt.RfcStr, ".. Skipping!")
+				continue
+			} else {
+				array[i] = tin
+			}
+			if multiplier == 0 {
+				want = append(want, '"')
+				formatted := array[i].Format(format)
+				want = append(want, []byte(fmt.Sprintf("%v", formatted))...)
+				want = append(want, '"')
+			} else {
+				scaled := tt.UnixInt * multiplier
+				want = append(want, []byte(fmt.Sprintf("%d", scaled))...)
+			}
+			if i < len(internal.TimeIntegerTestcases)-1 {
+				want = append(want, ',')
+			}
+		}
+		want = append(want, ']')
+
+		got = enc.AppendTimes([]byte{}, array, format)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendTimes(%v) %d %s\ngot:  %s\nwant: %s",
+				array, multiplier, format,
+				string(got),
+				string(want))
+		}
+	}
+
+	doOne(0, time.RFC3339)
+	doOne(1, timeFormatUnix)
+	doOne(1000, timeFormatUnixMs)
+	doOne(1000000, timeFormatUnixMicro)
+	doOne(1000000000, timeFormatUnixNano)
+}
+
+func TestAppendDurationFloat(t *testing.T) {
+	for _, tt := range internal.DurTestcases {
+		dur := tt.Duration
+		want := []byte{}
+		want = append(want, []byte(fmt.Sprintf("%v", dur.Microseconds()))...)
+		got := enc.AppendDuration([]byte{}, dur, time.Microsecond, "", false, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendDuration(%v)=\ngot:  %s\nwant: %s",
+				dur,
+				string(got),
+				string(want))
+		}
+
+		want = []byte{}
+		fraction := float64(dur) / float64(time.Millisecond)
+		want = append(want, []byte(fmt.Sprintf("%v", fraction))...)
+		got = enc.AppendDuration([]byte{}, dur, time.Millisecond, "", false, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendDuration(%v)=\ngot:  %s\nwant: %s",
+				dur,
+				string(got),
+				string(want))
+		}
+	}
+}
+func TestAppendDurationInteger(t *testing.T) {
+	for _, tt := range internal.DurTestcases {
+		dur := tt.Duration
+		want := []byte{}
+		whole := int(dur) / int(time.Microsecond)
+		want = append(want, []byte(fmt.Sprintf("%v", whole))...)
+		got := enc.AppendDuration([]byte{}, dur, time.Microsecond, "", true, -1)
+		if !bytes.Equal(got, want) {
+			t.Errorf("AppendDuration(%v)=\ngot:  %s\nwant: %s",
+				dur,
+				string(got),
+				string(want))
+		}
+	}
+}
+func TestAppendDurations(t *testing.T) {
+	array := make([]time.Duration, len(internal.DurTestcases))
+	want := make([]byte, 0)
+	want = append(want, '[')
+	for i, tt := range internal.DurTestcases {
+		array[i] = tt.Duration
+		whole := int(tt.Duration) / int(time.Microsecond)
+		want = append(want, []byte(fmt.Sprintf("%v", whole))...)
+		if i < len(internal.DurTestcases)-1 {
+			want = append(want, ',')
+		}
+	}
+	want = append(want, ']')
+
+	got := enc.AppendDurations([]byte{}, array, time.Microsecond, "", false, -1)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendDurations(%v)\ngot:  %s\nwant: %s",
+			array,
+			string(got),
+			string(want))
+	}
+
+	// now empty array case
+	array = make([]time.Duration, 0)
+	want = make([]byte, 0)
+	want = append(want, '[')
+	want = append(want, ']')
+	got = enc.AppendDurations([]byte{}, array, time.Microsecond, "", false, -1)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendDurations(%v)\ngot:  %s\nwant: %s",
+			array,
+			string(got),
+			string(want))
+	}
+}
+
+func BenchmarkAppendTime(b *testing.B) {
+	tests := map[string]string{
+		"Integer": "Feb 3, 2013 at 7:54pm (PST)",
+		"Float":   "2006-01-02T15:04:05.999999-08:00",
+	}
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+
+	for name, str := range tests {
+		t, err := time.Parse(time.RFC3339, str)
+		if err != nil {
+			t, _ = time.Parse(timeFloatFmt, str)
+		}
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				_ = enc.AppendTime(buf, t, "unused")
+			}
+		})
+	}
+}

internal/json/types.go

@@ -1,17 +1,60 @@
 package json
 
 import (
-	"encoding/json"
 	"fmt"
 	"math"
+	"net"
+	"reflect"
 	"strconv"
 )
 
-func AppendBool(dst []byte, val bool) []byte {
+// AppendNil inserts a 'Nil' object into the dst byte array.
+func (Encoder) AppendNil(dst []byte) []byte {
+	return append(dst, "null"...)
+}
+
+// AppendBeginMarker inserts a map start into the dst byte array.
+func (Encoder) AppendBeginMarker(dst []byte) []byte {
+	return append(dst, '{')
+}
+
+// AppendEndMarker inserts a map end into the dst byte array.
+func (Encoder) AppendEndMarker(dst []byte) []byte {
+	return append(dst, '}')
+}
+
+// AppendLineBreak appends a line break.
+func (Encoder) AppendLineBreak(dst []byte) []byte {
+	return append(dst, '\n')
+}
+
+// AppendArrayStart adds markers to indicate the start of an array.
+func (Encoder) AppendArrayStart(dst []byte) []byte {
+	return append(dst, '[')
+}
+
+// AppendArrayEnd adds markers to indicate the end of an array.
+func (Encoder) AppendArrayEnd(dst []byte) []byte {
+	return append(dst, ']')
+}
+
+// AppendArrayDelim adds markers to indicate end of a particular array element.
+func (Encoder) AppendArrayDelim(dst []byte) []byte {
+	if len(dst) > 0 {
+		return append(dst, ',')
+	}
+	return dst
+}
+
+// AppendBool converts the input bool to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendBool(dst []byte, val bool) []byte {
 	return strconv.AppendBool(dst, val)
 }
 
-func AppendBools(dst []byte, vals []bool) []byte {
+// AppendBools encodes the input bools to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendBools(dst []byte, vals []bool) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -26,11 +69,15 @@ func AppendBools(dst []byte, vals []bool) []byte {
 	return dst
 }
 
-func AppendInt(dst []byte, val int) []byte {
+// AppendInt converts the input int to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendInt(dst []byte, val int) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
-func AppendInts(dst []byte, vals []int) []byte {
+// AppendInts encodes the input ints to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendInts(dst []byte, vals []int) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -45,11 +92,15 @@ func AppendInts(dst []byte, vals []int) []byte {
 	return dst
 }
 
-func AppendInt8(dst []byte, val int8) []byte {
+// AppendInt8 converts the input []int8 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendInt8(dst []byte, val int8) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
-func AppendInts8(dst []byte, vals []int8) []byte {
+// AppendInts8 encodes the input int8s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendInts8(dst []byte, vals []int8) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -64,11 +115,15 @@ func AppendInts8(dst []byte, vals []int8) []byte {
 	return dst
 }
 
-func AppendInt16(dst []byte, val int16) []byte {
+// AppendInt16 converts the input int16 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendInt16(dst []byte, val int16) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
-func AppendInts16(dst []byte, vals []int16) []byte {
+// AppendInts16 encodes the input int16s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendInts16(dst []byte, vals []int16) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -83,11 +138,15 @@ func AppendInts16(dst []byte, vals []int16) []byte {
 	return dst
 }
 
-func AppendInt32(dst []byte, val int32) []byte {
+// AppendInt32 converts the input int32 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendInt32(dst []byte, val int32) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
-func AppendInts32(dst []byte, vals []int32) []byte {
+// AppendInts32 encodes the input int32s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendInts32(dst []byte, vals []int32) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -102,11 +161,15 @@ func AppendInts32(dst []byte, vals []int32) []byte {
 	return dst
 }
 
-func AppendInt64(dst []byte, val int64) []byte {
+// AppendInt64 converts the input int64 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendInt64(dst []byte, val int64) []byte {
 	return strconv.AppendInt(dst, val, 10)
 }
 
-func AppendInts64(dst []byte, vals []int64) []byte {
+// AppendInts64 encodes the input int64s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendInts64(dst []byte, vals []int64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -121,11 +184,15 @@ func AppendInts64(dst []byte, vals []int64) []byte {
 	return dst
 }
 
-func AppendUint(dst []byte, val uint) []byte {
+// AppendUint converts the input uint to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendUint(dst []byte, val uint) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
-func AppendUints(dst []byte, vals []uint) []byte {
+// AppendUints encodes the input uints to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendUints(dst []byte, vals []uint) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -140,11 +207,15 @@ func AppendUints(dst []byte, vals []uint) []byte {
 	return dst
 }
 
-func AppendUint8(dst []byte, val uint8) []byte {
+// AppendUint8 converts the input uint8 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendUint8(dst []byte, val uint8) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
-func AppendUints8(dst []byte, vals []uint8) []byte {
+// AppendUints8 encodes the input uint8s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendUints8(dst []byte, vals []uint8) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -159,11 +230,15 @@ func AppendUints8(dst []byte, vals []uint8) []byte {
 	return dst
 }
 
-func AppendUint16(dst []byte, val uint16) []byte {
+// AppendUint16 converts the input uint16 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendUint16(dst []byte, val uint16) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
-func AppendUints16(dst []byte, vals []uint16) []byte {
+// AppendUints16 encodes the input uint16s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendUints16(dst []byte, vals []uint16) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -178,11 +253,15 @@ func AppendUints16(dst []byte, vals []uint16) []byte {
 	return dst
 }
 
-func AppendUint32(dst []byte, val uint32) []byte {
+// AppendUint32 converts the input uint32 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendUint32(dst []byte, val uint32) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
-func AppendUints32(dst []byte, vals []uint32) []byte {
+// AppendUints32 encodes the input uint32s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendUints32(dst []byte, vals []uint32) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -197,11 +276,15 @@ func AppendUints32(dst []byte, vals []uint32) []byte {
 	return dst
 }
 
-func AppendUint64(dst []byte, val uint64) []byte {
-	return strconv.AppendUint(dst, uint64(val), 10)
+// AppendUint64 converts the input uint64 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendUint64(dst []byte, val uint64) []byte {
+	return strconv.AppendUint(dst, val, 10)
 }
 
-func AppendUints64(dst []byte, vals []uint64) []byte {
+// AppendUints64 encodes the input uint64s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendUints64(dst []byte, vals []uint64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
@@ -216,9 +299,9 @@ func AppendUints64(dst []byte, vals []uint64) []byte {
 	return dst
 }
 
-func AppendFloat(dst []byte, val float64, bitSize int) []byte {
+func appendFloat(dst []byte, val float64, bitSize, precision int) []byte {
 	// JSON does not permit NaN or Infinity. A typical JSON encoder would fail
-	// with an error, but a logging library wants the data to get thru so we
+	// with an error, but a logging library wants the data to get through so we
 	// make a tradeoff and store those types as string.
 	switch {
 	case math.IsNaN(val):
@@ -228,51 +311,156 @@ func AppendFloat(dst []byte, val float64, bitSize int) []byte {
 	case math.IsInf(val, -1):
 		return append(dst, `"-Inf"`...)
 	}
-	return strconv.AppendFloat(dst, val, 'f', -1, bitSize)
+	// convert as if by es6 number to string conversion
+	// see also https://cs.opensource.google/go/go/+/refs/tags/go1.20.3:src/encoding/json/encode.go;l=573
+	strFmt := byte('f')
+	// If precision is set to a value other than -1, we always just format the float using that precision.
+	if precision == -1 {
+		// Use float32 comparisons for underlying float32 value to get precise cutoffs right.
+		if abs := math.Abs(val); abs != 0 {
+			if bitSize == 64 && (abs < 1e-6 || abs >= 1e21) || bitSize == 32 && (float32(abs) < 1e-6 || float32(abs) >= 1e21) {
+				strFmt = 'e'
+			}
+		}
+	}
+	dst = strconv.AppendFloat(dst, val, strFmt, precision, bitSize)
+	if strFmt == 'e' {
+		// Clean up e-09 to e-9
+		n := len(dst)
+		if n >= 4 && dst[n-4] == 'e' && dst[n-3] == '-' && dst[n-2] == '0' {
+			dst[n-2] = dst[n-1]
+			dst = dst[:n-1]
+		}
+	}
+	return dst
 }
 
-func AppendFloat32(dst []byte, val float32) []byte {
-	return AppendFloat(dst, float64(val), 32)
+// AppendFloat32 converts the input float32 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendFloat32(dst []byte, val float32, precision int) []byte {
+	return appendFloat(dst, float64(val), 32, precision)
 }
 
-func AppendFloats32(dst []byte, vals []float32) []byte {
+// AppendFloats32 encodes the input float32s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendFloats32(dst []byte, vals []float32, precision int) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
 	dst = append(dst, '[')
-	dst = AppendFloat(dst, float64(vals[0]), 32)
+	dst = appendFloat(dst, float64(vals[0]), 32, precision)
 	if len(vals) > 1 {
 		for _, val := range vals[1:] {
-			dst = AppendFloat(append(dst, ','), float64(val), 32)
+			dst = appendFloat(append(dst, ','), float64(val), 32, precision)
 		}
 	}
 	dst = append(dst, ']')
 	return dst
 }
 
-func AppendFloat64(dst []byte, val float64) []byte {
-	return AppendFloat(dst, val, 64)
+// AppendFloat64 converts the input float64 to a string and
+// appends the encoded string to the input byte slice.
+func (Encoder) AppendFloat64(dst []byte, val float64, precision int) []byte {
+	return appendFloat(dst, val, 64, precision)
 }
 
-func AppendFloats64(dst []byte, vals []float64) []byte {
+// AppendFloats64 encodes the input float64s to json and
+// appends the encoded string list to the input byte slice.
+func (Encoder) AppendFloats64(dst []byte, vals []float64, precision int) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
 	dst = append(dst, '[')
-	dst = AppendFloat(dst, vals[0], 32)
+	dst = appendFloat(dst, vals[0], 64, precision)
 	if len(vals) > 1 {
 		for _, val := range vals[1:] {
-			dst = AppendFloat(append(dst, ','), val, 64)
+			dst = appendFloat(append(dst, ','), val, 64, precision)
 		}
 	}
 	dst = append(dst, ']')
 	return dst
 }
 
-func AppendInterface(dst []byte, i interface{}) []byte {
-	marshaled, err := json.Marshal(i)
+// AppendInterface marshals the input interface to a string and
+// appends the encoded string to the input byte slice.
+func (e Encoder) AppendInterface(dst []byte, i interface{}) []byte {
+	marshaled, err := JSONMarshalFunc(i)
 	if err != nil {
-		return AppendString(dst, fmt.Sprintf("marshaling error: %v", err))
+		return e.AppendString(dst, fmt.Sprintf("marshaling error: %v", err))
 	}
 	return append(dst, marshaled...)
 }
+
+// AppendType appends the parameter type (as a string) to the input byte slice.
+func (e Encoder) AppendType(dst []byte, i interface{}) []byte {
+	if i == nil {
+		return e.AppendString(dst, "<nil>")
+	}
+	return e.AppendString(dst, reflect.TypeOf(i).String())
+}
+
+// AppendObjectData takes in an object that is already in a byte array
+// and adds it to the dst.
+func (Encoder) AppendObjectData(dst []byte, o []byte) []byte {
+	// Three conditions apply here:
+	// 1. new content starts with '{' - which should be dropped   OR
+	// 2. new content starts with '{' - which should be replaced with ','
+	//    to separate with existing content OR
+	// 3. existing content has already other fields
+	if o[0] == '{' {
+		if len(dst) > 1 {
+			dst = append(dst, ',')
+		}
+		o = o[1:]
+	} else if len(dst) > 1 {
+		dst = append(dst, ',')
+	}
+	return append(dst, o...)
+}
+
+// AppendIPAddr adds a net.IP IPv4 or IPv6 address to dst.
+func (e Encoder) AppendIPAddr(dst []byte, ip net.IP) []byte {
+	return e.AppendString(dst, ip.String())
+}
+
+// AppendIPAddrs adds a []net.IP array of IPv4 or IPv6 address to dst.
+func (e Encoder) AppendIPAddrs(dst []byte, ips []net.IP) []byte {
+	if len(ips) == 0 {
+		return append(dst, '[', ']')
+	}
+	dst = append(dst, '[')
+	dst = e.AppendString(dst, ips[0].String())
+	if len(ips) > 1 {
+		for _, ip := range ips[1:] {
+			dst = e.AppendString(append(dst, ','), ip.String())
+		}
+	}
+	dst = append(dst, ']')
+	return dst
+}
+
+// AppendIPPrefix adds a net.IPNet IPv4 or IPv6 Prefix (address & mask) to dst.
+func (e Encoder) AppendIPPrefix(dst []byte, pfx net.IPNet) []byte {
+	return e.AppendString(dst, pfx.String())
+}
+
+// AppendIPPrefixes adds a []net.IPNet array of IPv4 or IPv6 Prefix (address & mask) to dst.
+func (e Encoder) AppendIPPrefixes(dst []byte, pfxs []net.IPNet) []byte {
+	if len(pfxs) == 0 {
+		return append(dst, '[', ']')
+	}
+	dst = append(dst, '[')
+	dst = e.AppendString(dst, pfxs[0].String())
+	if len(pfxs) > 1 {
+		for _, pfx := range pfxs[1:] {
+			dst = e.AppendString(append(dst, ','), pfx.String())
+		}
+	}
+	dst = append(dst, ']')
+	return dst
+}
+
+// AppendMACAddr adds a net.HardwareAddr MAC address to dst.
+func (e Encoder) AppendMACAddr(dst []byte, ha net.HardwareAddr) []byte {
+	return e.AppendString(dst, ha.String())
+}

internal/json/types_test.go

@@ -1,32 +1,443 @@
 package json
 
 import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
 	"math"
+	"net"
 	"reflect"
 	"testing"
+
+	"github.com/rs/zerolog/internal"
 )
 
-func Test_appendFloat64(t *testing.T) {
+func TestAppendNil(t *testing.T) {
+	got := enc.AppendNil([]byte{})
+	want := []byte(`null`)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendNil() = %s, want: %s",
+			string(got),
+			string(want))
+	}
+}
+func TestAppendBeginMarker(t *testing.T) {
+	got := enc.AppendBeginMarker([]byte{})
+	want := []byte(`{`)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendBeginMarker()\ngot:  %s, want: %s",
+			string(got),
+			string(want))
+	}
+}
+func TestAppendEndMarker(t *testing.T) {
+	got := enc.AppendEndMarker([]byte{})
+	want := []byte(`}`)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendEndMarker()\ngot:  %s, want: %s",
+			string(got),
+			string(want))
+	}
+}
+func TestAppendArrayStart(t *testing.T) {
+	got := enc.AppendArrayStart([]byte{})
+	want := []byte("[")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendArrayStart() = %s, want: %s",
+			string(got),
+			string(want))
+	}
+}
+func TestAppendArrayEnd(t *testing.T) {
+	got := enc.AppendArrayEnd([]byte{})
+	want := []byte("]")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendArrayEnd() = %s, want: %s",
+			string(got),
+			string(want))
+	}
+}
+func TestAppendArrayDelim(t *testing.T) {
+	got := enc.AppendArrayDelim([]byte{})
+	want := []byte("")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendArrayDelim() = 0x%s, want: 0x%s",
+			string(got),
+			string(want))
+	}
+
+	got = enc.AppendArrayDelim([]byte("a"))
+	want = []byte("a,")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendArrayDelim() = 0x%s, want: 0x%s",
+			string(got),
+			string(want))
+	}
+}
+func TestAppendLineBreak(t *testing.T) {
+	got := enc.AppendLineBreak([]byte{})
+	want := []byte("\n")
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendLineBreak() = 0x%s, want: 0x%s",
+			string(got),
+			string(want))
+	}
+}
+
+// inline copy from globals.go of InterfaceMarshalFunc used in tests to avoid import cycle
+func interfaceMarshalFunc(v interface{}) ([]byte, error) {
+	var buf bytes.Buffer
+	encoder := json.NewEncoder(&buf)
+	encoder.SetEscapeHTML(false)
+	err := encoder.Encode(v)
+	if err != nil {
+		return nil, err
+	}
+	b := buf.Bytes()
+	if len(b) > 0 {
+		// Remove trailing \n which is added by Encode.
+		return b[:len(b)-1], nil
+	}
+	return b, nil
+}
+
+func TestAppendInterface(t *testing.T) {
+	oldJSONMarshalFunc := JSONMarshalFunc
+	defer func() {
+		JSONMarshalFunc = oldJSONMarshalFunc
+	}()
+
+	JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return interfaceMarshalFunc(v)
+	}
+
+	var i int = 17
+	got := enc.AppendInterface([]byte{}, i)
+	want := make([]byte, 0)
+	want = append(want, []byte("17")...) // of type interface, two characters
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendInterface\ngot:  0x%s\nwant: 0x%s",
+			string(got),
+			string(want))
+	}
+
+	JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return nil, errors.New("test")
+	}
+
+	got = enc.AppendInterface([]byte{}, nil)
+	want = make([]byte, 0)
+	want = append(want, []byte("\"marshaling error: test\"")...) // of type interface, two characters
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendInterface\ngot:  0x%s\nwant: 0x%s",
+			string(got),
+			string(want))
+	}
+}
+
+func TestAppendType(t *testing.T) {
+	w := map[string]func(interface{}) []byte{
+		"AppendInt":                   func(v interface{}) []byte { return enc.AppendInt([]byte{}, v.(int)) },
+		"AppendInt8":                  func(v interface{}) []byte { return enc.AppendInt8([]byte{}, v.(int8)) },
+		"AppendInt16":                 func(v interface{}) []byte { return enc.AppendInt16([]byte{}, v.(int16)) },
+		"AppendInt32":                 func(v interface{}) []byte { return enc.AppendInt32([]byte{}, v.(int32)) },
+		"AppendInt64":                 func(v interface{}) []byte { return enc.AppendInt64([]byte{}, v.(int64)) },
+		"AppendUint":                  func(v interface{}) []byte { return enc.AppendUint([]byte{}, v.(uint)) },
+		"AppendUint8":                 func(v interface{}) []byte { return enc.AppendUint8([]byte{}, v.(uint8)) },
+		"AppendUint16":                func(v interface{}) []byte { return enc.AppendUint16([]byte{}, v.(uint16)) },
+		"AppendUint32":                func(v interface{}) []byte { return enc.AppendUint32([]byte{}, v.(uint32)) },
+		"AppendUint64":                func(v interface{}) []byte { return enc.AppendUint64([]byte{}, v.(uint64)) },
+		"AppendFloat32":               func(v interface{}) []byte { return enc.AppendFloat32([]byte{}, v.(float32), -1) },
+		"AppendFloat64":               func(v interface{}) []byte { return enc.AppendFloat64([]byte{}, v.(float64), -1) },
+		"AppendFloat32SmallPrecision": func(v interface{}) []byte { return enc.AppendFloat32([]byte{}, v.(float32), 1) },
+		"AppendFloat64SmallPrecision": func(v interface{}) []byte { return enc.AppendFloat64([]byte{}, v.(float64), 1) },
+	}
 	tests := []struct {
 		name  string
-		input float64
+		fn    string
+		input interface{}
 		want  []byte
 	}{
-		{"-Inf", math.Inf(-1), []byte(`"-Inf"`)},
-		{"+Inf", math.Inf(1), []byte(`"+Inf"`)},
-		{"NaN", math.NaN(), []byte(`"NaN"`)},
-		{"0", 0, []byte(`0`)},
-		{"-1.1", -1.1, []byte(`-1.1`)},
-		{"1e20", 1e20, []byte(`100000000000000000000`)},
-		{"1e21", 1e21, []byte(`1000000000000000000000`)},
+		{"AppendInt8(math.MaxInt8)", "AppendInt8", int8(math.MaxInt8), []byte("127")},
+		{"AppendInt16(math.MaxInt16)", "AppendInt16", int16(math.MaxInt16), []byte("32767")},
+		{"AppendInt32(math.MaxInt32)", "AppendInt32", int32(math.MaxInt32), []byte("2147483647")},
+		{"AppendInt64(math.MaxInt64)", "AppendInt64", int64(math.MaxInt64), []byte("9223372036854775807")},
+
+		{"AppendUint8(math.MaxUint8)", "AppendUint8", uint8(math.MaxUint8), []byte("255")},
+		{"AppendUint16(math.MaxUint16)", "AppendUint16", uint16(math.MaxUint16), []byte("65535")},
+		{"AppendUint32(math.MaxUint32)", "AppendUint32", uint32(math.MaxUint32), []byte("4294967295")},
+		{"AppendUint64(math.MaxUint64)", "AppendUint64", uint64(math.MaxUint64), []byte("18446744073709551615")},
+
+		{"AppendFloat32(-Inf)", "AppendFloat32", float32(math.Inf(-1)), []byte(`"-Inf"`)},
+		{"AppendFloat32(+Inf)", "AppendFloat32", float32(math.Inf(1)), []byte(`"+Inf"`)},
+		{"AppendFloat32(NaN)", "AppendFloat32", float32(math.NaN()), []byte(`"NaN"`)},
+		{"AppendFloat32(0)", "AppendFloat32", float32(0), []byte(`0`)},
+		{"AppendFloat32(-1.1)", "AppendFloat32", float32(-1.1), []byte(`-1.1`)},
+		{"AppendFloat32(1e20)", "AppendFloat32", float32(1e20), []byte(`100000000000000000000`)},
+		{"AppendFloat32(1e21)", "AppendFloat32", float32(1e21), []byte(`1e+21`)},
+
+		{"AppendFloat64(-Inf)", "AppendFloat64", float64(math.Inf(-1)), []byte(`"-Inf"`)},
+		{"AppendFloat64(+Inf)", "AppendFloat64", float64(math.Inf(1)), []byte(`"+Inf"`)},
+		{"AppendFloat64(NaN)", "AppendFloat64", float64(math.NaN()), []byte(`"NaN"`)},
+		{"AppendFloat64(0)", "AppendFloat64", float64(0), []byte(`0`)},
+		{"AppendFloat64(-1.1)", "AppendFloat64", float64(-1.1), []byte(`-1.1`)},
+		{"AppendFloat64(1e20)", "AppendFloat64", float64(1e20), []byte(`100000000000000000000`)},
+		{"AppendFloat64(1e21)", "AppendFloat64", float64(1e21), []byte(`1e+21`)},
+
+		{"AppendFloat32SmallPrecision(-1.123)", "AppendFloat32SmallPrecision", float32(-1.123), []byte(`-1.1`)},
+		{"AppendFloat64SmallPrecision(-1.123)", "AppendFloat64SmallPrecision", float64(-1.123), []byte(`-1.1`)},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := AppendFloat32([]byte{}, float32(tt.input)); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("appendFloat32() = %s, want %s", got, tt.want)
-			}
-			if got := AppendFloat64([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("appendFloat32() = %s, want %s", got, tt.want)
+			if got := w[tt.fn](tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("got %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendMAC(t *testing.T) {
+	MACtests := []struct {
+		input string
+		want  []byte
+	}{
+		{"01:23:45:67:89:ab", []byte(`"01:23:45:67:89:ab"`)},
+		{"cd:ef:11:22:33:44", []byte(`"cd:ef:11:22:33:44"`)},
+	}
+	for _, tt := range MACtests {
+		t.Run("MAC", func(t *testing.T) {
+			ha, _ := net.ParseMAC(tt.input)
+			if got := enc.AppendMACAddr([]byte{}, ha); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendMACAddr() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendBool(t *testing.T) {
+	for _, tc := range internal.BooleanTestCases {
+		s := enc.AppendBool([]byte{}, tc.Val)
+		got := string(s)
+		if got != tc.Json {
+			t.Errorf("AppendBool(%s)=0x%s, want: 0x%s",
+				tc.Json,
+				string(s),
+				string([]byte(tc.Binary)))
+		}
+	}
+}
+
+func TestAppendBoolArray(t *testing.T) {
+	for _, tc := range internal.BooleanArrayTestCases {
+		s := enc.AppendBools([]byte{}, tc.Val)
+		got := string(s)
+		if got != tc.Json {
+			t.Errorf("AppendBools(%s)=0x%s, want: 0x%s",
+				tc.Json,
+				hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.Binary)))
+		}
+	}
+
+	// now empty array case
+	array := make([]bool, 0)
+	want := make([]byte, 0)
+	want = append(want, []byte("[]")...) // start and end array
+	got := enc.AppendBools([]byte{}, array)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendBools(%v)\ngot:  0x%s\nwant: 0x%s",
+			array,
+			hex.EncodeToString(got),
+			hex.EncodeToString(want))
+	}
+
+	// now a large array case
+	array = make([]bool, 24)
+	want = make([]byte, 0)
+	want = append(want, []byte("[")...) // start a large array
+	for i := 0; i < 24; i++ {
+		array[i] = bool(i%2 == 1)
+		if array[i] {
+			want = append(want, []byte("true")...)
+		} else {
+			want = append(want, []byte("false")...)
+		}
+		if (i + 1) < 24 {
+			want = append(want, []byte(",")...)
+		}
+	}
+	want = append(want, []byte("]")...) // end a large array
+
+	got = enc.AppendBools([]byte{}, array)
+	if !bytes.Equal(got, want) {
+		t.Errorf("AppendBools(%v)\ngot:  0x%s\nwant: 0x%s",
+			array,
+			string(got),
+			string(want))
+	}
+}
+
+func TestAppendIP(t *testing.T) {
+	IPv4tests := []struct {
+		input net.IP
+		want  []byte
+	}{
+		{net.IP{0, 0, 0, 0}, []byte(`"0.0.0.0"`)},
+		{net.IP{192, 0, 2, 200}, []byte(`"192.0.2.200"`)},
+	}
+
+	for _, tt := range IPv4tests {
+		t.Run("IPv4", func(t *testing.T) {
+			if got := enc.AppendIPAddr([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIPAddr() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+	IPv6tests := []struct {
+		input net.IP
+		want  []byte
+	}{
+		{net.IPv6zero, []byte(`"::"`)},
+		{net.IPv6linklocalallnodes, []byte(`"ff02::1"`)},
+		{net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34}, []byte(`"2001:db8:85a3::8a2e:370:7334"`)},
+	}
+	for _, tt := range IPv6tests {
+		t.Run("IPv6", func(t *testing.T) {
+			if got := enc.AppendIPAddr([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIPAddr() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+var IPAddrArrayTestCases = []struct {
+	input []net.IP
+	want  []byte
+}{
+	{[]net.IP{}, []byte(`[]`)},
+	{[]net.IP{{127, 0, 0, 0}}, []byte(`["127.0.0.0"]`)},
+	{[]net.IP{{0, 0, 0, 0}, {192, 168, 0, 100}}, []byte(`["0.0.0.0","192.168.0.100"]`)},
+}
+
+func TestAppendIPAddrs(t *testing.T) {
+	for _, tt := range IPAddrArrayTestCases {
+		t.Run("IPAddrs", func(t *testing.T) {
+			if got := enc.AppendIPAddrs([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIPAddr() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+var IPPrefixArrayTestCases = []struct {
+	input []net.IPNet
+	want  []byte
+}{
+	{[]net.IPNet{}, []byte(`[]`)},
+	{[]net.IPNet{{IP: net.IP{127, 0, 0, 0}, Mask: net.CIDRMask(24, 32)}}, []byte(`["127.0.0.0/24"]`)},
+	{[]net.IPNet{{IP: net.IP{0, 0, 0, 0}, Mask: net.CIDRMask(0, 32)}, {IP: net.IP{192, 168, 0, 100}, Mask: net.CIDRMask(24, 32)}}, []byte(`["0.0.0.0/0","192.168.0.100/24"]`)},
+}
+
+func TestAppendIPPrefixes(t *testing.T) {
+	for _, tt := range IPPrefixArrayTestCases {
+		t.Run("IPPrefixes", func(t *testing.T) {
+			if got := enc.AppendIPPrefixes([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIPAddr() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendIPPrefix(t *testing.T) {
+	IPv4Prefixtests := []struct {
+		input net.IPNet
+		want  []byte
+	}{
+		{net.IPNet{IP: net.IP{0, 0, 0, 0}, Mask: net.IPv4Mask(0, 0, 0, 0)}, []byte(`"0.0.0.0/0"`)},
+		{net.IPNet{IP: net.IP{192, 0, 2, 200}, Mask: net.IPv4Mask(255, 255, 255, 0)}, []byte(`"192.0.2.200/24"`)},
+	}
+	for _, tt := range IPv4Prefixtests {
+		t.Run("IPv4", func(t *testing.T) {
+			if got := enc.AppendIPPrefix([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIPPrefix() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+	IPv6Prefixtests := []struct {
+		input net.IPNet
+		want  []byte
+	}{
+		{net.IPNet{IP: net.IPv6zero, Mask: net.CIDRMask(0, 128)}, []byte(`"::/0"`)},
+		{net.IPNet{IP: net.IPv6linklocalallnodes, Mask: net.CIDRMask(128, 128)}, []byte(`"ff02::1/128"`)},
+		{net.IPNet{IP: net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x00, 0x00, 0x00, 0x00, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34},
+			Mask: net.CIDRMask(64, 128)},
+			[]byte(`"2001:db8:85a3::8a2e:370:7334/64"`)},
+	}
+	for _, tt := range IPv6Prefixtests {
+		t.Run("IPv6", func(t *testing.T) {
+			if got := enc.AppendIPPrefix([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendIPPrefix() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendMACAddr(t *testing.T) {
+	MACtests := []struct {
+		input net.HardwareAddr
+		want  []byte
+	}{
+		{net.HardwareAddr{0x12, 0x34, 0x56, 0x78, 0x90, 0xab}, []byte(`"12:34:56:78:90:ab"`)},
+		{net.HardwareAddr{0x12, 0x34, 0x00, 0x00, 0x90, 0xab}, []byte(`"12:34:00:00:90:ab"`)},
+	}
+
+	for _, tt := range MACtests {
+		t.Run("MAC", func(t *testing.T) {
+			if got := enc.AppendMACAddr([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendMAC() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendType2(t *testing.T) {
+	typeTests := []struct {
+		label string
+		input interface{}
+		want  []byte
+	}{
+		{"int", 42, []byte(`"int"`)},
+		{"MAC", net.HardwareAddr{0x12, 0x34, 0x00, 0x00, 0x90, 0xab}, []byte(`"net.HardwareAddr"`)},
+		{"float64", float64(2.50), []byte(`"float64"`)},
+		{"nil", nil, []byte(`"<nil>"`)},
+		{"bool", true, []byte(`"bool"`)},
+	}
+
+	for _, tt := range typeTests {
+		t.Run(tt.label, func(t *testing.T) {
+			if got := enc.AppendType([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendType() = %s, want %s", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestAppendObjectData(t *testing.T) {
+	tests := []struct {
+		dst  []byte
+		obj  []byte
+		want []byte
+	}{
+		{[]byte{}, []byte(`{"foo":"bar"}`), []byte(`"foo":"bar"}`)},
+		{[]byte(`{"qux":"quz"`), []byte(`{"foo":"bar"}`), []byte(`{"qux":"quz","foo":"bar"}`)},
+		{[]byte{}, []byte(`"foo":"bar"`), []byte(`"foo":"bar"`)},
+		{[]byte(`{"qux":"quz"`), []byte(`"foo":"bar"`), []byte(`{"qux":"quz","foo":"bar"`)},
+	}
+	for _, tt := range tests {
+		t.Run("ObjectData", func(t *testing.T) {
+			if got := enc.AppendObjectData(tt.dst, tt.obj); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("appendObjectData() = %s, want %s", got, tt.want)
 			}
 		})
 	}

internal/testcases.go

@@ -0,0 +1,377 @@
+package internal
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"math"
+	"net"
+	"time"
+)
+
+var BooleanTestCases = []struct {
+	Val    bool
+	Binary string
+	Json   string
+}{
+	{true, "\xf5", "true"},
+	{false, "\xf4", "false"},
+}
+
+var BooleanArrayTestCases = []struct {
+	Val    []bool
+	Binary string
+	Json   string
+}{
+	{[]bool{}, "\x9f\xff", "[]"},
+	{[]bool{false}, "\x81\xf4", "[false]"},
+	{[]bool{true, false, true}, "\x83\xf5\xf4\xf5", "[true,false,true]"},
+	{[]bool{true, false, false, true, false, true}, "\x86\xf5\xf4\xf4\xf5\xf4\xf5", "[true,false,false,true,false,true]"},
+}
+
+var IntegerTestCases = []struct {
+	Val    int
+	Binary string
+}{
+	// Value included in the type.
+	{0, "\x00"},
+	{1, "\x01"},
+	{2, "\x02"},
+	{3, "\x03"},
+	{8, "\x08"},
+	{9, "\x09"},
+	{10, "\x0a"},
+	{22, "\x16"},
+	{23, "\x17"},
+
+	// Value in 1 byte.
+	{24, "\x18\x18"},
+	{25, "\x18\x19"},
+	{26, "\x18\x1a"},
+	{127, "\x18\x7f"},
+	{254, "\x18\xfe"},
+	{255, "\x18\xff"},
+
+	// Value in 2 bytes.
+	{256, "\x19\x01\x00"},
+	{257, "\x19\x01\x01"},
+	{1000, "\x19\x03\xe8"},
+	{0xFFFF, "\x19\xff\xff"},
+
+	// Value in 4 bytes.
+	{0x10000, "\x1a\x00\x01\x00\x00"},
+	{0x7FFFFFFE, "\x1a\x7f\xff\xff\xfe"},
+	{1000000, "\x1a\x00\x0f\x42\x40"},
+
+	// Negative number test cases.
+	// Value included in the type.
+	{-1, "\x20"},
+	{-2, "\x21"},
+	{-3, "\x22"},
+	{-10, "\x29"},
+	{-21, "\x34"},
+	{-22, "\x35"},
+	{-23, "\x36"},
+	{-24, "\x37"},
+
+	// Value in 1 byte.
+	{-25, "\x38\x18"},
+	{-26, "\x38\x19"},
+	{-100, "\x38\x63"},
+	{-128, "\x38\x7f"},
+	{-254, "\x38\xfd"},
+	{-255, "\x38\xfe"},
+	{-256, "\x38\xff"},
+
+	// Value in 2 bytes.
+	{-257, "\x39\x01\x00"},
+	{-258, "\x39\x01\x01"},
+	{-1000, "\x39\x03\xe7"},
+
+	// Value in 4 bytes.
+	{-0x10001, "\x3a\x00\x01\x00\x00"},
+	{-0x7FFFFFFE, "\x3a\x7f\xff\xff\xfd"},
+	{-1000000, "\x3a\x00\x0f\x42\x3f"},
+
+	//Constants
+	{math.MaxInt8, "\x18\x7f"},
+	{math.MinInt8, "\x38\x7f"},
+	{math.MaxInt16, "\x19\x7f\xff"},
+	{math.MinInt16, "\x39\x7f\xff"},
+	{math.MaxInt32, "\x1a\x7f\xff\xff\xff"},
+	{math.MinInt32, "\x3a\x7f\xff\xff\xff"},
+	{math.MaxInt64, "\x1b\x7f\xff\xff\xff\xff\xff\xff\xff"},
+	{math.MinInt64, "\x3b\x7f\xff\xff\xff\xff\xff\xff\xff"},
+}
+
+type UnsignedIntTestCase struct {
+	Val       uint
+	Binary    string
+	Bigbinary string
+}
+
+var AdditionalUnsignedIntegerTestCases = []UnsignedIntTestCase{
+	{0x7FFFFFFF, "\x18\xff", "\x1a\x7f\xff\xff\xff"},
+	{0x80000000, "\x19\xff\xff", "\x1a\x80\x00\x00\x00"},
+	{1000000, "\x1b\x80\x00\x00\x00\x00\x00\x00\x00", "\x1a\x00\x0f\x42\x40"},
+
+	//Constants
+	{math.MaxUint8, "\x18\xff", "\x18\xff"},
+	{math.MaxUint16, "\x19\xff\xff", "\x19\xff\xff"},
+	{math.MaxUint32, "\x1a\xff\xff\xff\xff", "\x1a\xff\xff\xff\xff"},
+	{math.MaxUint64, "\x1b\xff\xff\xff\xff\xff\xff\xff\xff", "\x1b\xff\xff\xff\xff\xff\xff\xff\xff"},
+}
+
+func unsignedIntegerTestCases() []UnsignedIntTestCase {
+	size := len(IntegerTestCases) + len(AdditionalUnsignedIntegerTestCases)
+	cases := make([]UnsignedIntTestCase, 0, size)
+	cases = append(cases, AdditionalUnsignedIntegerTestCases...)
+	for _, itc := range IntegerTestCases {
+		if itc.Val < 0 {
+			continue
+		}
+		cases = append(cases, UnsignedIntTestCase{Val: uint(itc.Val), Binary: itc.Binary, Bigbinary: itc.Binary})
+	}
+	return cases
+}
+
+var UnsignedIntegerTestCases = unsignedIntegerTestCases()
+
+var Float32TestCases = []struct {
+	Val    float32
+	Binary string
+}{
+	{0.0, "\xfa\x00\x00\x00\x00"},
+	{-0.0, "\xfa\x00\x00\x00\x00"},
+	{1.0, "\xfa\x3f\x80\x00\x00"},
+	{1.5, "\xfa\x3f\xc0\x00\x00"},
+	{65504.0, "\xfa\x47\x7f\xe0\x00"},
+	{-4.0, "\xfa\xc0\x80\x00\x00"},
+	{0.00006103515625, "\xfa\x38\x80\x00\x00"},
+	{float32(math.Inf(0)), "\xfa\x7f\x80\x00\x00"},
+	{float32(math.Inf(-1)), "\xfa\xff\x80\x00\x00"},
+	{float32(math.NaN()), "\xfa\x7f\xc0\x00\x00"},
+	{math.SmallestNonzeroFloat32, "\xfa\x00\x00\x00\x01"},
+	{math.MaxFloat32, "\xfa\x7f\x7f\xff\xff"},
+}
+
+var Float64TestCases = []struct {
+	Val    float64
+	Binary string
+}{
+	{0.0, "\xfa\x00\x00\x00\x00"},
+	{-0.0, "\xfa\x00\x00\x00\x00"},
+	{1.0, "\xfa\x3f\x80\x00\x00"},
+	{1.5, "\xfa\x3f\xc0\x00\x00"},
+	{65504.0, "\xfa\x47\x7f\xe0\x00"},
+	{-4.0, "\xfa\xc0\x80\x00\x00"},
+	{0.00006103515625, "\xfa\x38\x80\x00\x00"},
+	{math.Inf(0), "\xfa\x7f\x80\x00\x00\x00\x00\x00\x00"},
+	{math.Inf(-1), "\xfa\xff\x80\x00\x00\x00\x00\x00\x00"},
+	{math.NaN(), "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00"},
+	{math.SmallestNonzeroFloat64, "\xfa\x00\x00\x00\x00\x00\x00\x00\x01"},
+	{math.MaxFloat64, "\xfa\x7f\x7f\xff\xff"},
+}
+
+var IntegerArrayTestCases = []struct {
+	Val    []int
+	Binary string
+	Json   string
+}{
+	{[]int{}, "\x9f\xff", "[]"},
+	{[]int{32768}, "\x81\x19\x80\x00", "[32768]"},
+	{[]int{-1, 0, 200, 20}, "\x84\x20\x00\x18\xc8\x14", "[-1,0,200,20]"},
+	{[]int{-200, -10, 200, 400}, "\x84\x38\xc7\x29\x18\xc8\x19\x01\x90", "[-200,-10,200,400]"},
+	{[]int{1, 2, 3}, "\x83\x01\x02\x03", "[1,2,3]"},
+	{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25},
+		"\x98\x19\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x18\x18\x19",
+		"[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]"},
+}
+
+var IpAddrTestCases = []struct {
+	Ipaddr net.IP
+	Text   string
+	Binary string
+}{
+	{net.IP{10, 0, 0, 1}, "\"10.0.0.1\"", "\xd9\x01\x04\x44\x0a\x00\x00\x01"},
+	{net.IP{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3, 0x0, 0x0, 0x0, 0x0, 0x8a, 0x2e, 0x03, 0x70, 0x73, 0x34},
+		"\"2001:db8:85a3::8a2e:370:7334\"",
+		"\xd9\x01\x04\x50\x20\x01\x0d\xb8\x85\xa3\x00\x00\x00\x00\x8a\x2e\x03\x70\x73\x34"},
+}
+
+var IPAddrArrayTestCases = []struct {
+	Val    []net.IP
+	Binary string
+	Json   string
+}{
+	{[]net.IP{}, "\x9f\xff", "[]"},
+	{[]net.IP{{127, 0, 0, 0}}, "\x81\xd9\x01\x04\x44\x7f\x00\x00\x00", "[127.0.0.0]"},
+	{[]net.IP{{0, 0, 0, 0}, {192, 168, 0, 100}}, "\x82\xd9\x01\x04\x44\x00\x00\x00\x00\xd9\x01\x04\x44\xc0\xa8\x00\x64", "[0.0.0.0,192.168.0.100]"},
+}
+
+var IPPrefixTestCases = []struct {
+	Pfx    net.IPNet
+	Text   string // ASCII representation of pfx
+	Binary string // CBOR representation of pfx
+}{
+	{net.IPNet{IP: net.IP{0, 0, 0, 0}, Mask: net.CIDRMask(0, 32)}, "\"0.0.0.0/0\"", "\xd9\x01\x05\xa1\x44\x00\x00\x00\x00\x00"},
+	{net.IPNet{IP: net.IP{192, 168, 0, 100}, Mask: net.CIDRMask(24, 32)}, "\"192.168.0.100/24\"",
+		"\xd9\x01\x05\xa1\x44\xc0\xa8\x00\x64\x18\x18"},
+	{net.IPNet{IP: net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, Mask: net.CIDRMask(128, 128)}, "\"::1/128\"",
+		"\xd9\x01\x05\xa1\x50\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x18\x80"},
+}
+
+var IPPrefixArrayTestCases = []struct {
+	Val    []net.IPNet
+	Binary string
+	Json   string
+}{
+	{[]net.IPNet{}, "\x9f\xff", "[]"},
+	{[]net.IPNet{{IP: net.IP{127, 0, 0, 0}, Mask: net.CIDRMask(24, 32)}}, "\x81\xd9\x01\x05\xa1\x44\x7f\x00\x00\x00\x18\x18", "[127.0.0.0/24]"},
+	{[]net.IPNet{{IP: net.IP{0, 0, 0, 0}, Mask: net.CIDRMask(0, 32)}, {IP: net.IP{192, 168, 0, 100}, Mask: net.CIDRMask(24, 32)}}, "\x82\xd9\x01\x05\xa1\x44\x00\x00\x00\x00\x00\xd9\x01\x05\xa1\x44\xc0\xa8\x00\x64\x18\x18", "[0.0.0.0/0,192.168.0.100/24]"},
+}
+
+var MacAddrTestCases = []struct {
+	Macaddr net.HardwareAddr
+	Text    string // ASCII representation of macaddr
+	Binary  string // CBOR representation of macaddr
+}{
+	{net.HardwareAddr{0x12, 0x34, 0x56, 0x78, 0x90, 0xab}, "\"12:34:56:78:90:ab\"", "\xd9\x01\x04\x46\x12\x34\x56\x78\x90\xab"},
+	{net.HardwareAddr{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3}, "\"20:01:0d:b8:85:a3\"", "\xd9\x01\x04\x46\x20\x01\x0d\xb8\x85\xa3"},
+}
+
+var EncodeHexTests = []struct {
+	In  byte
+	Out string
+}{
+	{0x00, `"00"`},
+	{0x0f, `"0f"`},
+	{0x10, `"10"`},
+	{0xf0, `"f0"`},
+	{0xff, `"ff"`},
+}
+
+var EncodeStringTests = []struct {
+	In  string
+	Out string
+}{
+	{"", `""`},
+	{"\\", `"\\"`},
+	{"\x00", `"\u0000"`},
+	{"\x01", `"\u0001"`},
+	{"\x02", `"\u0002"`},
+	{"\x03", `"\u0003"`},
+	{"\x04", `"\u0004"`},
+	{"\x05", `"\u0005"`},
+	{"\x06", `"\u0006"`},
+	{"\x07", `"\u0007"`},
+	{"\x08", `"\b"`},
+	{"\x09", `"\t"`},
+	{"\x0a", `"\n"`},
+	{"\x0b", `"\u000b"`},
+	{"\x0c", `"\f"`},
+	{"\x0d", `"\r"`},
+	{"\x0e", `"\u000e"`},
+	{"\x0f", `"\u000f"`},
+	{"\x10", `"\u0010"`},
+	{"\x11", `"\u0011"`},
+	{"\x12", `"\u0012"`},
+	{"\x13", `"\u0013"`},
+	{"\x14", `"\u0014"`},
+	{"\x15", `"\u0015"`},
+	{"\x16", `"\u0016"`},
+	{"\x17", `"\u0017"`},
+	{"\x18", `"\u0018"`},
+	{"\x19", `"\u0019"`},
+	{"\x1a", `"\u001a"`},
+	{"\x1b", `"\u001b"`},
+	{"\x1c", `"\u001c"`},
+	{"\x1d", `"\u001d"`},
+	{"\x1e", `"\u001e"`},
+	{"\x1f", `"\u001f"`},
+	{"✭", `"✭"`},
+	{"foo\xc2\x7fbar", `"foo\ufffd\u007fbar"`}, // invalid sequence
+	{"ascii", `"ascii"`},
+	{"\"a", `"\"a"`},
+	{"\x1fa", `"\u001fa"`},
+	{"foo\"bar\"baz", `"foo\"bar\"baz"`},
+	{"\x1ffoo\x1fbar\x1fbaz", `"\u001ffoo\u001fbar\u001fbaz"`},
+	{"emoji \u2764\ufe0f!", `"emoji ❤️!"`},
+}
+
+var EncodeStringsTests = []struct {
+	In  []string
+	Out string
+}{
+	{nil, `[]`},
+	{[]string{}, `[]`},
+	{[]string{"A"}, `["A"]`},
+	{[]string{"A", "B"}, `["A","B"]`},
+}
+
+var EncodeStringerTests = []struct {
+	In     fmt.Stringer
+	Out    string
+	Binary string
+}{
+	{nil, `null`, "\xf6"},
+	{fmt.Stringer(nil), `null`, "\xf6"},
+	{net.IPv4bcast, `"255.255.255.255"`, "\x6f\x32\x35\x35\x2e\x32\x35\x35\x2e\x32\x35\x35\x2e\x32\x35\x35"},
+}
+
+var EncodeStringersTests = []struct {
+	In     []fmt.Stringer
+	Out    string
+	Binary string
+}{
+	{nil, `[]`, "\x9f\xff"},
+	{[]fmt.Stringer{}, `[]`, "\x9f\xff"},
+	{[]fmt.Stringer{net.IPv4bcast}, `["255.255.255.255"]`, "\x9f\x6f255.255.255.255\xff"},
+	{[]fmt.Stringer{net.IPv4allsys, net.IPv4allrouter}, `["224.0.0.1","224.0.0.2"]`, "\x9f\x69224.0.0.1\x69224.0.0.2\xff"},
+}
+
+var TimeIntegerTestcases = []struct {
+	Txt     string
+	Binary  string
+	RfcStr  string
+	UnixInt int
+}{
+	{"2013-02-03T19:54:00-08:00", "\xc1\x1a\x51\x0f\x30\xd8", "2013-02-04T03:54:00Z", 1359950040},
+	{"1950-02-03T19:54:00-08:00", "\xc1\x3a\x25\x71\x93\xa7", "1950-02-04T03:54:00Z", -628200360},
+}
+
+var TimeFloatTestcases = []struct {
+	RfcStr  string
+	Out     string
+	UnixInt int
+}{
+	{"2006-01-02T15:04:05.999999-08:00", "\xc1\xfb\x41\xd0\xee\x6c\x59\x7f\xff\xfc", 1136243045},
+	{"1956-01-02T15:04:05.999999-08:00", "\xc1\xfb\xc1\xba\x53\x81\x1a\x00\x00\x11", -441680155},
+}
+
+var DurTestcases = []struct {
+	Duration   time.Duration
+	FloatOut   string
+	IntegerOut string
+}{
+	{1000, "\xfb\x3f\xf0\x00\x00\x00\x00\x00\x00", "\x01"},
+	{2000, "\xfb\x40\x00\x00\x00\x00\x00\x00\x00", "\x02"},
+	{200000, "\xfb\x40\x69\x00\x00\x00\x00\x00\x00", "\x18\xc8"},
+}
+
+// inline copy from globals.go of InterfaceMarshalFunc used in tests to avoid import cycle
+func InterfaceMarshalFunc(v interface{}) ([]byte, error) {
+	var buf bytes.Buffer
+	encoder := json.NewEncoder(&buf)
+	encoder.SetEscapeHTML(false)
+	err := encoder.Encode(v)
+	if err != nil {
+		return nil, err
+	}
+	b := buf.Bytes()
+	if len(b) > 0 {
+		// Remove trailing \n which is added by Encode.
+		return b[:len(b)-1], nil
+	}
+	return b, nil
+}

journald/journald.go

@@ -0,0 +1,150 @@
+//go:build !windows
+// +build !windows
+
+// Package journald provides a io.Writer to send the logs
+// to journalD component of systemd.
+
+package journald
+
+// This file provides a zerolog writer so that logs printed
+// using zerolog library can be sent to a journalD.
+
+// Zerolog's Top level key/Value Pairs are translated to
+// journald's args - all Values are sent to journald as strings.
+// And all key strings are converted to uppercase and sanitized
+// by replacing any characters not in [A-Z0-9_] with '_' before
+// sending to journald (as required by journald).
+
+// In addition, entire log message (all Key Value Pairs), is also
+// sent to journald under the key "JSON".
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/coreos/go-systemd/v22/journal"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/internal/cbor"
+)
+
+const defaultJournalDPrio = journal.PriNotice
+
+// SendFunc is the function used to send logs to journald.
+// It can be replaced in tests for mocking. If nil, journal.Send is used directly.
+// This variable should only be modified in tests and must not be changed while the
+// writer is in use. Tests that modify this variable should not use t.Parallel().
+var SendFunc func(string, journal.Priority, map[string]string) error
+
+// NewJournalDWriter returns a zerolog log destination
+// to be used as parameter to New() calls. Writing logs
+// to this writer will send the log messages to journalD
+// running in this system.
+func NewJournalDWriter() io.Writer {
+	return journalWriter{}
+}
+
+type journalWriter struct {
+}
+
+// levelToJPrio converts zerolog Level string into
+// journalD's priority values. JournalD has more
+// priorities than zerolog.
+func levelToJPrio(zLevel string) journal.Priority {
+	lvl, _ := zerolog.ParseLevel(zLevel)
+
+	switch lvl {
+	case zerolog.TraceLevel:
+		return journal.PriDebug
+	case zerolog.DebugLevel:
+		return journal.PriDebug
+	case zerolog.InfoLevel:
+		return journal.PriInfo
+	case zerolog.WarnLevel:
+		return journal.PriWarning
+	case zerolog.ErrorLevel:
+		return journal.PriErr
+	case zerolog.FatalLevel:
+		return journal.PriCrit
+	case zerolog.PanicLevel:
+		return journal.PriEmerg
+	case zerolog.NoLevel:
+		return journal.PriNotice
+	}
+	return defaultJournalDPrio
+}
+
+// sanitizeKey converts a key to uppercase and replaces invalid characters with '_'
+// JournalD requires keys start with A-Z and contain only  A-Z, 0-9, or _
+func sanitizeKey(key string) string {
+	sanitized := strings.Map(func(r rune) rune {
+		if r >= 'a' && r <= 'z' {
+			return r - 'a' + 'A'
+		} else if (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' {
+			return r
+		} else {
+			return '_'
+		}
+	}, key)
+	if len(sanitized) == 0 || sanitized[0] >= '0' && sanitized[0] <= '9' || sanitized[0] == '_' {
+		sanitized = "X" + sanitized
+	}
+	return sanitized
+}
+
+func (w journalWriter) Write(p []byte) (n int, err error) {
+	var event map[string]interface{}
+	origPLen := len(p)
+	p = cbor.DecodeIfBinaryToBytes(p)
+	d := json.NewDecoder(bytes.NewReader(p))
+	d.UseNumber()
+	err = d.Decode(&event)
+	jPrio := defaultJournalDPrio
+	args := make(map[string]string)
+	if err != nil {
+		return
+	}
+	if l, ok := event[zerolog.LevelFieldName].(string); ok {
+		jPrio = levelToJPrio(l)
+	}
+
+	msg := ""
+	for key, value := range event {
+		jKey := sanitizeKey(key)
+		switch key {
+		case zerolog.LevelFieldName, zerolog.TimestampFieldName:
+			continue
+		case zerolog.MessageFieldName:
+			msg, _ = value.(string)
+			continue
+		}
+
+		switch v := value.(type) {
+		case string:
+			args[jKey] = v
+		case json.Number:
+			args[jKey] = fmt.Sprint(value)
+		default:
+			b, err := zerolog.InterfaceMarshalFunc(value)
+			if err != nil {
+				args[jKey] = fmt.Sprintf("[error: %v]", err)
+			} else {
+				args[jKey] = string(b)
+			}
+		}
+	}
+	args["JSON"] = string(p)
+	if SendFunc != nil {
+		err = SendFunc(msg, jPrio, args)
+	} else {
+		err = journal.Send(msg, jPrio, args)
+	}
+
+	if err == nil {
+		n = origPLen
+	}
+
+	return
+}

journald/journald_test.go

@@ -0,0 +1,282 @@
+//go:build linux
+// +build linux
+
+package journald
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/coreos/go-systemd/v22/journal"
+	"github.com/rs/zerolog"
+)
+
+func ExampleNewJournalDWriter() {
+	log := zerolog.New(NewJournalDWriter())
+	log.Info().Str("foo", "bar").Uint64("small", 123).Float64("float", 3.14).Uint64("big", 1152921504606846976).Msg("Journal Test")
+	// Output:
+}
+
+/*
+
+There is no automated way to verify the output - since the output is sent
+to journald process and method to retrieve is journalctl. Will find a way
+to automate the process and fix this test.
+
+$ journalctl -o verbose -f
+
+Thu 2018-04-26 22:30:20.768136 PDT [s=3284d695bde946e4b5017c77a399237f;i=329f0;b=98c0dca0debc4b98a5b9534e910e7dd6;m=7a702e35dd4;t=56acdccd2ed0a;x=4690034cf0348614]
+    PRIORITY=6
+    _AUDIT_LOGINUID=1000
+    _BOOT_ID=98c0dca0debc4b98a5b9534e910e7dd6
+    _MACHINE_ID=926ed67eb4744580948de70fb474975e
+    _HOSTNAME=sprint
+    _UID=1000
+    _GID=1000
+    _CAP_EFFECTIVE=0
+    _SYSTEMD_SLICE=-.slice
+    _TRANSPORT=journal
+    _SYSTEMD_CGROUP=/
+    _AUDIT_SESSION=2945
+    MESSAGE=Journal Test
+    FOO=bar
+    BIG=1152921504606846976
+    _COMM=journald.test
+    SMALL=123
+    FLOAT=3.14
+    JSON={"level":"info","foo":"bar","small":123,"float":3.14,"big":1152921504606846976,"message":"Journal Test"}
+    _PID=27103
+    _SOURCE_REALTIME_TIMESTAMP=1524807020768136
+*/
+
+func TestSanitizeKey(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"test", "TEST"},
+		{"Test", "TEST"},
+		{"test-key", "TEST_KEY"},
+		{"Test.Key", "TEST_KEY"},
+		{"test_key123", "TEST_KEY123"},
+		{"invalid@key!", "INVALID_KEY_"},
+		{"a1B2_c3D4", "A1B2_C3D4"},
+		{"_", "X_"},
+		{"", "X"},
+		{"123", "X123"},
+		{"a-b.c_d", "A_B_C_D"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			result := sanitizeKey(tt.input)
+			if result != tt.expected {
+				t.Errorf("sanitizeKey(%q) = %q; want %q", tt.input, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestWriteReturnsNoOfWrittenBytes(t *testing.T) {
+	input := []byte(`{"level":"info","time":1570912626,"message":"Starting..."}`)
+	wr := NewJournalDWriter()
+	want := len(input)
+	got, err := wr.Write(input)
+
+	if err != nil {
+		t.Errorf("Unexpected error %v", err)
+	}
+
+	if want != got {
+		t.Errorf("Expected %d bytes to be written got %d", want, got)
+	}
+}
+
+func TestMultiWrite(t *testing.T) {
+	var (
+		w1 = new(bytes.Buffer)
+		w2 = new(bytes.Buffer)
+		w3 = NewJournalDWriter()
+	)
+
+	zerolog.ErrorHandler = func(err error) {
+		if err == io.ErrShortWrite {
+			t.Errorf("Unexpected ShortWriteError")
+			t.FailNow()
+		}
+	}
+
+	log := zerolog.New(io.MultiWriter(w1, w2, w3)).With().Logger()
+
+	for i := 0; i < 10; i++ {
+		log.Info().Msg("Tick!")
+	}
+}
+
+func TestWriteWithVariousTypes(t *testing.T) {
+	mock := &mockSend{}
+	oldSend := SendFunc
+	SendFunc = mock.send
+	defer func() { SendFunc = oldSend }()
+
+	wr := NewJournalDWriter()
+	log := zerolog.New(wr)
+
+	// This should cover the default case in the switch for value types
+	log.Info().Bool("flag", true).Str("foo", "bar").Uint64("small", 123).Float64("float", 3.14).Uint64("big", 1152921504606846976).Interface("data", map[string]int{"a": 1}).Msg("Test various types")
+
+	// Verify the call
+	if len(mock.calls) != 1 {
+		t.Fatalf("Expected 1 call, got %d", len(mock.calls))
+	}
+
+	call := mock.calls[0]
+
+	// Check that flag is sanitized to FLAG and value is "true"
+	if call.args["FLAG"] != "true" {
+		t.Errorf("Expected FLAG=true, got %s", call.args["FLAG"])
+	}
+
+	// Check that data is marshaled (should be a JSON string)
+	expectedData := `{"a":1}`
+	if call.args["DATA"] != expectedData {
+		t.Errorf("Expected DATA=%q, got %q", expectedData, call.args["DATA"])
+	}
+}
+
+func TestWriteWithAllLevels(t *testing.T) {
+	wr := NewJournalDWriter()
+
+	// Save original FatalExitFunc
+	oldFatalExitFunc := zerolog.FatalExitFunc
+	defer func() { zerolog.FatalExitFunc = oldFatalExitFunc }()
+
+	// Set FatalExitFunc to prevent actual exit
+	zerolog.FatalExitFunc = func() {}
+
+	log := zerolog.New(wr)
+
+	// Test all zerolog levels to cover levelToJPrio switch cases
+	log.Trace().Msg("Trace level")
+	log.Debug().Msg("Debug level")
+	log.Info().Msg("Info level")
+	log.Warn().Msg("Warn level")
+	log.Error().Msg("Error level")
+	log.Log().Msg("No level")
+
+	// For Fatal, it will call FatalExitFunc instead of exiting
+	log.Fatal().Msg("Fatal level")
+
+	// For Panic, use recover to catch the panic, do last because it will stop of this test execution
+	defer func() {
+		if r := recover(); r == nil {
+			t.Error("Expected panic from Panic level")
+		}
+	}()
+	log.Panic().Msg("Panic level")
+
+}
+
+func TestWriteOutputs(t *testing.T) {
+	mock := &mockSend{}
+	oldSend := SendFunc
+	SendFunc = mock.send
+	defer func() { SendFunc = oldSend }()
+
+	wr := NewJournalDWriter()
+	log := zerolog.New(wr)
+
+	// Log a message with various fields
+	log.Info().Str("test-key", "value").Int("number", 42).Msg("Test message")
+
+	// Check that SendFunc was called
+	if len(mock.calls) != 1 {
+		t.Fatalf("Expected 1 call to SendFunc, got %d", len(mock.calls))
+	}
+
+	call := mock.calls[0]
+
+	// Check message
+	if call.msg != "Test message" {
+		t.Errorf("Expected msg 'Test message', got %q", call.msg)
+	}
+
+	// Check priority
+	if call.prio != journal.PriInfo {
+		t.Errorf("Expected prio %d (PriInfo), got %d", journal.PriInfo, call.prio)
+	}
+
+	// Check args
+	expectedArgs := map[string]string{
+		"TEST_KEY": "value",
+		"NUMBER":   "42",
+		"JSON":     `{"level":"info","test-key":"value","number":42,"message":"Test message"}` + "\n",
+	}
+
+	for k, v := range expectedArgs {
+		if call.args[k] != v {
+			t.Errorf("Expected args[%q] = %q, got %q", k, v, call.args[k])
+		}
+	}
+
+	// Check that LEVEL is not in args (since it's skipped)
+	if _, ok := call.args["LEVEL"]; ok {
+		t.Error("LEVEL should not be in args")
+	}
+}
+
+func TestWriteWithMarshalError(t *testing.T) {
+	mock := &mockSend{}
+	oldSend := SendFunc
+	SendFunc = mock.send
+	defer func() { SendFunc = oldSend }()
+
+	// Save original marshal func
+	originalMarshal := zerolog.InterfaceMarshalFunc
+	defer func() { zerolog.InterfaceMarshalFunc = originalMarshal }()
+
+	// Set marshal func to fail
+	zerolog.InterfaceMarshalFunc = func(v interface{}) ([]byte, error) {
+		return nil, fmt.Errorf("fake error")
+	}
+
+	wr := NewJournalDWriter()
+	log := zerolog.New(wr)
+
+	// This should trigger the error handling in the default case
+	log.Info().Interface("data", map[string]int{"a": 1}).Msg("Test with error")
+
+	// Verify the call
+	if len(mock.calls) != 1 {
+		t.Fatalf("Expected 1 call, got %d", len(mock.calls))
+	}
+
+	call := mock.calls[0]
+
+	// Check that data has the error message
+	got := call.args["DATA"]
+	want := "error: fake error"
+	if !strings.Contains(got, want) {
+		t.Errorf("Expected DATA to contain %q, got %q", want, got)
+	}
+}
+
+type mockSend struct {
+	calls []struct {
+		msg  string
+		prio journal.Priority
+		args map[string]string
+	}
+}
+
+func (m *mockSend) send(msg string, prio journal.Priority, args map[string]string) error {
+	m.calls = append(m.calls, struct {
+		msg  string
+		prio journal.Priority
+		args map[string]string
+	}{msg, prio, args})
+	return nil
+}

log.go

@@ -2,83 +2,129 @@
 //
 // A global Logger can be use for simple logging:
 //
-//     import "github.com/rs/zerolog/log"
+//	import "github.com/rs/zerolog/log"
 //
-//     log.Info().Msg("hello world")
-//     // Output: {"time":1494567715,"level":"info","message":"hello world"}
+//	log.Info().Msg("hello world")
+//	// Output: {"time":1494567715,"level":"info","message":"hello world"}
 //
 // NOTE: To import the global logger, import the "log" subpackage "github.com/rs/zerolog/log".
 //
 // Fields can be added to log messages:
 //
-//     log.Info().Str("foo", "bar").Msg("hello world")
-//     // Output: {"time":1494567715,"level":"info","message":"hello world","foo":"bar"}
+//	log.Info().Str("foo", "bar").Msg("hello world")
+//	// Output: {"time":1494567715,"level":"info","message":"hello world","foo":"bar"}
 //
 // Create logger instance to manage different outputs:
 //
-//     logger := zerolog.New(os.Stderr).With().Timestamp().Logger()
-//     logger.Info().
-//            Str("foo", "bar").
-//            Msg("hello world")
-//     // Output: {"time":1494567715,"level":"info","message":"hello world","foo":"bar"}
+//	logger := zerolog.New(os.Stderr).With().Timestamp().Logger()
+//	logger.Info().
+//	       Str("foo", "bar").
+//	       Msg("hello world")
+//	// Output: {"time":1494567715,"level":"info","message":"hello world","foo":"bar"}
 //
 // Sub-loggers let you chain loggers with additional context:
 //
-//     sublogger := log.With().Str("component": "foo").Logger()
-//     sublogger.Info().Msg("hello world")
-//     // Output: {"time":1494567715,"level":"info","message":"hello world","component":"foo"}
+//	sublogger := log.With().Str("component", "foo").Logger()
+//	sublogger.Info().Msg("hello world")
+//	// Output: {"time":1494567715,"level":"info","message":"hello world","component":"foo"}
 //
 // Level logging
 //
-//     zerolog.SetGlobalLevel(zerolog.InfoLevel)
+//	zerolog.SetGlobalLevel(zerolog.InfoLevel)
 //
-//     log.Debug().Msg("filtered out message")
-//     log.Info().Msg("routed message")
+//	log.Debug().Msg("filtered out message")
+//	log.Info().Msg("routed message")
 //
-//     if e := log.Debug(); e.Enabled() {
-//         // Compute log output only if enabled.
-//         value := compute()
-//         e.Str("foo": value).Msg("some debug message")
-//     }
-//     // Output: {"level":"info","time":1494567715,"routed message"}
+//	if e := log.Debug(); e.Enabled() {
+//	    // Compute log output only if enabled.
+//	    value := compute()
+//	    e.Str("foo": value).Msg("some debug message")
+//	}
+//	// Output: {"level":"info","time":1494567715,"routed message"}
 //
 // Customize automatic field names:
 //
-//     log.TimestampFieldName = "t"
-//     log.LevelFieldName = "p"
-//     log.MessageFieldName = "m"
+//	log.TimestampFieldName = "t"
+//	log.LevelFieldName = "p"
+//	log.MessageFieldName = "m"
 //
-//     log.Info().Msg("hello world")
-//     // Output: {"t":1494567715,"p":"info","m":"hello world"}
+//	log.Info().Msg("hello world")
+//	// Output: {"t":1494567715,"p":"info","m":"hello world"}
 //
 // Log with no level and message:
 //
-//     log.Log().Str("foo","bar").Msg("")
-//     // Output: {"time":1494567715,"foo":"bar"}
+//	log.Log().Str("foo","bar").Msg("")
+//	// Output: {"time":1494567715,"foo":"bar"}
 //
 // Add contextual fields to global Logger:
 //
-//     log.Logger = log.With().Str("foo", "bar").Logger()
+//	log.Logger = log.With().Str("foo", "bar").Logger()
 //
 // Sample logs:
 //
-//     sampled := log.Sample(10)
-//     sampled.Info().Msg("will be logged every 10 messages")
+//	sampled := log.Sample(&zerolog.BasicSampler{N: 10})
+//	sampled.Info().Msg("will be logged every 10 messages")
 //
+// Log with contextual hooks:
+//
+//	// Create the hook:
+//	type SeverityHook struct{}
+//
+//	func (h SeverityHook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
+//	     if level != zerolog.NoLevel {
+//	         e.Str("severity", level.String())
+//	     }
+//	}
+//
+//	// And use it:
+//	var h SeverityHook
+//	log := zerolog.New(os.Stdout).Hook(h)
+//	log.Warn().Msg("")
+//	// Output: {"level":"warn","severity":"warn"}
+//
+// # Caveats
+//
+// Field duplication:
+//
+// There is no fields deduplication out-of-the-box.
+// Using the same key multiple times creates new key in final JSON each time.
+//
+//	logger := zerolog.New(os.Stderr).With().Timestamp().Logger()
+//	logger.Info().
+//	       Timestamp().
+//	       Msg("dup")
+//	// Output: {"level":"info","time":1494567715,"time":1494567715,"message":"dup"}
+//
+// In this case, many consumers will take the last value,
+// but this is not guaranteed; check yours if in doubt.
+//
+// Concurrency safety:
+//
+// Be careful when calling UpdateContext. It is not concurrency safe. Use the With method to create a child logger:
+//
+//	func handler(w http.ResponseWriter, r *http.Request) {
+//	    // Create a child logger for concurrency safety
+//	    logger := log.Logger.With().Logger()
+//
+//	    // Add context fields, for example User-Agent from HTTP headers
+//	    logger.UpdateContext(func(c zerolog.Context) zerolog.Context {
+//	        ...
+//	    })
+//	}
 package zerolog
 
 import (
+	"context"
+	"errors"
+	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"strconv"
-	"sync/atomic"
-
-	"github.com/rs/zerolog/internal/json"
+	"strings"
 )
 
 // Level defines log levels.
-type Level uint8
+type Level int8
 
 const (
 	// DebugLevel defines debug log level.
@@ -93,50 +139,101 @@ const (
 	FatalLevel
 	// PanicLevel defines panic log level.
 	PanicLevel
+	// NoLevel defines an absent log level.
+	NoLevel
 	// Disabled disables the logger.
 	Disabled
+
+	// TraceLevel defines trace log level.
+	TraceLevel Level = -1
+	// Values less than TraceLevel are handled as numbers.
 )
 
 func (l Level) String() string {
 	switch l {
+	case TraceLevel:
+		return LevelTraceValue
 	case DebugLevel:
-		return "debug"
+		return LevelDebugValue
 	case InfoLevel:
-		return "info"
+		return LevelInfoValue
 	case WarnLevel:
-		return "warn"
+		return LevelWarnValue
 	case ErrorLevel:
-		return "error"
+		return LevelErrorValue
 	case FatalLevel:
-		return "fatal"
+		return LevelFatalValue
 	case PanicLevel:
-		return "panic"
+		return LevelPanicValue
+	case Disabled:
+		return "disabled"
+	case NoLevel:
+		return ""
 	}
-	return ""
+	return strconv.Itoa(int(l))
 }
 
-const (
-	// Often samples log every 10 events.
-	Often = 10
-	// Sometimes samples log every 100 events.
-	Sometimes = 100
-	// Rarely samples log every 1000 events.
-	Rarely = 1000
-)
+// ParseLevel converts a level string into a zerolog Level value.
+// returns an error if the input string does not match known values.
+func ParseLevel(levelStr string) (Level, error) {
+	switch {
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(TraceLevel)):
+		return TraceLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(DebugLevel)):
+		return DebugLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(InfoLevel)):
+		return InfoLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(WarnLevel)):
+		return WarnLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(ErrorLevel)):
+		return ErrorLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(FatalLevel)):
+		return FatalLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(PanicLevel)):
+		return PanicLevel, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(Disabled)):
+		return Disabled, nil
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(NoLevel)):
+		return NoLevel, nil
+	}
+	i, err := strconv.Atoi(levelStr)
+	if err != nil {
+		return NoLevel, fmt.Errorf("Unknown Level String: '%s', defaulting to NoLevel", levelStr)
+	}
+	if i > 127 || i < -128 {
+		return NoLevel, fmt.Errorf("Out-Of-Bounds Level: '%d', defaulting to NoLevel", i)
+	}
+	return Level(i), nil
+}
 
-var disabledEvent = newEvent(levelWriterAdapter{ioutil.Discard}, 0, false)
+// UnmarshalText implements encoding.TextUnmarshaler to allow for easy reading from toml/yaml/json formats
+func (l *Level) UnmarshalText(text []byte) error {
+	if l == nil {
+		return errors.New("can't unmarshal a nil *Level")
+	}
+	var err error
+	*l, err = ParseLevel(string(text))
+	return err
+}
+
+// MarshalText implements encoding.TextMarshaler to allow for easy writing into toml/yaml/json formats
+func (l Level) MarshalText() ([]byte, error) {
+	return []byte(LevelFieldMarshalFunc(l)), nil
+}
 
 // A Logger represents an active logging object that generates lines
 // of JSON output to an io.Writer. Each logging operation makes a single
-// call to the Writer's Write method. There is no guaranty on access
+// call to the Writer's Write method. There is no guarantee on access
 // serialization to the Writer. If your Writer is not thread safe,
 // you may consider a sync wrapper.
 type Logger struct {
 	w       LevelWriter
 	level   Level
-	sample  uint32
-	counter *uint32
+	sampler Sampler
 	context []byte
+	hooks   []Hook
+	stack   bool
+	ctx     context.Context
 }
 
 // New creates a root logger with given output writer. If the output writer implements
@@ -144,17 +241,17 @@ type Logger struct {
 // one.
 //
 // Each logging operation makes a single call to the Writer's Write method. There is no
-// guaranty on access serialization to the Writer. If your Writer is not thread safe,
+// guarantee on access serialization to the Writer. If your Writer is not thread safe,
 // you may consider using sync wrapper.
 func New(w io.Writer) Logger {
 	if w == nil {
-		w = ioutil.Discard
+		w = io.Discard
 	}
 	lw, ok := w.(LevelWriter)
 	if !ok {
-		lw = levelWriterAdapter{w}
+		lw = LevelWriterAdapter{w}
 	}
-	return Logger{w: lw}
+	return Logger{w: lw, level: TraceLevel}
 }
 
 // Nop returns a disabled logger for which all operation are no-op.
@@ -166,8 +263,15 @@ func Nop() Logger {
 func (l Logger) Output(w io.Writer) Logger {
 	l2 := New(w)
 	l2.level = l.level
-	l2.sample = l.sample
-	copy(l2.context, l.context)
+	l2.sampler = l.sampler
+	l2.stack = l.stack
+	if len(l.hooks) > 0 {
+		l2.hooks = append(l2.hooks, l.hooks...)
+	}
+	if l.context != nil {
+		l2.context = make([]byte, len(l.context), cap(l.context))
+		copy(l2.context, l.context)
+	}
 	return l2
 }
 
@@ -178,91 +282,144 @@ func (l Logger) With() Context {
 	if context != nil {
 		l.context = append(l.context, context...)
 	} else {
-		// first byte of context is presence of timestamp or not
-		l.context = append(l.context, 0)
+		// This is needed for AppendKey to not check len of input
+		// thus making it inlinable
+		l.context = enc.AppendBeginMarker(l.context)
 	}
 	return Context{l}
 }
 
-// Level creates a child logger with the minimum accepted level set to level.
-func (l Logger) Level(lvl Level) Logger {
-	return Logger{
-		w:       l.w,
-		level:   lvl,
-		sample:  l.sample,
-		counter: l.counter,
-		context: l.context,
+// UpdateContext updates the internal logger's context.
+//
+// Caution: This method is not concurrency safe.
+// Use the With method to create a child logger before modifying the context from concurrent goroutines.
+func (l *Logger) UpdateContext(update func(c Context) Context) {
+	if l.disabled() {
+		return
 	}
+	if cap(l.context) == 0 {
+		l.context = make([]byte, 0, 500)
+	}
+	if len(l.context) == 0 {
+		l.context = enc.AppendBeginMarker(l.context)
+	}
+	c := update(Context{*l})
+	l.context = c.l.context
 }
 
-// Sample returns a logger that only let one message out of every to pass thru.
-func (l Logger) Sample(every int) Logger {
-	if every == 0 {
-		// Create a child with no sampling.
-		return Logger{
-			w:       l.w,
-			level:   l.level,
-			context: l.context,
-		}
-	}
-	return Logger{
-		w:       l.w,
-		level:   l.level,
-		sample:  uint32(every),
-		counter: new(uint32),
-		context: l.context,
+// Level creates a child logger with the minimum accepted level set to level.
+func (l Logger) Level(lvl Level) Logger {
+	l.level = lvl
+	return l
+}
+
+// GetLevel returns the current Level of l.
+func (l Logger) GetLevel() Level {
+	return l.level
+}
+
+// Sample returns a logger with the s sampler.
+func (l Logger) Sample(s Sampler) Logger {
+	l.sampler = s
+	return l
+}
+
+// Hook returns a logger with the h Hook.
+func (l Logger) Hook(hooks ...Hook) Logger {
+	if len(hooks) == 0 {
+		return l
 	}
+	newHooks := make([]Hook, len(l.hooks), len(l.hooks)+len(hooks))
+	copy(newHooks, l.hooks)
+	l.hooks = append(newHooks, hooks...)
+	return l
+}
+
+// Trace starts a new message with trace level.
+//
+// You must call Msg on the returned event in order to send the event.
+func (l *Logger) Trace() *Event {
+	return l.newEvent(TraceLevel, nil)
 }
 
 // Debug starts a new message with debug level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Debug() *Event {
-	return l.newEvent(DebugLevel, true, nil)
+func (l *Logger) Debug() *Event {
+	return l.newEvent(DebugLevel, nil)
 }
 
 // Info starts a new message with info level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Info() *Event {
-	return l.newEvent(InfoLevel, true, nil)
+func (l *Logger) Info() *Event {
+	return l.newEvent(InfoLevel, nil)
 }
 
 // Warn starts a new message with warn level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Warn() *Event {
-	return l.newEvent(WarnLevel, true, nil)
+func (l *Logger) Warn() *Event {
+	return l.newEvent(WarnLevel, nil)
 }
 
 // Error starts a new message with error level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Error() *Event {
-	return l.newEvent(ErrorLevel, true, nil)
+func (l *Logger) Error() *Event {
+	return l.newEvent(ErrorLevel, nil)
 }
 
-// Fatal starts a new message with fatal level. The os.Exit(1) function
-// is called by the Msg method.
+// Err starts a new message with error level with err as a field if not nil or
+// with info level if err is nil.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Fatal() *Event {
-	return l.newEvent(FatalLevel, true, func(msg string) { os.Exit(1) })
+func (l *Logger) Err(err error) *Event {
+	if err != nil {
+		return l.Error().Err(err)
+	}
+
+	return l.Info()
 }
 
-// Panic starts a new message with panic level. The message is also sent
-// to the panic function.
+// Fatal starts a new message with fatal level. The FatalExitFunc interceptor function
+// is called by the Msg method, which by default terminates the program immediately
+// using os.Exit(1), any desired behavior can be implemented by setting FatalExitFunc.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Panic() *Event {
-	return l.newEvent(PanicLevel, true, func(msg string) { panic(msg) })
+func (l *Logger) Fatal() *Event {
+	return l.newEvent(FatalLevel, func(msg string) {
+		if closer, ok := l.w.(io.Closer); ok {
+			// Close the writer to flush any buffered message. Otherwise the message
+			// could be lost if FatalExitFunc() terminates the program immediately or
+			// os.Exit(1) is called if not FatalExitFunc isn't set (default).
+			closer.Close()
+		}
+		if FatalExitFunc != nil {
+			FatalExitFunc()
+		} else {
+			os.Exit(1) // untestable: terminates the program, cannot be covered
+		}
+	})
 }
 
-// WithLevel starts a new message with level.
+// Panic starts a new message with panic level. The panic() function
+// is called by the Msg method, which stops the ordinary flow of a goroutine.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) WithLevel(level Level) *Event {
+func (l *Logger) Panic() *Event {
+	return l.newEvent(PanicLevel, func(msg string) { panic(msg) })
+}
+
+// WithLevel starts a new message with level. Unlike Fatal and Panic
+// methods, WithLevel does not terminate the program or stop the ordinary
+// flow of a goroutine when used with their respective levels.
+//
+// You must call Msg on the returned event in order to send the event.
+func (l *Logger) WithLevel(level Level) *Event {
 	switch level {
+	case TraceLevel:
+		return l.Trace()
 	case DebugLevel:
 		return l.Debug()
 	case InfoLevel:
@@ -272,13 +429,15 @@ func (l Logger) WithLevel(level Level) *Event {
 	case ErrorLevel:
 		return l.Error()
 	case FatalLevel:
-		return l.Fatal()
+		return l.newEvent(FatalLevel, nil)
 	case PanicLevel:
-		return l.Panic()
+		return l.newEvent(PanicLevel, nil)
+	case NoLevel:
+		return l.Log()
 	case Disabled:
-		return disabledEvent
+		return nil
 	default:
-		panic("zerolog: WithLevel(): invalid level: " + strconv.Itoa(int(level)))
+		return l.newEvent(level, nil)
 	}
 }
 
@@ -286,10 +445,32 @@ func (l Logger) WithLevel(level Level) *Event {
 // will still disable events produced by this method.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Log() *Event {
-	// We use panic level with addLevelField=false to make Log passthrough all
-	// levels except Disabled.
-	return l.newEvent(PanicLevel, false, nil)
+func (l *Logger) Log() *Event {
+	return l.newEvent(NoLevel, nil)
+}
+
+// Print sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Print.
+func (l *Logger) Print(v ...interface{}) {
+	if e := l.Debug(); e.Enabled() {
+		e.CallerSkipFrame(1).Msg(fmt.Sprint(v...))
+	}
+}
+
+// Printf sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Printf.
+func (l *Logger) Printf(format string, v ...interface{}) {
+	if e := l.Debug(); e.Enabled() {
+		e.CallerSkipFrame(1).Msg(fmt.Sprintf(format, v...))
+	}
+}
+
+// Println sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Println.
+func (l *Logger) Println(v ...interface{}) {
+	if e := l.Debug(); e.Enabled() {
+		e.CallerSkipFrame(1).Msg(fmt.Sprintln(v...))
+	}
 }
 
 // Write implements the io.Writer interface. This is useful to set as a writer
@@ -300,48 +481,48 @@ func (l Logger) Write(p []byte) (n int, err error) {
 		// Trim CR added by stdlog.
 		p = p[0 : n-1]
 	}
-	l.Log().Msg(string(p))
+	l.Log().CallerSkipFrame(1).Msg(string(p))
 	return
 }
 
-func (l Logger) newEvent(level Level, addLevelField bool, done func(string)) *Event {
+func (l *Logger) newEvent(level Level, done func(string)) *Event {
 	enabled := l.should(level)
 	if !enabled {
-		return disabledEvent
-	}
-	lvl := InfoLevel
-	if addLevelField {
-		lvl = level
-	}
-	e := newEvent(l.w, lvl, enabled)
-	e.done = done
-	if l.context != nil && len(l.context) > 0 && l.context[0] > 0 {
-		// first byte of context is ts flag
-		e.buf = json.AppendTime(json.AppendKey(e.buf, TimestampFieldName), TimestampFunc(), TimeFieldFormat)
-	}
-	if addLevelField {
-		e.Str(LevelFieldName, level.String())
-	}
-	if l.sample > 0 && SampleFieldName != "" {
-		e.Uint32(SampleFieldName, l.sample)
-	}
-	if l.context != nil && len(l.context) > 1 {
-		if len(e.buf) > 1 {
-			e.buf = append(e.buf, ',')
+		if done != nil {
+			done("")
 		}
-		e.buf = append(e.buf, l.context[1:]...)
+		return nil
+	}
+	e := newEvent(l.w, level, l.stack, l.ctx, l.hooks)
+	e.done = done
+	if level != NoLevel && LevelFieldName != "" {
+		e.Str(LevelFieldName, LevelFieldMarshalFunc(level))
+	}
+	if len(l.context) > 1 {
+		e.buf = enc.AppendObjectData(e.buf, l.context)
 	}
 	return e
 }
 
+func (l *Logger) scratchEvent() *Event {
+	return newEvent(LevelWriterAdapter{io.Discard}, DebugLevel, l.stack, l.ctx, l.hooks)
+}
+
+// disabled returns true if the logger is a disabled or nop logger.
+func (l *Logger) disabled() bool {
+	return l.w == nil || l.level == Disabled
+}
+
 // should returns true if the log event should be logged.
-func (l Logger) should(lvl Level) bool {
-	if lvl < l.level || lvl < globalLevel() {
+func (l *Logger) should(lvl Level) bool {
+	if l.disabled() {
 		return false
 	}
-	if l.sample > 0 && l.counter != nil && !samplingDisabled() {
-		c := atomic.AddUint32(l.counter, 1)
-		return c%l.sample == 0
+	if lvl < l.level || lvl < GlobalLevel() {
+		return false
+	}
+	if l.sampler != nil && !samplingDisabled() {
+		return l.sampler.Sample(lvl)
 	}
 	return true
 }

log/log.go

@@ -3,6 +3,7 @@ package log
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"os"
 
@@ -22,14 +23,34 @@ func With() zerolog.Context {
 	return Logger.With()
 }
 
-// Level crestes a child logger with the minium accepted level set to level.
+// Level creates a child logger with the minimum accepted level set to level.
 func Level(level zerolog.Level) zerolog.Logger {
 	return Logger.Level(level)
 }
 
-// Sample returns a logger that only let one message out of every to pass thru.
-func Sample(every int) zerolog.Logger {
-	return Logger.Sample(every)
+// Sample returns a logger with the s sampler.
+func Sample(s zerolog.Sampler) zerolog.Logger {
+	return Logger.Sample(s)
+}
+
+// Hook returns a logger with the h Hook.
+func Hook(h zerolog.Hook) zerolog.Logger {
+	return Logger.Hook(h)
+}
+
+// Err starts a new message with error level with err as a field if not nil or
+// with info level if err is nil.
+//
+// You must call Msg on the returned event in order to send the event.
+func Err(err error) *zerolog.Event {
+	return Logger.Err(err)
+}
+
+// Trace starts a new message with trace level.
+//
+// You must call Msg on the returned event in order to send the event.
+func Trace() *zerolog.Event {
+	return Logger.Trace()
 }
 
 // Debug starts a new message with debug level.
@@ -76,16 +97,35 @@ func Panic() *zerolog.Event {
 	return Logger.Panic()
 }
 
+// WithLevel starts a new message with level.
+//
+// You must call Msg on the returned event in order to send the event.
+func WithLevel(level zerolog.Level) *zerolog.Event {
+	return Logger.WithLevel(level)
+}
+
 // Log starts a new message with no level. Setting zerolog.GlobalLevel to
-// zerlog.Disabled will still disable events produced by this method.
+// zerolog.Disabled will still disable events produced by this method.
 //
 // You must call Msg on the returned event in order to send the event.
 func Log() *zerolog.Event {
 	return Logger.Log()
 }
 
+// Print sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Print.
+func Print(v ...interface{}) {
+	Logger.Debug().CallerSkipFrame(1).Msg(fmt.Sprint(v...))
+}
+
+// Printf sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Printf.
+func Printf(format string, v ...interface{}) {
+	Logger.Debug().CallerSkipFrame(1).Msgf(format, v...)
+}
+
 // Ctx returns the Logger associated with the ctx. If no logger
 // is associated, a disabled logger is returned.
-func Ctx(ctx context.Context) zerolog.Logger {
+func Ctx(ctx context.Context) *zerolog.Logger {
 	return zerolog.Ctx(ctx)
 }

log/log_example_test.go

@@ -0,0 +1,246 @@
+//go:build !binary_log
+// +build !binary_log
+
+package log_test
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"flag"
+	"os"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+// setup would normally be an init() function, however, there seems
+// to be something awry with the testing framework when we set the
+// global Logger from an init()
+func setup() {
+	// UNIX Time is faster and smaller than most timestamps
+	// If you set zerolog.TimeFieldFormat to an empty string,
+	// logs will write with UNIX time
+	zerolog.TimeFieldFormat = ""
+	// In order to always output a static time to stdout for these
+	// examples to pass, we need to override zerolog.TimestampFunc
+	// and log.Logger globals -- you would not normally need to do this
+	zerolog.TimestampFunc = func() time.Time {
+		return time.Date(2008, 1, 8, 17, 5, 05, 0, time.UTC)
+	}
+	log.Logger = zerolog.New(os.Stdout).With().Timestamp().Logger()
+}
+
+// Simple logging example using the Print function in the log package
+// Note that both Print and Printf are at the debug log level by default
+func ExamplePrint() {
+	setup()
+
+	log.Print("hello world")
+	// Output: {"level":"debug","time":1199811905,"message":"hello world"}
+}
+
+// Simple logging example using the Printf function in the log package
+func ExamplePrintf() {
+	setup()
+
+	log.Printf("hello %s", "world")
+	// Output: {"level":"debug","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log with no particular "level"
+func ExampleLog() {
+	setup()
+	log.Log().Msg("hello world")
+
+	// Output: {"time":1199811905,"message":"hello world"}
+}
+
+// Example of a conditional level based on the presence of an error.
+func ExampleErr() {
+	setup()
+	err := errors.New("some error")
+	log.Err(err).Msg("hello world")
+	log.Err(nil).Msg("hello world")
+
+	// Output: {"level":"error","error":"some error","time":1199811905,"message":"hello world"}
+	// {"level":"info","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "trace")
+func ExampleTrace() {
+	setup()
+	log.Trace().Msg("hello world")
+
+	// Output: {"level":"trace","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "debug")
+func ExampleDebug() {
+	setup()
+	log.Debug().Msg("hello world")
+
+	// Output: {"level":"debug","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "info")
+func ExampleInfo() {
+	setup()
+	log.Info().Msg("hello world")
+
+	// Output: {"level":"info","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "warn")
+func ExampleWarn() {
+	setup()
+	log.Warn().Msg("hello world")
+
+	// Output: {"level":"warn","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "error")
+func ExampleError() {
+	setup()
+	log.Error().Msg("hello world")
+
+	// Output: {"level":"error","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "fatal")
+func ExampleFatal() {
+	setup()
+	err := errors.New("A repo man spends his life getting into tense situations")
+	service := "myservice"
+
+	log.Fatal().
+		Err(err).
+		Str("service", service).
+		Msgf("Cannot start %s", service)
+
+	// Outputs: {"level":"fatal","time":1199811905,"error":"A repo man spends his life getting into tense situations","service":"myservice","message":"Cannot start myservice"}
+}
+
+// Example of a log at a particular "level" (in this case, "panic")
+func ExamplePanic() {
+	setup()
+
+	log.Panic().Msg("Cannot start")
+	// Outputs: {"level":"panic","time":1199811905,"message":"Cannot start"} then panics
+}
+
+// This example uses command-line flags to demonstrate various outputs
+// depending on the chosen log level.
+func Example() {
+	setup()
+	debug := flag.Bool("debug", false, "sets log level to debug")
+
+	flag.Parse()
+
+	// Default level for this example is info, unless debug flag is present
+	zerolog.SetGlobalLevel(zerolog.InfoLevel)
+	if *debug {
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+	}
+
+	log.Debug().Msg("This message appears only when log level set to Debug")
+	log.Info().Msg("This message appears when log level set to Debug or Info")
+
+	if e := log.Debug(); e.Enabled() {
+		// Compute log output only if enabled.
+		value := "bar"
+		e.Str("foo", value).Msg("some debug message")
+	}
+
+	// Output: {"level":"info","time":1199811905,"message":"This message appears when log level set to Debug or Info"}
+}
+
+// Example of using the Output function in the log package to change the output destination
+func ExampleOutput() {
+	setup()
+
+	out := &bytes.Buffer{}
+	tee := log.Output(out)
+	tee.Info().Msg("hello world")
+	written := out.Len()
+
+	log.Info().Int("bytes", written).Msg("wrote")
+	// Output: {"level":"info","bytes":59,"time":1199811905,"message":"wrote"}
+}
+
+// Example of using the With function to add context fields
+func ExampleWith() {
+	setup()
+
+	// you have to assign the result of With() to a new Logger and can't inline the level calls
+	// because they need a *Logger receiver
+	augmented := log.With().Str("service", "myservice").Logger()
+	augmented.Info().Msg("hello world")
+	// Output: {"level":"info","service":"myservice","time":1199811905,"message":"hello world"}
+}
+
+// Example of using the Level function to set the log level
+func ExampleLevel() {
+	setup()
+
+	// you have to assign the result of Level() to a new Logger and can't inline the level calls
+	// because they need a *Logger receiver
+	leveled := log.Level(zerolog.ErrorLevel)
+	leveled.Info().Msg("hello world")
+	leveled.Error().Msg("I said HELLO")
+	// Output: {"level":"error","time":1199811905,"message":"I said HELLO"}
+}
+
+type valueKeyType int
+
+var valueKey valueKeyType = 42
+
+var captainHook = zerolog.HookFunc(func(e *zerolog.Event, l zerolog.Level, msg string) {
+	e.Interface("key", e.GetCtx().Value(valueKey))
+	e.Bool("is_error", l > zerolog.ErrorLevel)
+	e.Int("msg_len", len(msg))
+})
+
+// Example of using the Logger Hook function to add hooks
+func ExampleLogger_Hook() {
+	setup()
+
+	hooked := log.Hook(captainHook)
+	hooked.Info().Msg("watch out!")
+	// Output: {"level":"info","time":1199811905,"key":null,"is_error":false,"msg_len":10,"message":"watch out!"}
+}
+
+// Example of using the WithLevel function to set the log level
+func ExampleWithLevel() {
+	setup()
+
+	// you have to assign the result of Level() to a new Logger and can't inline the level calls
+	// because they need a *Logger receiver
+	event := log.WithLevel(zerolog.ErrorLevel)
+	event.Msg("taxes are due")
+	// Output: {"level":"error","time":1199811905,"message":"taxes are due"}
+}
+
+// Example of using the Ctx function in the log package to log with context
+func ExampleCtx() {
+	setup()
+
+	hooked := log.Hook(captainHook)
+	ctx := context.WithValue(context.Background(), valueKey, "12345")
+	logger := hooked.With().Ctx(ctx).Logger()
+	log.Ctx(logger.WithContext(ctx)).Info().Msg("hello world")
+	// Output: {"level":"info","time":1199811905,"key":"12345","is_error":false,"msg_len":11,"message":"hello world"}
+}
+
+// Example of using the Sample function in the log package to set a sampler
+func ExampleSample() {
+	setup()
+
+	sampled := log.Sample(&zerolog.BasicSampler{N: 2})
+	sampled.Info().Msg("hello world")
+	sampled.Info().Msg("I said, hello world")
+	sampled.Info().Msg("Can you here me now world")
+	// Output: {"level":"info","time":1199811905,"message":"hello world"}
+	// {"level":"info","time":1199811905,"message":"Can you here me now world"}
+}

log_example_test.go

@@ -1,8 +1,12 @@
+// +build !binary_log
+
 package zerolog_test
 
 import (
 	"errors"
+	"fmt"
 	stdlog "log"
+	"net"
 	"os"
 	"time"
 
@@ -13,7 +17,6 @@ func ExampleNew() {
 	log := zerolog.New(os.Stdout)
 
 	log.Info().Msg("hello world")
-
 	// Output: {"level":"info","message":"hello world"}
 }
 
@@ -38,15 +41,77 @@ func ExampleLogger_Level() {
 }
 
 func ExampleLogger_Sample() {
-	log := zerolog.New(os.Stdout).Sample(2)
+	log := zerolog.New(os.Stdout).Sample(&zerolog.BasicSampler{N: 2})
 
 	log.Info().Msg("message 1")
 	log.Info().Msg("message 2")
 	log.Info().Msg("message 3")
 	log.Info().Msg("message 4")
 
-	// Output: {"level":"info","sample":2,"message":"message 2"}
-	// {"level":"info","sample":2,"message":"message 4"}
+	// Output: {"level":"info","message":"message 1"}
+	// {"level":"info","message":"message 3"}
+}
+
+type LevelNameHook struct{}
+
+func (h LevelNameHook) Run(e *zerolog.Event, l zerolog.Level, msg string) {
+	if l != zerolog.NoLevel {
+		e.Str("level_name", l.String())
+	} else {
+		e.Str("level_name", "NoLevel")
+	}
+}
+
+type MessageHook string
+
+func (h MessageHook) Run(e *zerolog.Event, l zerolog.Level, msg string) {
+	e.Str("the_message", msg)
+}
+
+func ExampleLogger_Hook() {
+	var levelNameHook LevelNameHook
+	var messageHook MessageHook = "The message"
+
+	log := zerolog.New(os.Stdout).Hook(levelNameHook, messageHook)
+
+	log.Info().Msg("hello world")
+
+	// Output: {"level":"info","level_name":"info","the_message":"hello world","message":"hello world"}
+}
+
+func ExampleLogger_Print() {
+	log := zerolog.New(os.Stdout)
+
+	log.Print("hello world")
+
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Printf() {
+	log := zerolog.New(os.Stdout)
+
+	log.Printf("hello %s", "world")
+
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Println() {
+	log := zerolog.New(os.Stdout)
+
+	log.Println("hello world")
+
+	// Output: {"level":"debug","message":"hello world\n"}
+}
+
+func ExampleLogger_Trace() {
+	log := zerolog.New(os.Stdout)
+
+	log.Trace().
+		Str("foo", "bar").
+		Int("n", 123).
+		Msg("hello world")
+
+	// Output: {"level":"trace","foo":"bar","n":123,"message":"hello world"}
 }
 
 func ExampleLogger_Debug() {
@@ -127,12 +192,13 @@ func ExampleLogger_Log() {
 func ExampleEvent_Dict() {
 	log := zerolog.New(os.Stdout)
 
-	log.Log().
-		Str("foo", "bar").
-		Dict("dict", zerolog.Dict().
-			Str("bar", "baz").
-			Int("n", 1),
-		).
+	e := log.Log().
+		Str("foo", "bar")
+
+	e.Dict("dict", e.CreateDict().
+		Str("bar", "baz").
+		Int("n", 1),
+	).
 		Msg("hello world")
 
 	// Output: {"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
@@ -150,6 +216,22 @@ func (u User) MarshalZerologObject(e *zerolog.Event) {
 		Time("created", u.Created)
 }
 
+type Price struct {
+	val  uint64
+	prec int
+	unit string
+}
+
+func (p Price) MarshalZerologObject(e *zerolog.Event) {
+	denom := uint64(1)
+	for i := 0; i < p.prec; i++ {
+		denom *= 10
+	}
+	result := []byte(p.unit)
+	result = append(result, fmt.Sprintf("%d.%d", p.val/denom, p.val%denom)...)
+	e.Str("price", string(result))
+}
+
 type Users []User
 
 func (uu Users) MarshalZerologArray(a *zerolog.Array) {
@@ -161,15 +243,20 @@ func (uu Users) MarshalZerologArray(a *zerolog.Array) {
 func ExampleEvent_Array() {
 	log := zerolog.New(os.Stdout)
 
-	log.Log().
-		Str("foo", "bar").
-		Array("array", zerolog.Arr().
-			Str("baz").
-			Int(1),
-		).
+	e := log.Log().
+		Str("foo", "bar")
+
+	e.Array("array", e.CreateArray().
+		Str("baz").
+		Int(1).
+		Dict(e.CreateDict().
+			Str("bar", "baz").
+			Int("n", 1),
+		),
+	).
 		Msg("hello world")
 
-	// Output: {"foo":"bar","array":["baz",1],"message":"hello world"}
+	// Output: {"foo":"bar","array":["baz",1,{"bar":"baz","n":1}],"message":"hello world"}
 }
 
 func ExampleEvent_Array_object() {
@@ -203,6 +290,47 @@ func ExampleEvent_Object() {
 	// Output: {"foo":"bar","user":{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},"message":"hello world"}
 }
 
+func ExampleEvent_Objects() {
+	log := zerolog.New(os.Stdout)
+
+	// User implements zerolog.LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+	u2 := User{"Bono", 54, time.Time{}}
+	users := []User{u, u2}
+
+	log.Log().
+		Objects("users", zerolog.AsLogObjectMarshalers(users)).
+		Msg("hello world")
+	// Output: {"users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bono","age":54,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleEvent_ObjectsV() {
+	log := zerolog.New(os.Stdout)
+
+	// User implements zerolog.LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+	u2 := User{"Bono", 54, time.Time{}}
+
+	log.Log().
+		ObjectsV("users", u, u2).
+		Msg("hello world")
+
+	// Output:  {"users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bono","age":54,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleEvent_EmbedObject() {
+	log := zerolog.New(os.Stdout)
+
+	price := Price{val: 6449, prec: 2, unit: "$"}
+
+	log.Log().
+		Str("foo", "bar").
+		EmbedObject(price).
+		Msg("hello world")
+
+	// Output: {"foo":"bar","price":"$64.49","message":"hello world"}
+}
+
 func ExampleEvent_Interface() {
 	log := zerolog.New(os.Stdout)
 
@@ -221,7 +349,7 @@ func ExampleEvent_Interface() {
 }
 
 func ExampleEvent_Dur() {
-	d := time.Duration(10 * time.Second)
+	d := 10 * time.Second
 
 	log := zerolog.New(os.Stdout)
 
@@ -235,8 +363,8 @@ func ExampleEvent_Dur() {
 
 func ExampleEvent_Durs() {
 	d := []time.Duration{
-		time.Duration(10 * time.Second),
-		time.Duration(20 * time.Second),
+		10 * time.Second,
+		20 * time.Second,
 	}
 
 	log := zerolog.New(os.Stdout)
@@ -249,28 +377,62 @@ func ExampleEvent_Durs() {
 	// Output: {"foo":"bar","durs":[10000,20000],"message":"hello world"}
 }
 
-func ExampleContext_Dict() {
-	log := zerolog.New(os.Stdout).With().
-		Str("foo", "bar").
-		Dict("dict", zerolog.Dict().
-			Str("bar", "baz").
-			Int("n", 1),
-		).Logger()
+func ExampleEvent_Fields_map() {
+	fields := map[string]interface{}{
+		"bar": "baz",
+		"n":   1,
+	}
 
-	log.Log().Msg("hello world")
+	log := zerolog.New(os.Stdout)
+
+	log.Log().
+		Str("foo", "bar").
+		Fields(fields).
+		Msg("hello world")
+
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleEvent_Fields_slice() {
+	fields := []interface{}{
+		"bar", "baz",
+		"n", 1,
+	}
+
+	log := zerolog.New(os.Stdout)
+
+	log.Log().
+		Str("foo", "bar").
+		Fields(fields).
+		Msg("hello world")
+
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleContext_Dict() {
+	ctx := zerolog.New(os.Stdout).With().
+		Str("foo", "bar")
+
+	logger := ctx.Dict("dict", ctx.CreateDict().
+		Str("bar", "baz").
+		Int("n", 1),
+	).Logger()
+
+	logger.Log().Msg("hello world")
 
 	// Output: {"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
 }
 
 func ExampleContext_Array() {
-	log := zerolog.New(os.Stdout).With().
-		Str("foo", "bar").
-		Array("array", zerolog.Arr().
-			Str("baz").
-			Int(1),
-		).Logger()
+	ctx := zerolog.New(os.Stdout).With().
+		Str("foo", "bar")
 
-	log.Log().Msg("hello world")
+	logger := ctx.Array("array", ctx.CreateArray().
+		Str("baz").
+		Int(1),
+	).Logger()
+
+	logger.Log().Msg("hello world")
 
 	// Output: {"foo":"bar","array":["baz",1],"message":"hello world"}
 }
@@ -305,6 +467,47 @@ func ExampleContext_Object() {
 
 	// Output: {"foo":"bar","user":{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},"message":"hello world"}
 }
+func ExampleContext_Objects() {
+	// User implements zerolog.LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+	u2 := User{"Bono", 54, time.Time{}}
+
+	log := zerolog.New(os.Stdout).With().
+		Str("foo", "bar").
+		Objects("users", []zerolog.LogObjectMarshaler{u, u2}).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bono","age":54,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleContext_ObjectsV() {
+	// User implements zerolog.LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+	u2 := User{"Bono", 54, time.Time{}}
+
+	log := zerolog.New(os.Stdout).With().
+		Str("foo", "bar").
+		ObjectsV("users", u, u2). // shows variadic version with distinct element arguments
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bono","age":54,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleContext_EmbedObject() {
+	price := Price{val: 6449, prec: 2, unit: "$"}
+
+	log := zerolog.New(os.Stdout).With().
+		Str("foo", "bar").
+		EmbedObject(price).
+		Logger()
+
+	log.Log().Msg("hello world")
+	// Output: {"foo":"bar","price":"$64.49","message":"hello world"}
+}
 
 func ExampleContext_Interface() {
 	obj := struct {
@@ -324,7 +527,7 @@ func ExampleContext_Interface() {
 }
 
 func ExampleContext_Dur() {
-	d := time.Duration(10 * time.Second)
+	d := 10 * time.Second
 
 	log := zerolog.New(os.Stdout).With().
 		Str("foo", "bar").
@@ -338,8 +541,8 @@ func ExampleContext_Dur() {
 
 func ExampleContext_Durs() {
 	d := []time.Duration{
-		time.Duration(10 * time.Second),
-		time.Duration(20 * time.Second),
+		10 * time.Second,
+		20 * time.Second,
 	}
 
 	log := zerolog.New(os.Stdout).With().
@@ -351,3 +554,133 @@ func ExampleContext_Durs() {
 
 	// Output: {"foo":"bar","durs":[10000,20000],"message":"hello world"}
 }
+
+func ExampleContext_IPAddr() {
+	hostIP := net.IP{192, 168, 0, 100}
+	log := zerolog.New(os.Stdout).With().
+		IPAddr("HostIP", hostIP).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"HostIP":"192.168.0.100","message":"hello world"}
+}
+
+func ExampleContext_IPAddrs() {
+	hostIP := net.IP{192, 168, 0, 100}
+	log := zerolog.New(os.Stdout).With().
+		IPAddrs("HostIP", []net.IP{hostIP}).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"HostIP":["192.168.0.100"],"message":"hello world"}
+}
+
+func ExampleContext_IPPrefix() {
+	route := net.IPNet{IP: net.IP{192, 168, 0, 0}, Mask: net.CIDRMask(24, 32)}
+	log := zerolog.New(os.Stdout).With().
+		IPPrefix("Route", route).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"Route":"192.168.0.0/24","message":"hello world"}
+}
+
+func ExampleContext_IPPrefixes() {
+	route := net.IPNet{IP: net.IP{192, 168, 0, 0}, Mask: net.CIDRMask(24, 32)}
+	log := zerolog.New(os.Stdout).With().
+		IPPrefixes("Route", []net.IPNet{route}).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"Route":["192.168.0.0/24"],"message":"hello world"}
+}
+
+func ExampleContext_MACAddr() {
+	mac := net.HardwareAddr{0x00, 0x14, 0x22, 0x01, 0x23, 0x45}
+	log := zerolog.New(os.Stdout).With().
+		MACAddr("hostMAC", mac).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"hostMAC":"00:14:22:01:23:45","message":"hello world"}
+}
+
+func ExampleContext_Fields_map() {
+	fields := map[string]interface{}{
+		"bar": "baz",
+		"n":   1,
+	}
+
+	log := zerolog.New(os.Stdout).With().
+		Str("foo", "bar").
+		Fields(fields).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleContext_Fields_slice() {
+	fields := []interface{}{
+		"bar", "baz",
+		"n", 1,
+	}
+
+	log := zerolog.New(os.Stdout).With().
+		Str("foo", "bar").
+		Fields(fields).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"foo":"bar","bar":"baz","n":1,"message":"hello world"}
+}
+
+func ExampleContext_Times() {
+	t1 := time.Time{}
+	t2 := t1.Add(time.Second * 10)
+	t := []time.Time{t1, t2}
+
+	log := zerolog.New(os.Stdout).With().
+		Str("foo", "bar").
+		Times("times", t).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"foo":"bar","times":["0001-01-01T00:00:00Z","0001-01-01T00:00:10Z"],"message":"hello world"}
+}
+
+func ExampleEvent_Stringers() {
+	log := zerolog.New(os.Stdout)
+
+	// net.IP values implement fmt.Stringer and can be used with StringersV
+	a := net.IP{127, 0, 0, 1}
+	b := net.IP{127, 0, 0, 2}
+	ips := []net.IP{a, b}
+
+	log.Log().
+		Stringers("ips", zerolog.AsStringers(ips)).
+		Msg("hello world")
+	// Output: {"ips":["127.0.0.1","127.0.0.2"],"message":"hello world"}
+}
+
+func ExampleContext_StringersV() {
+	// net.IP values implement fmt.Stringer and can be used with StringersV
+	a := net.IPv4bcast
+	b := net.IPv4allrouter
+
+	log := zerolog.New(os.Stdout).With().
+		StringersV("ips", a, b).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	// Output: {"ips":["255.255.255.255","224.0.0.2"],"message":"hello world"}
+}

not_go112.go

@@ -0,0 +1,5 @@
+// +build !go1.12
+
+package zerolog
+
+const contextCallerSkipFrameCount = 3

pkgerrors/stacktrace.go

@@ -0,0 +1,82 @@
+package pkgerrors
+
+import (
+	"github.com/pkg/errors"
+)
+
+var (
+	StackSourceFileName     = "source"
+	StackSourceLineName     = "line"
+	StackSourceFunctionName = "func"
+)
+
+type state struct {
+	b []byte
+}
+
+// Write implement fmt.Formatter interface.
+func (s *state) Write(b []byte) (n int, err error) {
+	s.b = b
+	return len(b), nil
+}
+
+// Width implement fmt.Formatter interface.
+func (s *state) Width() (wid int, ok bool) {
+	return 0, false
+}
+
+// Precision implement fmt.Formatter interface.
+func (s *state) Precision() (prec int, ok bool) {
+	return 0, false
+}
+
+// Flag implement fmt.Formatter interface.
+func (s *state) Flag(c int) bool {
+	return false
+}
+
+func frameField(f errors.Frame, s *state, c rune) string {
+	f.Format(s, c)
+	return string(s.b)
+}
+
+// MarshalStack implements pkg/errors stack trace marshaling.
+//
+// zerolog.ErrorStackMarshaler = MarshalStack
+func MarshalStack(err error) interface{} {
+	type stackTracer interface {
+		StackTrace() errors.StackTrace
+	}
+	var sterr stackTracer
+	var ok bool
+	for err != nil {
+		sterr, ok = err.(stackTracer)
+		if ok {
+			break
+		}
+
+		u, ok := err.(interface {
+			Unwrap() error
+		})
+		if !ok {
+			return nil
+		}
+
+		err = u.Unwrap()
+	}
+	if sterr == nil {
+		return nil
+	}
+
+	st := sterr.StackTrace()
+	s := &state{}
+	out := make([]map[string]string, 0, len(st))
+	for _, frame := range st {
+		out = append(out, map[string]string{
+			StackSourceFileName:     frameField(frame, s, 's'),
+			StackSourceLineName:     frameField(frame, s, 'd'),
+			StackSourceFunctionName: frameField(frame, s, 'n'),
+		})
+	}
+	return out
+}

pkgerrors/stacktrace_test.go

@@ -0,0 +1,90 @@
+// +build !binary_log
+
+package pkgerrors
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+	"testing"
+
+	"github.com/pkg/errors"
+	"github.com/rs/zerolog"
+)
+
+func TestLogStack(t *testing.T) {
+	zerolog.ErrorStackMarshaler = MarshalStack
+
+	out := &bytes.Buffer{}
+	log := zerolog.New(out)
+
+	err := fmt.Errorf("from error: %w", errors.New("error message"))
+	log.Log().Stack().Err(err).Msg("")
+
+	got := out.String()
+	want := `\{"stack":\[\{"func":"TestLogStack","line":"21","source":"stacktrace_test.go"\},.*\],"error":"from error: error message"\}\n`
+	if ok, _ := regexp.MatchString(want, got); !ok {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestLogStackFields(t *testing.T) {
+	zerolog.ErrorStackMarshaler = MarshalStack
+
+	out := &bytes.Buffer{}
+	log := zerolog.New(out)
+
+	err := fmt.Errorf("from error: %w", errors.New("error message"))
+	log.Log().Stack().Fields([]interface{}{"error", err}).Msg("")
+
+	got := out.String()
+	want := `\{"error":"from error: error message","stack":\[\{"func":"TestLogStackFields","line":"37","source":"stacktrace_test.go"\},.*\]\}\n`
+	if ok, _ := regexp.MatchString(want, got); !ok {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestLogStackFromContext(t *testing.T) {
+	zerolog.ErrorStackMarshaler = MarshalStack
+
+	out := &bytes.Buffer{}
+	log := zerolog.New(out).With().Stack().Logger() // calling Stack() on log context instead of event
+
+	err := fmt.Errorf("from error: %w", errors.New("error message"))
+	log.Log().Err(err).Msg("") // not explicitly calling Stack()
+
+	got := out.String()
+	want := `\{"stack":\[\{"func":"TestLogStackFromContext","line":"53","source":"stacktrace_test.go"\},.*\],"error":"from error: error message"\}\n`
+	if ok, _ := regexp.MatchString(want, got); !ok {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestLogStackFromContextWith(t *testing.T) {
+	zerolog.ErrorStackMarshaler = MarshalStack
+
+	err := fmt.Errorf("from error: %w", errors.New("error message"))
+	out := &bytes.Buffer{}
+	log := zerolog.New(out).With().Stack().Err(err).Logger() // calling Stack() on log context instead of event
+
+	log.Error().Msg("")
+
+	got := out.String()
+	want := `\{"level":"error","stack":\[\{"func":"TestLogStackFromContextWith","line":"66","source":"stacktrace_test.go"\},.*\],"error":"from error: error message"\}\n`
+	if ok, _ := regexp.MatchString(want, got); !ok {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func BenchmarkLogStack(b *testing.B) {
+	zerolog.ErrorStackMarshaler = MarshalStack
+	out := &bytes.Buffer{}
+	log := zerolog.New(out)
+	err := errors.Wrap(errors.New("error message"), "from error")
+	b.ReportAllocs()
+
+	for i := 0; i < b.N; i++ {
+		log.Log().Stack().Err(err).Msg("")
+		out.Reset()
+	}
+}

sampler.go

@@ -0,0 +1,137 @@
+package zerolog
+
+import (
+	"math/rand"
+	"sync/atomic"
+	"time"
+)
+
+var (
+	// Often samples log every ~ 10 events.
+	Often = RandomSampler(10)
+	// Sometimes samples log every ~ 100 events.
+	Sometimes = RandomSampler(100)
+	// Rarely samples log every ~ 1000 events.
+	Rarely = RandomSampler(1000)
+)
+
+// Sampler defines an interface to a log sampler.
+type Sampler interface {
+	// Sample returns true if the event should be part of the sample, false if
+	// the event should be dropped.
+	Sample(lvl Level) bool
+}
+
+// RandomSampler use a PRNG to randomly sample an event out of N events,
+// regardless of their level.
+type RandomSampler uint32
+
+// Sample implements the Sampler interface.
+func (s RandomSampler) Sample(lvl Level) bool {
+	if s <= 0 {
+		return false
+	}
+	if rand.Intn(int(s)) != 0 {
+		return false
+	}
+	return true
+}
+
+// BasicSampler is a sampler that will send every Nth events, regardless of
+// their level.
+type BasicSampler struct {
+	N       uint32
+	counter uint32
+}
+
+// Sample implements the Sampler interface.
+func (s *BasicSampler) Sample(lvl Level) bool {
+	n := s.N
+	if n == 0 {
+		return false
+	}
+	if n == 1 {
+		return true
+	}
+	c := atomic.AddUint32(&s.counter, 1)
+	return c%n == 1
+}
+
+// BurstSampler lets Burst events pass per Period then pass the decision to
+// NextSampler. If Sampler is not set, all subsequent events are rejected.
+type BurstSampler struct {
+	// Burst is the maximum number of event per period allowed before calling
+	// NextSampler.
+	Burst uint32
+	// Period defines the burst period. If 0, NextSampler is always called.
+	Period time.Duration
+	// NextSampler is the sampler used after the burst is reached. If nil,
+	// events are always rejected after the burst.
+	NextSampler Sampler
+
+	counter uint32
+	resetAt int64
+}
+
+// Sample implements the Sampler interface.
+func (s *BurstSampler) Sample(lvl Level) bool {
+	if s.Burst > 0 && s.Period > 0 {
+		if s.inc() <= s.Burst {
+			return true
+		}
+	}
+	if s.NextSampler == nil {
+		return false
+	}
+	return s.NextSampler.Sample(lvl)
+}
+
+func (s *BurstSampler) inc() uint32 {
+	now := TimestampFunc().UnixNano()
+	resetAt := atomic.LoadInt64(&s.resetAt)
+	var c uint32
+	if now >= resetAt {
+		c = 1
+		atomic.StoreUint32(&s.counter, c)
+		newResetAt := now + s.Period.Nanoseconds()
+		reset := atomic.CompareAndSwapInt64(&s.resetAt, resetAt, newResetAt)
+		if !reset {
+			// Lost the race with another goroutine trying to reset.
+			c = atomic.AddUint32(&s.counter, 1)
+		}
+	} else {
+		c = atomic.AddUint32(&s.counter, 1)
+	}
+	return c
+}
+
+// LevelSampler applies a different sampler for each level.
+type LevelSampler struct {
+	TraceSampler, DebugSampler, InfoSampler, WarnSampler, ErrorSampler Sampler
+}
+
+func (s LevelSampler) Sample(lvl Level) bool {
+	switch lvl {
+	case TraceLevel:
+		if s.TraceSampler != nil {
+			return s.TraceSampler.Sample(lvl)
+		}
+	case DebugLevel:
+		if s.DebugSampler != nil {
+			return s.DebugSampler.Sample(lvl)
+		}
+	case InfoLevel:
+		if s.InfoSampler != nil {
+			return s.InfoSampler.Sample(lvl)
+		}
+	case WarnLevel:
+		if s.WarnSampler != nil {
+			return s.WarnSampler.Sample(lvl)
+		}
+	case ErrorLevel:
+		if s.ErrorSampler != nil {
+			return s.ErrorSampler.Sample(lvl)
+		}
+	}
+	return true
+}

sampler_test.go

@@ -0,0 +1,182 @@
+//go:build !binary_log
+// +build !binary_log
+
+package zerolog
+
+import (
+	"testing"
+	"time"
+)
+
+var samplers = []struct {
+	name    string
+	sampler func() Sampler
+	total   int
+	wantMin int
+	wantMax int
+}{
+	{
+		"BasicSampler_1",
+		func() Sampler {
+			return &BasicSampler{N: 1}
+		},
+		100, 100, 100,
+	},
+	{
+		"BasicSampler_5",
+		func() Sampler {
+			return &BasicSampler{N: 5}
+		},
+		100, 20, 20,
+	},
+	{
+		"BasicSampler_0",
+		func() Sampler {
+			return &BasicSampler{N: 0}
+		},
+		100, 0, 0,
+	},
+	{
+		"RandomSampler",
+		func() Sampler {
+			return RandomSampler(5)
+		},
+		100, 10, 30,
+	},
+	{
+		"RandomSampler_0",
+		func() Sampler {
+			return RandomSampler(0)
+		},
+		100, 0, 0,
+	},
+	{
+		"BurstSampler",
+		func() Sampler {
+			return &BurstSampler{Burst: 20, Period: time.Second}
+		},
+		100, 20, 20,
+	},
+	{
+		"BurstSampler_0",
+		func() Sampler {
+			return &BurstSampler{Burst: 0, Period: time.Second}
+		},
+		100, 0, 0,
+	},
+	{
+		"BurstSamplerNext",
+		func() Sampler {
+			return &BurstSampler{Burst: 20, Period: time.Second, NextSampler: &BasicSampler{N: 5}}
+		},
+		120, 40, 40,
+	},
+}
+
+func TestSamplers(t *testing.T) {
+	for i := range samplers {
+		s := samplers[i]
+		t.Run(s.name, func(t *testing.T) {
+			sampler := s.sampler()
+			got := 0
+			for t := s.total; t > 0; t-- {
+				if sampler.Sample(0) {
+					got++
+				}
+			}
+			if got < s.wantMin || got > s.wantMax {
+				t.Errorf("%s.Sample(0) == true %d on %d, want [%d, %d]", s.name, got, s.total, s.wantMin, s.wantMax)
+			}
+		})
+	}
+}
+
+func BenchmarkSamplers(b *testing.B) {
+	for i := range samplers {
+		s := samplers[i]
+		b.Run(s.name, func(b *testing.B) {
+			sampler := s.sampler()
+			b.RunParallel(func(pb *testing.PB) {
+				for pb.Next() {
+					sampler.Sample(0)
+				}
+			})
+		})
+	}
+}
+
+func TestBurst(t *testing.T) {
+	sampler := &BurstSampler{Burst: 1, Period: time.Second}
+
+	t0 := time.Now()
+	now := t0
+	mockedTime := func() time.Time {
+		return now
+	}
+
+	TimestampFunc = mockedTime
+	defer func() { TimestampFunc = time.Now }()
+
+	scenario := []struct {
+		tm   time.Time
+		want bool
+	}{
+		{t0, true},
+		{t0.Add(time.Second - time.Nanosecond), false},
+		{t0.Add(time.Second), true},
+		{t0.Add(time.Second + time.Nanosecond), false},
+	}
+
+	for i, step := range scenario {
+		now = step.tm
+		got := sampler.Sample(NoLevel)
+		if got != step.want {
+			t.Errorf("step %d (t=%s): expect %t got %t", i, step.tm, step.want, got)
+		}
+	}
+}
+
+func TestLevelSampler(t *testing.T) {
+	// Create mock samplers that return true for specific levels
+	traceSampler := &BasicSampler{N: 1} // Always sample
+	debugSampler := &BasicSampler{N: 0} // Never sample
+	infoSampler := &BasicSampler{N: 1}  // Always sample
+	warnSampler := &BasicSampler{N: 0}  // Never sample
+	errorSampler := &BasicSampler{N: 1} // Always sample
+
+	sampler := LevelSampler{
+		TraceSampler: traceSampler,
+		DebugSampler: debugSampler,
+		InfoSampler:  infoSampler,
+		WarnSampler:  warnSampler,
+		ErrorSampler: errorSampler,
+	}
+
+	// Test each level
+	if !sampler.Sample(TraceLevel) {
+		t.Error("TraceLevel should be sampled")
+	}
+	if sampler.Sample(DebugLevel) {
+		t.Error("DebugLevel should not be sampled")
+	}
+	if !sampler.Sample(InfoLevel) {
+		t.Error("InfoLevel should be sampled")
+	}
+	if sampler.Sample(WarnLevel) {
+		t.Error("WarnLevel should not be sampled")
+	}
+	if !sampler.Sample(ErrorLevel) {
+		t.Error("ErrorLevel should be sampled")
+	}
+
+	// Test levels not covered by the LevelSampler sampler (FatalLevel, PanicLevel, NoLevel) - should return true
+	if !sampler.Sample(FatalLevel) {
+		t.Error("FatalLevel should return true when no sampler is set")
+	}
+	if !sampler.Sample(PanicLevel) {
+		t.Error("PanicLevel should return true when no sampler is set")
+	}
+	if !sampler.Sample(NoLevel) {
+		t.Error("NoLevel should return true when no sampler is set")
+	}
+}

slog.go

@@ -0,0 +1,247 @@
+package zerolog
+
+import (
+	"context"
+	"log/slog"
+	"time"
+)
+
+// SlogHandler implements the slog.Handler interface using a zerolog.Logger
+// as the underlying log backend. This allows code that uses the standard
+// library's slog package to route log output through zerolog.
+type SlogHandler struct {
+	logger Logger
+	prefix string // group prefix for nested groups
+	attrs  []slog.Attr
+}
+
+// NewSlogHandler creates a new slog.Handler that writes log records to the
+// given zerolog.Logger. The handler maps slog levels to zerolog levels and
+// converts slog attributes to zerolog fields.
+func NewSlogHandler(logger Logger) *SlogHandler {
+	return &SlogHandler{logger: logger}
+}
+
+// Enabled reports whether the handler handles records at the given level.
+// It mirrors Logger.should's level and writer checks (without sampling).
+func (h *SlogHandler) Enabled(_ context.Context, level slog.Level) bool {
+	if h.logger.w == nil {
+		return false
+	}
+	zl := slogToZerologLevel(level)
+	if zl < GlobalLevel() {
+		return false
+	}
+	return zl >= h.logger.level
+}
+
+// Handle handles the Record. It converts the slog.Record into a zerolog event
+// and writes it using the underlying zerolog.Logger.
+func (h *SlogHandler) Handle(ctx context.Context, record slog.Record) error {
+	zlevel := slogToZerologLevel(record.Level)
+	event := h.logger.WithLevel(zlevel)
+	if event == nil {
+		return nil
+	}
+
+	// Propagate slog context to the zerolog event so that hooks
+	// relying on Event.GetCtx() (e.g. tracing) can access it.
+	if ctx != nil {
+		event = event.Ctx(ctx)
+	}
+
+	// Add pre-attached attrs from WithAttrs
+	for _, a := range h.attrs {
+		event = appendSlogAttr(event, a, h.prefix)
+	}
+
+	// Add attrs from the record itself
+	record.Attrs(func(a slog.Attr) bool {
+		event = appendSlogAttr(event, a, h.prefix)
+		return true
+	})
+
+	// Add timestamp from the slog record, but only if the logger doesn't
+	// already have a timestampHook (added via .With().Timestamp()) to
+	// avoid duplicate timestamp keys in the output.
+	if !record.Time.IsZero() && !h.hasTimestampHook() {
+		event.Time(TimestampFieldName, record.Time)
+	}
+
+	event.Msg(record.Message)
+	return nil
+}
+
+// hasTimestampHook reports whether the logger has a timestampHook installed,
+// which would cause duplicate timestamp fields if we also emit record.Time.
+func (h *SlogHandler) hasTimestampHook() bool {
+	for _, hook := range h.logger.hooks {
+		if _, ok := hook.(timestampHook); ok {
+			return true
+		}
+	}
+	return false
+}
+
+// WithAttrs returns a new Handler with the given attributes pre-attached.
+// These attributes will be included in every subsequent log record.
+func (h *SlogHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	if len(attrs) == 0 {
+		return h
+	}
+	h2 := h.clone()
+	h2.attrs = append(h2.attrs, attrs...)
+	return h2
+}
+
+// WithGroup returns a new Handler with the given group name. All subsequent
+// attributes will be nested under this group name in the output.
+func (h *SlogHandler) WithGroup(name string) slog.Handler {
+	if name == "" {
+		return h
+	}
+	h2 := h.clone()
+	if h2.prefix != "" {
+		h2.prefix = h2.prefix + "." + name
+	} else {
+		h2.prefix = name
+	}
+	return h2
+}
+
+func (h *SlogHandler) clone() *SlogHandler {
+	h2 := &SlogHandler{
+		logger: h.logger,
+		prefix: h.prefix,
+	}
+	if len(h.attrs) > 0 {
+		h2.attrs = make([]slog.Attr, len(h.attrs))
+		copy(h2.attrs, h.attrs)
+	}
+	return h2
+}
+
+// slogToZerologLevel maps slog levels to zerolog levels.
+//
+// slog levels:  Debug=-4, Info=0, Warn=4, Error=8
+// zerolog levels: Trace=-1, Debug=0, Info=1, Warn=2, Error=3, Fatal=4, Panic=5
+func slogToZerologLevel(level slog.Level) Level {
+	switch {
+	case level < slog.LevelDebug:
+		return TraceLevel
+	case level < slog.LevelInfo:
+		return DebugLevel
+	case level < slog.LevelWarn:
+		return InfoLevel
+	case level < slog.LevelError:
+		return WarnLevel
+	default:
+		return ErrorLevel
+	}
+}
+
+// zerologToSlogLevel maps zerolog levels to slog levels.
+func zerologToSlogLevel(level Level) slog.Level {
+	switch level {
+	case TraceLevel:
+		return slog.LevelDebug - 4
+	case DebugLevel:
+		return slog.LevelDebug
+	case InfoLevel:
+		return slog.LevelInfo
+	case WarnLevel:
+		return slog.LevelWarn
+	case ErrorLevel:
+		return slog.LevelError
+	case FatalLevel:
+		return slog.LevelError + 4
+	case PanicLevel:
+		return slog.LevelError + 8
+	default:
+		return slog.LevelInfo
+	}
+}
+
+// joinPrefix concatenates a prefix and key with a dot separator.
+// It avoids allocations when either prefix or key is empty.
+func joinPrefix(prefix, key string) string {
+	if prefix == "" {
+		return key
+	}
+	if key == "" {
+		return prefix
+	}
+	return prefix + "." + key
+}
+
+// appendSlogAttr appends a single slog.Attr to the zerolog event, handling
+// type-specific encoding to avoid reflection where possible.
+func appendSlogAttr(event *Event, attr slog.Attr, prefix string) *Event {
+	if event == nil {
+		return event
+	}
+
+	// Resolve the attribute to handle LogValuer types.
+	// This handles slog.KindLogValuer implicitly by unwrapping
+	// any values that implement slog.LogValuer to their resolved form.
+	attr.Value = attr.Value.Resolve()
+
+	// For group kinds, handle grouping before key concatenation
+	if attr.Value.Kind() == slog.KindGroup {
+		attrs := attr.Value.Group()
+		if len(attrs) == 0 {
+			return event
+		}
+		groupPrefix := joinPrefix(prefix, attr.Key)
+		for _, ga := range attrs {
+			event = appendSlogAttr(event, ga, groupPrefix)
+		}
+		return event
+	}
+
+	// Skip empty keys for non-group attributes
+	if attr.Key == "" {
+		return event
+	}
+
+	key := joinPrefix(prefix, attr.Key)
+	val := attr.Value
+
+	switch val.Kind() {
+	case slog.KindString:
+		event = event.Str(key, val.String())
+	case slog.KindInt64:
+		event = event.Int64(key, val.Int64())
+	case slog.KindUint64:
+		event = event.Uint64(key, val.Uint64())
+	case slog.KindFloat64:
+		event = event.Float64(key, val.Float64())
+	case slog.KindBool:
+		event = event.Bool(key, val.Bool())
+	case slog.KindDuration:
+		event = event.Dur(key, val.Duration())
+	case slog.KindTime:
+		event = event.Time(key, val.Time())
+	case slog.KindAny:
+		v := val.Any()
+		switch cv := v.(type) {
+		case error:
+			event = event.AnErr(key, cv)
+		case time.Duration:
+			event = event.Dur(key, cv)
+		case time.Time:
+			event = event.Time(key, cv)
+		case []byte:
+			event = event.Bytes(key, cv)
+		default:
+			event = event.Interface(key, v)
+		}
+	default:
+		event = event.Interface(key, val.Any())
+	}
+
+	return event
+}
+
+// Verify at compile time that SlogHandler satisfies the slog.Handler interface.
+var _ slog.Handler = (*SlogHandler)(nil)

slog_test.go

@@ -0,0 +1,559 @@
+package zerolog_test
+
+import (
+	"context"
+	"bytes"
+	"encoding/json"
+	"errors"
+	"log/slog"
+	"testing"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/internal/cbor"
+)
+
+func newSlogLogger(buf *bytes.Buffer) *slog.Logger {
+	zl := zerolog.New(buf)
+	return slog.New(zerolog.NewSlogHandler(zl))
+}
+
+// decodeOutput converts the buffer contents to a JSON string,
+// handling CBOR-encoded output when built with the binary_log tag.
+func decodeOutput(buf *bytes.Buffer) string {
+	p := buf.Bytes()
+	if len(p) == 0 || p[0] < 0x7F {
+		return buf.String()
+	}
+	return cbor.DecodeObjectToStr(p) + "\n"
+}
+
+func decodeJSON(t *testing.T, buf *bytes.Buffer) map[string]interface{} {
+	t.Helper()
+	var m map[string]interface{}
+	s := decodeOutput(buf)
+	if err := json.Unmarshal([]byte(s), &m); err != nil {
+		t.Fatalf("failed to decode JSON %q: %v", s, err)
+	}
+	return m
+}
+
+func TestSlogHandler_BasicInfo(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("hello world")
+
+	m := decodeJSON(t, &buf)
+	if m["level"] != "info" {
+		t.Errorf("expected level info, got %v", m["level"])
+	}
+	if m["message"] != "hello world" {
+		t.Errorf("expected message 'hello world', got %v", m["message"])
+	}
+}
+
+func TestSlogHandler_Debug(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf).Level(zerolog.DebugLevel)
+	logger := slog.New(zerolog.NewSlogHandler(zl))
+
+	logger.Debug("debug msg")
+
+	m := decodeJSON(t, &buf)
+	if m["level"] != "debug" {
+		t.Errorf("expected level debug, got %v", m["level"])
+	}
+	if m["message"] != "debug msg" {
+		t.Errorf("expected message 'debug msg', got %v", m["message"])
+	}
+}
+
+func TestSlogHandler_Warn(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Warn("warn msg")
+
+	m := decodeJSON(t, &buf)
+	if m["level"] != "warn" {
+		t.Errorf("expected level warn, got %v", m["level"])
+	}
+}
+
+func TestSlogHandler_Error(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Error("error msg")
+
+	m := decodeJSON(t, &buf)
+	if m["level"] != "error" {
+		t.Errorf("expected level error, got %v", m["level"])
+	}
+}
+
+func TestSlogHandler_WithStringAttr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", "key", "value")
+
+	m := decodeJSON(t, &buf)
+	if m["key"] != "value" {
+		t.Errorf("expected key=value, got %v", m["key"])
+	}
+}
+
+func TestSlogHandler_WithIntAttr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", slog.Int("count", 42))
+
+	m := decodeJSON(t, &buf)
+	if m["count"] != float64(42) {
+		t.Errorf("expected count=42, got %v", m["count"])
+	}
+}
+
+func TestSlogHandler_WithBoolAttr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", slog.Bool("flag", true))
+
+	m := decodeJSON(t, &buf)
+	if m["flag"] != true {
+		t.Errorf("expected flag=true, got %v", m["flag"])
+	}
+}
+
+func TestSlogHandler_WithFloat64Attr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", slog.Float64("pi", 3.14))
+
+	m := decodeJSON(t, &buf)
+	if m["pi"] != 3.14 {
+		t.Errorf("expected pi=3.14, got %v", m["pi"])
+	}
+}
+
+func TestSlogHandler_WithTimeAttr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	ts := time.Date(2024, 1, 15, 12, 0, 0, 0, time.UTC)
+	logger.Info("test", slog.Time("created", ts))
+
+	m := decodeJSON(t, &buf)
+	if m["created"] == nil {
+		t.Error("expected created field to be present")
+	}
+}
+
+func TestSlogHandler_WithDurationAttr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", slog.Duration("elapsed", 5*time.Second))
+
+	m := decodeJSON(t, &buf)
+	if m["elapsed"] == nil {
+		t.Error("expected elapsed field to be present")
+	}
+}
+
+func TestSlogHandler_WithErrorAttr(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", slog.Any("err", errors.New("something failed")))
+
+	m := decodeJSON(t, &buf)
+	if m["err"] != "something failed" {
+		t.Errorf("expected err='something failed', got %v", m["err"])
+	}
+}
+
+func TestSlogHandler_WithAttrs(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	child := handler.WithAttrs([]slog.Attr{
+		slog.String("component", "auth"),
+		slog.Int("version", 2),
+	})
+	logger := slog.New(child)
+
+	logger.Info("request handled")
+
+	m := decodeJSON(t, &buf)
+	if m["component"] != "auth" {
+		t.Errorf("expected component=auth, got %v", m["component"])
+	}
+	if m["version"] != float64(2) {
+		t.Errorf("expected version=2, got %v", m["version"])
+	}
+	if m["message"] != "request handled" {
+		t.Errorf("expected message 'request handled', got %v", m["message"])
+	}
+}
+
+func TestSlogHandler_WithAttrsEmpty(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	// WithAttrs with empty slice should return same handler
+	child := handler.WithAttrs(nil)
+	if child != handler {
+		t.Error("expected WithAttrs(nil) to return same handler")
+	}
+}
+
+func TestSlogHandler_WithGroup(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	child := handler.WithGroup("request")
+	logger := slog.New(child)
+
+	logger.Info("handled", "method", "GET", "status", 200)
+
+	m := decodeJSON(t, &buf)
+	if m["request.method"] != "GET" {
+		t.Errorf("expected request.method=GET, got %v", m["request.method"])
+	}
+	if m["request.status"] != float64(200) {
+		t.Errorf("expected request.status=200, got %v", m["request.status"])
+	}
+}
+
+func TestSlogHandler_WithGroupEmpty(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	// WithGroup with empty name should return same handler
+	child := handler.WithGroup("")
+	if child != handler {
+		t.Error("expected WithGroup('') to return same handler")
+	}
+}
+
+func TestSlogHandler_WithNestedGroups(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	child := handler.WithGroup("http").WithGroup("request")
+	logger := slog.New(child)
+
+	logger.Info("handled", "method", "POST")
+
+	m := decodeJSON(t, &buf)
+	if m["http.request.method"] != "POST" {
+		t.Errorf("expected http.request.method=POST, got %v", m["http.request.method"])
+	}
+}
+
+func TestSlogHandler_WithGroupAndAttrs(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	child := handler.WithGroup("server").WithAttrs([]slog.Attr{
+		slog.String("host", "localhost"),
+	})
+	logger := slog.New(child)
+
+	logger.Info("started", "port", 8080)
+
+	m := decodeJSON(t, &buf)
+	if m["server.host"] != "localhost" {
+		t.Errorf("expected server.host=localhost, got %v", m["server.host"])
+	}
+	if m["server.port"] != float64(8080) {
+		t.Errorf("expected server.port=8080, got %v", m["server.port"])
+	}
+}
+
+func TestSlogHandler_GroupAttrInRecord(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", slog.Group("user",
+		slog.String("name", "alice"),
+		slog.Int("age", 30),
+	))
+
+	m := decodeJSON(t, &buf)
+	if m["user.name"] != "alice" {
+		t.Errorf("expected user.name=alice, got %v", m["user.name"])
+	}
+	if m["user.age"] != float64(30) {
+		t.Errorf("expected user.age=30, got %v", m["user.age"])
+	}
+}
+
+func TestSlogHandler_LevelFiltering(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf).Level(zerolog.WarnLevel)
+	handler := zerolog.NewSlogHandler(zl)
+
+	// Debug should be filtered
+	if handler.Enabled(nil, slog.LevelDebug) {
+		t.Error("expected debug to be filtered at warn level")
+	}
+	// Info should be filtered
+	if handler.Enabled(nil, slog.LevelInfo) {
+		t.Error("expected info to be filtered at warn level")
+	}
+	// Warn should pass
+	if !handler.Enabled(nil, slog.LevelWarn) {
+		t.Error("expected warn to be enabled at warn level")
+	}
+	// Error should pass
+	if !handler.Enabled(nil, slog.LevelError) {
+		t.Error("expected error to be enabled at warn level")
+	}
+}
+
+func TestSlogHandler_FilteredMessageNotWritten(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf).Level(zerolog.ErrorLevel)
+	logger := slog.New(zerolog.NewSlogHandler(zl))
+
+	logger.Info("should not appear")
+
+	if buf.Len() != 0 {
+		t.Errorf("expected no output for filtered message, got %q", buf.String())
+	}
+}
+
+func TestSlogHandler_MultipleAttrs(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("multi",
+		slog.String("a", "1"),
+		slog.Int("b", 2),
+		slog.Bool("c", true),
+		slog.Float64("d", 3.5),
+	)
+
+	m := decodeJSON(t, &buf)
+	if m["a"] != "1" {
+		t.Errorf("expected a=1, got %v", m["a"])
+	}
+	if m["b"] != float64(2) {
+		t.Errorf("expected b=2, got %v", m["b"])
+	}
+	if m["c"] != true {
+		t.Errorf("expected c=true, got %v", m["c"])
+	}
+	if m["d"] != 3.5 {
+		t.Errorf("expected d=3.5, got %v", m["d"])
+	}
+}
+
+func TestSlogHandler_LogValuer(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("test", "addr", testLogValuer{host: "example.com", port: 443})
+
+	m := decodeJSON(t, &buf)
+	// LogValuer resolves to a group
+	if m["addr.host"] != "example.com" {
+		t.Errorf("expected addr.host=example.com, got %v", m["addr.host"])
+	}
+	if m["addr.port"] != float64(443) {
+		t.Errorf("expected addr.port=443, got %v", m["addr.port"])
+	}
+}
+
+type testLogValuer struct {
+	host string
+	port int
+}
+
+func (v testLogValuer) LogValue() slog.Value {
+	return slog.GroupValue(
+		slog.String("host", v.host),
+		slog.Int("port", v.port),
+	)
+}
+
+func TestSlogHandler_WithAttrsImmutability(t *testing.T) {
+	var buf1, buf2 bytes.Buffer
+	zl1 := zerolog.New(&buf1)
+	zl2 := zerolog.New(&buf2)
+
+	handler := zerolog.NewSlogHandler(zl1)
+	child1 := handler.WithAttrs([]slog.Attr{slog.String("from", "child1")})
+	_ = zerolog.NewSlogHandler(zl2).WithAttrs([]slog.Attr{slog.String("from", "child2")})
+
+	slog.New(child1).Info("test")
+
+	m := decodeJSON(t, &buf1)
+	if m["from"] != "child1" {
+		t.Errorf("expected from=child1, got %v", m["from"])
+	}
+}
+
+func TestSlogHandler_LevelMapping(t *testing.T) {
+	tests := []struct {
+		slogLevel slog.Level
+		wantLevel string
+	}{
+		{slog.LevelDebug - 4, "trace"},
+		{slog.LevelDebug, "debug"},
+		{slog.LevelInfo, "info"},
+		{slog.LevelWarn, "warn"},
+		{slog.LevelError, "error"},
+	}
+
+	for _, tt := range tests {
+		var buf bytes.Buffer
+		zl := zerolog.New(&buf).Level(zerolog.TraceLevel)
+		logger := slog.New(zerolog.NewSlogHandler(zl))
+
+		logger.Log(nil, tt.slogLevel, "test")
+
+		m := decodeJSON(t, &buf)
+		if m["level"] != tt.wantLevel {
+			t.Errorf("slog level %d: expected zerolog level %q, got %q",
+				tt.slogLevel, tt.wantLevel, m["level"])
+		}
+		buf.Reset()
+	}
+}
+
+func TestSlogHandler_EmptyMessage(t *testing.T) {
+	var buf bytes.Buffer
+	logger := newSlogLogger(&buf)
+
+	logger.Info("", "key", "val")
+
+	m := decodeJSON(t, &buf)
+	if m["key"] != "val" {
+		t.Errorf("expected key=val, got %v", m["key"])
+	}
+}
+
+func TestSlogHandler_WithContext(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf).With().Str("service", "api").Logger()
+	logger := slog.New(zerolog.NewSlogHandler(zl))
+
+	logger.Info("request")
+
+	m := decodeJSON(t, &buf)
+	if m["service"] != "api" {
+		t.Errorf("expected service=api, got %v", m["service"])
+	}
+	if m["message"] != "request" {
+		t.Errorf("expected message 'request', got %v", m["message"])
+	}
+}
+
+func TestSlogHandler_EnabledRespectsGlobalLevel(t *testing.T) {
+	var buf bytes.Buffer
+	zl := zerolog.New(&buf).Level(zerolog.DebugLevel)
+	handler := zerolog.NewSlogHandler(zl)
+
+	// Logger level is debug, so info should be enabled
+	if !handler.Enabled(nil, slog.LevelInfo) {
+		t.Fatal("expected info to be enabled before setting global level")
+	}
+
+	// Set global level to error
+	zerolog.SetGlobalLevel(zerolog.ErrorLevel)
+	defer zerolog.SetGlobalLevel(zerolog.TraceLevel)
+
+	// Now info should be disabled even though logger level allows it
+	if handler.Enabled(nil, slog.LevelInfo) {
+		t.Error("expected info to be disabled when GlobalLevel is error")
+	}
+	// Error should still be enabled
+	if !handler.Enabled(nil, slog.LevelError) {
+		t.Error("expected error to be enabled when GlobalLevel is error")
+	}
+}
+
+func TestSlogHandler_EnabledNilWriter(t *testing.T) {
+	zl := zerolog.Nop()
+	handler := zerolog.NewSlogHandler(zl)
+
+	if handler.Enabled(nil, slog.LevelError) {
+		t.Error("expected disabled for nop logger")
+	}
+}
+
+func TestSlogHandler_HandlePropagatesContext(t *testing.T) {
+	var buf bytes.Buffer
+	type ctxKey struct{}
+	ctx := context.WithValue(context.Background(), ctxKey{}, "test-value")
+
+	var gotCtx context.Context
+	hook := zerolog.HookFunc(func(e *zerolog.Event, level zerolog.Level, msg string) {
+		gotCtx = e.GetCtx()
+	})
+
+	zl := zerolog.New(&buf).Hook(hook)
+	handler := zerolog.NewSlogHandler(zl)
+
+	record := slog.NewRecord(time.Now(), slog.LevelInfo, "test", 0)
+	_ = handler.Handle(ctx, record)
+
+	if gotCtx == nil {
+		t.Fatal("expected context to be propagated to event")
+	}
+	if gotCtx.Value(ctxKey{}) != "test-value" {
+		t.Error("expected context value to be preserved")
+	}
+}
+
+func TestSlogHandler_NoDuplicateTimestamp(t *testing.T) {
+	var buf bytes.Buffer
+	// Create logger with Timestamp() hook - this adds "time" automatically
+	zl := zerolog.New(&buf).With().Timestamp().Logger()
+	handler := zerolog.NewSlogHandler(zl)
+
+	record := slog.NewRecord(time.Now(), slog.LevelInfo, "test", 0)
+	_ = handler.Handle(context.Background(), record)
+
+	output := decodeOutput(&buf)
+	// Count occurrences of the timestamp field name - should appear exactly once
+	count := 0
+	for i := 0; i < len(output); i++ {
+		if i+4 <= len(output) && output[i:i+4] == "time" {
+			count++
+		}
+	}
+	if count > 1 {
+		t.Errorf("expected at most 1 timestamp field, got %d in output: %s", count, output)
+	}
+}
+
+func TestSlogHandler_TimestampWithoutHook(t *testing.T) {
+	var buf bytes.Buffer
+	// Logger without Timestamp() hook - Handle should add the timestamp
+	zl := zerolog.New(&buf)
+	handler := zerolog.NewSlogHandler(zl)
+
+	ts := time.Date(2024, 6, 15, 12, 0, 0, 0, time.UTC)
+	record := slog.NewRecord(ts, slog.LevelInfo, "test", 0)
+	_ = handler.Handle(context.Background(), record)
+
+	m := decodeJSON(t, &buf)
+	if m[zerolog.TimestampFieldName] == nil {
+		t.Error("expected timestamp field when logger has no timestamp hook")
+	}
+}

syslog.go

@@ -1,8 +1,15 @@
 // +build !windows
+// +build !binary_log
 
 package zerolog
 
-import "io"
+import (
+	"io"
+)
+
+// See http://cee.mitre.org/language/1.0-beta1/clt.html#syslog
+// or https://www.rsyslog.com/json-elasticsearch/
+const ceePrefix = "@cee:"
 
 // SyslogWriter is an interface matching a syslog.Writer struct.
 type SyslogWriter interface {
@@ -16,37 +23,67 @@ type SyslogWriter interface {
 }
 
 type syslogWriter struct {
-	w SyslogWriter
+	w      SyslogWriter
+	prefix string
 }
 
 // SyslogLevelWriter wraps a SyslogWriter and call the right syslog level
 // method matching the zerolog level.
 func SyslogLevelWriter(w SyslogWriter) LevelWriter {
-	return syslogWriter{w}
+	return syslogWriter{w, ""}
+}
+
+// SyslogCEEWriter wraps a SyslogWriter with a SyslogLevelWriter that adds a
+// MITRE CEE prefix for JSON syslog entries, compatible with rsyslog 
+// and syslog-ng JSON logging support. 
+// See https://www.rsyslog.com/json-elasticsearch/
+func SyslogCEEWriter(w SyslogWriter) LevelWriter {
+	return syslogWriter{w, ceePrefix}
 }
 
 func (sw syslogWriter) Write(p []byte) (n int, err error) {
-	return sw.w.Write(p)
+	var pn int
+	if sw.prefix != "" {
+		pn, err = sw.w.Write([]byte(sw.prefix))
+		if err != nil {
+			return pn, err
+		}
+	}
+	n, err = sw.w.Write(p)
+	return pn + n, err
 }
 
 // WriteLevel implements LevelWriter interface.
 func (sw syslogWriter) WriteLevel(level Level, p []byte) (n int, err error) {
 	switch level {
+	case TraceLevel:
 	case DebugLevel:
-		err = sw.w.Debug(string(p))
+		err = sw.w.Debug(sw.prefix + string(p))
 	case InfoLevel:
-		err = sw.w.Info(string(p))
+		err = sw.w.Info(sw.prefix + string(p))
 	case WarnLevel:
-		err = sw.w.Warning(string(p))
+		err = sw.w.Warning(sw.prefix + string(p))
 	case ErrorLevel:
-		err = sw.w.Err(string(p))
+		err = sw.w.Err(sw.prefix + string(p))
 	case FatalLevel:
-		err = sw.w.Emerg(string(p))
+		err = sw.w.Emerg(sw.prefix + string(p))
 	case PanicLevel:
-		err = sw.w.Crit(string(p))
+		err = sw.w.Crit(sw.prefix + string(p))
+	case NoLevel:
+		err = sw.w.Info(sw.prefix + string(p))
 	default:
 		panic("invalid level")
 	}
+	// Any CEE prefix is not part of the message, so we don't include its length
 	n = len(p)
 	return
 }
+
+// Call the underlying writer's Close method if it is an io.Closer. Otherwise
+// does nothing.
+func (sw syslogWriter) Close() error {
+	if c, ok := sw.w.(io.Closer); ok {
+		return c.Close()
+	}
+	return nil
+}

syslog_test.go

@@ -1,7 +1,15 @@
+// +build !binary_log
+// +build !windows
+
 package zerolog
 
-import "testing"
-import "reflect"
+import (
+	"bytes"
+	"io"
+	"reflect"
+	"strings"
+	"testing"
+)
 
 type syslogEvent struct {
 	level string
@@ -12,7 +20,11 @@ type syslogTestWriter struct {
 }
 
 func (w *syslogTestWriter) Write(p []byte) (int, error) {
-	return 0, nil
+	return len(p), nil
+}
+func (w *syslogTestWriter) Trace(m string) error {
+	w.events = append(w.events, syslogEvent{"Trace", m})
+	return nil
 }
 func (w *syslogTestWriter) Debug(m string) error {
 	w.events = append(w.events, syslogEvent{"Debug", m})
@@ -42,17 +54,183 @@ func (w *syslogTestWriter) Crit(m string) error {
 func TestSyslogWriter(t *testing.T) {
 	sw := &syslogTestWriter{}
 	log := New(SyslogLevelWriter(sw))
+	log.Trace().Msg("trace")
 	log.Debug().Msg("debug")
 	log.Info().Msg("info")
 	log.Warn().Msg("warn")
 	log.Error().Msg("error")
+	log.Log().Msg("nolevel")
 	want := []syslogEvent{
 		{"Debug", `{"level":"debug","message":"debug"}` + "\n"},
 		{"Info", `{"level":"info","message":"info"}` + "\n"},
 		{"Warning", `{"level":"warn","message":"warn"}` + "\n"},
 		{"Err", `{"level":"error","message":"error"}` + "\n"},
+		{"Info", `{"message":"nolevel"}` + "\n"},
 	}
 	if got := sw.events; !reflect.DeepEqual(got, want) {
 		t.Errorf("Invalid syslog message routing: want %v, got %v", want, got)
 	}
 }
+
+type testCEEwriter struct {
+	buf *bytes.Buffer
+}
+
+// Only implement one method as we're just testing the prefixing
+func (c testCEEwriter) Debug(m string) error { return nil }
+
+func (c testCEEwriter) Info(m string) error {
+	_, err := c.buf.Write([]byte(m))
+	return err
+}
+
+func (c testCEEwriter) Warning(m string) error { return nil }
+
+func (c testCEEwriter) Err(m string) error { return nil }
+
+func (c testCEEwriter) Emerg(m string) error { return nil }
+
+func (c testCEEwriter) Crit(m string) error { return nil }
+
+func (c testCEEwriter) Write(b []byte) (int, error) {
+	return c.buf.Write(b)
+}
+
+func TestSyslogWriter_WithCEE(t *testing.T) {
+	var buf bytes.Buffer
+	sw := testCEEwriter{&buf}
+	log := New(SyslogCEEWriter(sw))
+	log.Info().Str("key", "value").Msg("message string")
+	got := buf.String()
+	want := "@cee:{"
+	if !strings.HasPrefix(got, want) {
+		t.Errorf("Bad CEE message start: want %v, got %v", want, got)
+	}
+}
+
+type errorSyslogWriter struct {
+	*syslogTestWriter
+	writeError error
+}
+
+func (w *errorSyslogWriter) Write(p []byte) (int, error) {
+	if w.writeError != nil {
+		return 0, w.writeError
+	}
+	return len(p), nil
+}
+
+func TestSyslogWriter_Write(t *testing.T) {
+	// Test Write method without prefix
+	sw := &syslogTestWriter{}
+	writer := SyslogLevelWriter(sw)
+
+	data := []byte("test message")
+	n, err := writer.Write(data)
+	if err != nil {
+		t.Errorf("Write failed: %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write returned wrong length: got %d, want %d", n, len(data))
+	}
+
+	// Test Write method with CEE prefix
+	sw2 := &syslogTestWriter{}
+	writer2 := SyslogCEEWriter(sw2)
+
+	data2 := []byte("test message")
+	n2, err2 := writer2.Write(data2)
+	if err2 != nil {
+		t.Errorf("Write with CEE failed: %v", err2)
+	}
+	expectedLen := len(ceePrefix) + len(data2)
+	if n2 != expectedLen {
+		t.Errorf("Write with CEE returned wrong length: got %d, want %d", n2, expectedLen)
+	}
+
+	// Test Write method with CEE prefix and error on prefix write
+	sw3 := &errorSyslogWriter{syslogTestWriter: &syslogTestWriter{}, writeError: io.EOF}
+	writer3 := SyslogCEEWriter(sw3)
+
+	_, err3 := writer3.Write(data2)
+	if err3 != io.EOF {
+		t.Errorf("Write with CEE error failed: got %v, want %v", err3, io.EOF)
+	}
+}
+
+func TestSyslogWriter_WriteLevel_AllLevels(t *testing.T) {
+	sw := &syslogTestWriter{}
+	writer := SyslogLevelWriter(sw)
+
+	// Test all levels to ensure full coverage
+	writer.WriteLevel(TraceLevel, []byte(`{"level":"trace","message":"trace"}`+"\n"))
+	writer.WriteLevel(DebugLevel, []byte(`{"level":"debug","message":"debug"}`+"\n"))
+	writer.WriteLevel(InfoLevel, []byte(`{"level":"info","message":"info"}`+"\n"))
+	writer.WriteLevel(WarnLevel, []byte(`{"level":"warn","message":"warn"}`+"\n"))
+	writer.WriteLevel(ErrorLevel, []byte(`{"level":"error","message":"error"}`+"\n"))
+	writer.WriteLevel(FatalLevel, []byte(`{"level":"fatal","message":"fatal"}`+"\n"))
+	writer.WriteLevel(PanicLevel, []byte(`{"level":"panic","message":"panic"}`+"\n"))
+	writer.WriteLevel(NoLevel, []byte(`{"message":"nolevel"}`+"\n"))
+
+	want := []syslogEvent{
+		{"Debug", `{"level":"debug","message":"debug"}` + "\n"},
+		{"Info", `{"level":"info","message":"info"}` + "\n"},
+		{"Warning", `{"level":"warn","message":"warn"}` + "\n"},
+		{"Err", `{"level":"error","message":"error"}` + "\n"},
+		{"Emerg", `{"level":"fatal","message":"fatal"}` + "\n"},
+		{"Crit", `{"level":"panic","message":"panic"}` + "\n"},
+		{"Info", `{"message":"nolevel"}` + "\n"},
+	}
+	if got := sw.events; !reflect.DeepEqual(got, want) {
+		t.Errorf("Invalid syslog message routing: want %v, got %v", want, got)
+	}
+}
+
+type closableSyslogWriter struct {
+	*syslogTestWriter
+	closed bool
+}
+
+func (w *closableSyslogWriter) Close() error {
+	w.closed = true
+	return nil
+}
+
+func TestSyslogWriter_Close(t *testing.T) {
+	// Test with closable writer
+	sw := &closableSyslogWriter{syslogTestWriter: &syslogTestWriter{}}
+	writer := SyslogLevelWriter(sw).(syslogWriter) // Cast to concrete type to access Close
+
+	err := writer.Close()
+	if err != nil {
+		t.Errorf("Close failed: %v", err)
+	}
+	if !sw.closed {
+		t.Error("Close was not called on underlying writer")
+	}
+
+	// Test with non-closable writer
+	sw2 := &syslogTestWriter{}
+	writer2 := SyslogLevelWriter(sw2).(syslogWriter) // Cast to concrete type to access Close
+
+	err = writer2.Close()
+	if err != nil {
+		t.Errorf("Close failed for non-closable writer: %v", err)
+	}
+}
+
+func TestSyslogWriter_WriteLevel_InvalidLevel(t *testing.T) {
+	sw := &syslogTestWriter{}
+	writer := SyslogLevelWriter(sw)
+
+	// Test invalid level - should panic
+	defer func() {
+		if r := recover(); r == nil {
+			t.Error("Expected panic for invalid level")
+		} else if r != "invalid level" {
+			t.Errorf("Expected panic 'invalid level', got %v", r)
+		}
+	}()
+
+	writer.WriteLevel(Level(100), []byte("test"))
+}

writer.go

@@ -1,7 +1,12 @@
 package zerolog
 
 import (
+	"bytes"
 	"io"
+	"path"
+	"runtime"
+	"strconv"
+	"strings"
 	"sync"
 )
 
@@ -12,30 +17,39 @@ type LevelWriter interface {
 	WriteLevel(level Level, p []byte) (n int, err error)
 }
 
-type levelWriterAdapter struct {
+// LevelWriterAdapter adapts an io.Writer to support the LevelWriter interface.
+type LevelWriterAdapter struct {
 	io.Writer
 }
 
-func (lw levelWriterAdapter) WriteLevel(l Level, p []byte) (n int, err error) {
+// WriteLevel simply writes everything to the adapted writer, ignoring the level.
+func (lw LevelWriterAdapter) WriteLevel(l Level, p []byte) (n int, err error) {
 	return lw.Write(p)
 }
 
+// Call the underlying writer's Close method if it is an io.Closer. Otherwise
+// does nothing.
+func (lw LevelWriterAdapter) Close() error {
+	if closer, ok := lw.Writer.(io.Closer); ok {
+		return closer.Close()
+	}
+	return nil
+}
+
 type syncWriter struct {
 	mu sync.Mutex
 	lw LevelWriter
 }
 
 // SyncWriter wraps w so that each call to Write is synchronized with a mutex.
-// This syncer can be the call to writer's Write method is not thread safe.
-// Note that os.File Write operation is using write() syscall which is supposed
-// to be thread-safe on POSIX systems. So there is no need to use this with
-// os.File on such systems as zerolog guaranties to issue a single Write call
-// per log event.
+// This syncer can be used to wrap the call to writer's Write method if it is
+// not thread safe. Note that you do not need this wrapper for os.File Write
+// operations on POSIX and Windows systems as they are already thread-safe.
 func SyncWriter(w io.Writer) io.Writer {
 	if lw, ok := w.(LevelWriter); ok {
 		return &syncWriter{lw: lw}
 	}
-	return &syncWriter{lw: levelWriterAdapter{w}}
+	return &syncWriter{lw: LevelWriterAdapter{w}}
 }
 
 // Write implements the io.Writer interface.
@@ -52,36 +66,59 @@ func (s *syncWriter) WriteLevel(l Level, p []byte) (n int, err error) {
 	return s.lw.WriteLevel(l, p)
 }
 
+func (s *syncWriter) Close() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if closer, ok := s.lw.(io.Closer); ok {
+		return closer.Close()
+	}
+	return nil
+}
+
 type multiLevelWriter struct {
 	writers []LevelWriter
 }
 
 func (t multiLevelWriter) Write(p []byte) (n int, err error) {
 	for _, w := range t.writers {
-		n, err = w.Write(p)
-		if err != nil {
-			return
-		}
-		if n != len(p) {
-			err = io.ErrShortWrite
-			return
+		if _n, _err := w.Write(p); err == nil {
+			n = _n
+			if _err != nil {
+				err = _err
+			} else if _n != len(p) {
+				err = io.ErrShortWrite
+			}
 		}
 	}
-	return len(p), nil
+	return n, err
 }
 
 func (t multiLevelWriter) WriteLevel(l Level, p []byte) (n int, err error) {
 	for _, w := range t.writers {
-		n, err = w.WriteLevel(l, p)
-		if err != nil {
-			return
-		}
-		if n != len(p) {
-			err = io.ErrShortWrite
-			return
+		if _n, _err := w.WriteLevel(l, p); err == nil {
+			n = _n
+			if _err != nil {
+				err = _err
+			} else if _n != len(p) {
+				err = io.ErrShortWrite
+			}
 		}
 	}
-	return len(p), nil
+	return n, err
+}
+
+// Calls close on all the underlying writers that are io.Closers. If any of the
+// Close methods return an error, the remainder of the closers are not closed
+// and the error is returned.
+func (t multiLevelWriter) Close() error {
+	for _, w := range t.writers {
+		if closer, ok := w.(io.Closer); ok {
+			if err := closer.Close(); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
 }
 
 // MultiLevelWriter creates a writer that duplicates its writes to all the
@@ -93,8 +130,226 @@ func MultiLevelWriter(writers ...io.Writer) LevelWriter {
 		if lw, ok := w.(LevelWriter); ok {
 			lwriters = append(lwriters, lw)
 		} else {
-			lwriters = append(lwriters, levelWriterAdapter{w})
+			lwriters = append(lwriters, LevelWriterAdapter{w})
 		}
 	}
 	return multiLevelWriter{lwriters}
 }
+
+// TestingLog is the logging interface of testing.TB.
+type TestingLog interface {
+	Log(args ...interface{})
+	Logf(format string, args ...interface{})
+	Helper()
+}
+
+// TestWriter is a writer that writes to testing.TB.
+type TestWriter struct {
+	T TestingLog
+
+	// Frame skips caller frames to capture the original file and line numbers.
+	Frame int
+}
+
+// NewTestWriter creates a writer that logs to the testing.TB.
+func NewTestWriter(t TestingLog) TestWriter {
+	return TestWriter{T: t}
+}
+
+// Write to testing.TB.
+func (t TestWriter) Write(p []byte) (n int, err error) {
+	t.T.Helper()
+
+	n = len(p)
+
+	// Strip trailing newline because t.Log always adds one.
+	p = bytes.TrimRight(p, "\n")
+
+	// Try to correct the log file and line number to the caller.
+	if t.Frame > 0 {
+		_, origFile, origLine, _ := runtime.Caller(1)
+		_, frameFile, frameLine, ok := runtime.Caller(1 + t.Frame)
+		if ok {
+			erase := strings.Repeat("\b", len(path.Base(origFile))+len(strconv.Itoa(origLine))+3)
+			t.T.Logf("%s%s:%d: %s", erase, path.Base(frameFile), frameLine, p)
+			return n, err
+		}
+	}
+	t.T.Log(string(p))
+
+	return n, err
+}
+
+// ConsoleTestWriter creates an option that correctly sets the file frame depth for testing.TB log.
+func ConsoleTestWriter(t TestingLog) func(w *ConsoleWriter) {
+	return func(w *ConsoleWriter) {
+		w.Out = TestWriter{T: t, Frame: 6}
+	}
+}
+
+// FilteredLevelWriter writes only logs at Level or above to Writer.
+//
+// It should be used only in combination with MultiLevelWriter when you
+// want to write to multiple destinations at different levels. Otherwise
+// you should just set the level on the logger and filter events early.
+// When using MultiLevelWriter then you set the level on the logger to
+// the lowest of the levels you use for writers.
+type FilteredLevelWriter struct {
+	Writer LevelWriter
+	Level  Level
+}
+
+// Write writes to the underlying Writer.
+func (w *FilteredLevelWriter) Write(p []byte) (int, error) {
+	return w.Writer.Write(p)
+}
+
+// WriteLevel calls WriteLevel of the underlying Writer only if the level is equal
+// or above the Level.
+func (w *FilteredLevelWriter) WriteLevel(level Level, p []byte) (int, error) {
+	if level >= w.Level {
+		return w.Writer.WriteLevel(level, p)
+	}
+	return len(p), nil
+}
+
+// Call the underlying writer's Close method if it is an io.Closer. Otherwise
+// does nothing.
+func (w *FilteredLevelWriter) Close() error {
+	if closer, ok := w.Writer.(io.Closer); ok {
+		return closer.Close()
+	}
+	return nil
+}
+
+var triggerWriterPool = &sync.Pool{
+	New: func() interface{} {
+		return bytes.NewBuffer(make([]byte, 0, 1024))
+	},
+}
+
+// TriggerLevelWriter buffers log lines at the ConditionalLevel or below
+// until a trigger level (or higher) line is emitted. Log lines with level
+// higher than ConditionalLevel are always written out to the destination
+// writer. If trigger never happens, buffered log lines are never written out.
+//
+// It can be used to configure "log level per request".
+type TriggerLevelWriter struct {
+	// Destination writer. If LevelWriter is provided (usually), its WriteLevel is used
+	// instead of Write.
+	io.Writer
+
+	// ConditionalLevel is the level (and below) at which lines are buffered until
+	// a trigger level (or higher) line is emitted. Usually this is set to DebugLevel.
+	ConditionalLevel Level
+
+	// TriggerLevel is the lowest level that triggers the sending of the conditional
+	// level lines. Usually this is set to ErrorLevel.
+	TriggerLevel Level
+
+	buf       *bytes.Buffer
+	triggered bool
+	mu        sync.Mutex
+}
+
+func (w *TriggerLevelWriter) WriteLevel(l Level, p []byte) (n int, err error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	// At first trigger level or above log line, we flush the buffer and change the
+	// trigger state to triggered.
+	if !w.triggered && l >= w.TriggerLevel {
+		err := w.trigger()
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	// Unless triggered, we buffer everything at and below ConditionalLevel.
+	if !w.triggered && l <= w.ConditionalLevel {
+		if w.buf == nil {
+			w.buf = triggerWriterPool.Get().(*bytes.Buffer)
+		}
+
+		// We prefix each log line with a byte with the level.
+		// Hopefully we will never have a level value which equals a newline
+		// (which could interfere with reconstruction of log lines in the trigger method).
+		w.buf.WriteByte(byte(l))
+		w.buf.Write(p)
+		return len(p), nil
+	}
+
+	// Anything above ConditionalLevel is always passed through.
+	// Once triggered, everything is passed through.
+	if lw, ok := w.Writer.(LevelWriter); ok {
+		return lw.WriteLevel(l, p)
+	}
+	return w.Write(p)
+}
+
+// trigger expects lock to be held.
+func (w *TriggerLevelWriter) trigger() error {
+	if w.triggered {
+		return nil
+	}
+	w.triggered = true
+
+	if w.buf == nil {
+		return nil
+	}
+
+	p := w.buf.Bytes()
+	for len(p) > 0 {
+		// We do not use bufio.Scanner here because we already have full buffer
+		// in the memory and we do not want extra copying from the buffer to
+		// scanner's token slice, nor we want to hit scanner's token size limit,
+		// and we also want to preserve newlines.
+		i := bytes.IndexByte(p, '\n')
+		line := p[0 : i+1]
+		p = p[i+1:]
+		// We prefixed each log line with a byte with the level.
+		level := Level(line[0])
+		line = line[1:]
+		var err error
+		if lw, ok := w.Writer.(LevelWriter); ok {
+			_, err = lw.WriteLevel(level, line)
+		} else {
+			_, err = w.Write(line)
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// Trigger forces flushing the buffer and change the trigger state to
+// triggered, if the writer has not already been triggered before.
+func (w *TriggerLevelWriter) Trigger() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	return w.trigger()
+}
+
+// Close closes the writer and returns the buffer to the pool.
+func (w *TriggerLevelWriter) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if w.buf == nil {
+		return nil
+	}
+
+	// We return the buffer only if it has not grown above the limit.
+	// This prevents accumulation of large buffers in the pool just
+	// because occasionally a large buffer might be needed.
+	if w.buf.Cap() <= TriggerLevelWriterBufferReuseLimit {
+		w.buf.Reset()
+		triggerWriterPool.Put(w.buf)
+	}
+	w.buf = nil
+
+	return nil
+}

writer_test.go

@@ -1,10 +1,47 @@
+//go:build !binary_log && !windows
+// +build !binary_log,!windows
+
 package zerolog
 
 import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
 	"reflect"
 	"testing"
 )
 
+type closableBuffer struct {
+	*bytes.Buffer
+	closed     bool
+	closeError error
+}
+
+func (cb *closableBuffer) Close() error {
+	cb.closed = true
+	return cb.closeError
+}
+
+type errorWriter struct {
+	writeError error
+	shortWrite bool
+}
+
+func (ew *errorWriter) Write(p []byte) (int, error) {
+	if ew.writeError != nil {
+		return 0, ew.writeError
+	}
+	if ew.shortWrite {
+		return len(p) - 1, nil // Return short write
+	}
+	return len(p), nil
+}
+
+func (ew *errorWriter) WriteLevel(level Level, p []byte) (int, error) {
+	return ew.Write(p)
+}
+
 func TestMultiSyslogWriter(t *testing.T) {
 	sw := &syslogTestWriter{}
 	log := New(MultiLevelWriter(SyslogLevelWriter(sw)))
@@ -12,13 +49,502 @@ func TestMultiSyslogWriter(t *testing.T) {
 	log.Info().Msg("info")
 	log.Warn().Msg("warn")
 	log.Error().Msg("error")
+	log.Log().Msg("nolevel")
 	want := []syslogEvent{
 		{"Debug", `{"level":"debug","message":"debug"}` + "\n"},
 		{"Info", `{"level":"info","message":"info"}` + "\n"},
 		{"Warning", `{"level":"warn","message":"warn"}` + "\n"},
 		{"Err", `{"level":"error","message":"error"}` + "\n"},
+		{"Info", `{"message":"nolevel"}` + "\n"},
 	}
 	if got := sw.events; !reflect.DeepEqual(got, want) {
 		t.Errorf("Invalid syslog message routing: want %v, got %v", want, got)
 	}
 }
+
+var writeCalls int
+
+type mockedWriter struct {
+	wantErr bool
+}
+
+func (c mockedWriter) Write(p []byte) (int, error) {
+	writeCalls++
+
+	if c.wantErr {
+		return -1, errors.New("Expected error")
+	}
+
+	return len(p), nil
+}
+
+// Tests that a new writer is only used if it actually works.
+func TestResilientMultiWriter(t *testing.T) {
+	tests := []struct {
+		name    string
+		writers []io.Writer
+	}{
+		{
+			name: "All valid writers",
+			writers: []io.Writer{
+				mockedWriter{
+					wantErr: false,
+				},
+				mockedWriter{
+					wantErr: false,
+				},
+			},
+		},
+		{
+			name: "All invalid writers",
+			writers: []io.Writer{
+				mockedWriter{
+					wantErr: true,
+				},
+				mockedWriter{
+					wantErr: true,
+				},
+			},
+		},
+		{
+			name: "First invalid writer",
+			writers: []io.Writer{
+				mockedWriter{
+					wantErr: true,
+				},
+				mockedWriter{
+					wantErr: false,
+				},
+			},
+		},
+		{
+			name: "First valid writer",
+			writers: []io.Writer{
+				mockedWriter{
+					wantErr: false,
+				},
+				mockedWriter{
+					wantErr: true,
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		writers := tt.writers
+		multiWriter := MultiLevelWriter(writers...)
+
+		logger := New(multiWriter).With().Timestamp().Logger().Level(InfoLevel)
+		logger.Info().Msg("Test msg")
+
+		if len(writers) != writeCalls {
+			t.Errorf("Expected %d writers to have been called but only %d were.", len(writers), writeCalls)
+		}
+		writeCalls = 0
+	}
+}
+
+type testingLog struct {
+	testing.TB
+	buf bytes.Buffer
+}
+
+func (t *testingLog) Log(args ...interface{}) {
+	if _, err := t.buf.WriteString(fmt.Sprint(args...)); err != nil {
+		t.Error(err)
+	}
+}
+
+func (t *testingLog) Logf(format string, args ...interface{}) {
+	if _, err := t.buf.WriteString(fmt.Sprintf(format, args...)); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestTestWriter(t *testing.T) {
+	tests := []struct {
+		name  string
+		write []byte
+		want  []byte
+	}{{
+		name:  "newline",
+		write: []byte("newline\n"),
+		want:  []byte("newline"),
+	}, {
+		name:  "oneline",
+		write: []byte("oneline"),
+		want:  []byte("oneline"),
+	}, {
+		name:  "twoline",
+		write: []byte("twoline\n\n"),
+		want:  []byte("twoline"),
+	}}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tb := &testingLog{TB: t} // Capture TB log buffer.
+			w := TestWriter{T: tb}
+
+			n, err := w.Write(tt.write)
+			if err != nil {
+				t.Error(err)
+			}
+			if n != len(tt.write) {
+				t.Errorf("Expected %d write length but got %d", len(tt.write), n)
+			}
+			p := tb.buf.Bytes()
+			if !bytes.Equal(tt.want, p) {
+				t.Errorf("Expected %q, got %q.", tt.want, p)
+			}
+
+			log := New(NewConsoleWriter(ConsoleTestWriter(t)))
+			log.Info().Str("name", tt.name).Msg("Success!")
+
+			tb.buf.Reset()
+		})
+	}
+
+}
+
+func TestFilteredLevelWriter(t *testing.T) {
+	buf := bytes.Buffer{}
+	writer := FilteredLevelWriter{
+		Writer: LevelWriterAdapter{&buf},
+		Level:  InfoLevel,
+	}
+	_, err := writer.WriteLevel(DebugLevel, []byte("no"))
+	if err != nil {
+		t.Error(err)
+	}
+	_, err = writer.WriteLevel(InfoLevel, []byte("yes"))
+	if err != nil {
+		t.Error(err)
+	}
+	p := buf.Bytes()
+	if want := "yes"; !bytes.Equal([]byte(want), p) {
+		t.Errorf("Expected %q, got %q.", want, p)
+	}
+}
+
+type testWrite struct {
+	Level
+	Line []byte
+}
+
+func TestTriggerLevelWriter(t *testing.T) {
+	tests := []struct {
+		write []testWrite
+		want  []byte
+		all   []byte
+	}{{
+		[]testWrite{
+			{DebugLevel, []byte("no\n")},
+			{InfoLevel, []byte("yes\n")},
+		},
+		[]byte("yes\n"),
+		[]byte("yes\nno\n"),
+	}, {
+		[]testWrite{
+			{DebugLevel, []byte("yes1\n")},
+			{InfoLevel, []byte("yes2\n")},
+			{ErrorLevel, []byte("yes3\n")},
+			{DebugLevel, []byte("yes4\n")},
+		},
+		[]byte("yes2\nyes1\nyes3\nyes4\n"),
+		[]byte("yes2\nyes1\nyes3\nyes4\n"),
+	}}
+
+	for k, tt := range tests {
+		t.Run(fmt.Sprintf("case=%d", k), func(t *testing.T) {
+			buf := bytes.Buffer{}
+			writer := TriggerLevelWriter{Writer: LevelWriterAdapter{&buf}, ConditionalLevel: DebugLevel, TriggerLevel: ErrorLevel}
+			t.Cleanup(func() { writer.Close() })
+			for _, w := range tt.write {
+				_, err := writer.WriteLevel(w.Level, w.Line)
+				if err != nil {
+					t.Error(err)
+				}
+			}
+			p := buf.Bytes()
+			if want := tt.want; !bytes.Equal([]byte(want), p) {
+				t.Errorf("Expected %q, got %q.", want, p)
+			}
+			err := writer.Trigger()
+			if err != nil {
+				t.Error(err)
+			}
+			p = buf.Bytes()
+			if want := tt.all; !bytes.Equal([]byte(want), p) {
+				t.Errorf("Expected %q, got %q.", want, p)
+			}
+		})
+	}
+}
+
+func TestLevelWriterAdapter_Close(t *testing.T) {
+	// Test with closable writer
+	buf := &bytes.Buffer{}
+	adapter := LevelWriterAdapter{Writer: buf}
+
+	// bytes.Buffer doesn't implement io.Closer, so Close should return nil
+	err := adapter.Close()
+	if err != nil {
+		t.Errorf("Close should not return error for non-closable writer: %v", err)
+	}
+
+	// Test with closable writer
+	closableBuf := &closableBuffer{Buffer: &bytes.Buffer{}}
+	adapter2 := LevelWriterAdapter{Writer: closableBuf}
+
+	err = adapter2.Close()
+	if err != nil {
+		t.Errorf("Close should not return error: %v", err)
+	}
+	if !closableBuf.closed {
+		t.Error("Close should have been called on closable writer")
+	}
+}
+
+func TestSyncWriter(t *testing.T) {
+	buf := &bytes.Buffer{}
+
+	// Test SyncWriter with regular io.Writer
+	syncWriter := SyncWriter(buf)
+
+	// Test Write
+	data := []byte("test data")
+	n, err := syncWriter.Write(data)
+	if err != nil {
+		t.Errorf("Write failed: %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write returned wrong length: got %d, want %d", n, len(data))
+	}
+	if got := buf.String(); got != string(data) {
+		t.Errorf("Write wrote wrong data: got %q, want %q", got, string(data))
+	}
+
+	// Test SyncWriter with LevelWriter - use it with a logger
+	levelBuf := &bytes.Buffer{}
+	levelWriter := LevelWriterAdapter{levelBuf}
+	syncLevelWriter := SyncWriter(levelWriter)
+
+	logger := New(syncLevelWriter)
+	logger.Info().Msg("test message")
+
+	expected := `{"level":"info","message":"test message"}` + "\n"
+	if got := levelBuf.String(); got != expected {
+		t.Errorf("SyncWriter with LevelWriter failed: got %q, want %q", got, expected)
+	}
+
+	// Test SyncWriter Close with closable writer
+	closableBuf := &closableBuffer{Buffer: &bytes.Buffer{}, closed: false}
+	closableSyncWriter := SyncWriter(closableBuf)
+
+	if closeable, ok := closableSyncWriter.(io.Closer); !ok {
+		t.Error("SyncWriter should implement Close method")
+	} else {
+		err := closeable.Close()
+		if err != nil {
+			t.Errorf("Close failed: %v", err)
+		}
+	}
+	if !closableBuf.closed {
+		t.Error("Close should have been called on closable writer")
+	}
+
+	// Test SyncWriter Close with closable writer that returns error
+	errorBuf := &closableBuffer{Buffer: &bytes.Buffer{}, closed: false, closeError: io.EOF}
+	errorSyncWriter := SyncWriter(errorBuf)
+
+	if closeable, ok := errorSyncWriter.(io.Closer); !ok {
+		t.Error("SyncWriter should implement Close method")
+	} else {
+		err := closeable.Close()
+		if err != io.EOF {
+			t.Errorf("Close should have returned EOF error, got: %v", err)
+		}
+	}
+	if !errorBuf.closed {
+		t.Error("Close should have been called on closable writer")
+	}
+}
+
+func TestMultiLevelWriter_Write(t *testing.T) {
+	// Test successful writes
+	buf1 := &bytes.Buffer{}
+	buf2 := &bytes.Buffer{}
+
+	multiWriter := MultiLevelWriter(buf1, buf2)
+
+	data := []byte("test data")
+	n, err := multiWriter.Write(data)
+	if err != nil {
+		t.Errorf("Write failed: %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write returned wrong length: got %d, want %d", n, len(data))
+	}
+
+	if got1 := buf1.String(); got1 != string(data) {
+		t.Errorf("First writer got wrong data: got %q, want %q", got1, string(data))
+	}
+	if got2 := buf2.String(); got2 != string(data) {
+		t.Errorf("Second writer got wrong data: got %q, want %q", got2, string(data))
+	}
+
+	// Test with error writer
+	errorWriter1 := &errorWriter{writeError: io.EOF}
+	buf3 := &bytes.Buffer{}
+
+	errorMultiWriter := MultiLevelWriter(errorWriter1, buf3)
+
+	_, err = errorMultiWriter.Write(data)
+	if err != io.EOF {
+		t.Errorf("Write should have returned EOF error, got: %v", err)
+	}
+
+	// Test with short write
+	shortWriter := &errorWriter{shortWrite: true}
+	buf4 := &bytes.Buffer{}
+
+	shortMultiWriter := MultiLevelWriter(shortWriter, buf4)
+
+	_, err = shortMultiWriter.Write(data)
+	if err != io.ErrShortWrite {
+		t.Errorf("Write should have returned ErrShortWrite, got: %v", err)
+	}
+}
+
+func TestMultiLevelWriter_WriteLevel(t *testing.T) {
+	// Test successful writes
+	buf1 := &bytes.Buffer{}
+	buf2 := &bytes.Buffer{}
+
+	multiWriter := MultiLevelWriter(buf1, buf2)
+
+	data := []byte("test level data")
+	n, err := multiWriter.WriteLevel(InfoLevel, data)
+	if err != nil {
+		t.Errorf("WriteLevel failed: %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("WriteLevel returned wrong length: got %d, want %d", n, len(data))
+	}
+
+	if got1 := buf1.String(); got1 != string(data) {
+		t.Errorf("First writer got wrong data: got %q, want %q", got1, string(data))
+	}
+	if got2 := buf2.String(); got2 != string(data) {
+		t.Errorf("Second writer got wrong data: got %q, want %q", got2, string(data))
+	}
+
+	// Test with error writer
+	errorWriter1 := &errorWriter{writeError: io.EOF}
+	buf3 := &bytes.Buffer{}
+
+	errorMultiWriter := MultiLevelWriter(errorWriter1, buf3)
+
+	_, err = errorMultiWriter.WriteLevel(InfoLevel, data)
+	if err != io.EOF {
+		t.Errorf("WriteLevel should have returned EOF error, got: %v", err)
+	}
+}
+
+func TestMultiLevelWriter_Close(t *testing.T) {
+	buf1 := &closableBuffer{Buffer: &bytes.Buffer{}, closed: false}
+	buf2 := &bytes.Buffer{} // non-closable
+
+	multiWriter := MultiLevelWriter(buf1, buf2)
+
+	// Cast to concrete type to access Close
+	mw := multiWriter.(multiLevelWriter)
+
+	err := mw.Close()
+	if err != nil {
+		t.Errorf("Close failed: %v", err)
+	}
+
+	if !buf1.closed {
+		t.Error("First closable writer should have been closed")
+	}
+
+	// Test multiLevelWriter Close with error
+	errorBuf1 := &closableBuffer{Buffer: &bytes.Buffer{}, closed: false, closeError: io.EOF}
+	errorBuf2 := &bytes.Buffer{} // non-closable
+
+	errorMultiWriter := MultiLevelWriter(errorBuf1, errorBuf2)
+	emw := errorMultiWriter.(multiLevelWriter)
+
+	err = emw.Close()
+	if err != io.EOF {
+		t.Errorf("Close should have returned EOF error, got: %v", err)
+	}
+	if !errorBuf1.closed {
+		t.Error("First closable writer should have been closed")
+	}
+}
+
+func TestNewTestWriter(t *testing.T) {
+	writer := NewTestWriter(t)
+
+	if writer.T != t {
+		t.Error("NewTestWriter should set the testing interface")
+	}
+	if writer.Frame != 0 {
+		t.Errorf("NewTestWriter should set Frame to 0, got %d", writer.Frame)
+	}
+}
+
+func TestFilteredLevelWriter_Write(t *testing.T) {
+	buf := &bytes.Buffer{}
+	filteredWriter := FilteredLevelWriter{
+		Writer: LevelWriterAdapter{buf},
+		Level:  InfoLevel,
+	}
+
+	data := []byte("test data")
+	n, err := filteredWriter.Write(data)
+	if err != nil {
+		t.Errorf("Write failed: %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write returned wrong length: got %d, want %d", n, len(data))
+	}
+
+	if got := buf.String(); got != string(data) {
+		t.Errorf("Write should always write: got %q, want %q", got, string(data))
+	}
+}
+
+func TestFilteredLevelWriter_Close(t *testing.T) {
+	buf := &closableBuffer{Buffer: &bytes.Buffer{}, closed: false}
+	filteredWriter := FilteredLevelWriter{
+		Writer: LevelWriterAdapter{buf},
+		Level:  InfoLevel,
+	}
+
+	err := filteredWriter.Close()
+	if err != nil {
+		t.Errorf("Close failed: %v", err)
+	}
+
+	if !buf.closed {
+		t.Error("Underlying closable writer should have been closed")
+	}
+
+	// Test FilteredLevelWriter Close with error
+	errorBuf := &closableBuffer{Buffer: &bytes.Buffer{}, closed: false, closeError: io.EOF}
+	errorFilteredWriter := FilteredLevelWriter{
+		Writer: LevelWriterAdapter{errorBuf},
+		Level:  InfoLevel,
+	}
+
+	err = errorFilteredWriter.Close()
+	if err != io.EOF {
+		t.Errorf("Close should have returned EOF error, got: %v", err)
+	}
+	if !errorBuf.closed {
+		t.Error("Underlying closable writer should have been closed")
+	}
+}