Fix prettylog piping (#644)

See: https://github.com/rs/zerolog/issues/583

.github/workflows/test.yml

@@ -4,17 +4,17 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.15.x, 1.16.x]
+        go-version: [1.18.x, 1.21.x]
         os: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
     - name: Install Go
-      uses: actions/setup-go@v2
+      uses: actions/setup-go@v4
       with:
         go-version: ${{ matrix.go-version }}
     - name: Checkout code
-      uses: actions/checkout@v2
-    - uses: actions/cache@v2
+      uses: actions/checkout@v4
+    - uses: actions/cache@v3
       with:
         path: ~/go/pkg/mod
         key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
@@ -24,4 +24,13 @@ jobs:
       run: go test -race -bench . -benchmem ./...
     - name: Test CBOR
       run: go test -tags binary_log ./...
-
+  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

README.md

@@ -1,6 +1,6 @@
 # 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.
 
@@ -24,7 +24,7 @@ Find out [who uses zerolog](https://github.com/rs/zerolog/wiki/Who-uses-zerolog)
 * [Sampling](#log-sampling)
 * [Hooks](#hooks)
 * [Contextual fields](#contextual-logging)
-* `context.Context` integration
+* [`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)
@@ -399,6 +399,8 @@ 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")
@@ -406,10 +408,29 @@ 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 {
+    short := file
+    for i := len(file) - 1; i > 0; i-- {
+        if file[i] == '/' {
+            short = file[i+1:]
+            break
+        }
+    }
+    file = short
+    return 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 follow:
+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) {
@@ -490,6 +511,58 @@ 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`.
@@ -560,11 +633,11 @@ func main() {
 // 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. Call this with `zerolog.Disabled` to disable logging altogether (quiet mode).
@@ -604,7 +677,7 @@ Most fields are also available in the slice format (`Strs` for `[]string`, `Errs
 
 ## Binary Encoding
 
-In addition to the default JSON encoding, `zerolog` can produce binary logs using [CBOR](http://cbor.io) encoding. The choice of encoding can be decided at compile time using the build tag `binary_log` as follows:
+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 .
@@ -621,7 +694,7 @@ with zerolog library is [CSD](https://github.com/toravir/csd/).
 
 ## Benchmarks
 
-See [logbench](http://hackemist.com/logbench/) for more comprehensive and up-to-date 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):
 
@@ -682,6 +755,8 @@ Log a static string, without any context or `printf`-style templating:
 
 ## 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
@@ -693,3 +768,19 @@ logger.Info().
 ```
 
 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 {
+        ...
+    })
+}
+```

array.go

@@ -49,7 +49,7 @@ func (*Array) MarshalZerologArray(*Array) {
 func (a *Array) write(dst []byte) []byte {
 	dst = enc.AppendArrayStart(dst)
 	if len(a.buf) > 0 {
-		dst = append(append(dst, a.buf...))
+		dst = append(dst, a.buf...)
 	}
 	dst = enc.AppendArrayEnd(dst)
 	putArray(a)
@@ -57,7 +57,7 @@ func (a *Array) write(dst []byte) []byte {
 }
 
 // Object marshals an object that implement the LogObjectMarshaler
-// interface and append append it to the array.
+// interface and appends it to the array.
 func (a *Array) Object(obj LogObjectMarshaler) *Array {
 	e := Dict()
 	obj.MarshalZerologObject(e)
@@ -67,19 +67,19 @@ func (a *Array) Object(obj LogObjectMarshaler) *Array {
 	return a
 }
 
-// Str append 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 = enc.AppendString(enc.AppendArrayDelim(a.buf), val)
 	return a
 }
 
-// Bytes append 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 = enc.AppendBytes(enc.AppendArrayDelim(a.buf), val)
 	return a
 }
 
-// Hex append append the val as a hex 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
@@ -115,97 +115,97 @@ func (a *Array) Err(err error) *Array {
 	return a
 }
 
-// Bool append append the val as a bool to the array.
+// Bool appends the val as a bool to the array.
 func (a *Array) Bool(b bool) *Array {
 	a.buf = enc.AppendBool(enc.AppendArrayDelim(a.buf), b)
 	return a
 }
 
-// Int append 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 = enc.AppendInt(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int8 append 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 = enc.AppendInt8(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int16 append 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 = enc.AppendInt16(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int32 append 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 = enc.AppendInt32(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Int64 append 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 = enc.AppendInt64(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint append 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 = enc.AppendUint(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint8 append 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 = enc.AppendUint8(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint16 append 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 = enc.AppendUint16(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint32 append 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 = enc.AppendUint32(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Uint64 append 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 = enc.AppendUint64(enc.AppendArrayDelim(a.buf), i)
 	return a
 }
 
-// Float32 append 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 = enc.AppendFloat32(enc.AppendArrayDelim(a.buf), f)
 	return a
 }
 
-// Float64 append 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 = enc.AppendFloat64(enc.AppendArrayDelim(a.buf), f)
 	return a
 }
 
-// Time append 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 = enc.AppendTime(enc.AppendArrayDelim(a.buf), t, TimeFieldFormat)
 	return a
 }
 
-// Dur append append d to the array.
+// Dur appends d to the array.
 func (a *Array) Dur(d time.Duration) *Array {
 	a.buf = enc.AppendDuration(enc.AppendArrayDelim(a.buf), d, DurationFieldUnit, DurationFieldInteger)
 	return a
 }
 
-// Interface append 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)

benchmark_test.go

@@ -1,8 +1,9 @@
 package zerolog
 
 import (
+	"context"
 	"errors"
-	"io/ioutil"
+	"io"
 	"net"
 	"testing"
 	"time"
@@ -14,7 +15,7 @@ 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() {
@@ -24,7 +25,7 @@ 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() {
@@ -34,7 +35,7 @@ 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() {
@@ -44,7 +45,7 @@ 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).
@@ -59,7 +60,7 @@ func BenchmarkContextFields(b *testing.B) {
 }
 
 func BenchmarkContextAppend(b *testing.B) {
-	logger := New(ioutil.Discard).With().
+	logger := New(io.Discard).With().
 		Str("foo", "bar").
 		Logger()
 	b.ResetTimer()
@@ -71,7 +72,7 @@ func BenchmarkContextAppend(b *testing.B) {
 }
 
 func BenchmarkLogFields(b *testing.B) {
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
@@ -101,7 +102,7 @@ func BenchmarkLogArrayObject(b *testing.B) {
 	obj1 := obj{"a", "b", 2}
 	obj2 := obj{"c", "d", 3}
 	obj3 := obj{"e", "f", 4}
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
@@ -160,6 +161,7 @@ func BenchmarkLogFieldType(b *testing.B) {
 		{"a", "a", 0},
 	}
 	errs := []error{errors.New("a"), errors.New("b"), errors.New("c"), errors.New("d"), errors.New("e")}
+	ctx := context.Background()
 	types := map[string]func(e *Event) *Event{
 		"Bool": func(e *Event) *Event {
 			return e.Bool("k", bools[0])
@@ -191,6 +193,9 @@ func BenchmarkLogFieldType(b *testing.B) {
 		"Errs": func(e *Event) *Event {
 			return e.Errs("k", errs)
 		},
+		"Ctx": func(e *Event) *Event {
+			return e.Ctx(ctx)
+		},
 		"Time": func(e *Event) *Event {
 			return e.Time("k", times[0])
 		},
@@ -219,7 +224,7 @@ func BenchmarkLogFieldType(b *testing.B) {
 			return e.Object("k", objects[0])
 		},
 	}
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	for name := range types {
 		f := types[name]
@@ -284,6 +289,7 @@ func BenchmarkContextFieldType(b *testing.B) {
 		{"a", "a", 0},
 	}
 	errs := []error{errors.New("a"), errors.New("b"), errors.New("c"), errors.New("d"), errors.New("e")}
+	ctx := context.Background()
 	types := map[string]func(c Context) Context{
 		"Bool": func(c Context) Context {
 			return c.Bool("k", bools[0])
@@ -318,6 +324,9 @@ func BenchmarkContextFieldType(b *testing.B) {
 		"Errs": func(c Context) Context {
 			return c.Errs("k", errs)
 		},
+		"Ctx": func(c Context) Context {
+			return c.Ctx(ctx)
+		},
 		"Time": func(c Context) Context {
 			return c.Time("k", times[0])
 		},
@@ -349,7 +358,7 @@ func BenchmarkContextFieldType(b *testing.B) {
 			return c.Timestamp()
 		},
 	}
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	for name := range types {
 		f := types[name]

binary_test.go

@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 
-	//	"io/ioutil"
 	stdlog "log"
 	"time"
 )

cmd/lint/README.md

@@ -1,5 +1,7 @@
 # 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
@@ -27,7 +29,7 @@ The command accepts only one argument - the package to be inspected - and 4 opti
 - 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 dependecy tree
+    - 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
 

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/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 +1,62 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/rs/zerolog"
+)
+
+func isInputFromPipe() bool {
+	fileInfo, _ := os.Stdin.Stat()
+	return fileInfo.Mode()&os.ModeCharDevice == 0
+}
+
+func processInput(reader io.Reader) error {
+	writer := zerolog.NewConsoleWriter()
+
+	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() {
+
+	if isInputFromPipe() {
+		_ = processInput(os.Stdin)
+	} else if len(os.Args) > 1 {
+		for _, filename := range os.Args[1:] {
+			// 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); 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

@@ -12,6 +12,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/mattn/go-colorable"
 )
 
 const (
@@ -61,6 +63,9 @@ type ConsoleWriter struct {
 	// PartsExclude defines parts to not display in output.
 	PartsExclude []string
 
+	// FieldsExclude defines contextual fields to not display in output.
+	FieldsExclude []string
+
 	FormatTimestamp     Formatter
 	FormatLevel         Formatter
 	FormatCaller        Formatter
@@ -69,6 +74,10 @@ type ConsoleWriter struct {
 	FormatFieldValue    Formatter
 	FormatErrFieldName  Formatter
 	FormatErrFieldValue Formatter
+
+	FormatExtra func(map[string]interface{}, *bytes.Buffer) error
+
+	FormatPrepare func(map[string]interface{}) error
 }
 
 // NewConsoleWriter creates and initializes a new ConsoleWriter.
@@ -83,11 +92,21 @@ func NewConsoleWriter(options ...func(w *ConsoleWriter)) ConsoleWriter {
 		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()
 	}
@@ -107,24 +126,59 @@ func (w ConsoleWriter) Write(p []byte) (n int, err error) {
 		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
@@ -133,7 +187,8 @@ func (w ConsoleWriter) writeFields(evt map[string]interface{}, buf *bytes.Buffer
 	}
 	sort.Strings(fields)
 
-	if len(fields) > 0 {
+	// 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(' ')
 	}
 
@@ -194,7 +249,7 @@ func (w ConsoleWriter) writeFields(evt map[string]interface{}, buf *bytes.Buffer
 		case json.Number:
 			buf.WriteString(fv(fValue))
 		default:
-			b, err := json.Marshal(fValue)
+			b, err := InterfaceMarshalFunc(fValue)
 			if err != nil {
 				fmt.Fprintf(buf, colorize("[error: %v]", colorRed, w.NoColor), err)
 			} else {
@@ -235,7 +290,7 @@ func (w ConsoleWriter) writePart(buf *bytes.Buffer, evt map[string]interface{},
 		}
 	case MessageFieldName:
 		if w.FormatMessage == nil {
-			f = consoleDefaultFormatMessage
+			f = consoleDefaultFormatMessage(w.NoColor, evt[LevelFieldName])
 		} else {
 			f = w.FormatMessage
 		}
@@ -256,10 +311,10 @@ func (w ConsoleWriter) writePart(buf *bytes.Buffer, evt map[string]interface{},
 	var s = f(evt[p])
 
 	if len(s) > 0 {
-		buf.WriteString(s)
-		if p != w.PartsOrder[len(w.PartsOrder)-1] { // Skip space for last part
-			buf.WriteByte(' ')
+		if buf.Len() > 0 {
+			buf.WriteByte(' ') // Write space only if not the first part
 		}
+		buf.WriteString(s)
 	}
 }
 
@@ -273,8 +328,13 @@ func needsQuote(s string) bool {
 	return false
 }
 
-// colorize returns the string s wrapped in ANSI code c, unless disabled is true.
+// 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)
 	}
@@ -300,27 +360,31 @@ func consoleDefaultFormatTimestamp(timeFormat string, noColor bool) Formatter {
 		t := "<nil>"
 		switch tt := i.(type) {
 		case string:
-			ts, err := time.Parse(TimeFieldFormat, tt)
+			ts, err := time.ParseInLocation(TimeFieldFormat, tt, time.Local)
 			if err != nil {
 				t = tt
 			} else {
-				t = ts.Format(timeFormat)
+				t = ts.Local().Format(timeFormat)
 			}
 		case json.Number:
 			i, err := tt.Int64()
 			if err != nil {
 				t = tt.String()
 			} else {
-				var sec, nsec int64 = i, 0
+				var sec, nsec int64
+
 				switch TimeFieldFormat {
-				case TimeFormatUnixMs:
-					nsec = int64(time.Duration(i) * time.Millisecond)
-					sec = 0
+				case TimeFormatUnixNano:
+					sec, nsec = 0, i
 				case TimeFormatUnixMicro:
-					nsec = int64(time.Duration(i) * time.Microsecond)
-					sec = 0
+					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).UTC()
+
+				ts := time.Unix(sec, nsec)
 				t = ts.Format(timeFormat)
 			}
 		}
@@ -332,27 +396,16 @@ func consoleDefaultFormatLevel(noColor bool) Formatter {
 	return func(i interface{}) string {
 		var l string
 		if ll, ok := i.(string); ok {
-			switch ll {
-			case LevelTraceValue:
-				l = colorize("TRC", colorMagenta, noColor)
-			case LevelDebugValue:
-				l = colorize("DBG", colorYellow, noColor)
-			case LevelInfoValue:
-				l = colorize("INF", colorGreen, noColor)
-			case LevelWarnValue:
-				l = colorize("WRN", colorRed, noColor)
-			case LevelErrorValue:
-				l = colorize(colorize("ERR", colorRed, noColor), colorBold, noColor)
-			case LevelFatalValue:
-				l = colorize(colorize("FTL", colorRed, noColor), colorBold, noColor)
-			case LevelPanicValue:
-				l = colorize(colorize("PNC", colorRed, noColor), colorBold, noColor)
-			default:
-				l = colorize("???", colorBold, noColor)
+			level, _ := ParseLevel(ll)
+			fl, ok := FormattedLevels[level]
+			if ok {
+				l = colorize(fl, LevelColors[level], noColor)
+			} else {
+				l = strings.ToUpper(ll)[0:3]
 			}
 		} else {
 			if i == nil {
-				l = colorize("???", colorBold, noColor)
+				l = "???"
 			} else {
 				l = strings.ToUpper(fmt.Sprintf("%s", i))[0:3]
 			}
@@ -379,11 +432,18 @@ func consoleDefaultFormatCaller(noColor bool) Formatter {
 	}
 }
 
-func consoleDefaultFormatMessage(i interface{}) string {
-	if i == nil {
-		return ""
+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)
+		}
 	}
-	return fmt.Sprintf("%s", i)
 }
 
 func consoleDefaultFormatFieldName(noColor bool) Formatter {
@@ -398,12 +458,12 @@ func consoleDefaultFormatFieldValue(i interface{}) string {
 
 func consoleDefaultFormatErrFieldName(noColor bool) Formatter {
 	return func(i interface{}) string {
-		return colorize(fmt.Sprintf("%s=", i), colorRed, noColor)
+		return colorize(fmt.Sprintf("%s=", i), colorCyan, noColor)
 	}
 }
 
 func consoleDefaultFormatErrFieldValue(noColor bool) Formatter {
 	return func(i interface{}) string {
-		return colorize(fmt.Sprintf("%s", i), colorRed, noColor)
+		return colorize(colorize(fmt.Sprintf("%s", i), colorBold, noColor), colorRed, noColor)
 	}
 }

console_test.go

@@ -3,7 +3,7 @@ package zerolog_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"strings"
 	"testing"
@@ -97,24 +97,44 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "\x1b[90m<nil>\x1b[0m \x1b[31mWRN\x1b[0m Foobar\n"
+		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}
 
-		d := time.Unix(0, 0).UTC().Format(time.RFC3339)
+		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 := "12:00AM DBG Foobar foo=bar\n"
+		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)
@@ -136,7 +156,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "Jan  1 00:20:34.000 DBG Foobar foo=bar\n"
+		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)
@@ -158,7 +178,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "Jan  1 00:20:34.567 DBG Foobar foo=bar\n"
+		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)
@@ -180,7 +200,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "Jan  1 00:20:34.567891 DBG Foobar foo=bar\n"
+		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)
@@ -196,7 +216,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "<nil> DBG  foo=bar\n"
+		expectedOutput := "<nil> DBG foo=bar\n"
 		actualOutput := buf.String()
 		if actualOutput != expectedOutput {
 			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
@@ -228,7 +248,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "\x1b[90m<nil>\x1b[0m \x1b[31mWRN\x1b[0m Foobar \x1b[36mfoo=\x1b[0mbar\n"
+		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)
@@ -239,7 +259,8 @@ func TestConsoleWriter(t *testing.T) {
 		buf := &bytes.Buffer{}
 		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
 
-		d := time.Unix(0, 0).UTC().Format(time.RFC3339)
+		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)
 
@@ -248,7 +269,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "12:00AM ERR Foobar error=Error aaa=bbb\n"
+		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)
@@ -264,7 +285,8 @@ func TestConsoleWriter(t *testing.T) {
 			t.Fatalf("Cannot get working directory: %s", err)
 		}
 
-		d := time.Unix(0, 0).UTC().Format(time.RFC3339)
+		ts := time.Unix(0, 0)
+		d := ts.UTC().Format(time.RFC3339)
 		evt := `{"time": "` + d + `", "level": "debug", "message": "Foobar", "foo": "bar", "caller": "` + cwd + `/foo/bar.go"}`
 		// t.Log(evt)
 
@@ -273,7 +295,7 @@ func TestConsoleWriter(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "12:00AM DBG foo/bar.go > Foobar foo=bar\n"
+		expectedOutput := ts.Format(time.Kitchen) + " DBG foo/bar.go > Foobar foo=bar\n"
 		actualOutput := buf.String()
 		if actualOutput != expectedOutput {
 			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
@@ -305,7 +327,8 @@ func TestConsoleWriterConfiguration(t *testing.T) {
 		buf := &bytes.Buffer{}
 		w := zerolog.ConsoleWriter{Out: buf, NoColor: true, TimeFormat: time.RFC3339}
 
-		d := time.Unix(0, 0).UTC().Format(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))
@@ -313,7 +336,7 @@ func TestConsoleWriterConfiguration(t *testing.T) {
 			t.Errorf("Unexpected error when writing output: %s", err)
 		}
 
-		expectedOutput := "1970-01-01T00:00:00Z INF Foobar\n"
+		expectedOutput := ts.Format(time.RFC3339) + " INF Foobar\n"
 		actualOutput := buf.String()
 		if actualOutput != expectedOutput {
 			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
@@ -354,6 +377,95 @@ func TestConsoleWriterConfiguration(t *testing.T) {
 			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) {
@@ -362,7 +474,7 @@ func BenchmarkConsoleWriter(b *testing.B) {
 
 	var msg = []byte(`{"level": "info", "foo": "bar", "message": "HELLO", "time": "1990-01-01"}`)
 
-	w := zerolog.ConsoleWriter{Out: ioutil.Discard, NoColor: false}
+	w := zerolog.ConsoleWriter{Out: io.Discard, NoColor: false}
 
 	for i := 0; i < b.N; i++ {
 		w.Write(msg)

context.go

@@ -1,8 +1,9 @@
 package zerolog
 
 import (
+	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"math"
 	"net"
 	"time"
@@ -22,7 +23,7 @@ func (c Context) Logger() Logger {
 // 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.context = appendFields(c.l.context, fields, c.l.stack)
 	return c
 }
 
@@ -56,7 +57,7 @@ func (c Context) Array(key string, arr LogArrayMarshaler) Context {
 
 // Object marshals an object that implement the LogObjectMarshaler interface.
 func (c Context) Object(key string, obj LogObjectMarshaler) Context {
-	e := newEvent(levelWriterAdapter{ioutil.Discard}, 0)
+	e := newEvent(LevelWriterAdapter{io.Discard}, 0)
 	e.Object(key, obj)
 	c.l.context = enc.AppendObjectData(c.l.context, e.buf)
 	putEvent(e)
@@ -65,7 +66,7 @@ func (c Context) Object(key string, obj LogObjectMarshaler) Context {
 
 // EmbedObject marshals and Embeds an object that implement the LogObjectMarshaler interface.
 func (c Context) EmbedObject(obj LogObjectMarshaler) Context {
-	e := newEvent(levelWriterAdapter{ioutil.Discard}, 0)
+	e := newEvent(LevelWriterAdapter{io.Discard}, 0)
 	e.EmbedObject(obj)
 	c.l.context = enc.AppendObjectData(c.l.context, e.buf)
 	putEvent(e)
@@ -162,9 +163,34 @@ func (c Context) Errs(key string, errs []error) Context {
 
 // Err adds the field "error" with serialized err to the logger context.
 func (c Context) Err(err error) Context {
+	if c.l.stack && ErrorStackMarshaler != nil {
+		switch m := ErrorStackMarshaler(err).(type) {
+		case nil:
+		case LogObjectMarshaler:
+			c = c.Object(ErrorStackFieldName, m)
+		case error:
+			if m != nil && !isNilValue(m) {
+				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 = enc.AppendBool(enc.AppendKey(c.l.context, key), b)
@@ -329,8 +355,9 @@ func (ts timestampHook) Run(e *Event, level Level, msg string) {
 
 var th = timestampHook{}
 
-// Timestamp adds the current local time as UNIX timestamp to the logger context with the "time" key.
+// 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 {
@@ -364,10 +391,24 @@ func (c Context) Durs(key string, d []time.Duration) Context {
 
 // Interface adds the field key with obj marshaled using reflection.
 func (c Context) Interface(key string, i interface{}) Context {
+	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)
+}
+
 type callerHook struct {
 	callerSkipFrameCount int
 }

ctx.go

@@ -14,10 +14,15 @@ func init() {
 
 type ctxKey struct{}
 
-// WithContext returns a copy of ctx with l associated. If an instance of Logger
-// is already in the context, the context is not updated.
+// 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.
 //
-// For instance, to add a field to an existing logger in the context, use this
+// 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()
@@ -25,17 +30,13 @@ type ctxKey struct{}
 //     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 {
-		if lp == l {
-			// Do not store same logger.
-			return ctx
-		}
-	} else if l.level == Disabled {
+//
+func (l Logger) WithContext(ctx context.Context) context.Context {
+	if _, ok := ctx.Value(ctxKey{}).(*Logger); !ok && l.level == Disabled {
 		// Do not store disabled logger.
 		return ctx
 	}
-	return context.WithValue(ctx, ctxKey{}, l)
+	return context.WithValue(ctx, ctxKey{}, &l)
 }
 
 // Ctx returns the Logger associated with the ctx. If no logger

ctx_test.go

@@ -1,14 +1,17 @@
 package zerolog
 
 import (
+	"bytes"
 	"context"
-	"io/ioutil"
+	"io"
 	"reflect"
 	"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) {
@@ -37,15 +40,15 @@ func TestCtx(t *testing.T) {
 }
 
 func TestCtxDisabled(t *testing.T) {
-	dl := New(ioutil.Discard).Level(Disabled)
+	dl := New(io.Discard).Level(Disabled)
 	ctx := dl.WithContext(context.Background())
 	if ctx != context.Background() {
 		t.Error("WithContext stored a disabled logger")
 	}
 
-	l := New(ioutil.Discard).With().Str("foo", "bar").Logger()
+	l := New(io.Discard).With().Str("foo", "bar").Logger()
 	ctx = l.WithContext(ctx)
-	if Ctx(ctx) != &l {
+	if !reflect.DeepEqual(Ctx(ctx), &l) {
 		t.Error("WithContext did not store logger")
 	}
 
@@ -53,18 +56,46 @@ func TestCtxDisabled(t *testing.T) {
 		return c.Str("bar", "baz")
 	})
 	ctx = l.WithContext(ctx)
-	if Ctx(ctx) != &l {
+	if !reflect.DeepEqual(Ctx(ctx), &l) {
 		t.Error("WithContext did not store updated logger")
 	}
 
 	l = l.Level(DebugLevel)
 	ctx = l.WithContext(ctx)
-	if Ctx(ctx) != &l {
+	if !reflect.DeepEqual(Ctx(ctx), &l) {
 		t.Error("WithContext did not store copied logger")
 	}
 
 	ctx = dl.WithContext(ctx)
-	if Ctx(ctx) != &dl {
-		t.Error("WithContext did not overide logger with a disabled logger")
+	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", "custom_value").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":"custom_value","age":29},"message":"test"}`+"\n"; got != want {
+		t.Errorf("got %q, want %q", got, want)
 	}
 }

diode/diode_test.go

@@ -3,9 +3,10 @@ package diode_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
+	"os/exec"
 	"testing"
 	"time"
 
@@ -30,8 +31,53 @@ func TestNewWriter(t *testing.T) {
 	}
 }
 
+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)
+	}
+	slurp, err := io.ReadAll(stderr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = cmd.Wait()
+	if err == nil {
+		t.Error("Expected log.Fatal to exit with non-zero status")
+	}
+
+	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)
+	}
+}
+
 func Benchmark(b *testing.B) {
-	log.SetOutput(ioutil.Discard)
+	log.SetOutput(io.Discard)
 	defer log.SetOutput(os.Stderr)
 	benchs := map[string]time.Duration{
 		"Waiter": 0,
@@ -39,7 +85,7 @@ func Benchmark(b *testing.B) {
 	}
 	for name, interval := range benchs {
 		b.Run(name, func(b *testing.B) {
-			w := diode.NewWriter(ioutil.Discard, 100000, interval, nil)
+			w := diode.NewWriter(io.Discard, 100000, interval, nil)
 			log := zerolog.New(w)
 			defer w.Close()
 

diode/internal/diodes/many_to_one.go

@@ -16,7 +16,7 @@ type ManyToOne struct {
 }
 
 // NewManyToOne creates a new diode (ring buffer). The ManyToOne diode
-// is optimzed for many writers (on go-routines B-n) and a single reader
+// 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.
@@ -66,7 +66,7 @@ func (d *ManyToOne) Set(data GenericDataType) {
 }
 
 // TryNext will attempt to read from the next slot of the ring buffer.
-// If there is not data available, it will return (nil, false).
+// 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))
@@ -80,7 +80,7 @@ func (d *ManyToOne) TryNext() (data GenericDataType, ok bool) {
 	}
 
 	// When the seq value is less than the current read index that means a
-	// value was read from idx that was previously written but has since has
+	// 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.
 	//

diode/internal/diodes/one_to_one.go

@@ -80,7 +80,7 @@ func (d *OneToOne) TryNext() (data GenericDataType, ok bool) {
 	}
 
 	// When the seq value is less than the current read index that means a
-	// value was read from idx that was previously written but has since has
+	// 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.
 	//

diode/internal/diodes/poller.go

@@ -24,18 +24,18 @@ 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 PollerConfigOption(func(c *Poller) {
+	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 PollerConfigOption(func(c *Poller) {
+	return func(c *Poller) {
 		c.ctx = ctx
-	})
+	}
 }
 
 // NewPoller returns a new Poller that wraps the given diode.

diode/internal/diodes/waiter.go

@@ -21,9 +21,9 @@ type WaiterConfigOption func(*Waiter)
 // will not change any results for adding data (Set()). Default is
 // context.Background().
 func WithWaiterContext(ctx context.Context) WaiterConfigOption {
-	return WaiterConfigOption(func(c *Waiter) {
+	return func(c *Waiter) {
 		c.ctx = ctx
-	})
+	}
 }
 
 // NewWaiter returns a new Waiter that wraps the given diode.
@@ -39,7 +39,12 @@ func NewWaiter(d Diode, opts ...WaiterConfigOption) *Waiter {
 
 	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

encoder_cbor.go

@@ -24,6 +24,9 @@ func init() {
 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.

encoder_json.go

@@ -6,6 +6,7 @@ package zerolog
 // JSON encoded byte stream.
 
 import (
+	"encoding/base64"
 	"github.com/rs/zerolog/internal/json"
 )
 
@@ -25,6 +26,17 @@ func init() {
 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)

event.go

@@ -1,6 +1,7 @@
 package zerolog
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"os"
@@ -24,9 +25,10 @@ type Event struct {
 	w         LevelWriter
 	level     Level
 	done      func(msg string)
-	stack     bool   // enable error stack trace
-	ch        []Hook // hooks from context
-	skipFrame int    // The number of additional frames to skip when printing the caller.
+	stack     bool            // enable error stack trace
+	ch        []Hook          // hooks from context
+	skipFrame int             // The number of additional frames to skip when printing the caller.
+	ctx       context.Context // Optional Go context for event
 }
 
 func putEvent(e *Event) {
@@ -129,6 +131,13 @@ func (e *Event) Msgf(format string, v ...interface{}) {
 	e.msg(fmt.Sprintf(format, v...))
 }
 
+func (e *Event) MsgFunc(createMsg func() string) {
+	if e == nil {
+		return
+	}
+	e.msg(createMsg())
+}
+
 func (e *Event) msg(msg string) {
 	for _, hook := range e.ch {
 		hook.Run(e, e.level, msg)
@@ -155,7 +164,7 @@ func (e *Event) Fields(fields interface{}) *Event {
 	if e == nil {
 		return e
 	}
-	e.buf = appendFields(e.buf, fields)
+	e.buf = appendFields(e.buf, fields, e.stack)
 	return e
 }
 
@@ -311,6 +320,18 @@ func (e *Event) RawJSON(key string, b []byte) *Event {
 	return e
 }
 
+// RawCBOR adds already encoded CBOR to the log line under key.
+//
+// No sanity check is performed on b
+// Note: The full featureset of CBOR is supported as data will not be mapped to json but stored as data-url
+func (e *Event) RawCBOR(key string, b []byte) *Event {
+	if e == nil {
+		return e
+	}
+	e.buf = appendCBOR(enc.AppendKey(e.buf, key), b)
+	return e
+}
+
 // AnErr adds the field key with serialized err to the *Event context.
 // If err is nil, no field is added.
 func (e *Event) AnErr(key string, err error) *Event {
@@ -398,6 +419,28 @@ func (e *Event) Stack() *Event {
 	return e
 }
 
+// Ctx adds the Go Context to the *Event context.  The context is not rendered
+// in the output message, but is available to hooks and to Func() calls via the
+// GetCtx() accessor. A typical use case is to extract tracing information from
+// the Go Ctx.
+func (e *Event) Ctx(ctx context.Context) *Event {
+	if e != nil {
+		e.ctx = ctx
+	}
+	return e
+}
+
+// GetCtx retrieves the Go context.Context which is optionally stored in the
+// Event.  This allows Hooks and functions passed to Func() to retrieve values
+// which are stored in the context.Context.  This can be useful in tracing,
+// where span information is commonly propagated in the context.Context.
+func (e *Event) GetCtx() context.Context {
+	if e == nil || e.ctx == nil {
+		return context.Background()
+	}
+	return e.ctx
+}
+
 // Bool adds the field key with val as a bool to the *Event context.
 func (e *Event) Bool(key string, b bool) *Event {
 	if e == nil {
@@ -645,7 +688,7 @@ func (e *Event) Timestamp() *Event {
 	return e
 }
 
-// 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 (e *Event) Time(key string, t time.Time) *Event {
 	if e == nil {
 		return e
@@ -654,7 +697,7 @@ func (e *Event) Time(key string, t time.Time) *Event {
 	return e
 }
 
-// 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 (e *Event) Times(key string, t []time.Time) *Event {
 	if e == nil {
 		return e
@@ -700,6 +743,11 @@ func (e *Event) TimeDiff(key string, t time.Time, start time.Time) *Event {
 	return e
 }
 
+// Any is a wrapper around Event.Interface.
+func (e *Event) Any(key string, i interface{}) *Event {
+	return e.Interface(key, i)
+}
+
 // Interface adds the field key with i marshaled using reflection.
 func (e *Event) Interface(key string, i interface{}) *Event {
 	if e == nil {
@@ -712,6 +760,15 @@ func (e *Event) Interface(key string, i interface{}) *Event {
 	return e
 }
 
+// Type adds the field key with val's type using reflection.
+func (e *Event) Type(key string, val interface{}) *Event {
+	if e == nil {
+		return e
+	}
+	e.buf = enc.AppendType(enc.AppendKey(e.buf, key), val)
+	return e
+}
+
 // CallerSkipFrame instructs any future Caller calls to skip the specified number of frames.
 // This includes those added via hooks from the context.
 func (e *Event) CallerSkipFrame(skip int) *Event {
@@ -737,11 +794,11 @@ func (e *Event) caller(skip int) *Event {
 	if e == nil {
 		return e
 	}
-	_, file, line, ok := runtime.Caller(skip + e.skipFrame)
+	pc, file, line, ok := runtime.Caller(skip + e.skipFrame)
 	if !ok {
 		return e
 	}
-	e.buf = enc.AppendString(enc.AppendKey(e.buf, CallerFieldName), CallerMarshalFunc(file, line))
+	e.buf = enc.AppendString(enc.AppendKey(e.buf, CallerFieldName), CallerMarshalFunc(pc, file, line))
 	return e
 }
 

event_test.go

@@ -28,7 +28,7 @@ func TestEvent_AnErr(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			var buf bytes.Buffer
-			e := newEvent(levelWriterAdapter{&buf}, DebugLevel)
+			e := newEvent(LevelWriterAdapter{&buf}, DebugLevel)
 			e.AnErr("err", tt.err)
 			_ = e.write()
 			if got, want := strings.TrimSpace(buf.String()), tt.want; got != want {
@@ -40,7 +40,7 @@ func TestEvent_AnErr(t *testing.T) {
 
 func TestEvent_ObjectWithNil(t *testing.T) {
 	var buf bytes.Buffer
-	e := newEvent(levelWriterAdapter{&buf}, DebugLevel)
+	e := newEvent(LevelWriterAdapter{&buf}, DebugLevel)
 	_ = e.Object("obj", nil)
 	_ = e.write()
 
@@ -53,7 +53,7 @@ func TestEvent_ObjectWithNil(t *testing.T) {
 
 func TestEvent_EmbedObjectWithNil(t *testing.T) {
 	var buf bytes.Buffer
-	e := newEvent(levelWriterAdapter{&buf}, DebugLevel)
+	e := newEvent(LevelWriterAdapter{&buf}, DebugLevel)
 	_ = e.EmbedObject(nil)
 	_ = e.write()
 

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

@@ -12,13 +12,13 @@ func isNilValue(i interface{}) bool {
 	return (*[2]uintptr)(unsafe.Pointer(&i))[1] == 0
 }
 
-func appendFields(dst []byte, fields interface{}) []byte {
+func appendFields(dst []byte, fields interface{}, stack bool) []byte {
 	switch fields := fields.(type) {
 	case []interface{}:
 		if n := len(fields); n&0x1 == 1 { // odd number
 			fields = fields[:n-1]
 		}
-		dst = appendFieldList(dst, fields)
+		dst = appendFieldList(dst, fields, stack)
 	case map[string]interface{}:
 		keys := make([]string, 0, len(fields))
 		for key := range fields {
@@ -28,13 +28,13 @@ func appendFields(dst []byte, fields interface{}) []byte {
 		kv := make([]interface{}, 2)
 		for _, key := range keys {
 			kv[0], kv[1] = key, fields[key]
-			dst = appendFieldList(dst, kv)
+			dst = appendFieldList(dst, kv, stack)
 		}
 	}
 	return dst
 }
 
-func appendFieldList(dst []byte, kvList []interface{}) []byte {
+func appendFieldList(dst []byte, kvList []interface{}, stack bool) []byte {
 	for i, n := 0, len(kvList); i < n; i += 2 {
 		key, val := kvList[i], kvList[i+1]
 		if key, ok := key.(string); ok {
@@ -74,6 +74,21 @@ func appendFieldList(dst []byte, kvList []interface{}) []byte {
 			default:
 				dst = enc.AppendInterface(dst, m)
 			}
+
+			if stack && ErrorStackMarshaler != nil {
+				dst = enc.AppendKey(dst, ErrorStackFieldName)
+				switch m := ErrorStackMarshaler(val).(type) {
+				case nil:
+				case error:
+					if m != nil && !isNilValue(m) {
+						dst = enc.AppendString(dst, m.Error())
+					}
+				case string:
+					dst = enc.AppendString(dst, m)
+				default:
+					dst = enc.AppendInterface(dst, m)
+				}
+			}
 		case []error:
 			dst = enc.AppendArrayStart(dst)
 			for i, err := range val {

globals.go

@@ -19,6 +19,10 @@ const (
 	// 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"
 )
 
 var (
@@ -61,7 +65,7 @@ var (
 	CallerSkipFrameCount = 2
 
 	// CallerMarshalFunc allows customization of global caller marshaling
-	CallerMarshalFunc = func(file string, line int) string {
+	CallerMarshalFunc = func(pc uintptr, file string, line int) string {
 		return file + ":" + strconv.Itoa(line)
 	}
 
@@ -81,7 +85,7 @@ var (
 	InterfaceMarshalFunc = json.Marshal
 
 	// TimeFieldFormat defines the time format of the Time field type. If set to
-	// TimeFormatUnix, TimeFormatUnixMs or TimeFormatUnixMicro, the time is formatted as an UNIX
+	// TimeFormatUnix, TimeFormatUnixMs, TimeFormatUnixMicro or TimeFormatUnixNano, the time is formatted as a UNIX
 	// timestamp as integer.
 	TimeFieldFormat = time.RFC3339
 
@@ -104,6 +108,34 @@ var (
 	// 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
 )
 
 var (

go.mod

@@ -3,8 +3,10 @@ module github.com/rs/zerolog
 go 1.15
 
 require (
-	github.com/coreos/go-systemd/v22 v22.3.2
+	github.com/coreos/go-systemd/v22 v22.5.0
+	github.com/mattn/go-colorable v0.1.13
+	github.com/mattn/go-isatty v0.0.19 // indirect
 	github.com/pkg/errors v0.9.1
-	github.com/rs/xid v1.3.0
-	golang.org/x/tools v0.1.7
+	github.com/rs/xid v1.5.0
+	golang.org/x/sys v0.12.0 // indirect
 )

go.sum

@@ -1,34 +1,23 @@
-github.com/coreos/go-systemd/v22 v22.3.2 h1:D9/bQk5vlXQFZ6Kwuu6zaiXJ9oTPe68++AzAJc1DzSI=
-github.com/coreos/go-systemd/v22 v22.3.2/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+github.com/mattn/go-colorable v0.1.12 h1:jF+Du6AlPIjs2BiUiQlKOX0rt3SujHxPnksPKZbaA40=
+github.com/mattn/go-colorable v0.1.12/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
+github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APPA=
+github.com/mattn/go-isatty v0.0.19/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 v1.3.0 h1:6NjYksEUlhurdVehpc7S7dk6DAmcKv8V9gG0FsVN2U4=
-github.com/rs/xid v1.3.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
-github.com/yuin/goldmark v1.4.0/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 v0.4.2 h1:Gz96sIWK3OalVv/I/qNygP42zyoKp3xptRVCWRFEBvo=
-golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
-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 v0.0.0-20210805182204-aaa1db679c0d/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 v0.0.0-20210809222454-d867a43fc93e h1:WUoyKPm6nCo1BnNUvPGnFG3T5DUVem42yDJZZ4CNxMA=
-golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/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/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 v0.1.7 h1:6j8CgantCy3yc8JGBqkDLMKWqZ0RDU2g1HVgacojGWQ=
-golang.org/x/tools v0.1.7/go.mod h1:LGqMHiF4EqQNHR1JncWGqT5BVaXmza+X+BDGol+dOxo=
-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=
+github.com/rs/xid v1.5.0 h1:mKX4bl4iPYJtEIxp6CYiUuLQ/8DYMoz0PUdtGgMFRVc=
+github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6 h1:foEbQz/B0Oz6YIqu/69kfXPYeFQAuuMYFkjaqXzl5Wo=
+golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

hlog/hlog.go

@@ -3,7 +3,9 @@ package hlog
 
 import (
 	"context"
+	"net"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/rs/xid"
@@ -89,6 +91,35 @@ func RemoteAddrHandler(fieldKey string) func(next http.Handler) http.Handler {
 	}
 }
 
+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)
+		})
+	}
+}
+
 // UserAgentHandler adds the request's user-agent as a field to the context's logger
 // using fieldKey as field key.
 func UserAgentHandler(fieldKey string) func(next http.Handler) http.Handler {
@@ -121,6 +152,35 @@ func RefererHandler(fieldKey string) func(next http.Handler) http.Handler {
 	}
 }
 
+// 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 associated to the request if any.
@@ -191,14 +251,76 @@ func CustomHeaderHandler(fieldKey, header string) func(next http.Handler) http.H
 	}
 }
 
+// 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

@@ -48,8 +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"))
@@ -63,11 +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: {"level":"info","role":"my-service","host":"local-hostname","user":"current user","status":"ok","time":"2001-02-03T04:05:06Z","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

@@ -1,3 +1,4 @@
+//go:build go1.7
 // +build go1.7
 
 package hlog
@@ -6,7 +7,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -121,6 +122,38 @@ func TestRemoteAddrHandlerIPv6(t *testing.T) {
 	}
 }
 
+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) {
 	out := &bytes.Buffer{}
 	r := &http.Request{
@@ -200,6 +233,78 @@ func TestCustomHeaderHandler(t *testing.T) {
 	}
 }
 
+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{
@@ -228,10 +333,10 @@ func BenchmarkHandlers(b *testing.B) {
 	}))
 	h2 := MethodHandler("method")(RequestHandler("request")(h1))
 	handlers := map[string]http.Handler{
-		"Single":           NewHandler(zerolog.New(ioutil.Discard))(h1),
-		"Combined":         NewHandler(zerolog.New(ioutil.Discard))(h2),
-		"SingleDisabled":   NewHandler(zerolog.New(ioutil.Discard).Level(zerolog.Disabled))(h1),
-		"CombinedDisabled": NewHandler(zerolog.New(ioutil.Discard).Level(zerolog.Disabled))(h2),
+		"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]
@@ -275,3 +380,56 @@ func TestCtxWithID(t *testing.T) {
 		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)
+			}
+		})
+	}
+}

hook_test.go

@@ -2,10 +2,15 @@ package zerolog
 
 import (
 	"bytes"
-	"io/ioutil"
+	"context"
+	"io"
 	"testing"
 )
 
+type contextKeyType int
+
+var contextKey contextKeyType
+
 var (
 	levelNameHook = HookFunc(func(e *Event, level Level, msg string) {
 		levelName := level.String()
@@ -31,6 +36,12 @@ var (
 	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) {
@@ -120,6 +131,29 @@ func TestHook(t *testing.T) {
 			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("")
 		}},
@@ -138,7 +172,7 @@ func TestHook(t *testing.T) {
 }
 
 func BenchmarkHooks(b *testing.B) {
-	logger := New(ioutil.Discard)
+	logger := New(io.Discard)
 	b.ResetTimer()
 	b.Run("Nop/Single", func(b *testing.B) {
 		log := logger.Hook(nopHook)

internal/cbor/cbor.go

@@ -26,7 +26,8 @@ const (
 	additionalTypeBreak   byte = 31
 
 	// Tag Sub-types.
-	additionalTypeTimestamp byte = 01
+	additionalTypeTimestamp    byte = 01
+	additionalTypeEmbeddedCBOR byte = 63
 
 	// Extended Tags - from https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml
 	additionalTypeTagNetworkAddr   uint16 = 260
@@ -67,7 +68,7 @@ const (
 var IntegerTimeFieldFormat = time.RFC3339
 
 // NanoTimeFieldFormat indicates the format of timestamp decoded
-// from a float value (time in seconds and nano seconds).
+// from a float value (time in seconds and nanoseconds).
 var NanoTimeFieldFormat = time.RFC3339Nano
 
 func appendCborTypePrefix(dst []byte, major byte, number uint64) []byte {
@@ -91,7 +92,8 @@ func appendCborTypePrefix(dst []byte, major byte, number uint64) []byte {
 		minor = additionalTypeIntUint64
 
 	}
-	dst = append(dst, byte(major|minor))
+
+	dst = append(dst, major|minor)
 	byteCount--
 	for ; byteCount >= 0; byteCount-- {
 		dst = append(dst, byte(number>>(uint(byteCount)*8)))

internal/cbor/decode_stream.go

@@ -5,6 +5,7 @@ package cbor
 import (
 	"bufio"
 	"bytes"
+	"encoding/base64"
 	"fmt"
 	"io"
 	"math"
@@ -43,7 +44,7 @@ func readByte(src *bufio.Reader) byte {
 	return b
 }
 
-func decodeIntAdditonalType(src *bufio.Reader, minor byte) int64 {
+func decodeIntAdditionalType(src *bufio.Reader, minor byte) int64 {
 	val := int64(0)
 	if minor <= 23 {
 		val = int64(minor)
@@ -77,7 +78,7 @@ func decodeInteger(src *bufio.Reader) int64 {
 	if major != majorTypeUnsignedInt && major != majorTypeNegativeInt {
 		panic(fmt.Errorf("Major type is: %d in decodeInteger!! (expected 0 or 1)", major))
 	}
-	val := decodeIntAdditonalType(src, minor)
+	val := decodeIntAdditionalType(src, minor)
 	if major == 0 {
 		return val
 	}
@@ -204,7 +205,7 @@ func decodeString(src *bufio.Reader, noQuotes bool) []byte {
 	if !noQuotes {
 		result = append(result, '"')
 	}
-	length := decodeIntAdditonalType(src, minor)
+	length := decodeIntAdditionalType(src, minor)
 	len := int(length)
 	pbs := readNBytes(src, len)
 	result = append(result, pbs...)
@@ -213,6 +214,31 @@ func decodeString(src *bufio.Reader, noQuotes bool) []byte {
 	}
 	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)
@@ -222,7 +248,7 @@ func decodeUTF8String(src *bufio.Reader) []byte {
 		panic(fmt.Errorf("Major type is: %d in decodeUTF8String", major))
 	}
 	result := []byte{'"'}
-	length := decodeIntAdditonalType(src, minor)
+	length := decodeIntAdditionalType(src, minor)
 	len := int(length)
 	pbs := readNBytes(src, len)
 
@@ -238,7 +264,7 @@ func decodeUTF8String(src *bufio.Reader) []byte {
 			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.
 	result = append(result, pbs...)
 	return append(result, '"')
@@ -257,7 +283,7 @@ func array2Json(src *bufio.Reader, dst io.Writer) {
 	if minor == additionalTypeInfiniteCount {
 		unSpecifiedCount = true
 	} else {
-		length := decodeIntAdditonalType(src, minor)
+		length := decodeIntAdditionalType(src, minor)
 		len = int(length)
 	}
 	for i := 0; unSpecifiedCount || i < len; i++ {
@@ -266,7 +292,7 @@ func array2Json(src *bufio.Reader, dst io.Writer) {
 			if e != nil {
 				panic(e)
 			}
-			if pb[0] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+			if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
 				readByte(src)
 				break
 			}
@@ -277,7 +303,7 @@ func array2Json(src *bufio.Reader, dst io.Writer) {
 			if e != nil {
 				panic(e)
 			}
-			if pb[0] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+			if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
 				readByte(src)
 				break
 			}
@@ -301,7 +327,7 @@ func map2Json(src *bufio.Reader, dst io.Writer) {
 	if minor == additionalTypeInfiniteCount {
 		unSpecifiedCount = true
 	} else {
-		length := decodeIntAdditonalType(src, minor)
+		length := decodeIntAdditionalType(src, minor)
 		len = int(length)
 	}
 	dst.Write([]byte{'{'})
@@ -311,7 +337,7 @@ func map2Json(src *bufio.Reader, dst io.Writer) {
 			if e != nil {
 				panic(e)
 			}
-			if pb[0] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+			if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
 				readByte(src)
 				break
 			}
@@ -326,7 +352,7 @@ func map2Json(src *bufio.Reader, dst io.Writer) {
 				if e != nil {
 					panic(e)
 				}
-				if pb[0] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+				if pb[0] == majorTypeSimpleAndFloat|additionalTypeBreak {
 					readByte(src)
 					break
 				}
@@ -349,10 +375,24 @@ func decodeTagData(src *bufio.Reader) []byte {
 	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 := decodeIntAdditonalType(src, minor)
+		val := decodeIntAdditionalType(src, minor)
 
 		switch uint16(val) {
 		case additionalTypeEmbeddedJSON:
@@ -383,7 +423,7 @@ func decodeTagData(src *bufio.Reader) []byte {
 
 		case additionalTypeTagNetworkPrefix:
 			pb := readByte(src)
-			if pb != byte(majorTypeMap|0x1) {
+			if pb != majorTypeMap|0x1 {
 				panic(fmt.Errorf("IP Prefix is NOT of MAP of 1 elements as expected"))
 			}
 			octets := decodeString(src, true)

internal/cbor/string.go

@@ -8,7 +8,7 @@ func (e Encoder) AppendStrings(dst []byte, vals []string) []byte {
 	l := len(vals)
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -25,7 +25,7 @@ func (Encoder) AppendString(dst []byte, s string) []byte {
 	l := len(s)
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, majorTypeUtf8String, uint64(l))
 	}
@@ -64,7 +64,7 @@ func (Encoder) AppendBytes(dst, s []byte) []byte {
 	l := len(s)
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -77,7 +77,7 @@ func AppendEmbeddedJSON(dst, s []byte) []byte {
 	minor := additionalTypeEmbeddedJSON
 
 	// Append the TAG to indicate this is Embedded JSON.
-	dst = append(dst, byte(major|additionalTypeIntUint16))
+	dst = append(dst, major|additionalTypeIntUint16)
 	dst = append(dst, byte(minor>>8))
 	dst = append(dst, byte(minor&0xff))
 
@@ -87,7 +87,29 @@ func AppendEmbeddedJSON(dst, s []byte) []byte {
 	l := len(s)
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		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))
 	}

internal/cbor/time.go

@@ -7,7 +7,7 @@ import (
 func appendIntegerTimestamp(dst []byte, t time.Time) []byte {
 	major := majorTypeTags
 	minor := additionalTypeTimestamp
-	dst = append(dst, byte(major|minor))
+	dst = append(dst, major|minor)
 	secs := t.Unix()
 	var val uint64
 	if secs < 0 {
@@ -17,18 +17,18 @@ func appendIntegerTimestamp(dst []byte, t time.Time) []byte {
 		major = majorTypeUnsignedInt
 		val = uint64(secs)
 	}
-	dst = appendCborTypePrefix(dst, major, uint64(val))
+	dst = appendCborTypePrefix(dst, major, val)
 	return dst
 }
 
 func (e Encoder) appendFloatTimestamp(dst []byte, t time.Time) []byte {
 	major := majorTypeTags
 	minor := additionalTypeTimestamp
-	dst = append(dst, byte(major|minor))
+	dst = append(dst, major|minor)
 	secs := t.Unix()
 	nanos := t.Nanosecond()
 	var val float64
-	val = float64(secs)*1.0 + float64(nanos)*1E-9
+	val = float64(secs)*1.0 + float64(nanos)*1e-9
 	return e.AppendFloat64(dst, val)
 }
 
@@ -50,7 +50,7 @@ func (e Encoder) AppendTimes(dst []byte, vals []time.Time, unused string) []byte
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -82,7 +82,7 @@ func (e Encoder) AppendDurations(dst []byte, vals []time.Duration, unit time.Dur
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}

internal/cbor/types.go

@@ -4,21 +4,22 @@ import (
 	"fmt"
 	"math"
 	"net"
+	"reflect"
 )
 
 // AppendNil inserts a 'Nil' object into the dst byte array.
 func (Encoder) AppendNil(dst []byte) []byte {
-	return append(dst, byte(majorTypeSimpleAndFloat|additionalTypeNull))
+	return append(dst, majorTypeSimpleAndFloat|additionalTypeNull)
 }
 
 // AppendBeginMarker inserts a map start into the dst byte array.
 func (Encoder) AppendBeginMarker(dst []byte) []byte {
-	return append(dst, byte(majorTypeMap|additionalTypeInfiniteCount))
+	return append(dst, majorTypeMap|additionalTypeInfiniteCount)
 }
 
 // AppendEndMarker inserts a map end into the dst byte array.
 func (Encoder) AppendEndMarker(dst []byte) []byte {
-	return append(dst, byte(majorTypeSimpleAndFloat|additionalTypeBreak))
+	return append(dst, majorTypeSimpleAndFloat|additionalTypeBreak)
 }
 
 // AppendObjectData takes an object in form of a byte array and appends to dst.
@@ -30,12 +31,12 @@ func (Encoder) AppendObjectData(dst []byte, o []byte) []byte {
 
 // AppendArrayStart adds markers to indicate the start of an array.
 func (Encoder) AppendArrayStart(dst []byte) []byte {
-	return append(dst, byte(majorTypeArray|additionalTypeInfiniteCount))
+	return append(dst, majorTypeArray|additionalTypeInfiniteCount)
 }
 
 // AppendArrayEnd adds markers to indicate the end of an array.
 func (Encoder) AppendArrayEnd(dst []byte) []byte {
-	return append(dst, byte(majorTypeSimpleAndFloat|additionalTypeBreak))
+	return append(dst, majorTypeSimpleAndFloat|additionalTypeBreak)
 }
 
 // AppendArrayDelim adds markers to indicate end of a particular array element.
@@ -56,7 +57,7 @@ func (Encoder) AppendBool(dst []byte, val bool) []byte {
 	if val {
 		b = additionalTypeBoolTrue
 	}
-	return append(dst, byte(majorTypeSimpleAndFloat|b))
+	return append(dst, majorTypeSimpleAndFloat|b)
 }
 
 // AppendBools encodes and inserts an array of boolean values into the dst byte array.
@@ -68,7 +69,7 @@ func (e Encoder) AppendBools(dst []byte, vals []bool) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -88,7 +89,7 @@ func (Encoder) AppendInt(dst []byte, val int) []byte {
 	}
 	if contentVal <= additionalMax {
 		lb := byte(contentVal)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
 	}
@@ -104,7 +105,7 @@ func (e Encoder) AppendInts(dst []byte, vals []int) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -128,7 +129,7 @@ func (e Encoder) AppendInts8(dst []byte, vals []int8) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -152,7 +153,7 @@ func (e Encoder) AppendInts16(dst []byte, vals []int16) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -176,7 +177,7 @@ func (e Encoder) AppendInts32(dst []byte, vals []int32) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -196,7 +197,7 @@ func (Encoder) AppendInt64(dst []byte, val int64) []byte {
 	}
 	if contentVal <= additionalMax {
 		lb := byte(contentVal)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
 	}
@@ -212,7 +213,7 @@ func (e Encoder) AppendInts64(dst []byte, vals []int64) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -236,7 +237,7 @@ func (e Encoder) AppendUints(dst []byte, vals []uint) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -260,7 +261,7 @@ func (e Encoder) AppendUints8(dst []byte, vals []uint8) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -284,7 +285,7 @@ func (e Encoder) AppendUints16(dst []byte, vals []uint16) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -308,7 +309,7 @@ func (e Encoder) AppendUints32(dst []byte, vals []uint32) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -324,9 +325,9 @@ func (Encoder) AppendUint64(dst []byte, val uint64) []byte {
 	contentVal := val
 	if contentVal <= additionalMax {
 		lb := byte(contentVal)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
-		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
+		dst = appendCborTypePrefix(dst, major, contentVal)
 	}
 	return dst
 }
@@ -340,7 +341,7 @@ func (e Encoder) AppendUints64(dst []byte, vals []uint64) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -367,7 +368,7 @@ func (Encoder) AppendFloat32(dst []byte, val float32) []byte {
 	for i := uint(0); i < 4; i++ {
 		buf[i] = byte(n >> ((3 - i) * 8))
 	}
-	return append(append(dst, byte(major|subType)), buf[0], buf[1], buf[2], buf[3])
+	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.
@@ -379,7 +380,7 @@ func (e Encoder) AppendFloats32(dst []byte, vals []float32) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -402,7 +403,7 @@ func (Encoder) AppendFloat64(dst []byte, val float64) []byte {
 	major := majorTypeSimpleAndFloat
 	subType := additionalTypeFloat64
 	n := math.Float64bits(val)
-	dst = append(dst, byte(major|subType))
+	dst = append(dst, major|subType)
 	for i := uint(1); i <= 8; i++ {
 		b := byte(n >> ((8 - i) * 8))
 		dst = append(dst, b)
@@ -419,7 +420,7 @@ func (e Encoder) AppendFloats64(dst []byte, vals []float64) []byte {
 	}
 	if l <= additionalMax {
 		lb := byte(l)
-		dst = append(dst, byte(major|lb))
+		dst = append(dst, major|lb)
 	} else {
 		dst = appendCborTypePrefix(dst, major, uint64(l))
 	}
@@ -438,9 +439,17 @@ func (e Encoder) AppendInterface(dst []byte, i interface{}) []byte {
 	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 encodes and inserts an IP Address (IPv4 or IPv6).
 func (e Encoder) AppendIPAddr(dst []byte, ip net.IP) []byte {
-	dst = append(dst, byte(majorTypeTags|additionalTypeIntUint16))
+	dst = append(dst, majorTypeTags|additionalTypeIntUint16)
 	dst = append(dst, byte(additionalTypeTagNetworkAddr>>8))
 	dst = append(dst, byte(additionalTypeTagNetworkAddr&0xff))
 	return e.AppendBytes(dst, ip)
@@ -448,21 +457,21 @@ func (e Encoder) AppendIPAddr(dst []byte, ip net.IP) []byte {
 
 // AppendIPPrefix encodes and inserts an IP Address Prefix (Address + Mask Length).
 func (e Encoder) AppendIPPrefix(dst []byte, pfx net.IPNet) []byte {
-	dst = append(dst, byte(majorTypeTags|additionalTypeIntUint16))
+	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, byte(majorTypeMap|0x1))
+	dst = append(dst, majorTypeMap|0x1)
 	dst = e.AppendBytes(dst, pfx.IP)
 	maskLen, _ := pfx.Mask.Size()
 	return e.AppendUint8(dst, uint8(maskLen))
 }
 
-// AppendMACAddr encodes and inserts an Hardware (MAC) address.
+// AppendMACAddr encodes and inserts a Hardware (MAC) address.
 func (e Encoder) AppendMACAddr(dst []byte, ha net.HardwareAddr) []byte {
-	dst = append(dst, byte(majorTypeTags|additionalTypeIntUint16))
+	dst = append(dst, majorTypeTags|additionalTypeIntUint16)
 	dst = append(dst, byte(additionalTypeTagNetworkAddr>>8))
 	dst = append(dst, byte(additionalTypeTagNetworkAddr&0xff))
 	return e.AppendBytes(dst, ha)
@@ -470,7 +479,7 @@ func (e Encoder) AppendMACAddr(dst []byte, ha net.HardwareAddr) []byte {
 
 // AppendHex adds a TAG and inserts a hex bytes as a string.
 func (e Encoder) AppendHex(dst []byte, val []byte) []byte {
-	dst = append(dst, byte(majorTypeTags|additionalTypeIntUint16))
+	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_test.go

@@ -115,7 +115,6 @@ var integerTestCases = []struct {
 	{-0x10001, "\x3a\x00\x01\x00\x00"},
 	{-0x7FFFFFFE, "\x3a\x7f\xff\xff\xfd"},
 	{-1000000, "\x3a\x00\x0f\x42\x3f"},
-
 }
 
 func TestAppendInt(t *testing.T) {
@@ -212,7 +211,7 @@ var macAddrTestCases = []struct {
 	{net.HardwareAddr{0x20, 0x01, 0x0d, 0xb8, 0x85, 0xa3}, "\"20:01:0d:b8:85:a3\"", "\xd9\x01\x04\x46\x20\x01\x0d\xb8\x85\xa3"},
 }
 
-func TestAppendMacAddr(t *testing.T) {
+func TestAppendMACAddr(t *testing.T) {
 	for _, tc := range macAddrTestCases {
 		s := enc.AppendMACAddr([]byte{}, tc.macaddr)
 		got := string(s)

internal/json/string.go

@@ -37,7 +37,7 @@ func (e Encoder) 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.
@@ -56,7 +56,7 @@ func (Encoder) AppendString(dst []byte, s string) []byte {
 			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
@@ -99,7 +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]...)

internal/json/time.go

@@ -7,9 +7,10 @@ import (
 
 const (
 	// Import from zerolog/global.go
-	timeFormatUnix   = ""
-	timeFormatUnixMs = "UNIXMS"
+	timeFormatUnix      = ""
+	timeFormatUnixMs    = "UNIXMS"
 	timeFormatUnixMicro = "UNIXMICRO"
+	timeFormatUnixNano  = "UNIXNANO"
 )
 
 // AppendTime formats the input time with the given format
@@ -22,6 +23,8 @@ func (e Encoder) AppendTime(dst []byte, t time.Time, format string) []byte {
 		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), '"')
 }
@@ -33,7 +36,11 @@ func (Encoder) AppendTimes(dst []byte, vals []time.Time, format string) []byte {
 	case timeFormatUnix:
 		return appendUnixTimes(dst, vals)
 	case timeFormatUnixMs:
-		return appendUnixMsTimes(dst, vals)
+		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, '[', ']')
@@ -64,15 +71,15 @@ func appendUnixTimes(dst []byte, vals []time.Time) []byte {
 	return dst
 }
 
-func appendUnixMsTimes(dst []byte, vals []time.Time) []byte {
+func appendUnixNanoTimes(dst []byte, vals []time.Time, div int64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
 	}
 	dst = append(dst, '[')
-	dst = strconv.AppendInt(dst, vals[0].UnixNano()/1000000, 10)
+	dst = strconv.AppendInt(dst, vals[0].UnixNano()/div, 10)
 	if len(vals) > 1 {
 		for _, t := range vals[1:] {
-			dst = strconv.AppendInt(append(dst, ','), t.UnixNano()/1000000, 10)
+			dst = strconv.AppendInt(append(dst, ','), t.UnixNano()/div, 10)
 		}
 	}
 	dst = append(dst, ']')

internal/json/types.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math"
 	"net"
+	"reflect"
 	"strconv"
 )
 
@@ -278,7 +279,7 @@ func (Encoder) AppendUints32(dst []byte, vals []uint32) []byte {
 // 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, uint64(val), 10)
+	return strconv.AppendUint(dst, val, 10)
 }
 
 // AppendUints64 encodes the input uint64s to json and
@@ -300,7 +301,7 @@ func (Encoder) AppendUints64(dst []byte, vals []uint64) []byte {
 
 func appendFloat(dst []byte, val float64, bitSize 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):
@@ -369,6 +370,14 @@ func (e Encoder) AppendInterface(dst []byte, i interface{}) []byte {
 	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 {

internal/json/types_test.go

@@ -166,6 +166,28 @@ func Test_appendMac(t *testing.T) {
 	}
 }
 
+func Test_appendType(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 Test_appendObjectData(t *testing.T) {
 	tests := []struct {
 		dst  []byte

journald/journald.go

@@ -1,3 +1,4 @@
+//go:build !windows
 // +build !windows
 
 // Package journald provides a io.Writer to send the logs
@@ -69,11 +70,6 @@ func levelToJPrio(zLevel string) journal.Priority {
 }
 
 func (w journalWriter) Write(p []byte) (n int, err error) {
-	if !journal.Enabled() {
-		err = fmt.Errorf("cannot connect to journalD")
-		return
-	}
-
 	var event map[string]interface{}
 	origPLen := len(p)
 	p = cbor.DecodeIfBinaryToBytes(p)
@@ -81,7 +77,7 @@ func (w journalWriter) Write(p []byte) (n int, err error) {
 	d.UseNumber()
 	err = d.Decode(&event)
 	jPrio := defaultJournalDPrio
-	args := make(map[string]string, 0)
+	args := make(map[string]string)
 	if err != nil {
 		return
 	}
@@ -100,13 +96,13 @@ func (w journalWriter) Write(p []byte) (n int, err error) {
 			continue
 		}
 
-		switch value.(type) {
+		switch v := value.(type) {
 		case string:
-			args[jKey], _ = value.(string)
+			args[jKey] = v
 		case json.Number:
 			args[jKey] = fmt.Sprint(value)
 		default:
-			b, err := json.Marshal(value)
+			b, err := zerolog.InterfaceMarshalFunc(value)
 			if err != nil {
 				args[jKey] = fmt.Sprintf("[error: %v]", err)
 			} else {

log.go

@@ -82,8 +82,9 @@
 //     log.Warn().Msg("")
 //     // Output: {"level":"warn","severity":"warn"}
 //
+// # Caveats
 //
-// 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.
@@ -96,14 +97,30 @@
 //
 // 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"
+	"strings"
 )
 
 // Level defines log levels.
@@ -159,24 +176,24 @@ func (l Level) String() string {
 // 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 levelStr {
-	case LevelFieldMarshalFunc(TraceLevel):
+	switch {
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(TraceLevel)):
 		return TraceLevel, nil
-	case LevelFieldMarshalFunc(DebugLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(DebugLevel)):
 		return DebugLevel, nil
-	case LevelFieldMarshalFunc(InfoLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(InfoLevel)):
 		return InfoLevel, nil
-	case LevelFieldMarshalFunc(WarnLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(WarnLevel)):
 		return WarnLevel, nil
-	case LevelFieldMarshalFunc(ErrorLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(ErrorLevel)):
 		return ErrorLevel, nil
-	case LevelFieldMarshalFunc(FatalLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(FatalLevel)):
 		return FatalLevel, nil
-	case LevelFieldMarshalFunc(PanicLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(PanicLevel)):
 		return PanicLevel, nil
-	case LevelFieldMarshalFunc(Disabled):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(Disabled)):
 		return Disabled, nil
-	case LevelFieldMarshalFunc(NoLevel):
+	case strings.EqualFold(levelStr, LevelFieldMarshalFunc(NoLevel)):
 		return NoLevel, nil
 	}
 	i, err := strconv.Atoi(levelStr)
@@ -189,6 +206,21 @@ func ParseLevel(levelStr string) (Level, error) {
 	return Level(i), nil
 }
 
+// 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 guarantee on access
@@ -201,6 +233,7 @@ type Logger struct {
 	context []byte
 	hooks   []Hook
 	stack   bool
+	ctx     context.Context
 }
 
 // New creates a root logger with given output writer. If the output writer implements
@@ -212,11 +245,11 @@ type Logger struct {
 // 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, level: TraceLevel}
 }
@@ -258,7 +291,8 @@ func (l Logger) With() Context {
 
 // UpdateContext updates the internal logger's context.
 //
-// Use this method with caution. If unsure, prefer the With method.
+// 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 == disabledLogger {
 		return
@@ -291,8 +325,13 @@ func (l Logger) Sample(s Sampler) Logger {
 }
 
 // Hook returns a logger with the h Hook.
-func (l Logger) Hook(h Hook) Logger {
-	l.hooks = append(l.hooks, h)
+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
 }
 
@@ -348,7 +387,14 @@ func (l *Logger) Err(err error) *Event {
 //
 // You must call Msg on the returned event in order to send the event.
 func (l *Logger) Fatal() *Event {
-	return l.newEvent(FatalLevel, func(msg string) { os.Exit(1) })
+	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
+			// will be lost as os.Exit() terminates the program immediately.
+			closer.Close()
+		}
+		os.Exit(1)
+	})
 }
 
 // Panic starts a new message with panic level. The panic() function
@@ -361,7 +407,7 @@ func (l *Logger) Panic() *Event {
 
 // 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 gourotine when used with their respective levels.
+// 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 {
@@ -413,6 +459,14 @@ func (l *Logger) Printf(format string, v ...interface{}) {
 	}
 }
 
+// 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
 // for the standard library log.
 func (l Logger) Write(p []byte) (n int, err error) {
@@ -428,11 +482,15 @@ func (l Logger) Write(p []byte) (n int, err error) {
 func (l *Logger) newEvent(level Level, done func(string)) *Event {
 	enabled := l.should(level)
 	if !enabled {
+		if done != nil {
+			done("")
+		}
 		return nil
 	}
 	e := newEvent(l.w, level)
 	e.done = done
 	e.ch = l.hooks
+	e.ctx = l.ctx
 	if level != NoLevel && LevelFieldName != "" {
 		e.Str(LevelFieldName, LevelFieldMarshalFunc(level))
 	}
@@ -447,6 +505,9 @@ func (l *Logger) newEvent(level Level, done func(string)) *Event {
 
 // should returns true if the log event should be logged.
 func (l *Logger) should(lvl Level) bool {
+	if l.w == nil {
+		return false
+	}
 	if lvl < l.level || lvl < GlobalLevel() {
 		return false
 	}

log_example_test.go

@@ -72,7 +72,7 @@ func ExampleLogger_Hook() {
 	var levelNameHook LevelNameHook
 	var messageHook MessageHook = "The message"
 
-	log := zerolog.New(os.Stdout).Hook(levelNameHook).Hook(messageHook)
+	log := zerolog.New(os.Stdout).Hook(levelNameHook, messageHook)
 
 	log.Info().Msg("hello world")
 
@@ -95,6 +95,14 @@ func ExampleLogger_Printf() {
 	// 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)
 
@@ -311,7 +319,7 @@ func ExampleEvent_Interface() {
 }
 
 func ExampleEvent_Dur() {
-	d := time.Duration(10 * time.Second)
+	d := 10 * time.Second
 
 	log := zerolog.New(os.Stdout)
 
@@ -325,8 +333,8 @@ 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)
@@ -460,7 +468,7 @@ 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").
@@ -474,8 +482,8 @@ 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().
@@ -510,7 +518,7 @@ func ExampleContext_IPPrefix() {
 	// Output: {"Route":"192.168.0.0/24","message":"hello world"}
 }
 
-func ExampleContext_MacAddr() {
+func ExampleContext_MACAddr() {
 	mac := net.HardwareAddr{0x00, 0x14, 0x22, 0x01, 0x23, 0x45}
 	log := zerolog.New(os.Stdout).With().
 		MACAddr("hostMAC", mac).

log_test.go

@@ -2,6 +2,7 @@ package zerolog
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"net"
@@ -119,7 +120,8 @@ func TestWith(t *testing.T) {
 		Uint64("uint64", 10).
 		Float32("float32", 11.101).
 		Float64("float64", 12.30303).
-		Time("time", time.Time{})
+		Time("time", time.Time{}).
+		Ctx(context.Background())
 	_, file, line, _ := runtime.Caller(0)
 	caller := fmt.Sprintf("%s:%d", file, line+3)
 	log := ctx.Caller().Logger()
@@ -320,6 +322,7 @@ func TestFields(t *testing.T) {
 		Bytes("bytes", []byte("bar")).
 		Hex("hex", []byte{0x12, 0xef}).
 		RawJSON("json", []byte(`{"some":"json"}`)).
+		RawCBOR("cbor", []byte{0x83, 0x01, 0x82, 0x02, 0x03, 0x82, 0x04, 0x05}).
 		Func(func(e *Event) { e.Str("func", "func_output") }).
 		AnErr("some_err", nil).
 		Err(errors.New("some error")).
@@ -343,8 +346,9 @@ func TestFields(t *testing.T) {
 		Dur("dur", 1*time.Second).
 		Time("time", time.Time{}).
 		TimeDiff("diff", now, now.Add(-10*time.Second)).
+		Ctx(context.Background()).
 		Msg("")
-	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","string":"foo","stringer":"127.0.0.1","stringer_nil":null,"bytes":"bar","hex":"12ef","json":{"some":"json"},"func":"func_output","error":"some error","bool":true,"int":1,"int8":2,"int16":3,"int32":4,"int64":5,"uint":6,"uint8":7,"uint16":8,"uint32":9,"uint64":10,"IPv4":"192.168.0.100","IPv6":"2001:db8:85a3::8a2e:370:7334","Mac":"00:14:22:01:23:45","Prefix":"192.168.0.100/24","float32":11.1234,"float64":12.321321321,"dur":1000,"time":"0001-01-01T00:00:00Z","diff":10000}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","string":"foo","stringer":"127.0.0.1","stringer_nil":null,"bytes":"bar","hex":"12ef","json":{"some":"json"},"cbor":"data:application/cbor;base64,gwGCAgOCBAU=","func":"func_output","error":"some error","bool":true,"int":1,"int8":2,"int16":3,"int32":4,"int64":5,"uint":6,"uint8":7,"uint16":8,"uint32":9,"uint64":10,"IPv4":"192.168.0.100","IPv6":"2001:db8:85a3::8a2e:370:7334","Mac":"00:14:22:01:23:45","Prefix":"192.168.0.100/24","float32":11.1234,"float64":12.321321321,"dur":1000,"time":"0001-01-01T00:00:00Z","diff":10000}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -461,6 +465,7 @@ func TestFieldsDisabled(t *testing.T) {
 		Dur("dur", 1*time.Second).
 		Time("time", time.Time{}).
 		TimeDiff("diff", now, now.Add(-10*time.Second)).
+		Ctx(context.Background()).
 		Msg("")
 	if got, want := decodeIfBinaryToString(out.Bytes()), ""; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
@@ -782,7 +787,7 @@ func TestCallerMarshalFunc(t *testing.T) {
 
 	// test default behaviour this is really brittle due to the line numbers
 	// actually mattering for validation
-	_, file, line, _ := runtime.Caller(0)
+	pc, file, line, _ := runtime.Caller(0)
 	caller := fmt.Sprintf("%s:%d", file, line+2)
 	log.Log().Caller().Msg("msg")
 	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","message":"msg"}`+"\n"; got != want {
@@ -793,16 +798,16 @@ func TestCallerMarshalFunc(t *testing.T) {
 	// test custom behavior. In this case we'll take just the last directory
 	origCallerMarshalFunc := CallerMarshalFunc
 	defer func() { CallerMarshalFunc = origCallerMarshalFunc }()
-	CallerMarshalFunc = func(file string, line int) string {
+	CallerMarshalFunc = func(pc uintptr, file string, line int) string {
 		parts := strings.Split(file, "/")
 		if len(parts) > 1 {
 			return strings.Join(parts[len(parts)-2:], "/") + ":" + strconv.Itoa(line)
 		}
 
-		return file + ":" + strconv.Itoa(line)
+		return runtime.FuncForPC(pc).Name() + ":" + file + ":" + strconv.Itoa(line)
 	}
-	_, file, line, _ = runtime.Caller(0)
-	caller = CallerMarshalFunc(file, line+2)
+	pc, file, line, _ = runtime.Caller(0)
+	caller = CallerMarshalFunc(pc, file, line+2)
 	log.Log().Caller().Msg("msg")
 	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","message":"msg"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
@@ -907,6 +912,33 @@ func TestLevel_String(t *testing.T) {
 	}
 }
 
+func TestLevel_MarshalText(t *testing.T) {
+	tests := []struct {
+		name string
+		l    Level
+		want string
+	}{
+		{"trace", TraceLevel, "trace"},
+		{"debug", DebugLevel, "debug"},
+		{"info", InfoLevel, "info"},
+		{"warn", WarnLevel, "warn"},
+		{"error", ErrorLevel, "error"},
+		{"fatal", FatalLevel, "fatal"},
+		{"panic", PanicLevel, "panic"},
+		{"disabled", Disabled, "disabled"},
+		{"nolevel", NoLevel, ""},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got, err := tt.l.MarshalText(); err != nil {
+				t.Errorf("MarshalText couldn't marshal: %v", tt.l)
+			} else if string(got) != tt.want {
+				t.Errorf("String() = %v, want %v", string(got), tt.want)
+			}
+		})
+	}
+}
+
 func TestParseLevel(t *testing.T) {
 	type args struct {
 		levelStr string
@@ -943,3 +975,41 @@ func TestParseLevel(t *testing.T) {
 		})
 	}
 }
+
+func TestUnmarshalTextLevel(t *testing.T) {
+	type args struct {
+		levelStr string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    Level
+		wantErr bool
+	}{
+		{"trace", args{"trace"}, TraceLevel, false},
+		{"debug", args{"debug"}, DebugLevel, false},
+		{"info", args{"info"}, InfoLevel, false},
+		{"warn", args{"warn"}, WarnLevel, false},
+		{"error", args{"error"}, ErrorLevel, false},
+		{"fatal", args{"fatal"}, FatalLevel, false},
+		{"panic", args{"panic"}, PanicLevel, false},
+		{"disabled", args{"disabled"}, Disabled, false},
+		{"nolevel", args{""}, NoLevel, false},
+		{"-1", args{"-1"}, TraceLevel, false},
+		{"-2", args{"-2"}, Level(-2), false},
+		{"-3", args{"-3"}, Level(-3), false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var l Level
+			err := l.UnmarshalText([]byte(tt.args.levelStr))
+			if (err != nil) != tt.wantErr {
+				t.Errorf("UnmarshalText() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if l != tt.want {
+				t.Errorf("UnmarshalText() got = %v, want %v", l, tt.want)
+			}
+		})
+	}
+}

pkgerrors/stacktrace.go

@@ -42,15 +42,32 @@ func frameField(f errors.Frame, s *state, c rune) string {
 
 // MarshalStack implements pkg/errors stack trace marshaling.
 //
-//   zerolog.ErrorStackMarshaler = MarshalStack
+// zerolog.ErrorStackMarshaler = MarshalStack
 func MarshalStack(err error) interface{} {
 	type stackTracer interface {
 		StackTrace() errors.StackTrace
 	}
-	sterr, ok := err.(stackTracer)
-	if !ok {
+	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))

pkgerrors/stacktrace_test.go

@@ -4,6 +4,7 @@ package pkgerrors
 
 import (
 	"bytes"
+	"fmt"
 	"regexp"
 	"testing"
 
@@ -17,11 +18,27 @@ func TestLogStack(t *testing.T) {
 	out := &bytes.Buffer{}
 	log := zerolog.New(out)
 
-	err := errors.Wrap(errors.New("error message"), "from error")
+	err := fmt.Errorf("from error: %w", errors.New("error message"))
 	log.Log().Stack().Err(err).Msg("")
 
 	got := out.String()
-	want := `\{"stack":\[\{"func":"TestLogStack","line":"20","source":"stacktrace_test.go"\},.*\],"error":"from error: error message"\}\n`
+	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)
 	}
@@ -33,11 +50,27 @@ func TestLogStackFromContext(t *testing.T) {
 	out := &bytes.Buffer{}
 	log := zerolog.New(out).With().Stack().Logger() // calling Stack() on log context instead of event
 
-	err := errors.Wrap(errors.New("error message"), "from error")
+	err := fmt.Errorf("from error: %w", errors.New("error message"))
 	log.Log().Err(err).Msg("") // not explicitly calling Stack()
 
 	got := out.String()
-	want := `\{"stack":\[\{"func":"TestLogStackFromContext","line":"36","source":"stacktrace_test.go"\},.*\],"error":"from error: error message"\}\n`
+	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)
 	}

syslog.go

@@ -78,3 +78,12 @@ func (sw syslogWriter) WriteLevel(level Level, p []byte) (n int, err error) {
 	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

@@ -100,7 +100,7 @@ func TestSyslogWriter_WithCEE(t *testing.T) {
 	sw := testCEEwriter{&buf}
 	log := New(SyslogCEEWriter(sw))
 	log.Info().Str("key", "value").Msg("message string")
-	got := string(buf.Bytes())
+	got := buf.String()
 	want := "@cee:{"
 	if !strings.HasPrefix(got, want) {
 		t.Errorf("Bad CEE message start: want %v, got %v", want, got)

writer.go

@@ -17,14 +17,25 @@ 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
@@ -38,7 +49,7 @@ 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.
@@ -55,6 +66,15 @@ 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
 }
@@ -87,6 +107,20 @@ func (t multiLevelWriter) WriteLevel(l Level, p []byte) (n int, err error) {
 	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
 // provided writers, similar to the Unix tee(1) command. If some writers
 // implement LevelWriter, their WriteLevel method will be used instead of Write.
@@ -96,7 +130,7 @@ 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}
@@ -152,3 +186,161 @@ func ConsoleTestWriter(t TestingLog) 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
+}
+
+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

@@ -175,3 +175,78 @@ func TestTestWriter(t *testing.T) {
 	}
 
 }
+
+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)
+			}
+		})
+	}
+}