Update README with instruction about binary encoding

Adds support for binary logging (with cbor encoding) in addition to JSON. Use the binary_log compile tag to enable the feature.

.travis.yml

@@ -1,10 +1,13 @@
 language: go
 go:
-- 1.7
-- 1.8
-- tip
+- "1.7"
+- "1.8"
+- "1.9"
+- "1.10"
+- "master"
 matrix:
   allow_failures:
-      - go: tip
+      - go: "master"
 script:
-    go test -v -race -cpu=1,2,4 ./...
+  - go test -v -race -cpu=1,2,4 -bench . -benchmem ./...
+  - go test -v -tags binary_log -race -cpu=1,2,4 -bench . -benchmem ./...

README.md

@@ -4,54 +4,175 @@
 
 The zerolog package provides a fast and simple logger dedicated to JSON output.
 
-Zerolog's API is designed to provide both a great developer experience and stunning [performance](#performance). Its unique chaining API allows zerolog to write JSON log events by avoiding allocations and reflection.
+Zerolog's API is designed to provide both a great developer experience and stunning [performance](#benchmarks). Its unique chaining API allows zerolog to write JSON (or CBOR) log events by avoiding allocations and reflection.
 
-The uber's [zap](https://godoc.org/go.uber.org/zap) library pioneered this approach. Zerolog is taking this concept to the next level with simpler to use API and even better performance.
+Uber's [zap](https://godoc.org/go.uber.org/zap) library pioneered this approach. Zerolog is taking this concept to the next level with a simpler to use API and even better performance.
 
-To keep the code base and the API simple, zerolog focuses on JSON logging only. Pretty logging on the console is made possible using the provided `zerolog.ConsoleWriter`.
+To keep the code base and the API simple, zerolog focuses on efficient structured logging only. Pretty logging on the console is made possible using the provided (but inefficient) `zerolog.ConsoleWriter`.
 
 ![](pretty.png)
 
+## Who uses zerolog
+
+Find out [who uses zerolog](https://github.com/rs/zerolog/wiki/Who-uses-zerolog) and add your company / project to the list.
+
 ## Features
 
 * Blazing fast
 * Low to zero allocation
 * Level logging
 * Sampling
+* Hooks
 * Contextual fields
 * `context.Context` integration
 * `net/http` helpers
+* JSON and CBOR encoding formats
 * Pretty logging for development
 
-## Usage
+## Installation
 
 ```go
-import "github.com/rs/zerolog/log"
+go get -u github.com/rs/zerolog/log
 ```
+## Getting Started
 
-### A global logger can be use for simple logging
+### Simple Logging Example
+
+For simple logging, import the global logger package **github.com/rs/zerolog/log**
+```go
+package main
+
+import (
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+func main() {
+	// UNIX Time is faster and smaller than most timestamps
+	// If you set zerolog.TimeFieldFormat to an empty string,
+	// logs will write with UNIX time
+	zerolog.TimeFieldFormat = ""
+
+	log.Print("hello world")
+}
+
+// Output: {"time":1516134303,"level":"debug","message":"hello world"}
+```
+> Note: The default log level for `log.Print` is *debug*
+
+### Leveled Logging
+
+#### Simple Leveled Logging Example
 
 ```go
-log.Info().Msg("hello world")
+package main
 
-// Output: {"level":"info","time":1494567715,"message":"hello world"}
+import (
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+func main() {
+	zerolog.TimeFieldFormat = ""
+
+	log.Info().Msg("hello world")
+}
+
+// Output: {"time":1516134303,"level":"info","message":"hello world"}
 ```
 
-NOTE: To import the global logger, import the `log` subpackage `github.com/rs/zerolog/log`.
+**zerolog** allows for logging at the following levels (from highest to lowest):
+- panic (`zerolog.PanicLevel`, 5)
+- fatal (`zerolog.FatalLevel`, 4)
+- error (`zerolog.ErrorLevel`, 3)
+- warn (`zerolog.WarnLevel`, 2)
+- info (`zerolog.InfoLevel`, 1)
+- debug (`zerolog.DebugLevel`, 0)
+
+You can set the Global logging level to any of these options using the `SetGlobalLevel` function in the zerolog package, passing in one of the given constants above, e.g. `zerolog.InfoLevel` would be the "info" level.  Whichever level is chosen, all logs with a level greater than or equal to that level will be written. To turn off logging entirely, pass the `zerolog.Disabled` constant.
+
+#### Setting Global Log Level
+
+This example uses command-line flags to demonstrate various outputs depending on the chosen log level.
 
 ```go
-log.Fatal().
-    Err(err).
-    Str("service", service).
-    Msgf("Cannot start %s", service)
+package main
 
-// Output: {"level":"fatal","time":1494567715,"message":"Cannot start myservice","error":"some error","service":"myservice"}
-// Exit 1
+import (
+	"flag"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+func main() {
+	zerolog.TimeFieldFormat = ""
+	debug := flag.Bool("debug", false, "sets log level to debug")
+
+	flag.Parse()
+
+	// Default level for this example is info, unless debug flag is present
+	zerolog.SetGlobalLevel(zerolog.InfoLevel)
+	if *debug {
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+	}
+
+	log.Debug().Msg("This message appears only when log level set to Debug")
+	log.Info().Msg("This message appears when log level set to Debug or Info")
+
+	if e := log.Debug(); e.Enabled() {
+		// Compute log output only if enabled.
+		value := "bar"
+		e.Str("foo", value).Msg("some debug message")
+	}
+}
+```
+Info Output (no flag)
+```bash
+$ ./logLevelExample
+{"time":1516387492,"level":"info","message":"This message appears when log level set to Debug or Info"}
 ```
 
-NOTE: Using `Msgf` generates one allocation even when the logger is disabled.
+Debug Output (debug flag set)
+```bash
+$ ./logLevelExample -debug
+{"time":1516387573,"level":"debug","message":"This message appears only when log level set to Debug"}
+{"time":1516387573,"level":"info","message":"This message appears when log level set to Debug or Info"}
+{"time":1516387573,"level":"debug","foo":"bar","message":"some debug message"}
+```
 
-### Fields can be added to log messages
+#### Logging Fatal Messages
+
+```go
+package main
+
+import (
+	"errors"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+func main() {
+	err := errors.New("A repo man spends his life getting into tense situations")
+	service := "myservice"
+
+	zerolog.TimeFieldFormat = ""
+
+	log.Fatal().
+		Err(err).
+		Str("service", service).
+		Msgf("Cannot start %s", service)
+}
+
+// Output: {"time":1516133263,"level":"fatal","error":"A repo man spends his life getting into tense situations","service":"myservice","message":"Cannot start myservice"}
+//         exit status 1
+```
+> NOTE: Using `Msgf` generates one allocation even when the logger is disabled.
+
+### Contextual Logging
+
+#### Fields can be added to log messages
 
 ```go
 log.Info().
@@ -83,23 +204,6 @@ sublogger.Info().Msg("hello world")
 // Output: {"level":"info","time":1494567715,"message":"hello world","component":"foo"}
 ```
 
-### Level logging
-
-```go
-zerolog.SetGlobalLevel(zerolog.InfoLevel)
-
-log.Debug().Msg("filtered out message")
-log.Info().Msg("routed message")
-
-if e := log.Debug(); e.Enabled() {
-    // Compute log output only if enabled.
-    value := compute()
-    e.Str("foo": value).Msg("some debug message")
-}
-
-// Output: {"level":"info","time":1494567715,"message":"routed message"}
-```
-
 ### Pretty logging
 
 ```go
@@ -151,13 +255,63 @@ log.Log().Str("foo","bar").Msg("")
 log.Logger = log.With().Str("foo", "bar").Logger()
 ```
 
+### 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:
+
+```go
+d := diodes.NewManyToOne(1000, diodes.AlertFunc(func(missed int) {
+    fmt.Printf("Dropped %d messages\n", missed)
+}))
+w := diode.NewWriter(os.Stdout, d, 10*time.Millisecond)
+log := zerolog.New(w)
+log.Print("test")
+```
+
+You will need to install `code.cloudfoundry.org/go-diodes` to use this feature.
+
 ### Log Sampling
 
 ```go
-sampled := log.Sample(10)
+sampled := log.Sample(&zerolog.BasicSampler{N: 10})
 sampled.Info().Msg("will be logged every 10 messages")
 
-// Output: {"time":1494567715,"sample":10,"message":"will be logged every 10 messages"}
+// Output: {"time":1494567715,"level":"info","message":"will be logged every 10 messages"}
+```
+
+More advanced sampling:
+
+```go
+// Will let 5 debug messages per period of 1 second.
+// Over 5 debug message, 1 every 100 debug messages are logged.
+// Other levels are not sampled.
+sampled := log.Sample(zerolog.LevelSampler{
+    DebugSampler: &zerolog.BurstSampler{
+        Burst: 5,
+        Period: 1*time.Second,
+        NextSampler: &zerolog.BasicSampler{N: 100},
+    },
+})
+sampled.Debug().Msg("hello world")
+
+// Output: {"time":1494567715,"level":"debug","message":"hello world"}
+```
+
+### Hooks
+
+```go
+type SeverityHook struct{}
+
+func (h SeverityHook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
+    if level != zerolog.NoLevel {
+        e.Str("severity", level.String())
+    }
+}
+
+hooked := log.Hook(SeverityHook{})
+hooked.Warn().Msg("")
+
+// Output: {"level":"warn","severity":"warn"}
 ```
 
 ### Pass a sub-logger by context
@@ -249,7 +403,6 @@ Some settings can be changed and will by applied to all loggers:
 * `zerolog.LevelFieldName`: Can be set to customize level field name.
 * `zerolog.MessageFieldName`: Can be set to customize message field name.
 * `zerolog.ErrorFieldName`: Can be set to customize `Err` field name.
-* `zerolog.SampleFieldName`: Can be set to customize the field name added when sampling is enabled.
 * `zerolog.TimeFieldFormat`: Can be set to customize `Time` field value formatting. If set with an empty string, times are formated as UNIX timestamp.
 	// DurationFieldUnit defines the unit for time.Duration type fields added
 	// using the Dur method.
@@ -275,7 +428,15 @@ Some settings can be changed and will by applied to all loggers:
 * `Dict`: Adds a sub-key/value as a field of the event.
 * `Interface`: Uses reflection to marshal the type.
 
-## Performance
+## Binary Encoding
+
+In addition to the default JSON encoding, `zerolog` can produce binary logs using the [cbor](http://cbor.io) encoding. The choice of encoding can be decided at compile time using the build tag `binary_log` as follow:
+
+```
+go build -tags binary_log .
+```
+
+## Benchmarks
 
 All operations are allocation free (those numbers *include* JSON encoding):
 
@@ -287,7 +448,12 @@ BenchmarkContextFields-8   30000000	    44.9 ns/op	   0 B/op       0 allocs/op
 BenchmarkLogFields-8       10000000	   184 ns/op	   0 B/op       0 allocs/op
 ```
 
-Using Uber's zap [comparison benchmark](https://github.com/uber-go/zap#performance):
+There are a few Go logging benchmarks and comparisons that include zerolog.
+
+- [imkira/go-loggers-bench](https://github.com/imkira/go-loggers-bench)
+- [uber-common/zap](https://github.com/uber-go/zap#performance)
+
+Using Uber's zap comparison benchmark:
 
 Log a message and 10 fields:
 
@@ -329,3 +495,16 @@ Log a static string, without any context or `printf`-style templating:
 | apex/log | 2751 ns/op | 584 B/op | 11 allocs/op |
 | log15 | 5181 ns/op | 1592 B/op | 26 allocs/op |
 
+## Caveats
+
+Note that zerolog does de-duplication fields. Using the same key multiple times creates multiple keys in final JSON:
+
+```go
+logger := zerolog.New(os.Stderr).With().Timestamp().Logger()
+logger.Info().
+       Timestamp().
+       Msg("dup")
+// Output: {"level":"info","time":1494567715,"time":1494567715,"message":"dup"}
+```
+
+However, it’s not a big deal as JSON accepts dup keys; the last one prevails.

array.go

@@ -3,8 +3,6 @@ package zerolog
 import (
 	"sync"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 var arrayPool = &sync.Pool{
@@ -15,6 +13,8 @@ var arrayPool = &sync.Pool{
 	},
 }
 
+// Array is used to prepopulate an array of items
+// which can be re-used to add to log messages.
 type Array struct {
 	buf []byte
 }
@@ -26,16 +26,17 @@ func Arr() *Array {
 	return a
 }
 
+// MarshalZerologArray method here is no-op - since data is
+// already in the needed format.
 func (*Array) MarshalZerologArray(*Array) {
 }
 
 func (a *Array) write(dst []byte) []byte {
-	if len(a.buf) == 0 {
-		dst = append(dst, `[]`...)
-	} else {
-		a.buf[0] = '['
-		dst = append(append(dst, a.buf...), ']')
+	dst = appendArrayStart(dst)
+	if len(a.buf) > 0 {
+		dst = append(append(dst, a.buf...))
 	}
+	dst = appendArrayEnd(dst)
 	arrayPool.Put(a)
 	return dst
 }
@@ -43,119 +44,125 @@ func (a *Array) write(dst []byte) []byte {
 // Object marshals an object that implement the LogObjectMarshaler
 // interface and append it to the array.
 func (a *Array) Object(obj LogObjectMarshaler) *Array {
-	a.buf = append(a.buf, ',')
 	e := Dict()
 	obj.MarshalZerologObject(e)
-	e.buf = append(e.buf, '}')
-	a.buf = append(a.buf, e.buf...)
+	e.buf = appendEndMarker(e.buf)
+	a.buf = append(appendArrayDelim(a.buf), e.buf...)
+	eventPool.Put(e)
 	return a
 }
 
 // Str append the val as a string to the array.
 func (a *Array) Str(val string) *Array {
-	a.buf = json.AppendString(append(a.buf, ','), val)
+	a.buf = appendString(appendArrayDelim(a.buf), val)
 	return a
 }
 
 // Bytes append the val as a string to the array.
 func (a *Array) Bytes(val []byte) *Array {
-	a.buf = json.AppendBytes(append(a.buf, ','), val)
+	a.buf = appendBytes(appendArrayDelim(a.buf), val)
+	return a
+}
+
+// Hex append the val as a hex string to the array.
+func (a *Array) Hex(val []byte) *Array {
+	a.buf = appendHex(appendArrayDelim(a.buf), val)
 	return a
 }
 
 // Err append the err as a string to the array.
 func (a *Array) Err(err error) *Array {
-	a.buf = json.AppendError(append(a.buf, ','), err)
+	a.buf = appendError(appendArrayDelim(a.buf), err)
 	return a
 }
 
 // Bool append the val as a bool to the array.
 func (a *Array) Bool(b bool) *Array {
-	a.buf = json.AppendBool(append(a.buf, ','), b)
+	a.buf = appendBool(appendArrayDelim(a.buf), b)
 	return a
 }
 
 // Int append i as a int to the array.
 func (a *Array) Int(i int) *Array {
-	a.buf = json.AppendInt(append(a.buf, ','), i)
+	a.buf = appendInt(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Int8 append i as a int8 to the array.
 func (a *Array) Int8(i int8) *Array {
-	a.buf = json.AppendInt8(append(a.buf, ','), i)
+	a.buf = appendInt8(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Int16 append i as a int16 to the array.
 func (a *Array) Int16(i int16) *Array {
-	a.buf = json.AppendInt16(append(a.buf, ','), i)
+	a.buf = appendInt16(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Int32 append i as a int32 to the array.
 func (a *Array) Int32(i int32) *Array {
-	a.buf = json.AppendInt32(append(a.buf, ','), i)
+	a.buf = appendInt32(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Int64 append i as a int64 to the array.
 func (a *Array) Int64(i int64) *Array {
-	a.buf = json.AppendInt64(append(a.buf, ','), i)
+	a.buf = appendInt64(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Uint append i as a uint to the array.
 func (a *Array) Uint(i uint) *Array {
-	a.buf = json.AppendUint(append(a.buf, ','), i)
+	a.buf = appendUint(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Uint8 append i as a uint8 to the array.
 func (a *Array) Uint8(i uint8) *Array {
-	a.buf = json.AppendUint8(append(a.buf, ','), i)
+	a.buf = appendUint8(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Uint16 append i as a uint16 to the array.
 func (a *Array) Uint16(i uint16) *Array {
-	a.buf = json.AppendUint16(append(a.buf, ','), i)
+	a.buf = appendUint16(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Uint32 append i as a uint32 to the array.
 func (a *Array) Uint32(i uint32) *Array {
-	a.buf = json.AppendUint32(append(a.buf, ','), i)
+	a.buf = appendUint32(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Uint64 append i as a uint64 to the array.
 func (a *Array) Uint64(i uint64) *Array {
-	a.buf = json.AppendUint64(append(a.buf, ','), i)
+	a.buf = appendUint64(appendArrayDelim(a.buf), i)
 	return a
 }
 
 // Float32 append f as a float32 to the array.
 func (a *Array) Float32(f float32) *Array {
-	a.buf = json.AppendFloat32(append(a.buf, ','), f)
+	a.buf = appendFloat32(appendArrayDelim(a.buf), f)
 	return a
 }
 
 // Float64 append f as a float64 to the array.
 func (a *Array) Float64(f float64) *Array {
-	a.buf = json.AppendFloat64(append(a.buf, ','), f)
+	a.buf = appendFloat64(appendArrayDelim(a.buf), f)
 	return a
 }
 
 // Time append t formated as string using zerolog.TimeFieldFormat.
 func (a *Array) Time(t time.Time) *Array {
-	a.buf = json.AppendTime(append(a.buf, ','), t, TimeFieldFormat)
+	a.buf = appendTime(appendArrayDelim(a.buf), t, TimeFieldFormat)
 	return a
 }
 
 // Dur append d to the array.
 func (a *Array) Dur(d time.Duration) *Array {
-	a.buf = json.AppendDuration(append(a.buf, ','), d, DurationFieldUnit, DurationFieldInteger)
+	a.buf = appendDuration(appendArrayDelim(a.buf), d, DurationFieldUnit, DurationFieldInteger)
 	return a
 }
 
@@ -164,6 +171,6 @@ func (a *Array) Interface(i interface{}) *Array {
 	if obj, ok := i.(LogObjectMarshaler); ok {
 		return a.Object(obj)
 	}
-	a.buf = json.AppendInterface(append(a.buf, ','), i)
+	a.buf = appendInterface(appendArrayDelim(a.buf), i)
 	return a
 }

array_test.go

@@ -21,10 +21,12 @@ func TestArray(t *testing.T) {
 		Float32(11).
 		Float64(12).
 		Str("a").
+		Bytes([]byte("b")).
+		Hex([]byte{0x1f}).
 		Time(time.Time{}).
 		Dur(0)
-	want := `[true,1,2,3,4,5,6,7,8,9,10,11,12,"a","0001-01-01T00:00:00Z",0]`
-	if got := string(a.write([]byte{})); got != want {
+	want := `[true,1,2,3,4,5,6,7,8,9,10,11,12,"a","b","1f","0001-01-01T00:00:00Z",0]`
+	if got := decodeObjectToStr(a.write([]byte{})); got != want {
 		t.Errorf("Array.write()\ngot:  %s\nwant: %s", got, want)
 	}
 }

benchmark_test.go

@@ -57,6 +57,18 @@ func BenchmarkContextFields(b *testing.B) {
 	})
 }
 
+func BenchmarkContextAppend(b *testing.B) {
+	logger := New(ioutil.Discard).With().
+		Str("foo", "bar").
+		Logger()
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			logger.With().Str("bar", "baz")
+		}
+	})
+}
+
 func BenchmarkLogFields(b *testing.B) {
 	logger := New(ioutil.Discard)
 	b.ResetTimer()
@@ -84,6 +96,22 @@ func (o obj) MarshalZerologObject(e *Event) {
 		Int("priv", o.priv)
 }
 
+func BenchmarkLogArrayObject(b *testing.B) {
+	obj1 := obj{"a", "b", 2}
+	obj2 := obj{"c", "d", 3}
+	obj3 := obj{"e", "f", 4}
+	logger := New(ioutil.Discard)
+	b.ResetTimer()
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		arr := Arr()
+		arr.Object(&obj1)
+		arr.Object(&obj2)
+		arr.Object(&obj3)
+		logger.Info().Array("objects", arr).Msg("test")
+	}
+}
+
 func BenchmarkLogFieldType(b *testing.B) {
 	bools := []bool{true, false, true, false, true, false, true, false, true, false}
 	ints := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
@@ -203,3 +231,130 @@ func BenchmarkLogFieldType(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkContextFieldType(b *testing.B) {
+	oldFormat := TimeFieldFormat
+	TimeFieldFormat = ""
+	defer func() { TimeFieldFormat = oldFormat }()
+	bools := []bool{true, false, true, false, true, false, true, false, true, false}
+	ints := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	floats := []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	strings := []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j"}
+	durations := []time.Duration{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	times := []time.Time{
+		time.Unix(0, 0),
+		time.Unix(1, 0),
+		time.Unix(2, 0),
+		time.Unix(3, 0),
+		time.Unix(4, 0),
+		time.Unix(5, 0),
+		time.Unix(6, 0),
+		time.Unix(7, 0),
+		time.Unix(8, 0),
+		time.Unix(9, 0),
+	}
+	interfaces := []struct {
+		Pub  string
+		Tag  string `json:"tag"`
+		priv int
+	}{
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+		{"a", "a", 0},
+	}
+	objects := []obj{
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+		obj{"a", "a", 0},
+	}
+	errs := []error{errors.New("a"), errors.New("b"), errors.New("c"), errors.New("d"), errors.New("e")}
+	types := map[string]func(c Context) Context{
+		"Bool": func(c Context) Context {
+			return c.Bool("k", bools[0])
+		},
+		"Bools": func(c Context) Context {
+			return c.Bools("k", bools)
+		},
+		"Int": func(c Context) Context {
+			return c.Int("k", ints[0])
+		},
+		"Ints": func(c Context) Context {
+			return c.Ints("k", ints)
+		},
+		"Float": func(c Context) Context {
+			return c.Float64("k", floats[0])
+		},
+		"Floats": func(c Context) Context {
+			return c.Floats64("k", floats)
+		},
+		"Str": func(c Context) Context {
+			return c.Str("k", strings[0])
+		},
+		"Strs": func(c Context) Context {
+			return c.Strs("k", strings)
+		},
+		"Err": func(c Context) Context {
+			return c.Err(errs[0])
+		},
+		"Errs": func(c Context) Context {
+			return c.Errs("k", errs)
+		},
+		"Time": func(c Context) Context {
+			return c.Time("k", times[0])
+		},
+		"Times": func(c Context) Context {
+			return c.Times("k", times)
+		},
+		"Dur": func(c Context) Context {
+			return c.Dur("k", durations[0])
+		},
+		"Durs": func(c Context) Context {
+			return c.Durs("k", durations)
+		},
+		"Interface": func(c Context) Context {
+			return c.Interface("k", interfaces[0])
+		},
+		"Interfaces": func(c Context) Context {
+			return c.Interface("k", interfaces)
+		},
+		"Interface(Object)": func(c Context) Context {
+			return c.Interface("k", objects[0])
+		},
+		"Interface(Objects)": func(c Context) Context {
+			return c.Interface("k", objects)
+		},
+		"Object": func(c Context) Context {
+			return c.Object("k", objects[0])
+		},
+		"Timestamp": func(c Context) Context {
+			return c.Timestamp()
+		},
+	}
+	logger := New(ioutil.Discard)
+	b.ResetTimer()
+	for name := range types {
+		f := types[name]
+		b.Run(name, func(b *testing.B) {
+			b.RunParallel(func(pb *testing.PB) {
+				for pb.Next() {
+					l := f(logger.With()).Logger()
+					l.Info().Msg("")
+				}
+			})
+		})
+	}
+}

binary_test.go

@@ -0,0 +1,453 @@
+// +build binary_log
+
+package zerolog
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	//	"io/ioutil"
+	stdlog "log"
+	"time"
+)
+
+func ExampleBinaryNew() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Info().Msg("hello world")
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","message":"hello world"}
+}
+
+func ExampleLogger_With() {
+	dst := bytes.Buffer{}
+	log := New(&dst).
+		With().
+		Str("foo", "bar").
+		Logger()
+
+	log.Info().Msg("hello world")
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+
+	// Output: {"level":"info","foo":"bar","message":"hello world"}
+}
+
+func ExampleLogger_Level() {
+	dst := bytes.Buffer{}
+	log := New(&dst).Level(WarnLevel)
+
+	log.Info().Msg("filtered out message")
+	log.Error().Msg("kept message")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"error","message":"kept message"}
+}
+
+func ExampleLogger_Sample() {
+	dst := bytes.Buffer{}
+	log := New(&dst).Sample(&BasicSampler{N: 2})
+
+	log.Info().Msg("message 1")
+	log.Info().Msg("message 2")
+	log.Info().Msg("message 3")
+	log.Info().Msg("message 4")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","message":"message 2"}
+	// {"level":"info","message":"message 4"}
+}
+
+type LevelNameHook1 struct{}
+
+func (h LevelNameHook1) Run(e *Event, l Level, msg string) {
+	if l != NoLevel {
+		e.Str("level_name", l.String())
+	} else {
+		e.Str("level_name", "NoLevel")
+	}
+}
+
+type MessageHook string
+
+func (h MessageHook) Run(e *Event, l Level, msg string) {
+	e.Str("the_message", msg)
+}
+
+func ExampleLogger_Hook() {
+	var levelNameHook LevelNameHook1
+	var messageHook MessageHook = "The message"
+
+	dst := bytes.Buffer{}
+	log := New(&dst).Hook(levelNameHook).Hook(messageHook)
+
+	log.Info().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","level_name":"info","the_message":"hello world","message":"hello world"}
+}
+
+func ExampleLogger_Print() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Print("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Printf() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Printf("hello %s", "world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Debug() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Debug().
+		Str("foo", "bar").
+		Int("n", 123).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"debug","foo":"bar","n":123,"message":"hello world"}
+}
+
+func ExampleLogger_Info() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Info().
+		Str("foo", "bar").
+		Int("n", 123).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","foo":"bar","n":123,"message":"hello world"}
+}
+
+func ExampleLogger_Warn() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Warn().
+		Str("foo", "bar").
+		Msg("a warning message")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"warn","foo":"bar","message":"a warning message"}
+}
+
+func ExampleLogger_Error() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Error().
+		Err(errors.New("some error")).
+		Msg("error doing something")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"error","error":"some error","message":"error doing something"}
+}
+
+func ExampleLogger_WithLevel() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.WithLevel(InfoLevel).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"level":"info","message":"hello world"}
+}
+
+func ExampleLogger_Write() {
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Logger()
+
+	stdlog.SetFlags(0)
+	stdlog.SetOutput(log)
+
+	stdlog.Print("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","message":"hello world"}
+}
+
+func ExampleLogger_Log() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Str("bar", "baz").
+		Msg("")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","bar":"baz"}
+}
+
+func ExampleEvent_Dict() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Dict("dict", Dict().
+			Str("bar", "baz").
+			Int("n", 1),
+		).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
+}
+
+type User struct {
+	Name    string
+	Age     int
+	Created time.Time
+}
+
+func (u User) MarshalZerologObject(e *Event) {
+	e.Str("name", u.Name).
+		Int("age", u.Age).
+		Time("created", u.Created)
+}
+
+type Users []User
+
+func (uu Users) MarshalZerologArray(a *Array) {
+	for _, u := range uu {
+		a.Object(u)
+	}
+}
+
+func ExampleEvent_Array() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Array("array", Arr().
+			Str("baz").
+			Int(1),
+		).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","array":["baz",1],"message":"hello world"}
+}
+
+func ExampleEvent_Array_object() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	// Users implements LogArrayMarshaler
+	u := Users{
+		User{"John", 35, time.Time{}},
+		User{"Bob", 55, time.Time{}},
+	}
+
+	log.Log().
+		Str("foo", "bar").
+		Array("users", u).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bob","age":55,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleEvent_Object() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	// User implements LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+
+	log.Log().
+		Str("foo", "bar").
+		Object("user", u).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","user":{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},"message":"hello world"}
+}
+
+func ExampleEvent_Interface() {
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	obj := struct {
+		Name string `json:"name"`
+	}{
+		Name: "john",
+	}
+
+	log.Log().
+		Str("foo", "bar").
+		Interface("obj", obj).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","obj":{"name":"john"},"message":"hello world"}
+}
+
+func ExampleEvent_Dur() {
+	d := time.Duration(10 * time.Second)
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Dur("dur", d).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dur":10000,"message":"hello world"}
+}
+
+func ExampleEvent_Durs() {
+	d := []time.Duration{
+		time.Duration(10 * time.Second),
+		time.Duration(20 * time.Second),
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst)
+
+	log.Log().
+		Str("foo", "bar").
+		Durs("durs", d).
+		Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","durs":[10000,20000],"message":"hello world"}
+}
+
+func ExampleContext_Dict() {
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Dict("dict", Dict().
+			Str("bar", "baz").
+			Int("n", 1),
+		).Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dict":{"bar":"baz","n":1},"message":"hello world"}
+}
+
+func ExampleContext_Array() {
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Array("array", Arr().
+			Str("baz").
+			Int(1),
+		).Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","array":["baz",1],"message":"hello world"}
+}
+
+func ExampleContext_Array_object() {
+	// Users implements LogArrayMarshaler
+	u := Users{
+		User{"John", 35, time.Time{}},
+		User{"Bob", 55, time.Time{}},
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Array("users", u).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","users":[{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},{"name":"Bob","age":55,"created":"0001-01-01T00:00:00Z"}],"message":"hello world"}
+}
+
+func ExampleContext_Object() {
+	// User implements LogObjectMarshaler
+	u := User{"John", 35, time.Time{}}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Object("user", u).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","user":{"name":"John","age":35,"created":"0001-01-01T00:00:00Z"},"message":"hello world"}
+}
+
+func ExampleContext_Interface() {
+	obj := struct {
+		Name string `json:"name"`
+	}{
+		Name: "john",
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Interface("obj", obj).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","obj":{"name":"john"},"message":"hello world"}
+}
+
+func ExampleContext_Dur() {
+	d := time.Duration(10 * time.Second)
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Dur("dur", d).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","dur":10000,"message":"hello world"}
+}
+
+func ExampleContext_Durs() {
+	d := []time.Duration{
+		time.Duration(10 * time.Second),
+		time.Duration(20 * time.Second),
+	}
+
+	dst := bytes.Buffer{}
+	log := New(&dst).With().
+		Str("foo", "bar").
+		Durs("durs", d).
+		Logger()
+
+	log.Log().Msg("hello world")
+
+	fmt.Println(decodeIfBinaryToString(dst.Bytes()))
+	// Output: {"foo":"bar","durs":[10000,20000],"message":"hello world"}
+}

console.go

@@ -39,6 +39,7 @@ type ConsoleWriter struct {
 
 func (w ConsoleWriter) Write(p []byte) (n int, err error) {
 	var event map[string]interface{}
+	p = decodeIfBinaryToBytes(p)
 	err = json.Unmarshal(p, &event)
 	if err != nil {
 		return
@@ -75,8 +76,15 @@ func (w ConsoleWriter) Write(p []byte) (n int, err error) {
 			} else {
 				buf.WriteString(value)
 			}
-		default:
+		case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64:
 			fmt.Fprint(buf, value)
+		default:
+			b, err := json.Marshal(value)
+			if err != nil {
+				fmt.Fprintf(buf, "[error: %v]", err)
+			} else {
+				fmt.Fprint(buf, string(b))
+			}
 		}
 	}
 	buf.WriteByte('\n')

console_test.go

@@ -0,0 +1,14 @@
+package zerolog_test
+
+import (
+	"os"
+
+	"github.com/rs/zerolog"
+)
+
+func ExampleConsoleWriter_Write() {
+	log := zerolog.New(zerolog.ConsoleWriter{Out: os.Stdout, NoColor: true})
+
+	log.Info().Msg("hello world")
+	// Output: <nil> |INFO| hello world
+}

context.go

@@ -3,8 +3,6 @@ package zerolog
 import (
 	"io/ioutil"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 // Context configures a new sub-logger with contextual fields.
@@ -25,8 +23,8 @@ func (c Context) Fields(fields map[string]interface{}) Context {
 
 // Dict adds the field key with the dict to the logger context.
 func (c Context) Dict(key string, dict *Event) Context {
-	dict.buf = append(dict.buf, '}')
-	c.l.context = append(json.AppendKey(c.l.context, key), dict.buf...)
+	dict.buf = appendEndMarker(dict.buf)
+	c.l.context = append(appendKey(c.l.context, key), dict.buf...)
 	eventPool.Put(dict)
 	return c
 }
@@ -35,7 +33,7 @@ func (c Context) Dict(key string, dict *Event) Context {
 // Use zerolog.Arr() to create the array or pass a type that
 // implement the LogArrayMarshaler interface.
 func (c Context) Array(key string, arr LogArrayMarshaler) Context {
-	c.l.context = json.AppendKey(c.l.context, key)
+	c.l.context = appendKey(c.l.context, key)
 	if arr, ok := arr.(*Array); ok {
 		c.l.context = arr.write(c.l.context)
 		return c
@@ -55,41 +53,55 @@ func (c Context) Array(key string, arr LogArrayMarshaler) Context {
 func (c Context) Object(key string, obj LogObjectMarshaler) Context {
 	e := newEvent(levelWriterAdapter{ioutil.Discard}, 0, true)
 	e.Object(key, obj)
-	e.buf[0] = ',' // A new event starts as an object, we want to embed it.
-	c.l.context = append(c.l.context, e.buf...)
+	c.l.context = appendObjectData(c.l.context, e.buf)
 	eventPool.Put(e)
 	return c
 }
 
 // Str adds the field key with val as a string to the logger context.
 func (c Context) Str(key, val string) Context {
-	c.l.context = json.AppendString(json.AppendKey(c.l.context, key), val)
+	c.l.context = appendString(appendKey(c.l.context, key), val)
 	return c
 }
 
 // Strs adds the field key with val as a string to the logger context.
 func (c Context) Strs(key string, vals []string) Context {
-	c.l.context = json.AppendStrings(json.AppendKey(c.l.context, key), vals)
+	c.l.context = appendStrings(appendKey(c.l.context, key), vals)
 	return c
 }
 
 // Bytes adds the field key with val as a []byte to the logger context.
 func (c Context) Bytes(key string, val []byte) Context {
-	c.l.context = json.AppendBytes(json.AppendKey(c.l.context, key), val)
+	c.l.context = appendBytes(appendKey(c.l.context, key), val)
+	return c
+}
+
+// Hex adds the field key with val as a hex string to the logger context.
+func (c Context) Hex(key string, val []byte) Context {
+	c.l.context = appendHex(appendKey(c.l.context, key), val)
+	return c
+}
+
+// RawJSON adds already encoded JSON to context.
+//
+// No sanity check is performed on b; it must not contain carriage returns and
+// be valid JSON.
+func (c Context) RawJSON(key string, b []byte) Context {
+	c.l.context = appendJSON(appendKey(c.l.context, key), b)
 	return c
 }
 
 // AnErr adds the field key with err as a string to the logger context.
 func (c Context) AnErr(key string, err error) Context {
 	if err != nil {
-		c.l.context = json.AppendError(json.AppendKey(c.l.context, key), err)
+		c.l.context = appendError(appendKey(c.l.context, key), err)
 	}
 	return c
 }
 
 // Errs adds the field key with errs as an array of strings to the logger context.
 func (c Context) Errs(key string, errs []error) Context {
-	c.l.context = json.AppendErrors(json.AppendKey(c.l.context, key), errs)
+	c.l.context = appendErrors(appendKey(c.l.context, key), errs)
 	return c
 }
 
@@ -97,204 +109,224 @@ func (c Context) Errs(key string, errs []error) Context {
 // To customize the key name, change zerolog.ErrorFieldName.
 func (c Context) Err(err error) Context {
 	if err != nil {
-		c.l.context = json.AppendError(json.AppendKey(c.l.context, ErrorFieldName), err)
+		c.l.context = appendError(appendKey(c.l.context, ErrorFieldName), err)
 	}
 	return c
 }
 
 // Bool adds the field key with val as a bool to the logger context.
 func (c Context) Bool(key string, b bool) Context {
-	c.l.context = json.AppendBool(json.AppendKey(c.l.context, key), b)
+	c.l.context = appendBool(appendKey(c.l.context, key), b)
 	return c
 }
 
 // Bools adds the field key with val as a []bool to the logger context.
 func (c Context) Bools(key string, b []bool) Context {
-	c.l.context = json.AppendBools(json.AppendKey(c.l.context, key), b)
+	c.l.context = appendBools(appendKey(c.l.context, key), b)
 	return c
 }
 
 // Int adds the field key with i as a int to the logger context.
 func (c Context) Int(key string, i int) Context {
-	c.l.context = json.AppendInt(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInt(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints adds the field key with i as a []int to the logger context.
 func (c Context) Ints(key string, i []int) Context {
-	c.l.context = json.AppendInts(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInts(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Int8 adds the field key with i as a int8 to the logger context.
 func (c Context) Int8(key string, i int8) Context {
-	c.l.context = json.AppendInt8(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInt8(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints8 adds the field key with i as a []int8 to the logger context.
 func (c Context) Ints8(key string, i []int8) Context {
-	c.l.context = json.AppendInts8(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInts8(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Int16 adds the field key with i as a int16 to the logger context.
 func (c Context) Int16(key string, i int16) Context {
-	c.l.context = json.AppendInt16(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInt16(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints16 adds the field key with i as a []int16 to the logger context.
 func (c Context) Ints16(key string, i []int16) Context {
-	c.l.context = json.AppendInts16(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInts16(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Int32 adds the field key with i as a int32 to the logger context.
 func (c Context) Int32(key string, i int32) Context {
-	c.l.context = json.AppendInt32(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInt32(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints32 adds the field key with i as a []int32 to the logger context.
 func (c Context) Ints32(key string, i []int32) Context {
-	c.l.context = json.AppendInts32(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInts32(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Int64 adds the field key with i as a int64 to the logger context.
 func (c Context) Int64(key string, i int64) Context {
-	c.l.context = json.AppendInt64(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInt64(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Ints64 adds the field key with i as a []int64 to the logger context.
 func (c Context) Ints64(key string, i []int64) Context {
-	c.l.context = json.AppendInts64(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInts64(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint adds the field key with i as a uint to the logger context.
 func (c Context) Uint(key string, i uint) Context {
-	c.l.context = json.AppendUint(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUint(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints adds the field key with i as a []uint to the logger context.
 func (c Context) Uints(key string, i []uint) Context {
-	c.l.context = json.AppendUints(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUints(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint8 adds the field key with i as a uint8 to the logger context.
 func (c Context) Uint8(key string, i uint8) Context {
-	c.l.context = json.AppendUint8(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUint8(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints8 adds the field key with i as a []uint8 to the logger context.
 func (c Context) Uints8(key string, i []uint8) Context {
-	c.l.context = json.AppendUints8(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUints8(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint16 adds the field key with i as a uint16 to the logger context.
 func (c Context) Uint16(key string, i uint16) Context {
-	c.l.context = json.AppendUint16(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUint16(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints16 adds the field key with i as a []uint16 to the logger context.
 func (c Context) Uints16(key string, i []uint16) Context {
-	c.l.context = json.AppendUints16(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUints16(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint32 adds the field key with i as a uint32 to the logger context.
 func (c Context) Uint32(key string, i uint32) Context {
-	c.l.context = json.AppendUint32(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUint32(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints32 adds the field key with i as a []uint32 to the logger context.
 func (c Context) Uints32(key string, i []uint32) Context {
-	c.l.context = json.AppendUints32(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUints32(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uint64 adds the field key with i as a uint64 to the logger context.
 func (c Context) Uint64(key string, i uint64) Context {
-	c.l.context = json.AppendUint64(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUint64(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Uints64 adds the field key with i as a []uint64 to the logger context.
 func (c Context) Uints64(key string, i []uint64) Context {
-	c.l.context = json.AppendUints64(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendUints64(appendKey(c.l.context, key), i)
 	return c
 }
 
 // Float32 adds the field key with f as a float32 to the logger context.
 func (c Context) Float32(key string, f float32) Context {
-	c.l.context = json.AppendFloat32(json.AppendKey(c.l.context, key), f)
+	c.l.context = appendFloat32(appendKey(c.l.context, key), f)
 	return c
 }
 
 // Floats32 adds the field key with f as a []float32 to the logger context.
 func (c Context) Floats32(key string, f []float32) Context {
-	c.l.context = json.AppendFloats32(json.AppendKey(c.l.context, key), f)
+	c.l.context = appendFloats32(appendKey(c.l.context, key), f)
 	return c
 }
 
 // Float64 adds the field key with f as a float64 to the logger context.
 func (c Context) Float64(key string, f float64) Context {
-	c.l.context = json.AppendFloat64(json.AppendKey(c.l.context, key), f)
+	c.l.context = appendFloat64(appendKey(c.l.context, key), f)
 	return c
 }
 
 // Floats64 adds the field key with f as a []float64 to the logger context.
 func (c Context) Floats64(key string, f []float64) Context {
-	c.l.context = json.AppendFloats64(json.AppendKey(c.l.context, key), f)
+	c.l.context = appendFloats64(appendKey(c.l.context, key), f)
 	return c
 }
 
+type timestampHook struct{}
+
+func (ts timestampHook) Run(e *Event, level Level, msg string) {
+	e.Timestamp()
+}
+
+var th = timestampHook{}
+
 // Timestamp adds the current local time as UNIX timestamp to the logger context with the "time" key.
 // To customize the key name, change zerolog.TimestampFieldName.
+//
+// NOTE: It won't dedupe the "time" key if the *Context has one already.
 func (c Context) Timestamp() Context {
-	if len(c.l.context) > 0 {
-		c.l.context[0] = 1
-	} else {
-		c.l.context = append(c.l.context, 1)
-	}
+	c.l = c.l.Hook(th)
 	return c
 }
 
 // Time adds the field key with t formated as string using zerolog.TimeFieldFormat.
 func (c Context) Time(key string, t time.Time) Context {
-	c.l.context = json.AppendTime(json.AppendKey(c.l.context, key), t, TimeFieldFormat)
+	c.l.context = appendTime(appendKey(c.l.context, key), t, TimeFieldFormat)
 	return c
 }
 
 // Times adds the field key with t formated as string using zerolog.TimeFieldFormat.
 func (c Context) Times(key string, t []time.Time) Context {
-	c.l.context = json.AppendTimes(json.AppendKey(c.l.context, key), t, TimeFieldFormat)
+	c.l.context = appendTimes(appendKey(c.l.context, key), t, TimeFieldFormat)
 	return c
 }
 
 // Dur adds the fields key with d divided by unit and stored as a float.
 func (c Context) Dur(key string, d time.Duration) Context {
-	c.l.context = json.AppendDuration(json.AppendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldInteger)
+	c.l.context = appendDuration(appendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldInteger)
 	return c
 }
 
 // Durs adds the fields key with d divided by unit and stored as a float.
 func (c Context) Durs(key string, d []time.Duration) Context {
-	c.l.context = json.AppendDurations(json.AppendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldInteger)
+	c.l.context = appendDurations(appendKey(c.l.context, key), d, DurationFieldUnit, DurationFieldInteger)
 	return c
 }
 
 // Interface adds the field key with obj marshaled using reflection.
 func (c Context) Interface(key string, i interface{}) Context {
-	c.l.context = json.AppendInterface(json.AppendKey(c.l.context, key), i)
+	c.l.context = appendInterface(appendKey(c.l.context, key), i)
+	return c
+}
+
+type callerHook struct{}
+
+func (ch callerHook) Run(e *Event, level Level, msg string) {
+	e.caller(4)
+}
+
+var ch = callerHook{}
+
+// Caller adds the file:line of the caller with the zerolog.CallerFieldName key.
+func (c Context) Caller() Context {
+	c.l = c.l.Hook(ch)
 	return c
 }

ctx.go

@@ -5,25 +5,42 @@ import (
 	"io/ioutil"
 )
 
-var disabledLogger = New(ioutil.Discard).Level(Disabled)
+var disabledLogger *Logger
+
+func init() {
+	l := New(ioutil.Discard).Level(Disabled)
+	disabledLogger = &l
+}
 
 type ctxKey struct{}
 
-// WithContext returns a copy of ctx with l associated.
+// WithContext returns a copy of ctx with l associated. If an instance of Logger
+// is already in the context, the pointer to this logger is updated with l.
+//
+// For instance, to add a field to an existing logger in the context, use this
+// notation:
+//
+//     ctx := r.Context()
+//     l := zerolog.Ctx(ctx)
+//     ctx = l.With().Str("foo", "bar").WithContext(ctx)
 func (l Logger) WithContext(ctx context.Context) context.Context {
 	if lp, ok := ctx.Value(ctxKey{}).(*Logger); ok {
 		// Update existing pointer.
 		*lp = l
 		return ctx
 	}
+	if l.level == Disabled {
+		// Do not store disabled logger.
+		return ctx
+	}
 	return context.WithValue(ctx, ctxKey{}, &l)
 }
 
 // Ctx returns the Logger associated with the ctx. If no logger
 // is associated, a disabled logger is returned.
-func Ctx(ctx context.Context) Logger {
+func Ctx(ctx context.Context) *Logger {
 	if l, ok := ctx.Value(ctxKey{}).(*Logger); ok {
-		return *l
+		return l
 	}
 	return disabledLogger
 }

ctx_test.go

@@ -11,7 +11,7 @@ func TestCtx(t *testing.T) {
 	log := New(ioutil.Discard)
 	ctx := log.WithContext(context.Background())
 	log2 := Ctx(ctx)
-	if !reflect.DeepEqual(log, log2) {
+	if !reflect.DeepEqual(log, *log2) {
 		t.Error("Ctx did not return the expected logger")
 	}
 
@@ -19,12 +19,29 @@ func TestCtx(t *testing.T) {
 	log = log.Level(InfoLevel)
 	ctx = log.WithContext(ctx)
 	log2 = Ctx(ctx)
-	if !reflect.DeepEqual(log, log2) {
+	if !reflect.DeepEqual(log, *log2) {
 		t.Error("Ctx did not return the expected logger")
 	}
 
 	log2 = Ctx(context.Background())
-	if !reflect.DeepEqual(log2, disabledLogger) {
+	if log2 != disabledLogger {
 		t.Error("Ctx did not return the expected logger")
 	}
 }
+
+func TestCtxDisabled(t *testing.T) {
+	ctx := disabledLogger.WithContext(context.Background())
+	if ctx != context.Background() {
+		t.Error("WithContext stored a disabled logger")
+	}
+
+	ctx = New(ioutil.Discard).WithContext(ctx)
+	if reflect.DeepEqual(Ctx(ctx), disabledLogger) {
+		t.Error("WithContext did not store logger")
+	}
+
+	ctx = disabledLogger.WithContext(ctx)
+	if !reflect.DeepEqual(Ctx(ctx), disabledLogger) {
+		t.Error("WithContext did not update logger pointer with disabled logger")
+	}
+}

diode/diode.go

@@ -0,0 +1,88 @@
+// Package diode provides a thread-safe, lock-free, non-blocking io.Writer
+// wrapper.
+package diode
+
+import (
+	"context"
+	"io"
+	"sync"
+	"time"
+
+	diodes "code.cloudfoundry.org/go-diodes"
+)
+
+var bufPool = &sync.Pool{
+	New: func() interface{} {
+		return make([]byte, 0, 500)
+	},
+}
+
+// Writer is a io.Writer wrapper that uses a diode to make Write lock-free,
+// non-blocking and thread safe.
+type Writer struct {
+	w    io.Writer
+	d    *diodes.ManyToOne
+	p    *diodes.Poller
+	c    context.CancelFunc
+	done chan struct{}
+}
+
+// NewWriter creates a writer wrapping w with a many-to-one diode in order to
+// never block log producers and drop events if the writer can't keep up with
+// the flow of data.
+//
+// Use a diode.Writer when
+//
+//     d := diodes.NewManyToOne(1000, diodes.AlertFunc(func(missed int) {
+//         log.Printf("Dropped %d messages", missed)
+//     }))
+//     w := diode.NewWriter(w, d, 10 * time.Millisecond)
+//     log := zerolog.New(w)
+//
+// See code.cloudfoundry.org/go-diodes for more info on diode.
+func NewWriter(w io.Writer, manyToOneDiode *diodes.ManyToOne, poolInterval time.Duration) Writer {
+	ctx, cancel := context.WithCancel(context.Background())
+	dw := Writer{
+		w: w,
+		d: manyToOneDiode,
+		p: diodes.NewPoller(manyToOneDiode,
+			diodes.WithPollingInterval(poolInterval),
+			diodes.WithPollingContext(ctx)),
+		c:    cancel,
+		done: make(chan struct{}),
+	}
+	go dw.poll()
+	return dw
+}
+
+func (dw Writer) Write(p []byte) (n int, err error) {
+	// p is pooled in zerolog so we can't hold it passed this call, hence the
+	// copy.
+	p = append(bufPool.Get().([]byte), p...)
+	dw.d.Set(diodes.GenericDataType(&p))
+	return len(p), nil
+}
+
+// Close releases the diode poller and call Close on the wrapped writer if
+// io.Closer is implemented.
+func (dw Writer) Close() error {
+	dw.c()
+	<-dw.done
+	if w, ok := dw.w.(io.Closer); ok {
+		return w.Close()
+	}
+	return nil
+}
+
+func (dw Writer) poll() {
+	defer close(dw.done)
+	for {
+		d := dw.p.Next()
+		if d == nil {
+			return
+		}
+		p := *(*[]byte)(d)
+		dw.w.Write(p)
+		bufPool.Put(p[:0])
+	}
+}

diode/diode_example_test.go

@@ -0,0 +1,26 @@
+// +build !binary_log
+
+package diode_test
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	diodes "code.cloudfoundry.org/go-diodes"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/diode"
+)
+
+func ExampleNewWriter() {
+	d := diodes.NewManyToOne(1000, diodes.AlertFunc(func(missed int) {
+		fmt.Printf("Dropped %d messages\n", missed)
+	}))
+	w := diode.NewWriter(os.Stdout, d, 10*time.Millisecond)
+	log := zerolog.New(w)
+	log.Print("test")
+
+	w.Close()
+
+	// Output: {"level":"debug","message":"test"}
+}

diode/diode_test.go

@@ -0,0 +1,50 @@
+package diode_test
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"testing"
+	"time"
+
+	diodes "code.cloudfoundry.org/go-diodes"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/diode"
+	"github.com/rs/zerolog/internal/cbor"
+)
+
+func TestNewWriter(t *testing.T) {
+	d := diodes.NewManyToOne(1000, diodes.AlertFunc(func(missed int) {
+		fmt.Printf("Dropped %d messages\n", missed)
+	}))
+	buf := bytes.Buffer{}
+	w := diode.NewWriter(&buf, d, 10*time.Millisecond)
+	log := zerolog.New(w)
+	log.Print("test")
+
+	w.Close()
+	want := "{\"level\":\"debug\",\"message\":\"test\"}\n"
+	got := cbor.DecodeIfBinaryToString(buf.Bytes())
+	if got != want {
+		t.Errorf("Diode New Writer Test failed. got:%s, want:%s!", got, want)
+	}
+}
+
+func Benchmark(b *testing.B) {
+	log.SetOutput(ioutil.Discard)
+	defer log.SetOutput(os.Stderr)
+	d := diodes.NewManyToOne(100000, nil)
+	w := diode.NewWriter(ioutil.Discard, d, 10*time.Millisecond)
+	log := zerolog.New(w)
+	defer w.Close()
+
+	b.SetParallelism(1000)
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			log.Print("test")
+		}
+	})
+
+}

encoder_cbor.go

@@ -0,0 +1,218 @@
+// +build binary_log
+
+package zerolog
+
+// This file contains bindings to do binary encoding.
+
+import (
+	"time"
+
+	"github.com/rs/zerolog/internal/cbor"
+)
+
+func appendInterface(dst []byte, i interface{}) []byte {
+	return cbor.AppendInterface(dst, i)
+}
+
+func appendKey(dst []byte, s string) []byte {
+	return cbor.AppendKey(dst, s)
+}
+
+func appendFloats64(dst []byte, f []float64) []byte {
+	return cbor.AppendFloats64(dst, f)
+}
+
+func appendFloat64(dst []byte, f float64) []byte {
+	return cbor.AppendFloat64(dst, f)
+}
+
+func appendFloats32(dst []byte, f []float32) []byte {
+	return cbor.AppendFloats32(dst, f)
+}
+
+func appendFloat32(dst []byte, f float32) []byte {
+	return cbor.AppendFloat32(dst, f)
+}
+
+func appendUints64(dst []byte, i []uint64) []byte {
+	return cbor.AppendUints64(dst, i)
+}
+
+func appendUint64(dst []byte, i uint64) []byte {
+	return cbor.AppendUint64(dst, i)
+}
+
+func appendUints32(dst []byte, i []uint32) []byte {
+	return cbor.AppendUints32(dst, i)
+}
+
+func appendUint32(dst []byte, i uint32) []byte {
+	return cbor.AppendUint32(dst, i)
+}
+
+func appendUints16(dst []byte, i []uint16) []byte {
+	return cbor.AppendUints16(dst, i)
+}
+
+func appendUint16(dst []byte, i uint16) []byte {
+	return cbor.AppendUint16(dst, i)
+}
+
+func appendUints8(dst []byte, i []uint8) []byte {
+	return cbor.AppendUints8(dst, i)
+}
+
+func appendUint8(dst []byte, i uint8) []byte {
+	return cbor.AppendUint8(dst, i)
+}
+
+func appendUints(dst []byte, i []uint) []byte {
+	return cbor.AppendUints(dst, i)
+}
+
+func appendUint(dst []byte, i uint) []byte {
+	return cbor.AppendUint(dst, i)
+}
+
+func appendInts64(dst []byte, i []int64) []byte {
+	return cbor.AppendInts64(dst, i)
+}
+
+func appendInt64(dst []byte, i int64) []byte {
+	return cbor.AppendInt64(dst, i)
+}
+
+func appendInts32(dst []byte, i []int32) []byte {
+	return cbor.AppendInts32(dst, i)
+}
+
+func appendInt32(dst []byte, i int32) []byte {
+	return cbor.AppendInt32(dst, i)
+}
+
+func appendInts16(dst []byte, i []int16) []byte {
+	return cbor.AppendInts16(dst, i)
+}
+
+func appendInt16(dst []byte, i int16) []byte {
+	return cbor.AppendInt16(dst, i)
+}
+
+func appendInts8(dst []byte, i []int8) []byte {
+	return cbor.AppendInts8(dst, i)
+}
+
+func appendInt8(dst []byte, i int8) []byte {
+	return cbor.AppendInt8(dst, i)
+}
+
+func appendInts(dst []byte, i []int) []byte {
+	return cbor.AppendInts(dst, i)
+}
+
+func appendInt(dst []byte, i int) []byte {
+	return cbor.AppendInt(dst, i)
+}
+
+func appendBools(dst []byte, b []bool) []byte {
+	return cbor.AppendBools(dst, b)
+}
+
+func appendBool(dst []byte, b bool) []byte {
+	return cbor.AppendBool(dst, b)
+}
+
+func appendError(dst []byte, e error) []byte {
+	return cbor.AppendError(dst, e)
+}
+
+func appendErrors(dst []byte, e []error) []byte {
+	return cbor.AppendErrors(dst, e)
+}
+
+func appendString(dst []byte, s string) []byte {
+	return cbor.AppendString(dst, s)
+}
+
+func appendStrings(dst []byte, s []string) []byte {
+	return cbor.AppendStrings(dst, s)
+}
+
+func appendDuration(dst []byte, t time.Duration, d time.Duration, fmt bool) []byte {
+	return cbor.AppendDuration(dst, t, d, fmt)
+}
+
+func appendDurations(dst []byte, t []time.Duration, d time.Duration, fmt bool) []byte {
+	return cbor.AppendDurations(dst, t, d, fmt)
+}
+
+func appendTimes(dst []byte, t []time.Time, fmt string) []byte {
+	return cbor.AppendTimes(dst, t, fmt)
+}
+
+func appendTime(dst []byte, t time.Time, fmt string) []byte {
+	return cbor.AppendTime(dst, t, fmt)
+}
+
+func appendEndMarker(dst []byte) []byte {
+	return cbor.AppendEndMarker(dst)
+}
+
+func appendLineBreak(dst []byte) []byte {
+	// No line breaks needed in binary format.
+	return dst
+}
+
+func appendBeginMarker(dst []byte) []byte {
+	return cbor.AppendBeginMarker(dst)
+}
+
+func appendBytes(dst []byte, b []byte) []byte {
+	return cbor.AppendBytes(dst, b)
+}
+
+func appendArrayStart(dst []byte) []byte {
+	return cbor.AppendArrayStart(dst)
+}
+
+func appendArrayEnd(dst []byte) []byte {
+	return cbor.AppendArrayEnd(dst)
+}
+
+func appendArrayDelim(dst []byte) []byte {
+	return cbor.AppendArrayDelim(dst)
+}
+
+func appendObjectData(dst []byte, src []byte) []byte {
+        // Map begin character is present in the src, which
+        // should not be copied when appending to existing data.
+	return cbor.AppendObjectData(dst, src[1:])
+}
+
+func appendJSON(dst []byte, j []byte) []byte {
+	return cbor.AppendEmbeddedJSON(dst, j)
+}
+
+func appendNil(dst []byte) []byte {
+	return cbor.AppendNull(dst)
+}
+
+func appendHex(dst []byte, val []byte) []byte {
+	return cbor.AppendHex(dst, val)
+}
+
+// decodeIfBinaryToString - converts a binary formatted log msg to a
+// JSON formatted String Log message.
+func decodeIfBinaryToString(in []byte) string {
+	return cbor.DecodeIfBinaryToString(in)
+}
+
+func decodeObjectToStr(in []byte) string {
+	return cbor.DecodeObjectToStr(in)
+}
+
+// decodeIfBinaryToBytes - converts a binary formatted log msg to a
+// JSON formatted Bytes Log message.
+func decodeIfBinaryToBytes(in []byte) []byte {
+	return cbor.DecodeIfBinaryToBytes(in)
+}

encoder_json.go

@@ -0,0 +1,216 @@
+// +build !binary_log
+
+package zerolog
+
+// encoder_json.go file contains bindings to generate
+// JSON encoded byte stream.
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/rs/zerolog/internal/json"
+)
+
+func appendInterface(dst []byte, i interface{}) []byte {
+	return json.AppendInterface(dst, i)
+}
+
+func appendKey(dst []byte, s string) []byte {
+	return json.AppendKey(dst, s)
+}
+
+func appendFloats64(dst []byte, f []float64) []byte {
+	return json.AppendFloats64(dst, f)
+}
+
+func appendFloat64(dst []byte, f float64) []byte {
+	return json.AppendFloat64(dst, f)
+}
+
+func appendFloats32(dst []byte, f []float32) []byte {
+	return json.AppendFloats32(dst, f)
+}
+
+func appendFloat32(dst []byte, f float32) []byte {
+	return json.AppendFloat32(dst, f)
+}
+
+func appendUints64(dst []byte, i []uint64) []byte {
+	return json.AppendUints64(dst, i)
+}
+
+func appendUint64(dst []byte, i uint64) []byte {
+	return strconv.AppendUint(dst, uint64(i), 10)
+}
+
+func appendUints32(dst []byte, i []uint32) []byte {
+	return json.AppendUints32(dst, i)
+}
+
+func appendUint32(dst []byte, i uint32) []byte {
+	return strconv.AppendUint(dst, uint64(i), 10)
+}
+
+func appendUints16(dst []byte, i []uint16) []byte {
+	return json.AppendUints16(dst, i)
+}
+
+func appendUint16(dst []byte, i uint16) []byte {
+	return strconv.AppendUint(dst, uint64(i), 10)
+}
+
+func appendUints8(dst []byte, i []uint8) []byte {
+	return json.AppendUints8(dst, i)
+}
+
+func appendUint8(dst []byte, i uint8) []byte {
+	return strconv.AppendUint(dst, uint64(i), 10)
+}
+
+func appendUints(dst []byte, i []uint) []byte {
+	return json.AppendUints(dst, i)
+}
+
+func appendUint(dst []byte, i uint) []byte {
+	return strconv.AppendUint(dst, uint64(i), 10)
+}
+
+func appendInts64(dst []byte, i []int64) []byte {
+	return json.AppendInts64(dst, i)
+}
+
+func appendInt64(dst []byte, i int64) []byte {
+	return strconv.AppendInt(dst, int64(i), 10)
+}
+
+func appendInts32(dst []byte, i []int32) []byte {
+	return json.AppendInts32(dst, i)
+}
+
+func appendInt32(dst []byte, i int32) []byte {
+	return strconv.AppendInt(dst, int64(i), 10)
+}
+
+func appendInts16(dst []byte, i []int16) []byte {
+	return json.AppendInts16(dst, i)
+}
+
+func appendInt16(dst []byte, i int16) []byte {
+	return strconv.AppendInt(dst, int64(i), 10)
+}
+
+func appendInts8(dst []byte, i []int8) []byte {
+	return json.AppendInts8(dst, i)
+}
+
+func appendInt8(dst []byte, i int8) []byte {
+	return strconv.AppendInt(dst, int64(i), 10)
+}
+
+func appendInts(dst []byte, i []int) []byte {
+	return json.AppendInts(dst, i)
+}
+
+func appendInt(dst []byte, i int) []byte {
+	return strconv.AppendInt(dst, int64(i), 10)
+}
+
+func appendBools(dst []byte, b []bool) []byte {
+	return json.AppendBools(dst, b)
+}
+
+func appendBool(dst []byte, b bool) []byte {
+	return strconv.AppendBool(dst, b)
+}
+
+func appendError(dst []byte, e error) []byte {
+	return json.AppendError(dst, e)
+}
+
+func appendErrors(dst []byte, e []error) []byte {
+	return json.AppendErrors(dst, e)
+}
+
+func appendString(dst []byte, s string) []byte {
+	return json.AppendString(dst, s)
+}
+
+func appendStrings(dst []byte, s []string) []byte {
+	return json.AppendStrings(dst, s)
+}
+
+func appendDuration(dst []byte, t time.Duration, d time.Duration, fmt bool) []byte {
+	return json.AppendDuration(dst, t, d, fmt)
+}
+
+func appendDurations(dst []byte, t []time.Duration, d time.Duration, fmt bool) []byte {
+	return json.AppendDurations(dst, t, d, fmt)
+}
+
+func appendTimes(dst []byte, t []time.Time, fmt string) []byte {
+	return json.AppendTimes(dst, t, fmt)
+}
+
+func appendTime(dst []byte, t time.Time, fmt string) []byte {
+	return json.AppendTime(dst, t, fmt)
+}
+
+func appendEndMarker(dst []byte) []byte {
+	return append(dst, '}')
+}
+
+func appendLineBreak(dst []byte) []byte {
+	return append(dst, '\n')
+}
+
+func appendBeginMarker(dst []byte) []byte {
+	return append(dst, '{')
+}
+
+func appendBytes(dst []byte, b []byte) []byte {
+	return json.AppendBytes(dst, b)
+}
+
+func appendArrayStart(dst []byte) []byte {
+	return append(dst, '[')
+}
+
+func appendArrayEnd(dst []byte) []byte {
+	return append(dst, ']')
+}
+
+func appendArrayDelim(dst []byte) []byte {
+	if len(dst) > 0 {
+		return append(dst, ',')
+	}
+	return dst
+}
+
+func appendObjectData(dst []byte, src []byte) []byte {
+	return json.AppendObjectData(dst, src)
+}
+
+func appendJSON(dst []byte, j []byte) []byte {
+	return append(dst, j...)
+}
+
+func appendNil(dst []byte) []byte {
+	return append(dst, "null"...)
+}
+
+func decodeIfBinaryToString(in []byte) string {
+	return string(in)
+}
+
+func decodeObjectToStr(in []byte) string {
+	return string(in)
+}
+
+func decodeIfBinaryToBytes(in []byte) []byte {
+	return in
+}
+
+func appendHex(in []byte, val []byte) []byte {
+    return json.AppendHex(in, val)
+}

event.go

@@ -2,12 +2,11 @@ package zerolog
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
+	"runtime"
+	"strconv"
 	"sync"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 var eventPool = &sync.Pool{
@@ -21,11 +20,12 @@ var eventPool = &sync.Pool{
 // Event represents a log event. It is instanced by one of the level method of
 // Logger and finalized by the Msg or Msgf method.
 type Event struct {
-	buf     []byte
-	w       LevelWriter
-	level   Level
-	enabled bool
-	done    func(msg string)
+	buf   []byte
+	w     LevelWriter
+	level Level
+	done  func(msg string)
+	ch    []Hook // hooks from context
+	h     []Hook
 }
 
 // LogObjectMarshaler provides a strongly-typed and encoding-agnostic interface
@@ -45,20 +45,23 @@ func newEvent(w LevelWriter, level Level, enabled bool) *Event {
 		return &Event{}
 	}
 	e := eventPool.Get().(*Event)
-	e.buf = e.buf[:1]
-	e.buf[0] = '{'
+	e.buf = e.buf[:0]
+	e.h = e.h[:0]
+	e.buf = appendBeginMarker(e.buf)
 	e.w = w
 	e.level = level
-	e.enabled = true
 	return e
 }
 
 func (e *Event) write() (err error) {
-	if !e.enabled {
+	if e == nil {
 		return nil
 	}
-	e.buf = append(e.buf, '}', '\n')
-	_, err = e.w.WriteLevel(e.level, e.buf)
+	e.buf = appendEndMarker(e.buf)
+	e.buf = appendLineBreak(e.buf)
+	if e.w != nil {
+		_, err = e.w.WriteLevel(e.level, e.buf)
+	}
 	eventPool.Put(e)
 	return
 }
@@ -66,7 +69,7 @@ func (e *Event) write() (err error) {
 // Enabled return false if the *Event is going to be filtered out by
 // log level or sampling.
 func (e *Event) Enabled() bool {
-	return e.enabled
+	return e != nil
 }
 
 // Msg sends the *Event with msg added as the message field if not empty.
@@ -74,11 +77,27 @@ func (e *Event) Enabled() bool {
 // NOTICE: once this method is called, the *Event should be disposed.
 // Calling Msg twice can have unexpected result.
 func (e *Event) Msg(msg string) {
-	if !e.enabled {
+	if e == nil {
 		return
 	}
+	if len(e.ch) > 0 {
+		e.ch[0].Run(e, e.level, msg)
+		if len(e.ch) > 1 {
+			for _, hook := range e.ch[1:] {
+				hook.Run(e, e.level, msg)
+			}
+		}
+	}
+	if len(e.h) > 0 {
+		e.h[0].Run(e, e.level, msg)
+		if len(e.h) > 1 {
+			for _, hook := range e.h[1:] {
+				hook.Run(e, e.level, msg)
+			}
+		}
+	}
 	if msg != "" {
-		e.buf = json.AppendString(json.AppendKey(e.buf, MessageFieldName), msg)
+		e.buf = appendString(appendKey(e.buf, MessageFieldName), msg)
 	}
 	if e.done != nil {
 		defer e.done(msg)
@@ -93,24 +112,15 @@ func (e *Event) Msg(msg string) {
 // NOTICE: once this methid is called, the *Event should be disposed.
 // Calling Msg twice can have unexpected result.
 func (e *Event) Msgf(format string, v ...interface{}) {
-	if !e.enabled {
+	if e == nil {
 		return
 	}
-	msg := fmt.Sprintf(format, v...)
-	if msg != "" {
-		e.buf = json.AppendString(json.AppendKey(e.buf, MessageFieldName), msg)
-	}
-	if e.done != nil {
-		defer e.done(msg)
-	}
-	if err := e.write(); err != nil {
-		fmt.Fprintf(os.Stderr, "zerolog: could not write event: %v", err)
-	}
+	e.Msg(fmt.Sprintf(format, v...))
 }
 
 // Fields is a helper function to use a map to set fields using type assertion.
 func (e *Event) Fields(fields map[string]interface{}) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
 	e.buf = appendFields(e.buf, fields)
@@ -120,10 +130,11 @@ func (e *Event) Fields(fields map[string]interface{}) *Event {
 // Dict adds the field key with a dict to the event context.
 // Use zerolog.Dict() to create the dictionary.
 func (e *Event) Dict(key string, dict *Event) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = append(append(json.AppendKey(e.buf, key), dict.buf...), '}')
+	dict.buf = appendEndMarker(dict.buf)
+	e.buf = append(appendKey(e.buf, key), dict.buf...)
 	eventPool.Put(dict)
 	return e
 }
@@ -132,17 +143,17 @@ func (e *Event) Dict(key string, dict *Event) *Event {
 // Call usual field methods like Str, Int etc to add fields to this
 // event and give it as argument the *Event.Dict method.
 func Dict() *Event {
-	return newEvent(levelWriterAdapter{ioutil.Discard}, 0, true)
+	return newEvent(nil, 0, true)
 }
 
 // Array adds the field key with an array to the event context.
 // Use zerolog.Arr() to create the array or pass a type that
 // implement the LogArrayMarshaler interface.
 func (e *Event) Array(key string, arr LogArrayMarshaler) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendKey(e.buf, key)
+	e.buf = appendKey(e.buf, key)
 	var a *Array
 	if aa, ok := arr.(*Array); ok {
 		a = aa
@@ -155,44 +166,36 @@ func (e *Event) Array(key string, arr LogArrayMarshaler) *Event {
 }
 
 func (e *Event) appendObject(obj LogObjectMarshaler) {
-	pos := len(e.buf)
+	e.buf = appendBeginMarker(e.buf)
 	obj.MarshalZerologObject(e)
-	if pos < len(e.buf) {
-		// As MarshalZerologObject will use event API, the first field will be
-		// preceded by a comma. If at least one field has been added (buf grew),
-		// we replace this coma by the opening bracket.
-		e.buf[pos] = '{'
-	} else {
-		e.buf = append(e.buf, '{')
-	}
-	e.buf = append(e.buf, '}')
+	e.buf = appendEndMarker(e.buf)
 }
 
 // Object marshals an object that implement the LogObjectMarshaler interface.
 func (e *Event) Object(key string, obj LogObjectMarshaler) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendKey(e.buf, key)
+	e.buf = appendKey(e.buf, key)
 	e.appendObject(obj)
 	return e
 }
 
 // Str adds the field key with val as a string to the *Event context.
 func (e *Event) Str(key, val string) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendString(json.AppendKey(e.buf, key), val)
+	e.buf = appendString(appendKey(e.buf, key), val)
 	return e
 }
 
 // Strs adds the field key with vals as a []string to the *Event context.
 func (e *Event) Strs(key string, vals []string) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendStrings(json.AppendKey(e.buf, key), vals)
+	e.buf = appendStrings(appendKey(e.buf, key), vals)
 	return e
 }
 
@@ -201,21 +204,42 @@ func (e *Event) Strs(key string, vals []string) *Event {
 // Runes outside of normal ASCII ranges will be hex-encoded in the resulting
 // JSON.
 func (e *Event) Bytes(key string, val []byte) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendBytes(json.AppendKey(e.buf, key), val)
+	e.buf = appendBytes(appendKey(e.buf, key), val)
+	return e
+}
+
+// Hex adds the field key with val as a hex string to the *Event context.
+func (e *Event) Hex(key string, val []byte) *Event {
+	if e == nil {
+		return e
+	}
+	e.buf = appendHex(appendKey(e.buf, key), val)
+	return e
+}
+
+// RawJSON adds already encoded JSON to the log line under key.
+//
+// No sanity check is performed on b; it must not contain carriage returns and
+// be valid JSON.
+func (e *Event) RawJSON(key string, b []byte) *Event {
+	if e == nil {
+		return e
+	}
+	e.buf = appendJSON(appendKey(e.buf, key), b)
 	return e
 }
 
 // AnErr adds the field key with err as a string to the *Event context.
 // If err is nil, no field is added.
 func (e *Event) AnErr(key string, err error) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
 	if err != nil {
-		e.buf = json.AppendError(json.AppendKey(e.buf, key), err)
+		e.buf = appendError(appendKey(e.buf, key), err)
 	}
 	return e
 }
@@ -223,10 +247,10 @@ func (e *Event) AnErr(key string, err error) *Event {
 // Errs adds the field key with errs as an array of strings to the *Event context.
 // If err is nil, no field is added.
 func (e *Event) Errs(key string, errs []error) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendErrors(json.AppendKey(e.buf, key), errs)
+	e.buf = appendErrors(appendKey(e.buf, key), errs)
 	return e
 }
 
@@ -234,274 +258,277 @@ func (e *Event) Errs(key string, errs []error) *Event {
 // If err is nil, no field is added.
 // To customize the key name, change zerolog.ErrorFieldName.
 func (e *Event) Err(err error) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
 	if err != nil {
-		e.buf = json.AppendError(json.AppendKey(e.buf, ErrorFieldName), err)
+		e.buf = appendError(appendKey(e.buf, ErrorFieldName), err)
 	}
 	return e
 }
 
 // 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.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendBool(json.AppendKey(e.buf, key), b)
+	e.buf = appendBool(appendKey(e.buf, key), b)
 	return e
 }
 
 // Bools adds the field key with val as a []bool to the *Event context.
 func (e *Event) Bools(key string, b []bool) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendBools(json.AppendKey(e.buf, key), b)
+	e.buf = appendBools(appendKey(e.buf, key), b)
 	return e
 }
 
 // Int adds the field key with i as a int to the *Event context.
 func (e *Event) Int(key string, i int) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInt(json.AppendKey(e.buf, key), i)
+	e.buf = appendInt(appendKey(e.buf, key), i)
 	return e
 }
 
 // Ints adds the field key with i as a []int to the *Event context.
 func (e *Event) Ints(key string, i []int) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInts(json.AppendKey(e.buf, key), i)
+	e.buf = appendInts(appendKey(e.buf, key), i)
 	return e
 }
 
 // Int8 adds the field key with i as a int8 to the *Event context.
 func (e *Event) Int8(key string, i int8) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInt8(json.AppendKey(e.buf, key), i)
+	e.buf = appendInt8(appendKey(e.buf, key), i)
 	return e
 }
 
 // Ints8 adds the field key with i as a []int8 to the *Event context.
 func (e *Event) Ints8(key string, i []int8) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInts8(json.AppendKey(e.buf, key), i)
+	e.buf = appendInts8(appendKey(e.buf, key), i)
 	return e
 }
 
 // Int16 adds the field key with i as a int16 to the *Event context.
 func (e *Event) Int16(key string, i int16) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInt16(json.AppendKey(e.buf, key), i)
+	e.buf = appendInt16(appendKey(e.buf, key), i)
 	return e
 }
 
 // Ints16 adds the field key with i as a []int16 to the *Event context.
 func (e *Event) Ints16(key string, i []int16) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInts16(json.AppendKey(e.buf, key), i)
+	e.buf = appendInts16(appendKey(e.buf, key), i)
 	return e
 }
 
 // Int32 adds the field key with i as a int32 to the *Event context.
 func (e *Event) Int32(key string, i int32) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInt32(json.AppendKey(e.buf, key), i)
+	e.buf = appendInt32(appendKey(e.buf, key), i)
 	return e
 }
 
 // Ints32 adds the field key with i as a []int32 to the *Event context.
 func (e *Event) Ints32(key string, i []int32) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInts32(json.AppendKey(e.buf, key), i)
+	e.buf = appendInts32(appendKey(e.buf, key), i)
 	return e
 }
 
 // Int64 adds the field key with i as a int64 to the *Event context.
 func (e *Event) Int64(key string, i int64) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInt64(json.AppendKey(e.buf, key), i)
+	e.buf = appendInt64(appendKey(e.buf, key), i)
 	return e
 }
 
 // Ints64 adds the field key with i as a []int64 to the *Event context.
 func (e *Event) Ints64(key string, i []int64) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendInts64(json.AppendKey(e.buf, key), i)
+	e.buf = appendInts64(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uint adds the field key with i as a uint to the *Event context.
 func (e *Event) Uint(key string, i uint) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUint(json.AppendKey(e.buf, key), i)
+	e.buf = appendUint(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uints adds the field key with i as a []int to the *Event context.
 func (e *Event) Uints(key string, i []uint) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUints(json.AppendKey(e.buf, key), i)
+	e.buf = appendUints(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uint8 adds the field key with i as a uint8 to the *Event context.
 func (e *Event) Uint8(key string, i uint8) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUint8(json.AppendKey(e.buf, key), i)
+	e.buf = appendUint8(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uints8 adds the field key with i as a []int8 to the *Event context.
 func (e *Event) Uints8(key string, i []uint8) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUints8(json.AppendKey(e.buf, key), i)
+	e.buf = appendUints8(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uint16 adds the field key with i as a uint16 to the *Event context.
 func (e *Event) Uint16(key string, i uint16) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUint16(json.AppendKey(e.buf, key), i)
+	e.buf = appendUint16(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uints16 adds the field key with i as a []int16 to the *Event context.
 func (e *Event) Uints16(key string, i []uint16) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUints16(json.AppendKey(e.buf, key), i)
+	e.buf = appendUints16(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uint32 adds the field key with i as a uint32 to the *Event context.
 func (e *Event) Uint32(key string, i uint32) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUint32(json.AppendKey(e.buf, key), i)
+	e.buf = appendUint32(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uints32 adds the field key with i as a []int32 to the *Event context.
 func (e *Event) Uints32(key string, i []uint32) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUints32(json.AppendKey(e.buf, key), i)
+	e.buf = appendUints32(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uint64 adds the field key with i as a uint64 to the *Event context.
 func (e *Event) Uint64(key string, i uint64) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUint64(json.AppendKey(e.buf, key), i)
+	e.buf = appendUint64(appendKey(e.buf, key), i)
 	return e
 }
 
 // Uints64 adds the field key with i as a []int64 to the *Event context.
 func (e *Event) Uints64(key string, i []uint64) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendUints64(json.AppendKey(e.buf, key), i)
+	e.buf = appendUints64(appendKey(e.buf, key), i)
 	return e
 }
 
 // Float32 adds the field key with f as a float32 to the *Event context.
 func (e *Event) Float32(key string, f float32) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendFloat32(json.AppendKey(e.buf, key), f)
+	e.buf = appendFloat32(appendKey(e.buf, key), f)
 	return e
 }
 
 // Floats32 adds the field key with f as a []float32 to the *Event context.
 func (e *Event) Floats32(key string, f []float32) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendFloats32(json.AppendKey(e.buf, key), f)
+	e.buf = appendFloats32(appendKey(e.buf, key), f)
 	return e
 }
 
 // Float64 adds the field key with f as a float64 to the *Event context.
 func (e *Event) Float64(key string, f float64) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendFloat64(json.AppendKey(e.buf, key), f)
+	e.buf = appendFloat64(appendKey(e.buf, key), f)
 	return e
 }
 
 // Floats64 adds the field key with f as a []float64 to the *Event context.
 func (e *Event) Floats64(key string, f []float64) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendFloats64(json.AppendKey(e.buf, key), f)
+	e.buf = appendFloats64(appendKey(e.buf, key), f)
 	return e
 }
 
 // Timestamp adds the current local time as UNIX timestamp to the *Event context with the "time" key.
 // To customize the key name, change zerolog.TimestampFieldName.
+//
+// NOTE: It won't dedupe the "time" key if the *Event (or *Context) has one
+// already.
 func (e *Event) Timestamp() *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendTime(json.AppendKey(e.buf, TimestampFieldName), TimestampFunc(), TimeFieldFormat)
+	e.buf = appendTime(appendKey(e.buf, TimestampFieldName), TimestampFunc(), TimeFieldFormat)
 	return e
 }
 
 // Time adds the field key with t formated as string using zerolog.TimeFieldFormat.
 func (e *Event) Time(key string, t time.Time) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendTime(json.AppendKey(e.buf, key), t, TimeFieldFormat)
+	e.buf = appendTime(appendKey(e.buf, key), t, TimeFieldFormat)
 	return e
 }
 
 // Times adds the field key with t formated as string using zerolog.TimeFieldFormat.
 func (e *Event) Times(key string, t []time.Time) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendTimes(json.AppendKey(e.buf, key), t, TimeFieldFormat)
+	e.buf = appendTimes(appendKey(e.buf, key), t, TimeFieldFormat)
 	return e
 }
 
@@ -509,10 +536,10 @@ func (e *Event) Times(key string, t []time.Time) *Event {
 // If zerolog.DurationFieldInteger is true, durations are rendered as integer
 // instead of float.
 func (e *Event) Dur(key string, d time.Duration) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendDuration(json.AppendKey(e.buf, key), d, DurationFieldUnit, DurationFieldInteger)
+	e.buf = appendDuration(appendKey(e.buf, key), d, DurationFieldUnit, DurationFieldInteger)
 	return e
 }
 
@@ -520,10 +547,10 @@ func (e *Event) Dur(key string, d time.Duration) *Event {
 // If zerolog.DurationFieldInteger is true, durations are rendered as integer
 // instead of float.
 func (e *Event) Durs(key string, d []time.Duration) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
-	e.buf = json.AppendDurations(json.AppendKey(e.buf, key), d, DurationFieldUnit, DurationFieldInteger)
+	e.buf = appendDurations(appendKey(e.buf, key), d, DurationFieldUnit, DurationFieldInteger)
 	return e
 }
 
@@ -531,25 +558,42 @@ func (e *Event) Durs(key string, d []time.Duration) *Event {
 // If time t is not greater than start, duration will be 0.
 // Duration format follows the same principle as Dur().
 func (e *Event) TimeDiff(key string, t time.Time, start time.Time) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
 	var d time.Duration
 	if t.After(start) {
 		d = t.Sub(start)
 	}
-	e.buf = json.AppendDuration(json.AppendKey(e.buf, key), d, DurationFieldUnit, DurationFieldInteger)
+	e.buf = appendDuration(appendKey(e.buf, key), d, DurationFieldUnit, DurationFieldInteger)
 	return e
 }
 
 // Interface adds the field key with i marshaled using reflection.
 func (e *Event) Interface(key string, i interface{}) *Event {
-	if !e.enabled {
+	if e == nil {
 		return e
 	}
 	if obj, ok := i.(LogObjectMarshaler); ok {
 		return e.Object(key, obj)
 	}
-	e.buf = json.AppendInterface(json.AppendKey(e.buf, key), i)
+	e.buf = appendInterface(appendKey(e.buf, key), i)
+	return e
+}
+
+// Caller adds the file:line of the caller with the zerolog.CallerFieldName key.
+func (e *Event) Caller() *Event {
+	return e.caller(2)
+}
+
+func (e *Event) caller(skip int) *Event {
+	if e == nil {
+		return e
+	}
+	_, file, line, ok := runtime.Caller(skip)
+	if !ok {
+		return e
+	}
+	e.buf = appendString(appendKey(e.buf, CallerFieldName), file+":"+strconv.Itoa(line))
 	return e
 }

fields.go

@@ -3,8 +3,6 @@ package zerolog
 import (
 	"sort"
 	"time"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 func appendFields(dst []byte, fields map[string]interface{}) []byte {
@@ -14,82 +12,114 @@ func appendFields(dst []byte, fields map[string]interface{}) []byte {
 	}
 	sort.Strings(keys)
 	for _, key := range keys {
-		dst = json.AppendKey(dst, key)
+		dst = appendKey(dst, key)
 		switch val := fields[key].(type) {
 		case string:
-			dst = json.AppendString(dst, val)
+			dst = appendString(dst, val)
 		case []byte:
-			dst = json.AppendBytes(dst, val)
+			dst = appendBytes(dst, val)
 		case error:
-			dst = json.AppendError(dst, val)
+			dst = appendError(dst, val)
 		case []error:
-			dst = json.AppendErrors(dst, val)
+			dst = appendErrors(dst, val)
 		case bool:
-			dst = json.AppendBool(dst, val)
+			dst = appendBool(dst, val)
 		case int:
-			dst = json.AppendInt(dst, val)
+			dst = appendInt(dst, val)
 		case int8:
-			dst = json.AppendInt8(dst, val)
+			dst = appendInt8(dst, val)
 		case int16:
-			dst = json.AppendInt16(dst, val)
+			dst = appendInt16(dst, val)
 		case int32:
-			dst = json.AppendInt32(dst, val)
+			dst = appendInt32(dst, val)
 		case int64:
-			dst = json.AppendInt64(dst, val)
+			dst = appendInt64(dst, val)
 		case uint:
-			dst = json.AppendUint(dst, val)
+			dst = appendUint(dst, val)
 		case uint8:
-			dst = json.AppendUint8(dst, val)
+			dst = appendUint8(dst, val)
 		case uint16:
-			dst = json.AppendUint16(dst, val)
+			dst = appendUint16(dst, val)
 		case uint32:
-			dst = json.AppendUint32(dst, val)
+			dst = appendUint32(dst, val)
 		case uint64:
-			dst = json.AppendUint64(dst, val)
+			dst = appendUint64(dst, val)
 		case float32:
-			dst = json.AppendFloat32(dst, val)
+			dst = appendFloat32(dst, val)
 		case float64:
-			dst = json.AppendFloat64(dst, val)
+			dst = appendFloat64(dst, val)
 		case time.Time:
-			dst = json.AppendTime(dst, val, TimeFieldFormat)
+			dst = appendTime(dst, val, TimeFieldFormat)
 		case time.Duration:
-			dst = json.AppendDuration(dst, val, DurationFieldUnit, DurationFieldInteger)
+			dst = appendDuration(dst, val, DurationFieldUnit, DurationFieldInteger)
+		case *string:
+			dst = appendString(dst, *val)
+		case *bool:
+			dst = appendBool(dst, *val)
+		case *int:
+			dst = appendInt(dst, *val)
+		case *int8:
+			dst = appendInt8(dst, *val)
+		case *int16:
+			dst = appendInt16(dst, *val)
+		case *int32:
+			dst = appendInt32(dst, *val)
+		case *int64:
+			dst = appendInt64(dst, *val)
+		case *uint:
+			dst = appendUint(dst, *val)
+		case *uint8:
+			dst = appendUint8(dst, *val)
+		case *uint16:
+			dst = appendUint16(dst, *val)
+		case *uint32:
+			dst = appendUint32(dst, *val)
+		case *uint64:
+			dst = appendUint64(dst, *val)
+		case *float32:
+			dst = appendFloat32(dst, *val)
+		case *float64:
+			dst = appendFloat64(dst, *val)
+		case *time.Time:
+			dst = appendTime(dst, *val, TimeFieldFormat)
+		case *time.Duration:
+			dst = appendDuration(dst, *val, DurationFieldUnit, DurationFieldInteger)
 		case []string:
-			dst = json.AppendStrings(dst, val)
+			dst = appendStrings(dst, val)
 		case []bool:
-			dst = json.AppendBools(dst, val)
+			dst = appendBools(dst, val)
 		case []int:
-			dst = json.AppendInts(dst, val)
+			dst = appendInts(dst, val)
 		case []int8:
-			dst = json.AppendInts8(dst, val)
+			dst = appendInts8(dst, val)
 		case []int16:
-			dst = json.AppendInts16(dst, val)
+			dst = appendInts16(dst, val)
 		case []int32:
-			dst = json.AppendInts32(dst, val)
+			dst = appendInts32(dst, val)
 		case []int64:
-			dst = json.AppendInts64(dst, val)
+			dst = appendInts64(dst, val)
 		case []uint:
-			dst = json.AppendUints(dst, val)
+			dst = appendUints(dst, val)
 		// case []uint8:
 		// 	dst = appendUints8(dst, val)
 		case []uint16:
-			dst = json.AppendUints16(dst, val)
+			dst = appendUints16(dst, val)
 		case []uint32:
-			dst = json.AppendUints32(dst, val)
+			dst = appendUints32(dst, val)
 		case []uint64:
-			dst = json.AppendUints64(dst, val)
+			dst = appendUints64(dst, val)
 		case []float32:
-			dst = json.AppendFloats32(dst, val)
+			dst = appendFloats32(dst, val)
 		case []float64:
-			dst = json.AppendFloats64(dst, val)
+			dst = appendFloats64(dst, val)
 		case []time.Time:
-			dst = json.AppendTimes(dst, val, TimeFieldFormat)
+			dst = appendTimes(dst, val, TimeFieldFormat)
 		case []time.Duration:
-			dst = json.AppendDurations(dst, val, DurationFieldUnit, DurationFieldInteger)
+			dst = appendDurations(dst, val, DurationFieldUnit, DurationFieldInteger)
 		case nil:
-			dst = append(dst, "null"...)
+			dst = appendNil(dst)
 		default:
-			dst = json.AppendInterface(dst, val)
+			dst = appendInterface(dst, val)
 		}
 	}
 	return dst

globals.go

@@ -16,8 +16,8 @@ var (
 	// ErrorFieldName is the field name used for error fields.
 	ErrorFieldName = "error"
 
-	// SampleFieldName is the name of the field used to report sampling.
-	SampleFieldName = "sample"
+	// CallerFieldName is the field name used for caller field.
+	CallerFieldName = "caller"
 
 	// TimeFieldFormat defines the time format of the Time field type.
 	// If set to an empty string, the time is formatted as an UNIX timestamp

hlog/hlog.go

@@ -15,7 +15,7 @@ import (
 
 // FromRequest gets the logger in the request's context.
 // This is a shortcut for log.Ctx(r.Context())
-func FromRequest(r *http.Request) zerolog.Logger {
+func FromRequest(r *http.Request) *zerolog.Logger {
 	return log.Ctx(r.Context())
 }
 
@@ -23,7 +23,10 @@ func FromRequest(r *http.Request) zerolog.Logger {
 func NewHandler(log zerolog.Logger) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			r = r.WithContext(log.WithContext(r.Context()))
+			// Create a copy of the logger (including internal context slice)
+			// to prevent data race when using UpdateContext.
+			l := log.With().Logger()
+			r = r.WithContext(l.WithContext(r.Context()))
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -35,8 +38,9 @@ func URLHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			log := zerolog.Ctx(r.Context())
-			log = log.With().Str(fieldKey, r.URL.String()).Logger()
-			r = r.WithContext(log.WithContext(r.Context()))
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.URL.String())
+			})
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -48,8 +52,9 @@ func MethodHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			log := zerolog.Ctx(r.Context())
-			log = log.With().Str(fieldKey, r.Method).Logger()
-			r = r.WithContext(log.WithContext(r.Context()))
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.Method)
+			})
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -61,8 +66,9 @@ func RequestHandler(fieldKey string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			log := zerolog.Ctx(r.Context())
-			log = log.With().Str(fieldKey, r.Method+" "+r.URL.String()).Logger()
-			r = r.WithContext(log.WithContext(r.Context()))
+			log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+				return c.Str(fieldKey, r.Method+" "+r.URL.String())
+			})
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -75,8 +81,9 @@ func RemoteAddrHandler(fieldKey string) func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
 				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, host).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, host)
+				})
 			}
 			next.ServeHTTP(w, r)
 		})
@@ -90,8 +97,9 @@ func UserAgentHandler(fieldKey string) func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if ua := r.Header.Get("User-Agent"); ua != "" {
 				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, ua).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, ua)
+				})
 			}
 			next.ServeHTTP(w, r)
 		})
@@ -105,8 +113,9 @@ func RefererHandler(fieldKey string) func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if ref := r.Header.Get("Referer"); ref != "" {
 				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, ref).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, ref)
+				})
 			}
 			next.ServeHTTP(w, r)
 		})
@@ -115,7 +124,7 @@ func RefererHandler(fieldKey string) func(next http.Handler) http.Handler {
 
 type idKey struct{}
 
-// IDFromRequest returns the unique id accociated to the request if any.
+// IDFromRequest returns the unique id associated to the request if any.
 func IDFromRequest(r *http.Request) (id xid.ID, ok bool) {
 	if r == nil {
 		return
@@ -136,16 +145,18 @@ func IDFromRequest(r *http.Request) (id xid.ID, ok bool) {
 func RequestIDHandler(fieldKey, headerName string) func(next http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ctx := r.Context()
 			id, ok := IDFromRequest(r)
 			if !ok {
 				id = xid.New()
-				ctx := context.WithValue(r.Context(), idKey{}, id)
+				ctx = context.WithValue(ctx, idKey{}, id)
 				r = r.WithContext(ctx)
 			}
 			if fieldKey != "" {
-				log := zerolog.Ctx(r.Context())
-				log = log.With().Str(fieldKey, id.String()).Logger()
-				r = r.WithContext(log.WithContext(r.Context()))
+				log := zerolog.Ctx(ctx)
+				log.UpdateContext(func(c zerolog.Context) zerolog.Context {
+					return c.Str(fieldKey, id.String())
+				})
 			}
 			if headerName != "" {
 				w.Header().Set(headerName, id.String())

hlog/hlog_example_test.go

@@ -1,3 +1,5 @@
+// +build !binary_log
+
 package hlog_test
 
 import (
@@ -67,5 +69,5 @@ func Example_handler() {
 
 	h.ServeHTTP(httptest.NewRecorder(), &http.Request{})
 
-	// Output: {"time":"2001-02-03T04:05:06Z","level":"info","role":"my-service","host":"local-hostname","user":"current user","status":"ok","message":"Something happend"}
+	// Output: {"level":"info","role":"my-service","host":"local-hostname","user":"current user","status":"ok","time":"2001-02-03T04:05:06Z","message":"Something happend"}
 }

hlog/hlog_test.go

@@ -5,6 +5,7 @@ package hlog
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"net/http"
 	"net/url"
 	"testing"
@@ -14,8 +15,17 @@ import (
 	"net/http/httptest"
 
 	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/internal/cbor"
 )
 
+func decodeIfBinary(out *bytes.Buffer) string {
+	p := out.Bytes()
+	if len(p) == 0 || p[0] < 0x7F {
+		return out.String()
+	}
+	return cbor.DecodeObjectToStr(p) + "\n"
+}
+
 func TestNewHandler(t *testing.T) {
 	log := zerolog.New(nil).With().
 		Str("foo", "bar").
@@ -23,7 +33,7 @@ func TestNewHandler(t *testing.T) {
 	lh := NewHandler(log)
 	h := lh(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
-		if !reflect.DeepEqual(l, log) {
+		if !reflect.DeepEqual(*l, log) {
 			t.Fail()
 		}
 	}))
@@ -38,12 +48,12 @@ func TestURLHandler(t *testing.T) {
 	h := URLHandler("url")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"url":"/path?foo=bar"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"url":"/path?foo=bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestMethodHandler(t *testing.T) {
@@ -54,12 +64,12 @@ func TestMethodHandler(t *testing.T) {
 	h := MethodHandler("method")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"method":"POST"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"method":"POST"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRequestHandler(t *testing.T) {
@@ -71,12 +81,12 @@ func TestRequestHandler(t *testing.T) {
 	h := RequestHandler("request")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"request":"POST /path?foo=bar"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"request":"POST /path?foo=bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRemoteAddrHandler(t *testing.T) {
@@ -87,12 +97,12 @@ func TestRemoteAddrHandler(t *testing.T) {
 	h := RemoteAddrHandler("ip")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"ip":"1.2.3.4"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"ip":"1.2.3.4"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRemoteAddrHandlerIPv6(t *testing.T) {
@@ -103,12 +113,12 @@ func TestRemoteAddrHandlerIPv6(t *testing.T) {
 	h := RemoteAddrHandler("ip")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"ip":"2001:db8:a0b:12f0::1"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"ip":"2001:db8:a0b:12f0::1"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestUserAgentHandler(t *testing.T) {
@@ -121,12 +131,12 @@ func TestUserAgentHandler(t *testing.T) {
 	h := UserAgentHandler("ua")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"ua":"some user agent string"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"ua":"some user agent string"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRefererHandler(t *testing.T) {
@@ -139,12 +149,12 @@ func TestRefererHandler(t *testing.T) {
 	h := RefererHandler("referer")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := `{"referer":"http://foo.com/bar"}`+"\n", out.String(); want != got {
-			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
-		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(nil, r)
+	if want, got := `{"referer":"http://foo.com/bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
 }
 
 func TestRequestIDHandler(t *testing.T) {
@@ -164,10 +174,73 @@ func TestRequestIDHandler(t *testing.T) {
 		}
 		l := FromRequest(r)
 		l.Log().Msg("")
-		if want, got := fmt.Sprintf(`{"id":"%s"}`+"\n", id), out.String(); want != got {
+		if want, got := fmt.Sprintf(`{"id":"%s"}`+"\n", id), decodeIfBinary(out); want != got {
 			t.Errorf("Invalid log output, got: %s, want: %s", got, want)
 		}
 	}))
 	h = NewHandler(zerolog.New(out))(h)
 	h.ServeHTTP(httptest.NewRecorder(), r)
 }
+
+func TestCombinedHandlers(t *testing.T) {
+	out := &bytes.Buffer{}
+	r := &http.Request{
+		Method: "POST",
+		URL:    &url.URL{Path: "/path", RawQuery: "foo=bar"},
+	}
+	h := MethodHandler("method")(RequestHandler("request")(URLHandler("url")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))))
+	h = NewHandler(zerolog.New(out))(h)
+	h.ServeHTTP(nil, r)
+	if want, got := `{"method":"POST","request":"POST /path?foo=bar","url":"/path?foo=bar"}`+"\n", decodeIfBinary(out); want != got {
+		t.Errorf("Invalid log output, got: %s, want: %s", got, want)
+	}
+}
+
+func BenchmarkHandlers(b *testing.B) {
+	r := &http.Request{
+		Method: "POST",
+		URL:    &url.URL{Path: "/path", RawQuery: "foo=bar"},
+	}
+	h1 := URLHandler("url")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.Log().Msg("")
+	}))
+	h2 := MethodHandler("method")(RequestHandler("request")(h1))
+	handlers := map[string]http.Handler{
+		"Single":           NewHandler(zerolog.New(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),
+	}
+	for name := range handlers {
+		h := handlers[name]
+		b.Run(name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				h.ServeHTTP(nil, r)
+			}
+		})
+	}
+}
+
+func BenchmarkDataRace(b *testing.B) {
+	log := zerolog.New(nil).With().
+		Str("foo", "bar").
+		Logger()
+	lh := NewHandler(log)
+	h := lh(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		l := FromRequest(r)
+		l.UpdateContext(func(c zerolog.Context) zerolog.Context {
+			return c.Str("bar", "baz")
+		})
+		l.Log().Msg("")
+	}))
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			h.ServeHTTP(nil, &http.Request{})
+		}
+	})
+}

hook.go

@@ -0,0 +1,51 @@
+package zerolog
+
+// Hook defines an interface to a log hook.
+type Hook interface {
+	// Run runs the hook with the event.
+	Run(e *Event, level Level, message string)
+}
+
+// LevelHook applies a different hook for each level.
+type LevelHook struct {
+	NoLevelHook, DebugHook, InfoHook, WarnHook, ErrorHook, FatalHook, PanicHook Hook
+}
+
+// Run implements the Hook interface.
+func (h LevelHook) Run(e *Event, level Level, message string) {
+	switch level {
+	case DebugLevel:
+		if h.DebugHook != nil {
+			h.DebugHook.Run(e, level, message)
+		}
+	case InfoLevel:
+		if h.InfoHook != nil {
+			h.InfoHook.Run(e, level, message)
+		}
+	case WarnLevel:
+		if h.WarnHook != nil {
+			h.WarnHook.Run(e, level, message)
+		}
+	case ErrorLevel:
+		if h.ErrorHook != nil {
+			h.ErrorHook.Run(e, level, message)
+		}
+	case FatalLevel:
+		if h.FatalHook != nil {
+			h.FatalHook.Run(e, level, message)
+		}
+	case PanicLevel:
+		if h.PanicHook != nil {
+			h.PanicHook.Run(e, level, message)
+		}
+	case NoLevel:
+		if h.NoLevelHook != nil {
+			h.NoLevelHook.Run(e, level, message)
+		}
+	}
+}
+
+// NewLevelHook returns a new LevelHook.
+func NewLevelHook() LevelHook {
+	return LevelHook{}
+}

hook_test.go

@@ -0,0 +1,236 @@
+package zerolog
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+)
+
+type LevelNameHook struct{}
+
+func (h LevelNameHook) Run(e *Event, level Level, msg string) {
+	levelName := level.String()
+	if level == NoLevel {
+		levelName = "nolevel"
+	}
+	e.Str("level_name", levelName)
+}
+
+type SimpleHook struct{}
+
+func (h SimpleHook) Run(e *Event, level Level, msg string) {
+	e.Bool("has_level", level != NoLevel)
+	e.Str("test", "logged")
+}
+
+type CopyHook struct{}
+
+func (h CopyHook) Run(e *Event, level Level, msg string) {
+	hasLevel := level != NoLevel
+	e.Bool("copy_has_level", hasLevel)
+	if hasLevel {
+		e.Str("copy_level", level.String())
+	}
+	e.Str("copy_msg", msg)
+}
+
+type NopHook struct{}
+
+func (h NopHook) Run(e *Event, level Level, msg string) {
+}
+
+var (
+	levelNameHook LevelNameHook
+	simpleHook    SimpleHook
+	copyHook      CopyHook
+	nopHook       NopHook
+)
+
+func TestHook(t *testing.T) {
+	t.Run("Message", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook)
+		log.Log().Msg("test message")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level_name":"nolevel","message":"test message"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("NoLevel", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook)
+		log.Log().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level_name":"nolevel"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Print", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook)
+		log.Print("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"debug","level_name":"debug"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Error", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Copy/1", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(copyHook)
+		log.Log().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"copy_has_level":false,"copy_msg":""}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Copy/2", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(copyHook)
+		log.Info().Msg("a message")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"info","copy_has_level":true,"copy_level":"info","copy_msg":"a message","message":"a message"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Multi", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook).Hook(simpleHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Multi/Message", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook).Hook(simpleHook)
+		log.Error().Msg("a message")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error","has_level":true,"test":"logged","message":"a message"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Output/single/pre", func(t *testing.T) {
+		ignored := &bytes.Buffer{}
+		out := &bytes.Buffer{}
+		log := New(ignored).Hook(levelNameHook).Output(out)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Output/single/post", func(t *testing.T) {
+		ignored := &bytes.Buffer{}
+		out := &bytes.Buffer{}
+		log := New(ignored).Output(out).Hook(levelNameHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Output/multi/pre", func(t *testing.T) {
+		ignored := &bytes.Buffer{}
+		out := &bytes.Buffer{}
+		log := New(ignored).Hook(levelNameHook).Hook(simpleHook).Output(out)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Output/multi/post", func(t *testing.T) {
+		ignored := &bytes.Buffer{}
+		out := &bytes.Buffer{}
+		log := New(ignored).Output(out).Hook(levelNameHook).Hook(simpleHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("Output/mixed", func(t *testing.T) {
+		ignored := &bytes.Buffer{}
+		out := &bytes.Buffer{}
+		log := New(ignored).Hook(levelNameHook).Output(out).Hook(simpleHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("With/single/pre", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook).With().Str("with", "pre").Logger()
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","with":"pre","level_name":"error"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("With/single/post", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).With().Str("with", "post").Logger().Hook(levelNameHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","with":"post","level_name":"error"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("With/multi/pre", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook).Hook(simpleHook).With().Str("with", "pre").Logger()
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","with":"pre","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("With/multi/post", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).With().Str("with", "post").Logger().Hook(levelNameHook).Hook(simpleHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","with":"post","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("With/mixed", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Hook(levelNameHook).With().Str("with", "mixed").Logger().Hook(simpleHook)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error","with":"mixed","level_name":"error","has_level":true,"test":"logged"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+	t.Run("None", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out)
+		log.Error().Msg("")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"error"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+}
+
+func BenchmarkHooks(b *testing.B) {
+	logger := New(ioutil.Discard)
+	b.ResetTimer()
+	b.Run("Nop/Single", func(b *testing.B) {
+		log := logger.Hook(nopHook)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				log.Log().Msg("")
+			}
+		})
+	})
+	b.Run("Nop/Multi", func(b *testing.B) {
+		log := logger.Hook(nopHook).Hook(nopHook)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				log.Log().Msg("")
+			}
+		})
+	})
+	b.Run("Simple", func(b *testing.B) {
+		log := logger.Hook(simpleHook)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				log.Log().Msg("")
+			}
+		})
+	})
+}

internal/cbor/README.md

@@ -0,0 +1,74 @@
+Reference:
+   CBOR Encoding is described in RFC7049 https://tools.ietf.org/html/rfc7049
+
+
+Tests and benchmark:
+
+```
+sprint @ cbor>go test -v -benchmem -bench=.                                                                               
+=== RUN   TestDecodeInteger                                                                                               
+--- PASS: TestDecodeInteger (0.00s)                                                                                       
+=== RUN   TestDecodeString                                                                                                
+--- PASS: TestDecodeString (0.00s)                                                                                        
+=== RUN   TestDecodeArray                                                                                                 
+--- PASS: TestDecodeArray (0.00s)                                                                                         
+=== RUN   TestDecodeMap                                                                                                   
+--- PASS: TestDecodeMap (0.00s)                                                                                           
+=== RUN   TestDecodeBool                                                                                                  
+--- PASS: TestDecodeBool (0.00s)                                                                                          
+=== RUN   TestDecodeFloat                                                                                                 
+--- PASS: TestDecodeFloat (0.00s)                                                                                         
+=== RUN   TestDecodeTimestamp                                                                                             
+--- PASS: TestDecodeTimestamp (0.00s)                                                                                     
+=== RUN   TestDecodeCbor2Json                                                                                             
+--- PASS: TestDecodeCbor2Json (0.00s)                                                                                     
+=== RUN   TestAppendString                                                                                                
+--- PASS: TestAppendString (0.00s)                                                                                        
+=== RUN   TestAppendBytes                                                                                                 
+--- PASS: TestAppendBytes (0.00s)                                                                                         
+=== RUN   TestAppendTimeNow                                                                                               
+--- PASS: TestAppendTimeNow (0.00s)                                                                                       
+=== RUN   TestAppendTimePastPresentInteger                                                                                
+--- PASS: TestAppendTimePastPresentInteger (0.00s)                                                                        
+=== RUN   TestAppendTimePastPresentFloat                                                                                  
+--- PASS: TestAppendTimePastPresentFloat (0.00s)                                                                          
+=== RUN   TestAppendNull                                                                                                  
+--- PASS: TestAppendNull (0.00s)                                                                                          
+=== RUN   TestAppendBool                                                                                                  
+--- PASS: TestAppendBool (0.00s)                                                                                          
+=== RUN   TestAppendBoolArray
+--- PASS: TestAppendBoolArray (0.00s)
+=== RUN   TestAppendInt
+--- PASS: TestAppendInt (0.00s)
+=== RUN   TestAppendIntArray
+--- PASS: TestAppendIntArray (0.00s)
+=== RUN   TestAppendFloat32
+--- PASS: TestAppendFloat32 (0.00s)
+goos: linux
+goarch: amd64
+pkg: github.com/toravir/zerolog/internal/cbor
+BenchmarkAppendString/MultiBytesLast-4          30000000                43.3 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendString/NoEncoding-4              30000000                48.2 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendString/EncodingFirst-4           30000000                48.2 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendString/EncodingMiddle-4          30000000                41.7 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendString/EncodingLast-4            30000000                51.8 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendString/MultiBytesFirst-4         50000000                38.0 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendString/MultiBytesMiddle-4        50000000                38.0 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendTime/Integer-4                   50000000                39.6 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendTime/Float-4                     30000000                56.1 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/uint8-4                      50000000                29.1 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/uint16-4                     50000000                30.3 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/uint32-4                     50000000                37.1 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/int8-4                       100000000               21.5 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/int16-4                      50000000                25.8 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/int32-4                      50000000                26.7 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/int-Positive-4               100000000               21.5 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/int-Negative-4               100000000               20.7 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/uint64-4                     50000000                36.7 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendInt/int64-4                      30000000                39.6 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendFloat/Float32-4                  50000000                23.9 ns/op             0 B/op          0 allocs/op
+BenchmarkAppendFloat/Float64-4                  50000000                32.8 ns/op             0 B/op          0 allocs/op
+PASS
+ok      github.com/toravir/zerolog/internal/cbor        34.969s
+sprint @ cbor>
+```

internal/cbor/base.go

@@ -0,0 +1,43 @@
+package cbor
+
+// AppendKey adds a key (string) to the binary encoded log message
+func AppendKey(dst []byte, key string) []byte {
+	if len(dst) < 1 {
+		dst = AppendBeginMarker(dst)
+	}
+	return AppendString(dst, key)
+}
+
+// AppendError adds the Error to the log message if error is NOT nil
+func AppendError(dst []byte, err error) []byte {
+	if err == nil {
+		return append(dst, `null`...)
+	}
+	return AppendString(dst, err.Error())
+}
+
+// AppendErrors when given an array of errors,
+// adds them to the log message if a specific error is nil, then
+// Nil is added, or else the error string is added.
+func AppendErrors(dst []byte, errs []error) []byte {
+	if len(errs) == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	dst = AppendArrayStart(dst)
+	if errs[0] != nil {
+		dst = AppendString(dst, errs[0].Error())
+	} else {
+		dst = AppendNull(dst)
+	}
+	if len(errs) > 1 {
+		for _, err := range errs[1:] {
+			if err == nil {
+				dst = AppendNull(dst)
+				continue
+			}
+			dst = AppendString(dst, err.Error())
+		}
+	}
+	dst = AppendArrayEnd(dst)
+	return dst
+}

internal/cbor/cbor.go

@@ -0,0 +1,91 @@
+// Package cbor provides primitives for storing different data
+// in the CBOR (binary) format. CBOR is defined in RFC7049.
+package cbor
+
+import "time"
+
+const (
+	majorOffset   = 5
+	additionalMax = 23
+	//Non Values
+	additionalTypeBoolFalse byte = 20
+	additionalTypeBoolTrue  byte = 21
+	additionalTypeNull      byte = 22
+	//Integer (+ve and -ve) Sub-types
+	additionalTypeIntUint8  byte = 24
+	additionalTypeIntUint16 byte = 25
+	additionalTypeIntUint32 byte = 26
+	additionalTypeIntUint64 byte = 27
+	//Float Sub-types
+	additionalTypeFloat16 byte = 25
+	additionalTypeFloat32 byte = 26
+	additionalTypeFloat64 byte = 27
+	additionalTypeBreak   byte = 31
+	//Tag Sub-types
+	additionalTypeTimestamp    byte = 01
+	additionalTypeEmbeddedJSON byte = 31
+        additionalTypeTagHexString uint16 = 262
+	//Unspecified number of elements
+	additionalTypeInfiniteCount byte = 31
+)
+const (
+	majorTypeUnsignedInt    byte = iota << majorOffset // Major type 0
+	majorTypeNegativeInt                               // Major type 1
+	majorTypeByteString                                // Major type 2
+	majorTypeUtf8String                                // Major type 3
+	majorTypeArray                                     // Major type 4
+	majorTypeMap                                       // Major type 5
+	majorTypeTags                                      // Major type 6
+	majorTypeSimpleAndFloat                            // Major type 7
+)
+
+const (
+	maskOutAdditionalType byte = (7 << majorOffset)
+	maskOutMajorType      byte = 31
+)
+
+const (
+	float32Nan         = "\xfa\x7f\xc0\x00\x00"
+	float32PosInfinity = "\xfa\x7f\x80\x00\x00"
+	float32NegInfinity = "\xfa\xff\x80\x00\x00"
+	float64Nan         = "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00"
+	float64PosInfinity = "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00"
+	float64NegInfinity = "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00"
+)
+
+// IntegerTimeFieldFormat indicates the format of timestamp decoded
+// from an integer (time in seconds).
+var IntegerTimeFieldFormat = time.RFC3339
+
+// NanoTimeFieldFormat indicates the format of timestamp decoded
+// from a float value (time in seconds and nano seconds).
+var NanoTimeFieldFormat = time.RFC3339Nano
+
+func appendCborTypePrefix(dst []byte, major byte, number uint64) []byte {
+	byteCount := 8
+	var minor byte
+	switch {
+	case number < 256:
+		byteCount = 1
+		minor = additionalTypeIntUint8
+
+	case number < 65536:
+		byteCount = 2
+		minor = additionalTypeIntUint16
+
+	case number < 4294967296:
+		byteCount = 4
+		minor = additionalTypeIntUint32
+
+	default:
+		byteCount = 8
+		minor = additionalTypeIntUint64
+
+	}
+	dst = append(dst, byte(major|minor))
+	byteCount--
+	for ; byteCount >= 0; byteCount-- {
+		dst = append(dst, byte(number>>(uint(byteCount)*8)))
+	}
+	return dst
+}

internal/cbor/decoder.go

@@ -0,0 +1,548 @@
+package cbor
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+	"time"
+	"unicode/utf8"
+)
+
+var decodeTimeZone *time.Location
+
+const hexTable = "0123456789abcdef"
+
+func decodeIntAdditonalType(src []byte, minor byte) (int64, uint, error) {
+	val := int64(0)
+	bytesRead := 0
+	if minor <= 23 {
+		val = int64(minor)
+		bytesRead = 0
+	} else {
+		switch minor {
+		case additionalTypeIntUint8:
+			bytesRead = 1
+		case additionalTypeIntUint16:
+			bytesRead = 2
+		case additionalTypeIntUint32:
+			bytesRead = 4
+		case additionalTypeIntUint64:
+			bytesRead = 8
+		default:
+			return 0, 0, fmt.Errorf("Invalid Additional Type: %d in decodeInteger (expected <28)", minor)
+		}
+		for i := 0; i < bytesRead; i++ {
+			val = val * 256
+			val += int64(src[i])
+		}
+	}
+	return val, uint(bytesRead), nil
+}
+
+func decodeInteger(src []byte) (int64, uint, error) {
+	major := src[0] & maskOutAdditionalType
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeUnsignedInt && major != majorTypeNegativeInt {
+		return 0, 0, fmt.Errorf("Major type is: %d in decodeInteger!! (expected 0 or 1)", major)
+	}
+	val, bytesRead, err := decodeIntAdditonalType(src[1:], minor)
+	if err != nil {
+		return 0, 0, err
+	}
+	if major == 0 {
+		return val, 1 + bytesRead, nil
+	}
+	return (-1 - val), 1 + bytesRead, nil
+}
+
+func decodeFloat(src []byte) (float64, uint, error) {
+	major := (src[0] & maskOutAdditionalType)
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeSimpleAndFloat {
+		return 0, 0, fmt.Errorf("Incorrect Major type is: %d in decodeFloat", major)
+	}
+
+	switch minor {
+	case additionalTypeFloat16:
+		return 0, 0, fmt.Errorf("float16 is not suppported in decodeFloat")
+	case additionalTypeFloat32:
+		switch string(src[1:5]) {
+		case float32Nan:
+			return math.NaN(), 5, nil
+		case float32PosInfinity:
+			return math.Inf(0), 5, nil
+		case float32NegInfinity:
+			return math.Inf(-1), 5, nil
+		}
+		n := uint32(0)
+		for i := 0; i < 4; i++ {
+			n = n * 256
+			n += uint32(src[i+1])
+		}
+		val := math.Float32frombits(n)
+		return float64(val), 5, nil
+	case additionalTypeFloat64:
+		switch string(src[1:9]) {
+		case float64Nan:
+			return math.NaN(), 9, nil
+		case float64PosInfinity:
+			return math.Inf(0), 9, nil
+		case float64NegInfinity:
+			return math.Inf(-1), 9, nil
+		}
+		n := uint64(0)
+		for i := 0; i < 8; i++ {
+			n = n * 256
+			n += uint64(src[i+1])
+		}
+		val := math.Float64frombits(n)
+		return val, 9, nil
+	}
+	return 0, 0, fmt.Errorf("Invalid Additional Type: %d in decodeFloat", minor)
+}
+
+func decodeStringComplex(dst []byte, s string, pos uint) []byte {
+	i := int(pos)
+	const hex = "0123456789abcdef"
+	start := 0
+
+	for i < len(s) {
+		b := s[i]
+		if b >= utf8.RuneSelf {
+			r, size := utf8.DecodeRuneInString(s[i:])
+			if r == utf8.RuneError && size == 1 {
+				// In case of error, first append previous simple characters to
+				// the byte slice if any and append a replacement character code
+				// in place of the invalid sequence.
+				if start < i {
+					dst = append(dst, s[start:i]...)
+				}
+				dst = append(dst, `\ufffd`...)
+				i += size
+				start = i
+				continue
+			}
+			i += size
+			continue
+		}
+		if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
+			i++
+			continue
+		}
+		// We encountered a character that needs to be encoded.
+		// Let's append the previous simple characters to the byte slice
+		// and switch our operation to read and encode the remainder
+		// characters byte-by-byte.
+		if start < i {
+			dst = append(dst, s[start:i]...)
+		}
+		switch b {
+		case '"', '\\':
+			dst = append(dst, '\\', b)
+		case '\b':
+			dst = append(dst, '\\', 'b')
+		case '\f':
+			dst = append(dst, '\\', 'f')
+		case '\n':
+			dst = append(dst, '\\', 'n')
+		case '\r':
+			dst = append(dst, '\\', 'r')
+		case '\t':
+			dst = append(dst, '\\', 't')
+		default:
+			dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF])
+		}
+		i++
+		start = i
+	}
+	if start < len(s) {
+		dst = append(dst, s[start:]...)
+	}
+	return dst
+}
+
+func decodeString(src []byte, noQuotes bool) ([]byte, uint, error) {
+	major := src[0] & maskOutAdditionalType
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeByteString {
+		return []byte{}, 0, fmt.Errorf("Major type is: %d in decodeString", major)
+	}
+	result := []byte{'"'}
+	if noQuotes {
+		result = []byte{}
+	}
+	length, bytesRead, err := decodeIntAdditonalType(src[1:], minor)
+	if err != nil {
+		return []byte{}, 0, err
+	}
+	bytesRead++
+	st := bytesRead
+	len := uint(length)
+	bytesRead += len
+
+	result = append(result, src[st:st+len]...)
+	if noQuotes {
+		return result, bytesRead, nil
+	}
+	return append(result, '"'), bytesRead, nil
+}
+
+func decodeUTF8String(src []byte) ([]byte, uint, error) {
+	major := src[0] & maskOutAdditionalType
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeUtf8String {
+		return []byte{}, 0, fmt.Errorf("Major type is: %d in decodeUTF8String", major)
+	}
+	result := []byte{'"'}
+	length, bytesRead, err := decodeIntAdditonalType(src[1:], minor)
+	if err != nil {
+		return []byte{}, 0, err
+	}
+	bytesRead++
+	st := bytesRead
+	len := uint(length)
+	bytesRead += len
+
+	for i := st; i < bytesRead; i++ {
+		// Check if the character needs encoding. Control characters, slashes,
+		// and the double quote need json encoding. Bytes above the ascii
+		// boundary needs utf8 encoding.
+		if src[i] < 0x20 || src[i] > 0x7e || src[i] == '\\' || src[i] == '"' {
+			// We encountered a character that needs to be encoded. Switch
+			// to complex version of the algorithm.
+			dst := []byte{'"'}
+			dst = decodeStringComplex(dst, string(src[st:st+len]), i-st)
+			return append(dst, '"'), bytesRead, nil
+		}
+	}
+	// The string has no need for encoding an therefore is directly
+	// appended to the byte slice.
+	result = append(result, src[st:st+len]...)
+	return append(result, '"'), bytesRead, nil
+}
+
+func array2Json(src []byte, dst io.Writer) (uint, error) {
+	dst.Write([]byte{'['})
+	major := (src[0] & maskOutAdditionalType)
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeArray {
+		return 0, fmt.Errorf("Major type is: %d in array2Json", major)
+	}
+	len := 0
+	bytesRead := uint(0)
+	unSpecifiedCount := false
+	if minor == additionalTypeInfiniteCount {
+		unSpecifiedCount = true
+		bytesRead = 1
+	} else {
+		var length int64
+		var err error
+		length, bytesRead, err = decodeIntAdditonalType(src[1:], minor)
+		if err != nil {
+			fmt.Println("Error!!!")
+			return 0, err
+		}
+		len = int(length)
+		bytesRead++
+	}
+	curPos := bytesRead
+	for i := 0; unSpecifiedCount || i < len; i++ {
+		bc, err := Cbor2JsonOneObject(src[curPos:], dst)
+		if err != nil {
+			if src[curPos] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+				bytesRead++
+				break
+			}
+			return 0, err
+		}
+		curPos += bc
+		bytesRead += bc
+		if unSpecifiedCount {
+			if src[curPos] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+				bytesRead++
+				break
+			}
+			dst.Write([]byte{','})
+		} else if i+1 < len {
+			dst.Write([]byte{','})
+		}
+	}
+	dst.Write([]byte{']'})
+	return bytesRead, nil
+}
+
+func map2Json(src []byte, dst io.Writer) (uint, error) {
+	major := (src[0] & maskOutAdditionalType)
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeMap {
+		return 0, fmt.Errorf("Major type is: %d in map2Json", major)
+	}
+	len := 0
+	bytesRead := uint(0)
+	unSpecifiedCount := false
+	if minor == additionalTypeInfiniteCount {
+		unSpecifiedCount = true
+		bytesRead = 1
+	} else {
+		var length int64
+		var err error
+		length, bytesRead, err = decodeIntAdditonalType(src[1:], minor)
+		if err != nil {
+			fmt.Println("Error!!!")
+			return 0, err
+		}
+		len = int(length)
+		bytesRead++
+	}
+	if len%2 == 1 {
+		return 0, fmt.Errorf("Invalid Length of map %d - has to be even", len)
+	}
+	dst.Write([]byte{'{'})
+	curPos := bytesRead
+	for i := 0; unSpecifiedCount || i < len; i++ {
+		bc, err := Cbor2JsonOneObject(src[curPos:], dst)
+		if err != nil {
+			//We hit the BREAK
+			if src[curPos] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+				bytesRead++
+				break
+			}
+			return 0, err
+		}
+		curPos += bc
+		bytesRead += bc
+		if i%2 == 0 {
+			//Even position values are keys
+			dst.Write([]byte{':'})
+		} else {
+			if unSpecifiedCount {
+				if src[curPos] == byte(majorTypeSimpleAndFloat|additionalTypeBreak) {
+					bytesRead++
+					break
+				}
+				dst.Write([]byte{','})
+			} else if i+1 < len {
+				dst.Write([]byte{','})
+			}
+		}
+	}
+	dst.Write([]byte{'}'})
+	return bytesRead, nil
+}
+
+func decodeTagData(src []byte) ([]byte, uint, error) {
+	major := (src[0] & maskOutAdditionalType)
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeTags {
+		return nil, 0, fmt.Errorf("Major type is: %d in decodeTagData", major)
+	}
+	if minor == additionalTypeTimestamp {
+		tsMajor := src[1] & maskOutAdditionalType
+		if tsMajor == majorTypeUnsignedInt || tsMajor == majorTypeNegativeInt {
+			n, bc, err := decodeInteger(src[1:])
+			if err != nil {
+				return []byte{}, 0, err
+			}
+			t := time.Unix(n, 0)
+			if decodeTimeZone != nil {
+				t = t.In(decodeTimeZone)
+			} else {
+				t = t.In(time.UTC)
+			}
+			tsb := []byte{}
+			tsb = append(tsb, '"')
+			tsb = t.AppendFormat(tsb, IntegerTimeFieldFormat)
+			tsb = append(tsb, '"')
+			return tsb, 1 + bc, nil
+		} else if tsMajor == majorTypeSimpleAndFloat {
+			n, bc, err := decodeFloat(src[1:])
+			if err != nil {
+				return []byte{}, 0, err
+			}
+			secs := int64(n)
+			n -= float64(secs)
+			n *= float64(1e9)
+			t := time.Unix(secs, int64(n))
+			if decodeTimeZone != nil {
+				t = t.In(decodeTimeZone)
+			} else {
+				t = t.In(time.UTC)
+			}
+			tsb := []byte{}
+			tsb = append(tsb, '"')
+			tsb = t.AppendFormat(tsb, NanoTimeFieldFormat)
+			tsb = append(tsb, '"')
+			return tsb, 1 + bc, nil
+		} else {
+			return nil, 0, fmt.Errorf("TS format is neigther int nor float: %d", tsMajor)
+		}
+	} else if minor == additionalTypeEmbeddedJSON {
+		dataMajor := src[1] & maskOutAdditionalType
+		if dataMajor == majorTypeByteString {
+			emb, bc, err := decodeString(src[1:], true)
+			if err != nil {
+				return nil, 0, err
+			}
+			return emb, 1 + bc, nil
+		}
+		return nil, 0, fmt.Errorf("Unsupported embedded Type: %d in decodeEmbeddedJSON", dataMajor)
+	} else if minor == additionalTypeIntUint16 {
+            val,_,_ := decodeIntAdditonalType(src[1:], minor)
+            if uint16(val) == additionalTypeTagHexString {
+                emb, bc, _ := decodeString(src[3:], true)
+                dst := []byte{'"'}
+                for _, v := range emb {
+                        dst = append(dst, hexTable[v>>4], hexTable[v&0x0f])
+                }
+                return append(dst, '"'), 3+bc, nil
+            }
+        }
+	return nil, 0, fmt.Errorf("Unsupported Additional Type: %d in decodeTagData", minor)
+}
+
+func decodeSimpleFloat(src []byte) ([]byte, uint, error) {
+	major := (src[0] & maskOutAdditionalType)
+	minor := src[0] & maskOutMajorType
+	if major != majorTypeSimpleAndFloat {
+		return nil, 0, fmt.Errorf("Major type is: %d in decodeSimpleFloat", major)
+	}
+	switch minor {
+	case additionalTypeBoolTrue:
+		return []byte("true"), 1, nil
+	case additionalTypeBoolFalse:
+		return []byte("false"), 1, nil
+	case additionalTypeNull:
+		return []byte("null"), 1, nil
+
+	case additionalTypeFloat16:
+		fallthrough
+	case additionalTypeFloat32:
+		fallthrough
+	case additionalTypeFloat64:
+		v, bc, err := decodeFloat(src)
+		if err != nil {
+			return nil, 0, err
+		}
+		ba := []byte{}
+		switch {
+		case math.IsNaN(v):
+			return []byte("\"NaN\""), bc, nil
+		case math.IsInf(v, 1):
+			return []byte("\"+Inf\""), bc, nil
+		case math.IsInf(v, -1):
+			return []byte("\"-Inf\""), bc, nil
+		}
+		if bc == 5 {
+			ba = strconv.AppendFloat(ba, v, 'f', -1, 32)
+		} else {
+			ba = strconv.AppendFloat(ba, v, 'f', -1, 64)
+		}
+		return ba, bc, nil
+	default:
+		return nil, 0, fmt.Errorf("Invalid Additional Type: %d in decodeSimpleFloat", minor)
+	}
+}
+
+// Cbor2JsonOneObject takes in byte array and decodes ONE CBOR Object
+// usually a MAP. Use this when only ONE CBOR object needs decoding.
+// Decoded string is written to the dst.
+// Returns the bytes decoded and if any error was encountered.
+func Cbor2JsonOneObject(src []byte, dst io.Writer) (uint, error) {
+	var err error
+	major := (src[0] & maskOutAdditionalType)
+	bc := uint(0)
+	var s []byte
+	switch major {
+	case majorTypeUnsignedInt:
+		fallthrough
+	case majorTypeNegativeInt:
+		var n int64
+		n, bc, err = decodeInteger(src)
+		dst.Write([]byte(strconv.Itoa(int(n))))
+
+	case majorTypeByteString:
+		s, bc, err = decodeString(src, false)
+		dst.Write(s)
+
+	case majorTypeUtf8String:
+		s, bc, err = decodeUTF8String(src)
+		dst.Write(s)
+
+	case majorTypeArray:
+		bc, err = array2Json(src, dst)
+
+	case majorTypeMap:
+		bc, err = map2Json(src, dst)
+
+	case majorTypeTags:
+		s, bc, err = decodeTagData(src)
+		dst.Write(s)
+
+	case majorTypeSimpleAndFloat:
+		s, bc, err = decodeSimpleFloat(src)
+		dst.Write(s)
+	}
+	return bc, err
+}
+
+// Cbor2JsonManyObjects decodes all the CBOR Objects present in the
+// source byte array. It keeps on decoding until it runs out of bytes.
+// Decoded string is written to the dst. At the end of every CBOR Object
+// newline is written to the output stream.
+// Returns the number of bytes decoded and if any error was encountered.
+func Cbor2JsonManyObjects(src []byte, dst io.Writer) (uint, error) {
+	curPos := uint(0)
+	totalBytes := uint(len(src))
+	for curPos < totalBytes {
+		bc, err := Cbor2JsonOneObject(src[curPos:], dst)
+		if err != nil {
+			return curPos, err
+		}
+		dst.Write([]byte("\n"))
+		curPos += bc
+	}
+	return curPos, nil
+}
+
+// Detect if the bytes to be printed is Binary or not.
+func binaryFmt(p []byte) bool {
+	if len(p) > 0 && p[0] > 0x7F {
+		return true
+	}
+	return false
+}
+
+// DecodeIfBinaryToString converts a binary formatted log msg to a
+// JSON formatted String Log message - suitable for printing to Console/Syslog.
+func DecodeIfBinaryToString(in []byte) string {
+	if binaryFmt(in) {
+		var b bytes.Buffer
+		Cbor2JsonManyObjects(in, &b)
+		return b.String()
+	}
+	return string(in)
+}
+
+// DecodeObjectToStr checks if the input is a binary format, if so,
+// it will decode a single Object and return the decoded string.
+func DecodeObjectToStr(in []byte) string {
+	if binaryFmt(in) {
+		var b bytes.Buffer
+		Cbor2JsonOneObject(in, &b)
+		return b.String()
+	}
+	return string(in)
+}
+
+// DecodeIfBinaryToBytes checks if the input is a binary format, if so,
+// it will decode all Objects and return the decoded string as byte array.
+func DecodeIfBinaryToBytes(in []byte) []byte {
+	if binaryFmt(in) {
+		var b bytes.Buffer
+		Cbor2JsonManyObjects(in, &b)
+		return b.Bytes()
+	}
+	return in
+}

internal/cbor/decoder_test.go

@@ -0,0 +1,188 @@
+package cbor
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+	"time"
+)
+
+func TestDecodeInteger(t *testing.T) {
+	for _, tc := range integerTestCases {
+		gotv, gotc, err := decodeInteger([]byte(tc.binary))
+		if gotv != int64(tc.val) || int(gotc) != len(tc.binary) || err != nil {
+			t.Errorf("decodeInteger(0x%s)=0x%d, want: 0x%d",
+				hex.EncodeToString([]byte(tc.binary)), gotv, tc.val)
+		}
+	}
+}
+
+func TestDecodeString(t *testing.T) {
+	for _, tt := range encodeStringTests {
+		got, _, err := decodeUTF8String([]byte(tt.binary))
+		if err != nil {
+			t.Errorf("Got Error for the case: %s", hex.EncodeToString([]byte(tt.binary)))
+		}
+		if string(got) != "\""+tt.json+"\"" {
+			t.Errorf("DecodeString(0x%s)=%s, want:\"%s\"\n", hex.EncodeToString([]byte(tt.binary)), string(got),
+				hex.EncodeToString([]byte(tt.json)))
+		}
+	}
+}
+
+func TestDecodeArray(t *testing.T) {
+	for _, tc := range integerArrayTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		_, err := array2Json([]byte(tc.binary), buf)
+		if err != nil {
+			panic(err)
+		}
+		if buf.String() != tc.json {
+			t.Errorf("array2Json(0x%s)=%s, want: %s", hex.EncodeToString([]byte(tc.binary)), buf.String(), tc.json)
+		}
+	}
+	//Unspecified Length Array
+	var infiniteArrayTestCases = []struct {
+		in  string
+		out string
+	}{
+		{"\x9f\x20\x00\x18\xc8\x14\xff", "[-1,0,200,20]"},
+		{"\x9f\x38\xc7\x29\x18\xc8\x19\x01\x90\xff", "[-200,-10,200,400]"},
+		{"\x9f\x01\x02\x03\xff", "[1,2,3]"},
+		{"\x9f\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x18\x18\x19\xff",
+			"[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]"},
+	}
+	for _, tc := range infiniteArrayTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		_, err := array2Json([]byte(tc.in), buf)
+		if err != nil {
+			panic(err)
+		}
+		if buf.String() != tc.out {
+			t.Errorf("array2Json(0x%s)=%s, want: %s", hex.EncodeToString([]byte(tc.out)), buf.String(), tc.out)
+		}
+	}
+	for _, tc := range booleanArrayTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		_, err := array2Json([]byte(tc.binary), buf)
+		if err != nil {
+			t.Errorf("array2Json(0x%s) errored out: %s", hex.EncodeToString([]byte(tc.binary)), err.Error())
+		}
+		if buf.String() != tc.json {
+			t.Errorf("array2Json(0x%s)=%s, want: %s", hex.EncodeToString([]byte(tc.binary)), buf.String(), tc.json)
+		}
+	}
+	//TODO add cases for arrays of other types
+}
+
+var infiniteMapDecodeTestCases = []struct {
+	bin  []byte
+	json string
+}{
+	{[]byte("\xbf\x64IETF\x20\xff"), "{\"IETF\":-1}"},
+	{[]byte("\xbf\x65Array\x84\x20\x00\x18\xc8\x14\xff"), "{\"Array\":[-1,0,200,20]}"},
+}
+
+var mapDecodeTestCases = []struct {
+	bin  []byte
+	json string
+}{
+	{[]byte("\xa2\x64IETF\x20"), "{\"IETF\":-1}"},
+	{[]byte("\xa2\x65Array\x84\x20\x00\x18\xc8\x14"), "{\"Array\":[-1,0,200,20]}"},
+}
+
+func TestDecodeMap(t *testing.T) {
+	for _, tc := range mapDecodeTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		_, err := map2Json(tc.bin, buf)
+		if err != nil {
+			t.Errorf("map2Json(0x%s) returned error", err)
+		}
+		if buf.String() != tc.json {
+			t.Errorf("map2Json(0x%s)=%s, want: %s", hex.EncodeToString(tc.bin), buf.String(), tc.json)
+		}
+	}
+	for _, tc := range infiniteMapDecodeTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		_, err := map2Json(tc.bin, buf)
+		if err != nil {
+			t.Errorf("map2Json(0x%s) returned error", err)
+		}
+		if buf.String() != tc.json {
+			t.Errorf("map2Json(0x%s)=%s, want: %s", hex.EncodeToString(tc.bin), buf.String(), tc.json)
+		}
+	}
+}
+
+func TestDecodeBool(t *testing.T) {
+	for _, tc := range booleanTestCases {
+		got, _, err := decodeSimpleFloat([]byte(tc.binary))
+		if err != nil {
+			t.Errorf("decodeSimpleFloat(0x%s) errored %s", hex.EncodeToString([]byte(tc.binary)), err.Error())
+		}
+		if string(got) != tc.json {
+			t.Errorf("decodeSimpleFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.binary)), string(got), tc.json)
+		}
+	}
+}
+
+func TestDecodeFloat(t *testing.T) {
+	for _, tc := range float32TestCases {
+		got, _, err := decodeFloat([]byte(tc.binary))
+		if err != nil {
+			t.Errorf("decodeFloat(0x%s) returned error: %s", hex.EncodeToString([]byte(tc.binary)), err.Error())
+		}
+		if got != float64(tc.val) {
+			t.Errorf("decodeFloat(0x%s)=%f, want:%f", hex.EncodeToString([]byte(tc.binary)), got, tc.val)
+		}
+	}
+}
+
+func TestDecodeTimestamp(t *testing.T) {
+	decodeTimeZone, _ = time.LoadLocation("UTC")
+	for _, tc := range timeIntegerTestcases {
+		tm, _, err := decodeTagData([]byte(tc.binary))
+		if err != nil {
+			t.Errorf("decodeTagData(0x%s) returned error: %s", hex.EncodeToString([]byte(tc.binary)), err.Error())
+		}
+		if string(tm) != "\""+tc.rfcStr+"\"" {
+			t.Errorf("decodeFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.binary)), tm, tc.rfcStr)
+		}
+	}
+	for _, tc := range timeFloatTestcases {
+		tm, _, err := decodeTagData([]byte(tc.out))
+		if err != nil {
+			t.Errorf("decodeTagData(0x%s) returned error: %s", hex.EncodeToString([]byte(tc.out)), err.Error())
+		}
+		//Since we convert to float and back - it may be slightly off - so
+		//we cannot check for exact equality instead, we'll check it is
+		//very close to each other Less than a Microsecond (lets not yet do nanosec)
+
+		got, _ := time.Parse(string(tm), string(tm))
+		want, _ := time.Parse(tc.rfcStr, tc.rfcStr)
+		if got.Sub(want) > time.Microsecond {
+			t.Errorf("decodeFloat(0x%s)=%s, want:%s", hex.EncodeToString([]byte(tc.out)), tm, tc.rfcStr)
+		}
+	}
+}
+
+var compositeCborTestCases = []struct {
+	binary []byte
+	json   string
+}{
+	{[]byte("\xbf\x64IETF\x20\x65Array\x9f\x20\x00\x18\xc8\x14\xff\xff"), "{\"IETF\":-1,\"Array\":[-1,0,200,20]}\n"},
+	{[]byte("\xbf\x64IETF\x64YES!\x65Array\x9f\x20\x00\x18\xc8\x14\xff\xff"), "{\"IETF\":\"YES!\",\"Array\":[-1,0,200,20]}\n"},
+}
+
+func TestDecodeCbor2Json(t *testing.T) {
+	for _, tc := range compositeCborTestCases {
+		buf := bytes.NewBuffer([]byte{})
+		_, err := Cbor2JsonManyObjects(tc.binary, buf)
+		if err != nil {
+			t.Errorf("cbor2JsonManyObjects(0x%s) returned error", err)
+		}
+		if buf.String() != tc.json {
+			t.Errorf("cbor2JsonManyObjects(0x%s)=%s, want: %s", hex.EncodeToString(tc.binary), buf.String(), tc.json)
+		}
+	}
+}

internal/cbor/string.go

@@ -0,0 +1,63 @@
+package cbor
+
+// AppendStrings encodes and adds an array of strings to the dst byte array.
+func AppendStrings(dst []byte, vals []string) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendString(dst, v)
+	}
+	return dst
+}
+
+// AppendString encodes and adds a string to the dst byte array.
+func AppendString(dst []byte, s string) []byte {
+	major := majorTypeUtf8String
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, majorTypeUtf8String, uint64(l))
+	}
+	return append(dst, s...)
+}
+
+// AppendBytes encodes and adds an array of bytes to the dst byte array.
+func AppendBytes(dst, s []byte) []byte {
+	major := majorTypeByteString
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	return append(dst, s...)
+}
+
+// AppendEmbeddedJSON adds a tag and embeds input JSON as such.
+func AppendEmbeddedJSON(dst, s []byte) []byte {
+	major := majorTypeTags
+	minor := additionalTypeEmbeddedJSON
+	dst = append(dst, byte(major|minor))
+
+	major = majorTypeByteString
+
+	l := len(s)
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	return append(dst, s...)
+}

internal/cbor/string_test.go

@@ -0,0 +1,118 @@
+package cbor
+
+import (
+	"bytes"
+	"testing"
+)
+
+var encodeStringTests = []struct {
+	plain  string
+	binary string
+	json   string //begin and end quotes are implied
+}{
+	{"", "\x60", ""},
+	{"\\", "\x61\x5c", "\\\\"},
+	{"\x00", "\x61\x00", "\\u0000"},
+	{"\x01", "\x61\x01", "\\u0001"},
+	{"\x02", "\x61\x02", "\\u0002"},
+	{"\x03", "\x61\x03", "\\u0003"},
+	{"\x04", "\x61\x04", "\\u0004"},
+	{"*", "\x61*", "*"},
+	{"a", "\x61a", "a"},
+	{"IETF", "\x64IETF", "IETF"},
+	{"abcdefghijklmnopqrstuvwxyzABCD", "\x78\x1eabcdefghijklmnopqrstuvwxyzABCD", "abcdefghijklmnopqrstuvwxyzABCD"},
+	{"<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->",
+		"\x79\x01\x2c<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->",
+		"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->"},
+	{"emoji \u2764\ufe0f!", "\x6demoji ❤️!", "emoji \u2764\ufe0f!"},
+}
+
+var encodeByteTests = []struct {
+	plain  []byte
+	binary string
+}{
+	{[]byte{}, "\x40"},
+	{[]byte("\\"), "\x41\x5c"},
+	{[]byte("\x00"), "\x41\x00"},
+	{[]byte("\x01"), "\x41\x01"},
+	{[]byte("\x02"), "\x41\x02"},
+	{[]byte("\x03"), "\x41\x03"},
+	{[]byte("\x04"), "\x41\x04"},
+	{[]byte("*"), "\x41*"},
+	{[]byte("a"), "\x41a"},
+	{[]byte("IETF"), "\x44IETF"},
+	{[]byte("abcdefghijklmnopqrstuvwxyzABCD"), "\x58\x1eabcdefghijklmnopqrstuvwxyzABCD"},
+	{[]byte("<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->" +
+		"<------------------------------------  This is a 100 character string ----------------------------->"),
+		"\x59\x01\x2c<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->" +
+			"<------------------------------------  This is a 100 character string ----------------------------->"},
+	{[]byte("emoji \u2764\ufe0f!"), "\x4demoji ❤️!"},
+}
+
+func TestAppendString(t *testing.T) {
+	for _, tt := range encodeStringTests {
+		b := AppendString([]byte{}, tt.plain)
+		if got, want := string(b), tt.binary; got != want {
+			t.Errorf("appendString(%q) = %#q, want %#q", tt.plain, got, want)
+		}
+	}
+	//Test a large string > 65535 length
+
+	var buffer bytes.Buffer
+	for i := 0; i < 0x00011170; i++ { //70,000 character string
+		buffer.WriteString("a")
+	}
+	inp := buffer.String()
+	want := "\x7a\x00\x01\x11\x70" + inp
+	b := AppendString([]byte{}, inp)
+	if got := string(b); got != want {
+		t.Errorf("appendString(%q) = %#q, want %#q", inp, got, want)
+	}
+}
+
+func TestAppendBytes(t *testing.T) {
+	for _, tt := range encodeByteTests {
+		b := AppendBytes([]byte{}, tt.plain)
+		if got, want := string(b), tt.binary; got != want {
+			t.Errorf("appendString(%q) = %#q, want %#q", tt.plain, got, want)
+		}
+	}
+	//Test a large string > 65535 length
+
+	inp := []byte{}
+	for i := 0; i < 0x00011170; i++ { //70,000 character string
+		inp = append(inp, byte('a'))
+	}
+	want := "\x5a\x00\x01\x11\x70" + string(inp)
+	b := AppendBytes([]byte{}, inp)
+	if got := string(b); got != want {
+		t.Errorf("appendString(%q) = %#q, want %#q", inp, got, want)
+	}
+}
+func BenchmarkAppendString(b *testing.B) {
+	tests := map[string]string{
+		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingMiddle":   `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingLast":     `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
+		"MultiBytesFirst":  `❤️aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤️aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesLast":   `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤️`,
+	}
+	for name, str := range tests {
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 120)
+			for i := 0; i < b.N; i++ {
+				_ = AppendString(buf, str)
+			}
+		})
+	}
+}

internal/cbor/time.go

@@ -0,0 +1,93 @@
+package cbor
+
+import (
+	"time"
+)
+
+func appendIntegerTimestamp(dst []byte, t time.Time) []byte {
+	major := majorTypeTags
+	minor := additionalTypeTimestamp
+	dst = append(dst, byte(major|minor))
+	secs := t.Unix()
+	var val uint64
+	if secs < 0 {
+		major = majorTypeNegativeInt
+		val = uint64(-secs - 1)
+	} else {
+		major = majorTypeUnsignedInt
+		val = uint64(secs)
+	}
+	dst = appendCborTypePrefix(dst, major, uint64(val))
+	return dst
+}
+
+func appendFloatTimestamp(dst []byte, t time.Time) []byte {
+	major := majorTypeTags
+	minor := additionalTypeTimestamp
+	dst = append(dst, byte(major|minor))
+	secs := t.Unix()
+	nanos := t.Nanosecond()
+	var val float64
+	val = float64(secs)*1.0 + float64(nanos)*1E-9
+	return AppendFloat64(dst, val)
+}
+
+// AppendTime encodes and adds a timestamp to the dst byte array.
+func AppendTime(dst []byte, t time.Time, unused string) []byte {
+	utc := t.UTC()
+	if utc.Nanosecond() == 0 {
+		return appendIntegerTimestamp(dst, utc)
+	}
+	return appendFloatTimestamp(dst, utc)
+}
+
+// AppendTimes encodes and adds an array of timestamps to the dst byte array.
+func AppendTimes(dst []byte, vals []time.Time, unused string) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+
+	for _, t := range vals {
+		dst = AppendTime(dst, t, unused)
+	}
+	return dst
+}
+
+// AppendDuration encodes and adds a duration to the dst byte array.
+// useInt field indicates whether to store the duration as seconds (integer) or
+// as seconds+nanoseconds (float).
+func AppendDuration(dst []byte, d time.Duration, unit time.Duration, useInt bool) []byte {
+	if useInt {
+		return AppendInt64(dst, int64(d/unit))
+	}
+	return AppendFloat64(dst, float64(d)/float64(unit))
+}
+
+// AppendDurations encodes and adds an array of durations to the dst byte array.
+// useInt field indicates whether to store the duration as seconds (integer) or
+// as seconds+nanoseconds (float).
+func AppendDurations(dst []byte, vals []time.Duration, unit time.Duration, useInt bool) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, d := range vals {
+		dst = AppendDuration(dst, d, unit, useInt)
+	}
+	return dst
+}

internal/cbor/time_test.go

@@ -0,0 +1,99 @@
+package cbor
+
+import (
+	"encoding/hex"
+	"fmt"
+	"math"
+	"testing"
+	"time"
+)
+
+func TestAppendTimeNow(t *testing.T) {
+	tm := time.Now()
+	s := AppendTime([]byte{}, tm, "unused")
+	got := string(s)
+
+	tm1 := float64(tm.Unix()) + float64(tm.Nanosecond())*1E-9
+	tm2 := math.Float64bits(tm1)
+	var tm3 [8]byte
+	for i := uint(0); i < 8; i++ {
+		tm3[i] = byte(tm2 >> ((8 - i - 1) * 8))
+	}
+	want := append([]byte{0xc1, 0xfb}, tm3[:]...)
+	if got != string(want) {
+		t.Errorf("Appendtime(%s)=0x%s, want: 0x%s",
+			"time.Now()", hex.EncodeToString(s),
+			hex.EncodeToString(want))
+	}
+}
+
+var timeIntegerTestcases = []struct {
+	txt    string
+	binary string
+	rfcStr string
+}{
+	{"2013-02-03T19:54:00-08:00", "\xc1\x1a\x51\x0f\x30\xd8", "2013-02-04T03:54:00Z"},
+	{"1950-02-03T19:54:00-08:00", "\xc1\x3a\x25\x71\x93\xa7", "1950-02-04T03:54:00Z"},
+}
+
+func TestAppendTimePastPresentInteger(t *testing.T) {
+	for _, tt := range timeIntegerTestcases {
+		tin, err := time.Parse(time.RFC3339, tt.txt)
+		if err != nil {
+			fmt.Println("Cannot parse input", tt.txt, ".. Skipping!", err)
+			continue
+		}
+		b := AppendTime([]byte{}, tin, "unused")
+		if got, want := string(b), tt.binary; got != want {
+			t.Errorf("appendString(%s) = 0x%s, want 0x%s", tt.txt,
+				hex.EncodeToString(b),
+				hex.EncodeToString([]byte(want)))
+		}
+	}
+}
+
+var timeFloatTestcases = []struct {
+	rfcStr string
+	out    string
+}{
+	{"2006-01-02T15:04:05.999999-08:00", "\xc1\xfb\x41\xd0\xee\x6c\x59\x7f\xff\xfc"},
+	{"1956-01-02T15:04:05.999999-08:00", "\xc1\xfb\xc1\xba\x53\x81\x1a\x00\x00\x11"},
+}
+
+func TestAppendTimePastPresentFloat(t *testing.T) {
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+	for _, tt := range timeFloatTestcases {
+		tin, err := time.Parse(timeFloatFmt, tt.rfcStr)
+		if err != nil {
+			fmt.Println("Cannot parse input", tt.rfcStr, ".. Skipping!")
+			continue
+		}
+		b := AppendTime([]byte{}, tin, "unused")
+		if got, want := string(b), tt.out; got != want {
+			t.Errorf("appendString(%s) = 0x%s, want 0x%s", tt.rfcStr,
+				hex.EncodeToString(b),
+				hex.EncodeToString([]byte(want)))
+		}
+	}
+}
+
+func BenchmarkAppendTime(b *testing.B) {
+	tests := map[string]string{
+		"Integer": "Feb 3, 2013 at 7:54pm (PST)",
+		"Float":   "2006-01-02T15:04:05.999999-08:00",
+	}
+	const timeFloatFmt = "2006-01-02T15:04:05.999999-07:00"
+
+	for name, str := range tests {
+		t, err := time.Parse(time.RFC3339, str)
+		if err != nil {
+			t, _ = time.Parse(timeFloatFmt, str)
+		}
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				_ = AppendTime(buf, t, "unused")
+			}
+		})
+	}
+}

internal/cbor/types.go

@@ -0,0 +1,438 @@
+package cbor
+
+import (
+	"encoding/json"
+	"fmt"
+	"math"
+)
+
+// AppendNull inserts a 'Nil' object into the dst byte array.
+func AppendNull(dst []byte) []byte {
+	return append(dst, byte(majorTypeSimpleAndFloat|additionalTypeNull))
+}
+
+// AppendBeginMarker inserts a map start into the dst byte array.
+func AppendBeginMarker(dst []byte) []byte {
+	return append(dst, byte(majorTypeMap|additionalTypeInfiniteCount))
+}
+
+// AppendEndMarker inserts a map end into the dst byte array.
+func AppendEndMarker(dst []byte) []byte {
+	return append(dst, byte(majorTypeSimpleAndFloat|additionalTypeBreak))
+}
+
+// AppendBool encodes and inserts a boolean value into the dst byte array.
+func AppendBool(dst []byte, val bool) []byte {
+	b := additionalTypeBoolFalse
+	if val {
+		b = additionalTypeBoolTrue
+	}
+	return append(dst, byte(majorTypeSimpleAndFloat|b))
+}
+
+// AppendBools encodes and inserts an array of boolean values into the dst byte array.
+func AppendBools(dst []byte, vals []bool) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendBool(dst, v)
+	}
+	return dst
+}
+
+// AppendInt encodes and inserts an integer value into the dst byte array.
+func AppendInt(dst []byte, val int) []byte {
+	major := majorTypeUnsignedInt
+	contentVal := val
+	if val < 0 {
+		major = majorTypeNegativeInt
+		contentVal = -val - 1
+	}
+	if contentVal <= additionalMax {
+		lb := byte(contentVal)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
+	}
+	return dst
+}
+
+// AppendInts encodes and inserts an array of integer values into the dst byte array.
+func AppendInts(dst []byte, vals []int) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendInt(dst, v)
+	}
+	return dst
+}
+
+// AppendInt8 encodes and inserts an int8 value into the dst byte array.
+func AppendInt8(dst []byte, val int8) []byte {
+	return AppendInt(dst, int(val))
+}
+
+// AppendInts8 encodes and inserts an array of integer values into the dst byte array.
+func AppendInts8(dst []byte, vals []int8) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendInt(dst, int(v))
+	}
+	return dst
+}
+
+// AppendInt16 encodes and inserts a int16 value into the dst byte array.
+func AppendInt16(dst []byte, val int16) []byte {
+	return AppendInt(dst, int(val))
+}
+
+// AppendInts16 encodes and inserts an array of int16 values into the dst byte array.
+func AppendInts16(dst []byte, vals []int16) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendInt(dst, int(v))
+	}
+	return dst
+}
+
+// AppendInt32 encodes and inserts a int32 value into the dst byte array.
+func AppendInt32(dst []byte, val int32) []byte {
+	return AppendInt(dst, int(val))
+}
+
+// AppendInts32 encodes and inserts an array of int32 values into the dst byte array.
+func AppendInts32(dst []byte, vals []int32) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendInt(dst, int(v))
+	}
+	return dst
+}
+
+// AppendInt64 encodes and inserts a int64 value into the dst byte array.
+func AppendInt64(dst []byte, val int64) []byte {
+	major := majorTypeUnsignedInt
+	contentVal := val
+	if val < 0 {
+		major = majorTypeNegativeInt
+		contentVal = -val - 1
+	}
+	if contentVal <= additionalMax {
+		lb := byte(contentVal)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
+	}
+	return dst
+}
+
+// AppendInts64 encodes and inserts an array of int64 values into the dst byte array.
+func AppendInts64(dst []byte, vals []int64) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendInt64(dst, v)
+	}
+	return dst
+}
+
+// AppendUint encodes and inserts an unsigned integer value into the dst byte array.
+func AppendUint(dst []byte, val uint) []byte {
+	return AppendInt64(dst, int64(val))
+}
+
+// AppendUints encodes and inserts an array of unsigned integer values into the dst byte array.
+func AppendUints(dst []byte, vals []uint) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendUint(dst, v)
+	}
+	return dst
+}
+
+// AppendUint8 encodes and inserts a unsigned int8 value into the dst byte array.
+func AppendUint8(dst []byte, val uint8) []byte {
+	return AppendUint(dst, uint(val))
+}
+
+// AppendUints8 encodes and inserts an array of uint8 values into the dst byte array.
+func AppendUints8(dst []byte, vals []uint8) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendUint8(dst, v)
+	}
+	return dst
+}
+
+// AppendUint16 encodes and inserts a uint16 value into the dst byte array.
+func AppendUint16(dst []byte, val uint16) []byte {
+	return AppendUint(dst, uint(val))
+}
+
+// AppendUints16 encodes and inserts an array of uint16 values into the dst byte array.
+func AppendUints16(dst []byte, vals []uint16) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendUint16(dst, v)
+	}
+	return dst
+}
+
+// AppendUint32 encodes and inserts a uint32 value into the dst byte array.
+func AppendUint32(dst []byte, val uint32) []byte {
+	return AppendUint(dst, uint(val))
+}
+
+// AppendUints32 encodes and inserts an array of uint32 values into the dst byte array.
+func AppendUints32(dst []byte, vals []uint32) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendUint32(dst, v)
+	}
+	return dst
+}
+
+// AppendUint64 encodes and inserts a uint64 value into the dst byte array.
+func AppendUint64(dst []byte, val uint64) []byte {
+	major := majorTypeUnsignedInt
+	contentVal := val
+	if contentVal <= additionalMax {
+		lb := byte(contentVal)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(contentVal))
+	}
+	return dst
+}
+
+// AppendUints64 encodes and inserts an array of uint64 values into the dst byte array.
+func AppendUints64(dst []byte, vals []uint64) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendUint64(dst, v)
+	}
+	return dst
+}
+
+// AppendFloat32 encodes and inserts a single precision float value into the dst byte array.
+func AppendFloat32(dst []byte, val float32) []byte {
+	switch {
+	case math.IsNaN(float64(val)):
+		return append(dst, "\xfa\x7f\xc0\x00\x00"...)
+	case math.IsInf(float64(val), 1):
+		return append(dst, "\xfa\x7f\x80\x00\x00"...)
+	case math.IsInf(float64(val), -1):
+		return append(dst, "\xfa\xff\x80\x00\x00"...)
+	}
+	major := majorTypeSimpleAndFloat
+	subType := additionalTypeFloat32
+	n := math.Float32bits(val)
+	var buf [4]byte
+	for i := uint(0); i < 4; i++ {
+		buf[i] = byte(n >> ((3 - i) * 8))
+	}
+	return append(append(dst, byte(major|subType)), buf[0], buf[1], buf[2], buf[3])
+}
+
+// AppendFloats32 encodes and inserts an array of single precision float value into the dst byte array.
+func AppendFloats32(dst []byte, vals []float32) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendFloat32(dst, v)
+	}
+	return dst
+}
+
+// AppendFloat64 encodes and inserts a double precision float value into the dst byte array.
+func AppendFloat64(dst []byte, val float64) []byte {
+	switch {
+	case math.IsNaN(val):
+		return append(dst, "\xfb\x7f\xf8\x00\x00\x00\x00\x00\x00"...)
+	case math.IsInf(val, 1):
+		return append(dst, "\xfb\x7f\xf0\x00\x00\x00\x00\x00\x00"...)
+	case math.IsInf(val, -1):
+		return append(dst, "\xfb\xff\xf0\x00\x00\x00\x00\x00\x00"...)
+	}
+	major := majorTypeSimpleAndFloat
+	subType := additionalTypeFloat64
+	n := math.Float64bits(val)
+	dst = append(dst, byte(major|subType))
+	for i := uint(1); i <= 8; i++ {
+		b := byte(n >> ((8 - i) * 8))
+		dst = append(dst, b)
+	}
+	return dst
+}
+
+// AppendFloats64 encodes and inserts an array of double precision float values into the dst byte array.
+func AppendFloats64(dst []byte, vals []float64) []byte {
+	major := majorTypeArray
+	l := len(vals)
+	if l == 0 {
+		return AppendArrayEnd(AppendArrayStart(dst))
+	}
+	if l <= additionalMax {
+		lb := byte(l)
+		dst = append(dst, byte(major|lb))
+	} else {
+		dst = appendCborTypePrefix(dst, major, uint64(l))
+	}
+	for _, v := range vals {
+		dst = AppendFloat64(dst, v)
+	}
+	return dst
+}
+
+// AppendInterface takes an arbitrary object and converts it to JSON and embeds it dst.
+func AppendInterface(dst []byte, i interface{}) []byte {
+	marshaled, err := json.Marshal(i)
+	if err != nil {
+		return AppendString(dst, fmt.Sprintf("marshaling error: %v", err))
+	}
+	return AppendEmbeddedJSON(dst, marshaled)
+}
+
+// AppendObjectData takes an object in form of a byte array and appends to dst.
+func AppendObjectData(dst []byte, o []byte) []byte {
+	return append(dst, o...)
+}
+
+// AppendArrayStart adds markers to indicate the start of an array.
+func AppendArrayStart(dst []byte) []byte {
+	return append(dst, byte(majorTypeArray|additionalTypeInfiniteCount))
+}
+
+// AppendArrayEnd adds markers to indicate the end of an array.
+func AppendArrayEnd(dst []byte) []byte {
+	return append(dst, byte(majorTypeSimpleAndFloat|additionalTypeBreak))
+}
+
+// AppendArrayDelim adds markers to indicate end of a particular array element.
+func AppendArrayDelim(dst []byte) []byte {
+	//No delimiters needed in cbor
+	return dst
+}
+
+func AppendHex (dst []byte, val []byte) []byte {
+    dst = append(dst, byte(majorTypeTags|additionalTypeIntUint16))
+    dst = append(dst, byte(additionalTypeTagHexString>>8))
+    dst = append(dst, byte(additionalTypeTagHexString&0xff))
+    return AppendBytes(dst, val)
+}

internal/cbor/types_test.go

@@ -0,0 +1,253 @@
+package cbor
+
+import (
+	"encoding/hex"
+	"testing"
+)
+
+func TestAppendNull(t *testing.T) {
+	s := AppendNull([]byte{})
+	got := string(s)
+	want := "\xf6"
+	if got != want {
+		t.Errorf("appendNull() = 0x%s, want: 0x%s", hex.EncodeToString(s),
+			hex.EncodeToString([]byte(want)))
+	}
+}
+
+var booleanTestCases = []struct {
+	val    bool
+	binary string
+	json   string
+}{
+	{true, "\xf5", "true"},
+	{false, "\xf4", "false"},
+}
+
+func TestAppendBool(t *testing.T) {
+	for _, tc := range booleanTestCases {
+		s := AppendBool([]byte{}, tc.val)
+		got := string(s)
+		if got != tc.binary {
+			t.Errorf("AppendBool(%s)=0x%s, want: 0x%s",
+				tc.json, hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.binary)))
+		}
+	}
+}
+
+var booleanArrayTestCases = []struct {
+	val    []bool
+	binary string
+	json   string
+}{
+	{[]bool{true, false, true}, "\x83\xf5\xf4\xf5", "[true,false,true]"},
+	{[]bool{true, false, false, true, false, true}, "\x86\xf5\xf4\xf4\xf5\xf4\xf5", "[true,false,false,true,false,true]"},
+}
+
+func TestAppendBoolArray(t *testing.T) {
+	for _, tc := range booleanArrayTestCases {
+		s := AppendBools([]byte{}, tc.val)
+		got := string(s)
+		if got != tc.binary {
+			t.Errorf("AppendBools(%s)=0x%s, want: 0x%s",
+				tc.json, hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.binary)))
+		}
+	}
+}
+
+var integerTestCases = []struct {
+	val    int
+	binary string
+}{
+	// Value included in the type.
+	{0, "\x00"},
+	{1, "\x01"},
+	{2, "\x02"},
+	{3, "\x03"},
+	{8, "\x08"},
+	{9, "\x09"},
+	{10, "\x0a"},
+	{22, "\x16"},
+	{23, "\x17"},
+	// Value in 1 byte.
+	{24, "\x18\x18"},
+	{25, "\x18\x19"},
+	{26, "\x18\x1a"},
+	{100, "\x18\x64"},
+	{254, "\x18\xfe"},
+	{255, "\x18\xff"},
+	// Value in 2 bytes.
+	{256, "\x19\x01\x00"},
+	{257, "\x19\x01\x01"},
+	{1000, "\x19\x03\xe8"},
+	{0xFFFF, "\x19\xff\xff"},
+	// Value in 4 bytes.
+	{0x10000, "\x1a\x00\x01\x00\x00"},
+	{0xFFFFFFFE, "\x1a\xff\xff\xff\xfe"},
+	{1000000, "\x1a\x00\x0f\x42\x40"},
+	// Value in 8 bytes.
+	{0xabcd100000000, "\x1b\x00\x0a\xbc\xd1\x00\x00\x00\x00"},
+	{1000000000000, "\x1b\x00\x00\x00\xe8\xd4\xa5\x10\x00"},
+	// Negative number test cases.
+	// Value included in the type.
+	{-1, "\x20"},
+	{-2, "\x21"},
+	{-3, "\x22"},
+	{-10, "\x29"},
+	{-21, "\x34"},
+	{-22, "\x35"},
+	{-23, "\x36"},
+	{-24, "\x37"},
+	// Value in 1 byte.
+	{-25, "\x38\x18"},
+	{-26, "\x38\x19"},
+	{-100, "\x38\x63"},
+	{-254, "\x38\xfd"},
+	{-255, "\x38\xfe"},
+	{-256, "\x38\xff"},
+	// Value in 2 bytes.
+	{-257, "\x39\x01\x00"},
+	{-258, "\x39\x01\x01"},
+	{-1000, "\x39\x03\xe7"},
+	// Value in 4 bytes.
+	{-0x10001, "\x3a\x00\x01\x00\x00"},
+	{-0xFFFFFFFE, "\x3a\xff\xff\xff\xfd"},
+	{-1000000, "\x3a\x00\x0f\x42\x3f"},
+	// Value in 8 bytes.
+	{-0xabcd100000001, "\x3b\x00\x0a\xbc\xd1\x00\x00\x00\x00"},
+	{-1000000000001, "\x3b\x00\x00\x00\xe8\xd4\xa5\x10\x00"},
+}
+
+func TestAppendInt(t *testing.T) {
+	for _, tc := range integerTestCases {
+		s := AppendInt([]byte{}, tc.val)
+		got := string(s)
+		if got != tc.binary {
+			t.Errorf("AppendInt(0x%x)=0x%s, want: 0x%s",
+				tc.val, hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.binary)))
+		}
+	}
+}
+
+var integerArrayTestCases = []struct {
+	val    []int
+	binary string
+	json   string
+}{
+	{[]int{-1, 0, 200, 20}, "\x84\x20\x00\x18\xc8\x14", "[-1,0,200,20]"},
+	{[]int{-200, -10, 200, 400}, "\x84\x38\xc7\x29\x18\xc8\x19\x01\x90", "[-200,-10,200,400]"},
+	{[]int{1, 2, 3}, "\x83\x01\x02\x03", "[1,2,3]"},
+	{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25},
+		"\x98\x19\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x18\x18\x19",
+		"[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]"},
+}
+
+func TestAppendIntArray(t *testing.T) {
+	for _, tc := range integerArrayTestCases {
+		s := AppendInts([]byte{}, tc.val)
+		got := string(s)
+		if got != tc.binary {
+			t.Errorf("AppendInts(%s)=0x%s, want: 0x%s",
+				tc.json, hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.binary)))
+		}
+	}
+}
+
+var float32TestCases = []struct {
+	val    float32
+	binary string
+}{
+	{0.0, "\xfa\x00\x00\x00\x00"},
+	{-0.0, "\xfa\x00\x00\x00\x00"},
+	{1.0, "\xfa\x3f\x80\x00\x00"},
+	{1.5, "\xfa\x3f\xc0\x00\x00"},
+	{65504.0, "\xfa\x47\x7f\xe0\x00"},
+	{-4.0, "\xfa\xc0\x80\x00\x00"},
+	{0.00006103515625, "\xfa\x38\x80\x00\x00"},
+}
+
+func TestAppendFloat32(t *testing.T) {
+	for _, tc := range float32TestCases {
+		s := AppendFloat32([]byte{}, tc.val)
+		got := string(s)
+		if got != tc.binary {
+			t.Errorf("AppendFloat32(%f)=0x%s, want: 0x%s",
+				tc.val, hex.EncodeToString(s),
+				hex.EncodeToString([]byte(tc.binary)))
+		}
+	}
+}
+
+func BenchmarkAppendInt(b *testing.B) {
+	type st struct {
+		sz  byte
+		val int64
+	}
+	tests := map[string]st{
+		"int-Positive": {sz: 0, val: 10000},
+		"int-Negative": {sz: 0, val: -10000},
+		"uint8":        {sz: 1, val: 100},
+		"uint16":       {sz: 2, val: 0xfff},
+		"uint32":       {sz: 4, val: 0xffffff},
+		"uint64":       {sz: 8, val: 0xffffffffff},
+		"int8":         {sz: 21, val: -120},
+		"int16":        {sz: 22, val: -1200},
+		"int32":        {sz: 23, val: 32000},
+		"int64":        {sz: 24, val: 0xffffffffff},
+	}
+	for name, str := range tests {
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				switch str.sz {
+				case 0:
+					_ = AppendInt(buf, int(str.val))
+				case 1:
+					_ = AppendUint8(buf, uint8(str.val))
+				case 2:
+					_ = AppendUint16(buf, uint16(str.val))
+				case 4:
+					_ = AppendUint32(buf, uint32(str.val))
+				case 8:
+					_ = AppendUint64(buf, uint64(str.val))
+				case 21:
+					_ = AppendInt8(buf, int8(str.val))
+				case 22:
+					_ = AppendInt16(buf, int16(str.val))
+				case 23:
+					_ = AppendInt32(buf, int32(str.val))
+				case 24:
+					_ = AppendInt64(buf, int64(str.val))
+				}
+			}
+		})
+	}
+}
+
+func BenchmarkAppendFloat(b *testing.B) {
+	type st struct {
+		sz  byte
+		val float64
+	}
+	tests := map[string]st{
+		"Float32": {sz: 4, val: 10000.12345},
+		"Float64": {sz: 8, val: -10000.54321},
+	}
+	for name, str := range tests {
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				switch str.sz {
+				case 4:
+					_ = AppendFloat32(buf, float32(str.val))
+				case 8:
+					_ = AppendFloat64(buf, str.val)
+				}
+			}
+		})
+	}
+}

internal/json/base.go

@@ -1,13 +1,16 @@
 package json
 
+// AppendKey appends a new key to the output JSON.
 func AppendKey(dst []byte, key string) []byte {
-	if len(dst) > 1 {
+	if len(dst) > 1 && dst[len(dst)-1] != '{' {
 		dst = append(dst, ',')
 	}
 	dst = AppendString(dst, key)
 	return append(dst, ':')
 }
 
+// AppendError encodes the error string to json and appends
+// the encoded string to the input byte slice.
 func AppendError(dst []byte, err error) []byte {
 	if err == nil {
 		return append(dst, `null`...)
@@ -15,6 +18,8 @@ func AppendError(dst []byte, err error) []byte {
 	return AppendString(dst, err.Error())
 }
 
+// AppendErrors encodes the error strings to json and
+// appends the encoded string list to the input byte slice.
 func AppendErrors(dst []byte, errs []error) []byte {
 	if len(errs) == 0 {
 		return append(dst, '[', ']')

internal/json/bytes.go

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

internal/json/bytes_test.go

@@ -0,0 +1,82 @@
+package json
+
+import (
+	"testing"
+	"unicode"
+)
+
+func TestAppendBytes(t *testing.T) {
+	for _, tt := range encodeStringTests {
+		b := AppendBytes([]byte{}, []byte(tt.in))
+		if got, want := string(b), tt.out; got != want {
+			t.Errorf("appendBytes(%q) = %#q, want %#q", tt.in, got, want)
+		}
+	}
+}
+
+func TestAppendHex(t *testing.T) {
+	for _, tt := range encodeHexTests {
+		b := AppendHex([]byte{}, []byte{tt.in})
+		if got, want := string(b), tt.out; got != want {
+			t.Errorf("appendHex(%x) = %s, want %s", tt.in, got, want)
+		}
+	}
+}
+
+func TestStringBytes(t *testing.T) {
+	t.Parallel()
+	// Test that encodeState.stringBytes and encodeState.string use the same encoding.
+	var r []rune
+	for i := '\u0000'; i <= unicode.MaxRune; i++ {
+		r = append(r, i)
+	}
+	s := string(r) + "\xff\xff\xffhello" // some invalid UTF-8 too
+
+	enc := string(AppendString([]byte{}, s))
+	encBytes := string(AppendBytes([]byte{}, []byte(s)))
+
+	if enc != encBytes {
+		i := 0
+		for i < len(enc) && i < len(encBytes) && enc[i] == encBytes[i] {
+			i++
+		}
+		enc = enc[i:]
+		encBytes = encBytes[i:]
+		i = 0
+		for i < len(enc) && i < len(encBytes) && enc[len(enc)-i-1] == encBytes[len(encBytes)-i-1] {
+			i++
+		}
+		enc = enc[:len(enc)-i]
+		encBytes = encBytes[:len(encBytes)-i]
+
+		if len(enc) > 20 {
+			enc = enc[:20] + "..."
+		}
+		if len(encBytes) > 20 {
+			encBytes = encBytes[:20] + "..."
+		}
+
+		t.Errorf("encodings differ at %#q vs %#q", enc, encBytes)
+	}
+}
+
+func BenchmarkAppendBytes(b *testing.B) {
+	tests := map[string]string{
+		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingMiddle":   `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"EncodingLast":     `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
+		"MultiBytesFirst":  `❤️aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤️aaaaaaaaaaaaaaaaaaaaaaaa`,
+		"MultiBytesLast":   `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤️`,
+	}
+	for name, str := range tests {
+		byt := []byte(str)
+		b.Run(name, func(b *testing.B) {
+			buf := make([]byte, 0, 100)
+			for i := 0; i < b.N; i++ {
+				_ = AppendBytes(buf, byt)
+			}
+		})
+	}
+}

internal/json/string.go

@@ -4,6 +4,16 @@ import "unicode/utf8"
 
 const hex = "0123456789abcdef"
 
+var noEscapeTable = [256]bool{}
+
+func init() {
+	for i := 0; i <= 0x7e; i++ {
+		noEscapeTable[i] = i >= 0x20 && i != '\\' && i != '"'
+	}
+}
+
+// AppendStrings encodes the input strings to json and
+// appends the encoded string list to the input byte slice.
 func AppendStrings(dst []byte, vals []string) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -36,7 +46,7 @@ func AppendString(dst []byte, s string) []byte {
 		// Check if the character needs encoding. Control characters, slashes,
 		// and the double quote need json encoding. Bytes above the ascii
 		// boundary needs utf8 encoding.
-		if s[i] < 0x20 || s[i] > 0x7e || s[i] == '\\' || s[i] == '"' {
+		if !noEscapeTable[s[i]] {
 			// We encountered a character that needs to be encoded. Switch
 			// to complex version of the algorithm.
 			dst = appendStringComplex(dst, s, i)
@@ -74,76 +84,7 @@ func appendStringComplex(dst []byte, s string, i int) []byte {
 			i += size
 			continue
 		}
-		if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
-			i++
-			continue
-		}
-		// We encountered a character that needs to be encoded.
-		// Let's append the previous simple characters to the byte slice
-		// and switch our operation to read and encode the remainder
-		// characters byte-by-byte.
-		if start < i {
-			dst = append(dst, s[start:i]...)
-		}
-		switch b {
-		case '"', '\\':
-			dst = append(dst, '\\', b)
-		case '\b':
-			dst = append(dst, '\\', 'b')
-		case '\f':
-			dst = append(dst, '\\', 'f')
-		case '\n':
-			dst = append(dst, '\\', 'n')
-		case '\r':
-			dst = append(dst, '\\', 'r')
-		case '\t':
-			dst = append(dst, '\\', 't')
-		default:
-			dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF])
-		}
-		i++
-		start = i
-	}
-	if start < len(s) {
-		dst = append(dst, s[start:]...)
-	}
-	return dst
-}
-
-// AppendBytes is a mirror of appendString with []byte arg
-func AppendBytes(dst, s []byte) []byte {
-	dst = append(dst, '"')
-	for i := 0; i < len(s); i++ {
-		if s[i] < 0x20 || s[i] > 0x7e || s[i] == '\\' || s[i] == '"' {
-			dst = appendBytesComplex(dst, s, i)
-			return append(dst, '"')
-		}
-	}
-	dst = append(dst, s...)
-	return append(dst, '"')
-}
-
-// appendBytesComplex is a mirror of the appendStringComplex
-// with []byte arg
-func appendBytesComplex(dst, s []byte, i int) []byte {
-	start := 0
-	for i < len(s) {
-		b := s[i]
-		if b >= utf8.RuneSelf {
-			r, size := utf8.DecodeRune(s[i:])
-			if r == utf8.RuneError && size == 1 {
-				if start < i {
-					dst = append(dst, s[start:i]...)
-				}
-				dst = append(dst, `\ufffd`...)
-				i += size
-				start = i
-				continue
-			}
-			i += size
-			continue
-		}
-		if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
+		if noEscapeTable[b] {
 			i++
 			continue
 		}

internal/json/string_test.go

@@ -2,7 +2,6 @@ package json
 
 import (
 	"testing"
-	"unicode"
 )
 
 var encodeStringTests = []struct {
@@ -53,7 +52,18 @@ var encodeStringTests = []struct {
 	{"emoji \u2764\ufe0f!", `"emoji ❤️!"`},
 }
 
-func TestappendString(t *testing.T) {
+var encodeHexTests = []struct {
+	in  byte
+	out string
+}{
+	{0x00, `"00"`},
+	{0x0f, `"0f"`},
+	{0x10, `"10"`},
+	{0xf0, `"f0"`},
+	{0xff, `"ff"`},
+}
+
+func TestAppendString(t *testing.T) {
 	for _, tt := range encodeStringTests {
 		b := AppendString([]byte{}, tt.in)
 		if got, want := string(b), tt.out; got != want {
@@ -62,53 +72,7 @@ func TestappendString(t *testing.T) {
 	}
 }
 
-func TestappendBytes(t *testing.T) {
-	for _, tt := range encodeStringTests {
-		b := AppendBytes([]byte{}, []byte(tt.in))
-		if got, want := string(b), tt.out; got != want {
-			t.Errorf("appendBytes(%q) = %#q, want %#q", tt.in, got, want)
-		}
-	}
-}
-
-func TestStringBytes(t *testing.T) {
-	t.Parallel()
-	// Test that encodeState.stringBytes and encodeState.string use the same encoding.
-	var r []rune
-	for i := '\u0000'; i <= unicode.MaxRune; i++ {
-		r = append(r, i)
-	}
-	s := string(r) + "\xff\xff\xffhello" // some invalid UTF-8 too
-
-	enc := string(AppendString([]byte{}, s))
-	encBytes := string(AppendBytes([]byte{}, []byte(s)))
-
-	if enc != encBytes {
-		i := 0
-		for i < len(enc) && i < len(encBytes) && enc[i] == encBytes[i] {
-			i++
-		}
-		enc = enc[i:]
-		encBytes = encBytes[i:]
-		i = 0
-		for i < len(enc) && i < len(encBytes) && enc[len(enc)-i-1] == encBytes[len(encBytes)-i-1] {
-			i++
-		}
-		enc = enc[:len(enc)-i]
-		encBytes = encBytes[:len(encBytes)-i]
-
-		if len(enc) > 20 {
-			enc = enc[:20] + "..."
-		}
-		if len(encBytes) > 20 {
-			encBytes = encBytes[:20] + "..."
-		}
-
-		t.Errorf("encodings differ at %#q vs %#q", enc, encBytes)
-	}
-}
-
-func BenchmarkappendString(b *testing.B) {
+func BenchmarkAppendString(b *testing.B) {
 	tests := map[string]string{
 		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
 		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
@@ -127,24 +91,3 @@ func BenchmarkappendString(b *testing.B) {
 		})
 	}
 }
-
-func BenchmarkappendBytes(b *testing.B) {
-	tests := map[string]string{
-		"NoEncoding":       `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
-		"EncodingFirst":    `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
-		"EncodingMiddle":   `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
-		"EncodingLast":     `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
-		"MultiBytesFirst":  `❤️aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
-		"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤️aaaaaaaaaaaaaaaaaaaaaaaa`,
-		"MultiBytesLast":   `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤️`,
-	}
-	for name, str := range tests {
-		byt := []byte(str)
-		b.Run(name, func(b *testing.B) {
-			buf := make([]byte, 0, 100)
-			for i := 0; i < b.N; i++ {
-				_ = AppendBytes(buf, byt)
-			}
-		})
-	}
-}

internal/json/time.go

@@ -5,6 +5,8 @@ import (
 	"time"
 )
 
+// AppendTime formats the input time with the given format
+// and appends the encoded string to the input byte slice.
 func AppendTime(dst []byte, t time.Time, format string) []byte {
 	if format == "" {
 		return AppendInt64(dst, t.Unix())
@@ -12,6 +14,8 @@ func AppendTime(dst []byte, t time.Time, format string) []byte {
 	return append(t.AppendFormat(append(dst, '"'), format), '"')
 }
 
+// AppendTimes converts the input times with the given format
+// and appends the encoded string list to the input byte slice.
 func AppendTimes(dst []byte, vals []time.Time, format string) []byte {
 	if format == "" {
 		return appendUnixTimes(dst, vals)
@@ -45,6 +49,8 @@ func appendUnixTimes(dst []byte, vals []time.Time) []byte {
 	return dst
 }
 
+// AppendDuration formats the input duration with the given unit & format
+// and appends the encoded string to the input byte slice.
 func AppendDuration(dst []byte, d time.Duration, unit time.Duration, useInt bool) []byte {
 	if useInt {
 		return strconv.AppendInt(dst, int64(d/unit), 10)
@@ -52,6 +58,8 @@ func AppendDuration(dst []byte, d time.Duration, unit time.Duration, useInt bool
 	return AppendFloat64(dst, float64(d)/float64(unit))
 }
 
+// AppendDurations formats the input durations with the given unit & format
+// and appends the encoded string list to the input byte slice.
 func AppendDurations(dst []byte, vals []time.Duration, unit time.Duration, useInt bool) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')

internal/json/types.go

@@ -7,10 +7,14 @@ import (
 	"strconv"
 )
 
+// AppendBool converts the input bool to a string and
+// appends the encoded string to the input byte slice.
 func AppendBool(dst []byte, val bool) []byte {
 	return strconv.AppendBool(dst, val)
 }
 
+// AppendBools encodes the input bools to json and
+// appends the encoded string list to the input byte slice.
 func AppendBools(dst []byte, vals []bool) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -26,10 +30,14 @@ func AppendBools(dst []byte, vals []bool) []byte {
 	return dst
 }
 
+// AppendInt converts the input int to a string and
+// appends the encoded string to the input byte slice.
 func AppendInt(dst []byte, val int) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
+// AppendInts encodes the input ints to json and
+// appends the encoded string list to the input byte slice.
 func AppendInts(dst []byte, vals []int) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -45,10 +53,14 @@ func AppendInts(dst []byte, vals []int) []byte {
 	return dst
 }
 
+// AppendInt8 converts the input []int8 to a string and
+// appends the encoded string to the input byte slice.
 func AppendInt8(dst []byte, val int8) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
+// AppendInts8 encodes the input int8s to json and
+// appends the encoded string list to the input byte slice.
 func AppendInts8(dst []byte, vals []int8) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -64,10 +76,14 @@ func AppendInts8(dst []byte, vals []int8) []byte {
 	return dst
 }
 
+// AppendInt16 converts the input int16 to a string and
+// appends the encoded string to the input byte slice.
 func AppendInt16(dst []byte, val int16) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
+// AppendInts16 encodes the input int16s to json and
+// appends the encoded string list to the input byte slice.
 func AppendInts16(dst []byte, vals []int16) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -83,10 +99,14 @@ func AppendInts16(dst []byte, vals []int16) []byte {
 	return dst
 }
 
+// AppendInt32 converts the input int32 to a string and
+// appends the encoded string to the input byte slice.
 func AppendInt32(dst []byte, val int32) []byte {
 	return strconv.AppendInt(dst, int64(val), 10)
 }
 
+// AppendInts32 encodes the input int32s to json and
+// appends the encoded string list to the input byte slice.
 func AppendInts32(dst []byte, vals []int32) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -102,10 +122,14 @@ func AppendInts32(dst []byte, vals []int32) []byte {
 	return dst
 }
 
+// AppendInt64 converts the input int64 to a string and
+// appends the encoded string to the input byte slice.
 func AppendInt64(dst []byte, val int64) []byte {
 	return strconv.AppendInt(dst, val, 10)
 }
 
+// AppendInts64 encodes the input int64s to json and
+// appends the encoded string list to the input byte slice.
 func AppendInts64(dst []byte, vals []int64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -121,10 +145,14 @@ func AppendInts64(dst []byte, vals []int64) []byte {
 	return dst
 }
 
+// AppendUint converts the input uint to a string and
+// appends the encoded string to the input byte slice.
 func AppendUint(dst []byte, val uint) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
+// AppendUints encodes the input uints to json and
+// appends the encoded string list to the input byte slice.
 func AppendUints(dst []byte, vals []uint) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -140,10 +168,14 @@ func AppendUints(dst []byte, vals []uint) []byte {
 	return dst
 }
 
+// AppendUint8 converts the input uint8 to a string and
+// appends the encoded string to the input byte slice.
 func AppendUint8(dst []byte, val uint8) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
+// AppendUints8 encodes the input uint8s to json and
+// appends the encoded string list to the input byte slice.
 func AppendUints8(dst []byte, vals []uint8) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -159,10 +191,14 @@ func AppendUints8(dst []byte, vals []uint8) []byte {
 	return dst
 }
 
+// AppendUint16 converts the input uint16 to a string and
+// appends the encoded string to the input byte slice.
 func AppendUint16(dst []byte, val uint16) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
+// AppendUints16 encodes the input uint16s to json and
+// appends the encoded string list to the input byte slice.
 func AppendUints16(dst []byte, vals []uint16) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -178,10 +214,14 @@ func AppendUints16(dst []byte, vals []uint16) []byte {
 	return dst
 }
 
+// AppendUint32 converts the input uint32 to a string and
+// appends the encoded string to the input byte slice.
 func AppendUint32(dst []byte, val uint32) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
+// AppendUints32 encodes the input uint32s to json and
+// appends the encoded string list to the input byte slice.
 func AppendUints32(dst []byte, vals []uint32) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -197,10 +237,14 @@ func AppendUints32(dst []byte, vals []uint32) []byte {
 	return dst
 }
 
+// AppendUint64 converts the input uint64 to a string and
+// appends the encoded string to the input byte slice.
 func AppendUint64(dst []byte, val uint64) []byte {
 	return strconv.AppendUint(dst, uint64(val), 10)
 }
 
+// AppendUints64 encodes the input uint64s to json and
+// appends the encoded string list to the input byte slice.
 func AppendUints64(dst []byte, vals []uint64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -216,6 +260,8 @@ func AppendUints64(dst []byte, vals []uint64) []byte {
 	return dst
 }
 
+// AppendFloat converts the input float to a string and
+// appends the encoded string to the input byte slice.
 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
@@ -231,10 +277,14 @@ func AppendFloat(dst []byte, val float64, bitSize int) []byte {
 	return strconv.AppendFloat(dst, val, 'f', -1, bitSize)
 }
 
+// AppendFloat32 converts the input float32 to a string and
+// appends the encoded string to the input byte slice.
 func AppendFloat32(dst []byte, val float32) []byte {
 	return AppendFloat(dst, float64(val), 32)
 }
 
+// AppendFloats32 encodes the input float32s to json and
+// appends the encoded string list to the input byte slice.
 func AppendFloats32(dst []byte, vals []float32) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -250,10 +300,14 @@ func AppendFloats32(dst []byte, vals []float32) []byte {
 	return dst
 }
 
+// AppendFloat64 converts the input float64 to a string and
+// appends the encoded string to the input byte slice.
 func AppendFloat64(dst []byte, val float64) []byte {
 	return AppendFloat(dst, val, 64)
 }
 
+// AppendFloats64 encodes the input float64s to json and
+// appends the encoded string list to the input byte slice.
 func AppendFloats64(dst []byte, vals []float64) []byte {
 	if len(vals) == 0 {
 		return append(dst, '[', ']')
@@ -269,6 +323,8 @@ func AppendFloats64(dst []byte, vals []float64) []byte {
 	return dst
 }
 
+// AppendInterface marshals the input interface to a string and
+// appends the encoded string to the input byte slice.
 func AppendInterface(dst []byte, i interface{}) []byte {
 	marshaled, err := json.Marshal(i)
 	if err != nil {
@@ -276,3 +332,16 @@ func AppendInterface(dst []byte, i interface{}) []byte {
 	}
 	return append(dst, marshaled...)
 }
+
+func AppendObjectData(dst []byte, o []byte) []byte {
+	// Two conditions we want to put a ',' between existing content and
+	// new content:
+	// 1. new content starts with '{' - which shd be dropped   OR
+	// 2. existing content has already other fields
+	if o[0] == '{' {
+		o[0] = ','
+	} else if len(dst) > 1 {
+		dst = append(dst, ',')
+	}
+	return append(dst, o...)
+}

internal/json/types_test.go

@@ -6,27 +6,57 @@ import (
 	"testing"
 )
 
-func Test_appendFloat64(t *testing.T) {
+func TestAppendType(t *testing.T) {
+	w := map[string]func(interface{}) []byte{
+		"AppendInt":     func(v interface{}) []byte { return AppendInt([]byte{}, v.(int)) },
+		"AppendInt8":    func(v interface{}) []byte { return AppendInt8([]byte{}, v.(int8)) },
+		"AppendInt16":   func(v interface{}) []byte { return AppendInt16([]byte{}, v.(int16)) },
+		"AppendInt32":   func(v interface{}) []byte { return AppendInt32([]byte{}, v.(int32)) },
+		"AppendInt64":   func(v interface{}) []byte { return AppendInt64([]byte{}, v.(int64)) },
+		"AppendUint":    func(v interface{}) []byte { return AppendUint([]byte{}, v.(uint)) },
+		"AppendUint8":   func(v interface{}) []byte { return AppendUint8([]byte{}, v.(uint8)) },
+		"AppendUint16":  func(v interface{}) []byte { return AppendUint16([]byte{}, v.(uint16)) },
+		"AppendUint32":  func(v interface{}) []byte { return AppendUint32([]byte{}, v.(uint32)) },
+		"AppendUint64":  func(v interface{}) []byte { return AppendUint64([]byte{}, v.(uint64)) },
+		"AppendFloat32": func(v interface{}) []byte { return AppendFloat32([]byte{}, v.(float32)) },
+		"AppendFloat64": func(v interface{}) []byte { return AppendFloat64([]byte{}, v.(float64)) },
+	}
 	tests := []struct {
 		name  string
-		input float64
+		fn    string
+		input interface{}
 		want  []byte
 	}{
-		{"-Inf", math.Inf(-1), []byte(`"-Inf"`)},
-		{"+Inf", math.Inf(1), []byte(`"+Inf"`)},
-		{"NaN", math.NaN(), []byte(`"NaN"`)},
-		{"0", 0, []byte(`0`)},
-		{"-1.1", -1.1, []byte(`-1.1`)},
-		{"1e20", 1e20, []byte(`100000000000000000000`)},
-		{"1e21", 1e21, []byte(`1000000000000000000000`)},
+		{"AppendInt8(math.MaxInt8)", "AppendInt8", int8(math.MaxInt8), []byte("127")},
+		{"AppendInt16(math.MaxInt16)", "AppendInt16", int16(math.MaxInt16), []byte("32767")},
+		{"AppendInt32(math.MaxInt32)", "AppendInt32", int32(math.MaxInt32), []byte("2147483647")},
+		{"AppendInt64(math.MaxInt64)", "AppendInt64", int64(math.MaxInt64), []byte("9223372036854775807")},
+
+		{"AppendUint8(math.MaxUint8)", "AppendUint8", uint8(math.MaxUint8), []byte("255")},
+		{"AppendUint16(math.MaxUint16)", "AppendUint16", uint16(math.MaxUint16), []byte("65535")},
+		{"AppendUint32(math.MaxUint32)", "AppendUint32", uint32(math.MaxUint32), []byte("4294967295")},
+		{"AppendUint64(math.MaxUint64)", "AppendUint64", uint64(math.MaxUint64), []byte("18446744073709551615")},
+
+		{"AppendFloat32(-Inf)", "AppendFloat32", float32(math.Inf(-1)), []byte(`"-Inf"`)},
+		{"AppendFloat32(+Inf)", "AppendFloat32", float32(math.Inf(1)), []byte(`"+Inf"`)},
+		{"AppendFloat32(NaN)", "AppendFloat32", float32(math.NaN()), []byte(`"NaN"`)},
+		{"AppendFloat32(0)", "AppendFloat32", float32(0), []byte(`0`)},
+		{"AppendFloat32(-1.1)", "AppendFloat32", float32(-1.1), []byte(`-1.1`)},
+		{"AppendFloat32(1e20)", "AppendFloat32", float32(1e20), []byte(`100000000000000000000`)},
+		{"AppendFloat32(1e21)", "AppendFloat32", float32(1e21), []byte(`1000000000000000000000`)},
+
+		{"AppendFloat64(-Inf)", "AppendFloat64", float64(math.Inf(-1)), []byte(`"-Inf"`)},
+		{"AppendFloat64(+Inf)", "AppendFloat64", float64(math.Inf(1)), []byte(`"+Inf"`)},
+		{"AppendFloat64(NaN)", "AppendFloat64", float64(math.NaN()), []byte(`"NaN"`)},
+		{"AppendFloat64(0)", "AppendFloat64", float64(0), []byte(`0`)},
+		{"AppendFloat64(-1.1)", "AppendFloat64", float64(-1.1), []byte(`-1.1`)},
+		{"AppendFloat64(1e20)", "AppendFloat64", float64(1e20), []byte(`100000000000000000000`)},
+		{"AppendFloat64(1e21)", "AppendFloat64", float64(1e21), []byte(`1000000000000000000000`)},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := AppendFloat32([]byte{}, float32(tt.input)); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("appendFloat32() = %s, want %s", got, tt.want)
-			}
-			if got := AppendFloat64([]byte{}, tt.input); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("appendFloat32() = %s, want %s", got, tt.want)
+			if got := w[tt.fn](tt.input); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("got %s, want %s", got, tt.want)
 			}
 		})
 	}

log.go

@@ -62,19 +62,48 @@
 //
 // Sample logs:
 //
-//     sampled := log.Sample(10)
+//     sampled := log.Sample(&zerolog.BasicSampler{N: 10})
 //     sampled.Info().Msg("will be logged every 10 messages")
 //
+// Log with contextual hooks:
+//
+//     // Create the hook:
+//     type SeverityHook struct{}
+//
+//     func (h SeverityHook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
+//          if level != zerolog.NoLevel {
+//              e.Str("severity", level.String())
+//          }
+//     }
+//
+//     // And use it:
+//     var h SeverityHook
+//     log := zerolog.New(os.Stdout).Hook(h)
+//     log.Warn().Msg("")
+//     // Output: {"level":"warn","severity":"warn"}
+//
+//
+// Caveats
+//
+// There is no fields deduplication out-of-the-box.
+// Using the same key multiple times creates new key in final JSON each time.
+//
+//     logger := zerolog.New(os.Stderr).With().Timestamp().Logger()
+//     logger.Info().
+//            Timestamp().
+//            Msg("dup")
+//     // Output: {"level":"info","time":1494567715,"time":1494567715,"message":"dup"}
+//
+// However, it’s not a big deal though as JSON accepts dup keys,
+// the last one prevails.
 package zerolog
 
 import (
+	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"strconv"
-	"sync/atomic"
-
-	"github.com/rs/zerolog/internal/json"
 )
 
 // Level defines log levels.
@@ -93,6 +122,8 @@ const (
 	FatalLevel
 	// PanicLevel defines panic log level.
 	PanicLevel
+	// NoLevel defines an absent log level.
+	NoLevel
 	// Disabled disables the logger.
 	Disabled
 )
@@ -111,21 +142,12 @@ func (l Level) String() string {
 		return "fatal"
 	case PanicLevel:
 		return "panic"
+	case NoLevel:
+		return ""
 	}
 	return ""
 }
 
-const (
-	// Often samples log every 10 events.
-	Often = 10
-	// Sometimes samples log every 100 events.
-	Sometimes = 100
-	// Rarely samples log every 1000 events.
-	Rarely = 1000
-)
-
-var disabledEvent = newEvent(levelWriterAdapter{ioutil.Discard}, 0, false)
-
 // A Logger represents an active logging object that generates lines
 // of JSON output to an io.Writer. Each logging operation makes a single
 // call to the Writer's Write method. There is no guaranty on access
@@ -134,9 +156,9 @@ var disabledEvent = newEvent(levelWriterAdapter{ioutil.Discard}, 0, false)
 type Logger struct {
 	w       LevelWriter
 	level   Level
-	sample  uint32
-	counter *uint32
+	sampler Sampler
 	context []byte
+	hooks   []Hook
 }
 
 // New creates a root logger with given output writer. If the output writer implements
@@ -166,9 +188,14 @@ func Nop() Logger {
 func (l Logger) Output(w io.Writer) Logger {
 	l2 := New(w)
 	l2.level = l.level
-	l2.sample = l.sample
-	l2.context = make([]byte, len(l.context))
-	copy(l2.context, l.context)
+	l2.sampler = l.sampler
+	if len(l.hooks) > 0 {
+		l2.hooks = append(l2.hooks, l.hooks...)
+	}
+	if l.context != nil {
+		l2.context = make([]byte, len(l.context), cap(l.context))
+		copy(l2.context, l.context)
+	}
 	return l2
 }
 
@@ -178,91 +205,90 @@ func (l Logger) With() Context {
 	l.context = make([]byte, 0, 500)
 	if context != nil {
 		l.context = append(l.context, context...)
-	} else {
-		// first byte of context is presence of timestamp or not
-		l.context = append(l.context, 0)
 	}
 	return Context{l}
 }
 
-// Level creates a child logger with the minimum accepted level set to level.
-func (l Logger) Level(lvl Level) Logger {
-	return Logger{
-		w:       l.w,
-		level:   lvl,
-		sample:  l.sample,
-		counter: l.counter,
-		context: l.context,
+// UpdateContext updates the internal logger's context.
+//
+// Use this method with caution. If unsure, prefer the With method.
+func (l *Logger) UpdateContext(update func(c Context) Context) {
+	if l == disabledLogger {
+		return
 	}
+	if cap(l.context) == 0 {
+		l.context = make([]byte, 0, 500)
+	}
+	c := update(Context{*l})
+	l.context = c.l.context
 }
 
-// Sample returns a logger that only let one message out of every to pass thru.
-func (l Logger) Sample(every int) Logger {
-	if every == 0 {
-		// Create a child with no sampling.
-		return Logger{
-			w:       l.w,
-			level:   l.level,
-			context: l.context,
-		}
-	}
-	return Logger{
-		w:       l.w,
-		level:   l.level,
-		sample:  uint32(every),
-		counter: new(uint32),
-		context: l.context,
-	}
+// Level creates a child logger with the minimum accepted level set to level.
+func (l Logger) Level(lvl Level) Logger {
+	l.level = lvl
+	return l
+}
+
+// Sample returns a logger with the s sampler.
+func (l Logger) Sample(s Sampler) Logger {
+	l.sampler = s
+	return l
+}
+
+// Hook returns a logger with the h Hook.
+func (l Logger) Hook(h Hook) Logger {
+	l.hooks = append(l.hooks, h)
+	return l
 }
 
 // Debug starts a new message with debug level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Debug() *Event {
-	return l.newEvent(DebugLevel, true, nil)
+func (l *Logger) Debug() *Event {
+	return l.newEvent(DebugLevel, nil)
 }
 
 // Info starts a new message with info level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Info() *Event {
-	return l.newEvent(InfoLevel, true, nil)
+func (l *Logger) Info() *Event {
+	return l.newEvent(InfoLevel, nil)
 }
 
 // Warn starts a new message with warn level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Warn() *Event {
-	return l.newEvent(WarnLevel, true, nil)
+func (l *Logger) Warn() *Event {
+	return l.newEvent(WarnLevel, nil)
 }
 
 // Error starts a new message with error level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Error() *Event {
-	return l.newEvent(ErrorLevel, true, nil)
+func (l *Logger) Error() *Event {
+	return l.newEvent(ErrorLevel, nil)
 }
 
 // Fatal starts a new message with fatal level. The os.Exit(1) function
 // is called by the Msg method.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Fatal() *Event {
-	return l.newEvent(FatalLevel, true, func(msg string) { os.Exit(1) })
+func (l *Logger) Fatal() *Event {
+	return l.newEvent(FatalLevel, func(msg string) { os.Exit(1) })
 }
 
 // Panic starts a new message with panic level. The message is also sent
 // to the panic function.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Panic() *Event {
-	return l.newEvent(PanicLevel, true, func(msg string) { panic(msg) })
+func (l *Logger) Panic() *Event {
+	return l.newEvent(PanicLevel, func(msg string) { panic(msg) })
 }
 
 // WithLevel starts a new message with level.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) WithLevel(level Level) *Event {
+func (l *Logger) WithLevel(level Level) *Event {
 	switch level {
 	case DebugLevel:
 		return l.Debug()
@@ -276,8 +302,10 @@ func (l Logger) WithLevel(level Level) *Event {
 		return l.Fatal()
 	case PanicLevel:
 		return l.Panic()
+	case NoLevel:
+		return l.Log()
 	case Disabled:
-		return disabledEvent
+		return nil
 	default:
 		panic("zerolog: WithLevel(): invalid level: " + strconv.Itoa(int(level)))
 	}
@@ -287,10 +315,24 @@ func (l Logger) WithLevel(level Level) *Event {
 // will still disable events produced by this method.
 //
 // You must call Msg on the returned event in order to send the event.
-func (l Logger) Log() *Event {
-	// We use panic level with addLevelField=false to make Log passthrough all
-	// levels except Disabled.
-	return l.newEvent(PanicLevel, false, nil)
+func (l *Logger) Log() *Event {
+	return l.newEvent(NoLevel, nil)
+}
+
+// Print sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Print.
+func (l *Logger) Print(v ...interface{}) {
+	if e := l.Debug(); e.Enabled() {
+		e.Msg(fmt.Sprint(v...))
+	}
+}
+
+// Printf sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Printf.
+func (l *Logger) Printf(format string, v ...interface{}) {
+	if e := l.Debug(); e.Enabled() {
+		e.Msg(fmt.Sprintf(format, v...))
+	}
 }
 
 // Write implements the io.Writer interface. This is useful to set as a writer
@@ -305,44 +347,30 @@ func (l Logger) Write(p []byte) (n int, err error) {
 	return
 }
 
-func (l Logger) newEvent(level Level, addLevelField bool, done func(string)) *Event {
+func (l *Logger) newEvent(level Level, done func(string)) *Event {
 	enabled := l.should(level)
 	if !enabled {
-		return disabledEvent
+		return nil
 	}
-	lvl := InfoLevel
-	if addLevelField {
-		lvl = level
-	}
-	e := newEvent(l.w, lvl, enabled)
+	e := newEvent(l.w, level, true)
 	e.done = done
-	if l.context != nil && len(l.context) > 0 && l.context[0] > 0 {
-		// first byte of context is ts flag
-		e.buf = json.AppendTime(json.AppendKey(e.buf, TimestampFieldName), TimestampFunc(), TimeFieldFormat)
-	}
-	if addLevelField {
+	e.ch = l.hooks
+	if level != NoLevel {
 		e.Str(LevelFieldName, level.String())
 	}
-	if l.sample > 0 && SampleFieldName != "" {
-		e.Uint32(SampleFieldName, l.sample)
-	}
-	if l.context != nil && len(l.context) > 1 {
-		if len(e.buf) > 1 {
-			e.buf = append(e.buf, ',')
-		}
-		e.buf = append(e.buf, l.context[1:]...)
+	if l.context != nil && len(l.context) > 0 {
+		e.buf = appendObjectData(e.buf, l.context)
 	}
 	return e
 }
 
 // should returns true if the log event should be logged.
-func (l Logger) should(lvl Level) bool {
+func (l *Logger) should(lvl Level) bool {
 	if lvl < l.level || lvl < globalLevel() {
 		return false
 	}
-	if l.sample > 0 && l.counter != nil && !samplingDisabled() {
-		c := atomic.AddUint32(l.counter, 1)
-		return c%l.sample == 0
+	if l.sampler != nil && !samplingDisabled() {
+		return l.sampler.Sample(lvl)
 	}
 	return true
 }

log/log.go

@@ -22,14 +22,19 @@ func With() zerolog.Context {
 	return Logger.With()
 }
 
-// Level crestes a child logger with the minium accepted level set to level.
+// Level creates a child logger with the minimum accepted level set to level.
 func Level(level zerolog.Level) zerolog.Logger {
 	return Logger.Level(level)
 }
 
-// Sample returns a logger that only let one message out of every to pass thru.
-func Sample(every int) zerolog.Logger {
-	return Logger.Sample(every)
+// Sample returns a logger with the s sampler.
+func Sample(s zerolog.Sampler) zerolog.Logger {
+	return Logger.Sample(s)
+}
+
+// Hook returns a logger with the h Hook.
+func Hook(h zerolog.Hook) zerolog.Logger {
+	return Logger.Hook(h)
 }
 
 // Debug starts a new message with debug level.
@@ -76,16 +81,35 @@ func Panic() *zerolog.Event {
 	return Logger.Panic()
 }
 
+// WithLevel starts a new message with level.
+//
+// You must call Msg on the returned event in order to send the event.
+func WithLevel(level zerolog.Level) *zerolog.Event {
+	return Logger.WithLevel(level)
+}
+
 // Log starts a new message with no level. Setting zerolog.GlobalLevel to
-// zerlog.Disabled will still disable events produced by this method.
+// zerolog.Disabled will still disable events produced by this method.
 //
 // You must call Msg on the returned event in order to send the event.
 func Log() *zerolog.Event {
 	return Logger.Log()
 }
 
+// Print sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Print.
+func Print(v ...interface{}) {
+	Logger.Print(v...)
+}
+
+// Printf sends a log event using debug level and no extra field.
+// Arguments are handled in the manner of fmt.Printf.
+func Printf(format string, v ...interface{}) {
+	Logger.Printf(format, v...)
+}
+
 // Ctx returns the Logger associated with the ctx. If no logger
 // is associated, a disabled logger is returned.
-func Ctx(ctx context.Context) zerolog.Logger {
+func Ctx(ctx context.Context) *zerolog.Logger {
 	return zerolog.Ctx(ctx)
 }

log/log_example_test.go

@@ -0,0 +1,143 @@
+// +build !binary_log
+
+package log_test
+
+import (
+	"errors"
+	"flag"
+	"os"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+// setup would normally be an init() function, however, there seems
+// to be something awry with the testing framework when we set the
+// global Logger from an init()
+func setup() {
+	// UNIX Time is faster and smaller than most timestamps
+	// If you set zerolog.TimeFieldFormat to an empty string,
+	// logs will write with UNIX time
+	zerolog.TimeFieldFormat = ""
+	// In order to always output a static time to stdout for these
+	// examples to pass, we need to override zerolog.TimestampFunc
+	// and log.Logger globals -- you would not normally need to do this
+	zerolog.TimestampFunc = func() time.Time {
+		return time.Date(2008, 1, 8, 17, 5, 05, 0, time.UTC)
+	}
+	log.Logger = zerolog.New(os.Stdout).With().Timestamp().Logger()
+}
+
+// Simple logging example using the Print function in the log package
+// Note that both Print and Printf are at the debug log level by default
+func ExamplePrint() {
+	setup()
+
+	log.Print("hello world")
+	// Output: {"level":"debug","time":1199811905,"message":"hello world"}
+}
+
+// Simple logging example using the Printf function in the log package
+func ExamplePrintf() {
+	setup()
+
+	log.Printf("hello %s", "world")
+	// Output: {"level":"debug","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log with no particular "level"
+func ExampleLog() {
+	setup()
+	log.Log().Msg("hello world")
+
+	// Output: {"time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "debug")
+func ExampleDebug() {
+	setup()
+	log.Debug().Msg("hello world")
+
+	// Output: {"level":"debug","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "info")
+func ExampleInfo() {
+	setup()
+	log.Info().Msg("hello world")
+
+	// Output: {"level":"info","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "warn")
+func ExampleWarn() {
+	setup()
+	log.Warn().Msg("hello world")
+
+	// Output: {"level":"warn","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "error")
+func ExampleError() {
+	setup()
+	log.Error().Msg("hello world")
+
+	// Output: {"level":"error","time":1199811905,"message":"hello world"}
+}
+
+// Example of a log at a particular "level" (in this case, "fatal")
+func ExampleFatal() {
+	setup()
+	err := errors.New("A repo man spends his life getting into tense situations")
+	service := "myservice"
+
+	log.Fatal().
+		Err(err).
+		Str("service", service).
+		Msgf("Cannot start %s", service)
+
+	// Outputs: {"level":"fatal","time":1199811905,"error":"A repo man spends his life getting into tense situations","service":"myservice","message":"Cannot start myservice"}
+}
+
+// TODO: Panic
+
+// This example uses command-line flags to demonstrate various outputs
+// depending on the chosen log level.
+func Example() {
+	setup()
+	debug := flag.Bool("debug", false, "sets log level to debug")
+
+	flag.Parse()
+
+	// Default level for this example is info, unless debug flag is present
+	zerolog.SetGlobalLevel(zerolog.InfoLevel)
+	if *debug {
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+	}
+
+	log.Debug().Msg("This message appears only when log level set to Debug")
+	log.Info().Msg("This message appears when log level set to Debug or Info")
+
+	if e := log.Debug(); e.Enabled() {
+		// Compute log output only if enabled.
+		value := "bar"
+		e.Str("foo", value).Msg("some debug message")
+	}
+
+	// Output: {"level":"info","time":1199811905,"message":"This message appears when log level set to Debug or Info"}
+}
+
+// TODO: Output
+
+// TODO: With
+
+// TODO: Level
+
+// TODO: Sample
+
+// TODO: Hook
+
+// TODO: WithLevel
+
+// TODO: Ctx

log_example_test.go

@@ -1,3 +1,5 @@
+// +build !binary_log
+
 package zerolog_test
 
 import (
@@ -13,7 +15,6 @@ func ExampleNew() {
 	log := zerolog.New(os.Stdout)
 
 	log.Info().Msg("hello world")
-
 	// Output: {"level":"info","message":"hello world"}
 }
 
@@ -38,15 +39,58 @@ func ExampleLogger_Level() {
 }
 
 func ExampleLogger_Sample() {
-	log := zerolog.New(os.Stdout).Sample(2)
+	log := zerolog.New(os.Stdout).Sample(&zerolog.BasicSampler{N: 2})
 
 	log.Info().Msg("message 1")
 	log.Info().Msg("message 2")
 	log.Info().Msg("message 3")
 	log.Info().Msg("message 4")
 
-	// Output: {"level":"info","sample":2,"message":"message 2"}
-	// {"level":"info","sample":2,"message":"message 4"}
+	// Output: {"level":"info","message":"message 2"}
+	// {"level":"info","message":"message 4"}
+}
+
+type LevelNameHook struct{}
+
+func (h LevelNameHook) Run(e *zerolog.Event, l zerolog.Level, msg string) {
+	if l != zerolog.NoLevel {
+		e.Str("level_name", l.String())
+	} else {
+		e.Str("level_name", "NoLevel")
+	}
+}
+
+type MessageHook string
+
+func (h MessageHook) Run(e *zerolog.Event, l zerolog.Level, msg string) {
+	e.Str("the_message", msg)
+}
+
+func ExampleLogger_Hook() {
+	var levelNameHook LevelNameHook
+	var messageHook MessageHook = "The message"
+
+	log := zerolog.New(os.Stdout).Hook(levelNameHook).Hook(messageHook)
+
+	log.Info().Msg("hello world")
+
+	// Output: {"level":"info","level_name":"info","the_message":"hello world","message":"hello world"}
+}
+
+func ExampleLogger_Print() {
+	log := zerolog.New(os.Stdout)
+
+	log.Print("hello world")
+
+	// Output: {"level":"debug","message":"hello world"}
+}
+
+func ExampleLogger_Printf() {
+	log := zerolog.New(os.Stdout)
+
+	log.Printf("hello %s", "world")
+
+	// Output: {"level":"debug","message":"hello world"}
 }
 
 func ExampleLogger_Debug() {

log_test.go

@@ -3,7 +3,9 @@ package zerolog
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"reflect"
+	"runtime"
 	"testing"
 	"time"
 )
@@ -13,7 +15,7 @@ func TestLog(t *testing.T) {
 		out := &bytes.Buffer{}
 		log := New(out)
 		log.Log().Msg("")
-		if got, want := out.String(), "{}\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), "{}\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -22,7 +24,7 @@ func TestLog(t *testing.T) {
 		out := &bytes.Buffer{}
 		log := New(out)
 		log.Log().Str("foo", "bar").Msg("")
-		if got, want := out.String(), `{"foo":"bar"}`+"\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"foo":"bar"}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -34,7 +36,7 @@ func TestLog(t *testing.T) {
 			Str("foo", "bar").
 			Int("n", 123).
 			Msg("")
-		if got, want := out.String(), `{"foo":"bar","n":123}`+"\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"foo":"bar","n":123}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -45,7 +47,7 @@ func TestInfo(t *testing.T) {
 		out := &bytes.Buffer{}
 		log := New(out)
 		log.Info().Msg("")
-		if got, want := out.String(), `{"level":"info"}`+"\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"info"}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -54,7 +56,7 @@ func TestInfo(t *testing.T) {
 		out := &bytes.Buffer{}
 		log := New(out)
 		log.Info().Str("foo", "bar").Msg("")
-		if got, want := out.String(), `{"level":"info","foo":"bar"}`+"\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"info","foo":"bar"}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -66,7 +68,7 @@ func TestInfo(t *testing.T) {
 			Str("foo", "bar").
 			Int("n", 123).
 			Msg("")
-		if got, want := out.String(), `{"level":"info","foo":"bar","n":123}`+"\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"info","foo":"bar","n":123}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -74,8 +76,11 @@ func TestInfo(t *testing.T) {
 
 func TestWith(t *testing.T) {
 	out := &bytes.Buffer{}
-	log := New(out).With().
-		Str("foo", "bar").
+	ctx := New(out).With().
+		Str("string", "foo").
+		Bytes("bytes", []byte("bar")).
+		Hex("hex", []byte{0x12, 0xef}).
+		RawJSON("json", []byte(`{"some":"json"}`)).
 		AnErr("some_err", nil).
 		Err(errors.New("some error")).
 		Bool("bool", true).
@@ -91,10 +96,12 @@ func TestWith(t *testing.T) {
 		Uint64("uint64", 10).
 		Float32("float32", 11).
 		Float64("float64", 12).
-		Time("time", time.Time{}).
-		Logger()
+		Time("time", time.Time{})
+	_, file, line, _ := runtime.Caller(0)
+	caller := fmt.Sprintf("%s:%d", file, line+3)
+	log := ctx.Caller().Logger()
 	log.Log().Msg("")
-	if got, want := out.String(), `{"foo":"bar","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,"float32":11,"float64":12,"time":"0001-01-01T00:00:00Z"}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"string":"foo","bytes":"bar","hex":"12ef","json":{"some":"json"},"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,"float32":11,"float64":12,"time":"0001-01-01T00:00:00Z","caller":"`+caller+`"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -123,7 +130,33 @@ func TestFieldsMap(t *testing.T) {
 		"dur":     1 * time.Second,
 		"time":    time.Time{},
 	}).Msg("")
-	if got, want := out.String(), `{"bool":true,"bytes":"bar","dur":1000,"error":"some error","float32":11,"float64":12,"int":1,"int16":3,"int32":4,"int64":5,"int8":2,"nil":null,"string":"foo","time":"0001-01-01T00:00:00Z","uint":6,"uint16":8,"uint32":9,"uint64":10,"uint8":7}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"bool":true,"bytes":"bar","dur":1000,"error":"some error","float32":11,"float64":12,"int":1,"int16":3,"int32":4,"int64":5,"int8":2,"nil":null,"string":"foo","time":"0001-01-01T00:00:00Z","uint":6,"uint16":8,"uint32":9,"uint64":10,"uint8":7}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestFieldsMapPnt(t *testing.T) {
+	out := &bytes.Buffer{}
+	log := New(out)
+	log.Log().Fields(map[string]interface{}{
+		"string":  new(string),
+		"bool":    new(bool),
+		"int":     new(int),
+		"int8":    new(int8),
+		"int16":   new(int16),
+		"int32":   new(int32),
+		"int64":   new(int64),
+		"uint":    new(uint),
+		"uint8":   new(uint8),
+		"uint16":  new(uint16),
+		"uint32":  new(uint32),
+		"uint64":  new(uint64),
+		"float32": new(float32),
+		"float64": new(float64),
+		"dur":     new(time.Duration),
+		"time":    new(time.Time),
+	}).Msg("")
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"bool":false,"dur":0,"float32":0,"float64":0,"int":0,"int16":0,"int32":0,"int64":0,"int8":0,"string":"","time":"0001-01-01T00:00:00Z","uint":0,"uint16":0,"uint32":0,"uint64":0,"uint8":0}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -132,9 +165,14 @@ func TestFields(t *testing.T) {
 	out := &bytes.Buffer{}
 	log := New(out)
 	now := time.Now()
+	_, file, line, _ := runtime.Caller(0)
+	caller := fmt.Sprintf("%s:%d", file, line+3)
 	log.Log().
+		Caller().
 		Str("string", "foo").
 		Bytes("bytes", []byte("bar")).
+		Hex("hex", []byte{0x12, 0xef}).
+		RawJSON("json", []byte(`{"some":"json"}`)).
 		AnErr("some_err", nil).
 		Err(errors.New("some error")).
 		Bool("bool", true).
@@ -154,7 +192,7 @@ func TestFields(t *testing.T) {
 		Time("time", time.Time{}).
 		TimeDiff("diff", now, now.Add(-10*time.Second)).
 		Msg("")
-	if got, want := out.String(), `{"string":"foo","bytes":"bar","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,"float32":11,"float64":12,"dur":1000,"time":"0001-01-01T00:00:00Z","diff":10000}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"caller":"`+caller+`","string":"foo","bytes":"bar","hex":"12ef","json":{"some":"json"},"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,"float32":11,"float64":12,"dur":1000,"time":"0001-01-01T00:00:00Z","diff":10000}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -181,7 +219,7 @@ func TestFieldsArrayEmpty(t *testing.T) {
 		Durs("dur", []time.Duration{}).
 		Times("time", []time.Time{}).
 		Msg("")
-	if got, want := out.String(), `{"string":[],"err":[],"bool":[],"int":[],"int8":[],"int16":[],"int32":[],"int64":[],"uint":[],"uint8":[],"uint16":[],"uint32":[],"uint64":[],"float32":[],"float64":[],"dur":[],"time":[]}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"string":[],"err":[],"bool":[],"int":[],"int8":[],"int16":[],"int32":[],"int64":[],"uint":[],"uint8":[],"uint16":[],"uint32":[],"uint64":[],"float32":[],"float64":[],"dur":[],"time":[]}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -208,7 +246,7 @@ func TestFieldsArraySingleElement(t *testing.T) {
 		Durs("dur", []time.Duration{1 * time.Second}).
 		Times("time", []time.Time{time.Time{}}).
 		Msg("")
-	if got, want := out.String(), `{"string":["foo"],"err":["some error"],"bool":[true],"int":[1],"int8":[2],"int16":[3],"int32":[4],"int64":[5],"uint":[6],"uint8":[7],"uint16":[8],"uint32":[9],"uint64":[10],"float32":[11],"float64":[12],"dur":[1000],"time":["0001-01-01T00:00:00Z"]}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"string":["foo"],"err":["some error"],"bool":[true],"int":[1],"int8":[2],"int16":[3],"int32":[4],"int64":[5],"uint":[6],"uint8":[7],"uint16":[8],"uint32":[9],"uint64":[10],"float32":[11],"float64":[12],"dur":[1000],"time":["0001-01-01T00:00:00Z"]}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -235,7 +273,7 @@ func TestFieldsArrayMultipleElement(t *testing.T) {
 		Durs("dur", []time.Duration{1 * time.Second, 0}).
 		Times("time", []time.Time{time.Time{}, time.Time{}}).
 		Msg("")
-	if got, want := out.String(), `{"string":["foo","bar"],"err":["some error",null],"bool":[true,false],"int":[1,0],"int8":[2,0],"int16":[3,0],"int32":[4,0],"int64":[5,0],"uint":[6,0],"uint8":[7,0],"uint16":[8,0],"uint32":[9,0],"uint64":[10,0],"float32":[11,0],"float64":[12,0],"dur":[1000,0],"time":["0001-01-01T00:00:00Z","0001-01-01T00:00:00Z"]}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"string":["foo","bar"],"err":["some error",null],"bool":[true,false],"int":[1,0],"int8":[2,0],"int16":[3,0],"int32":[4,0],"int64":[5,0],"uint":[6,0],"uint8":[7,0],"uint16":[8,0],"uint32":[9,0],"uint64":[10,0],"float32":[11,0],"float64":[12,0],"dur":[1000,0],"time":["0001-01-01T00:00:00Z","0001-01-01T00:00:00Z"]}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -247,6 +285,7 @@ func TestFieldsDisabled(t *testing.T) {
 	log.Debug().
 		Str("string", "foo").
 		Bytes("bytes", []byte("bar")).
+		Hex("hex", []byte{0x12, 0xef}).
 		AnErr("some_err", nil).
 		Err(errors.New("some error")).
 		Bool("bool", true).
@@ -266,15 +305,16 @@ func TestFieldsDisabled(t *testing.T) {
 		Time("time", time.Time{}).
 		TimeDiff("diff", now, now.Add(-10*time.Second)).
 		Msg("")
-	if got, want := out.String(), ""; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), ""; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
 
 func TestMsgf(t *testing.T) {
 	out := &bytes.Buffer{}
-	New(out).Log().Msgf("one %s %.1f %d %v", "two", 3.4, 5, errors.New("six"))
-	if got, want := out.String(), `{"message":"one two 3.4 5 six"}`+"\n"; got != want {
+	log := New(out)
+	log.Log().Msgf("one %s %.1f %d %v", "two", 3.4, 5, errors.New("six"))
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"message":"one two 3.4 5 six"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -283,7 +323,7 @@ func TestWithAndFieldsCombined(t *testing.T) {
 	out := &bytes.Buffer{}
 	log := New(out).With().Str("f1", "val").Str("f2", "val").Logger()
 	log.Log().Str("f3", "val").Msg("")
-	if got, want := out.String(), `{"f1":"val","f2":"val","f3":"val"}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"f1":"val","f2":"val","f3":"val"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -293,7 +333,43 @@ func TestLevel(t *testing.T) {
 		out := &bytes.Buffer{}
 		log := New(out).Level(Disabled)
 		log.Info().Msg("test")
-		if got, want := out.String(), ""; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), ""; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+
+	t.Run("NoLevel/Disabled", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Level(Disabled)
+		log.Log().Msg("test")
+		if got, want := decodeIfBinaryToString(out.Bytes()), ""; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+
+	t.Run("NoLevel/Info", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Level(InfoLevel)
+		log.Log().Msg("test")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"message":"test"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+
+	t.Run("NoLevel/Panic", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Level(PanicLevel)
+		log.Log().Msg("test")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"message":"test"}`+"\n"; got != want {
+			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+		}
+	})
+
+	t.Run("NoLevel/WithLevel", func(t *testing.T) {
+		out := &bytes.Buffer{}
+		log := New(out).Level(InfoLevel)
+		log.WithLevel(NoLevel).Msg("test")
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"message":"test"}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -302,7 +378,7 @@ func TestLevel(t *testing.T) {
 		out := &bytes.Buffer{}
 		log := New(out).Level(InfoLevel)
 		log.Info().Msg("test")
-		if got, want := out.String(), `{"level":"info","message":"test"}`+"\n"; got != want {
+		if got, want := decodeIfBinaryToString(out.Bytes()), `{"level":"info","message":"test"}`+"\n"; got != want {
 			t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 		}
 	})
@@ -310,12 +386,12 @@ func TestLevel(t *testing.T) {
 
 func TestSampling(t *testing.T) {
 	out := &bytes.Buffer{}
-	log := New(out).Sample(2)
+	log := New(out).Sample(&BasicSampler{N: 2})
 	log.Log().Int("i", 1).Msg("")
 	log.Log().Int("i", 2).Msg("")
 	log.Log().Int("i", 3).Msg("")
 	log.Log().Int("i", 4).Msg("")
-	if got, want := out.String(), "{\"sample\":2,\"i\":2}\n{\"sample\":2,\"i\":4}\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), "{\"i\":2}\n{\"i\":4}\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -332,6 +408,7 @@ func (lw *levelWriter) Write(p []byte) (int, error) {
 }
 
 func (lw *levelWriter) WriteLevel(lvl Level, p []byte) (int, error) {
+	p = decodeIfBinaryToBytes(p)
 	lw.ops = append(lw.ops, struct {
 		l Level
 		p string
@@ -351,10 +428,12 @@ func TestLevelWriter(t *testing.T) {
 	log.Info().Msg("2")
 	log.Warn().Msg("3")
 	log.Error().Msg("4")
+	log.Log().Msg("nolevel-1")
 	log.WithLevel(DebugLevel).Msg("5")
 	log.WithLevel(InfoLevel).Msg("6")
 	log.WithLevel(WarnLevel).Msg("7")
 	log.WithLevel(ErrorLevel).Msg("8")
+	log.WithLevel(NoLevel).Msg("nolevel-2")
 
 	want := []struct {
 		l Level
@@ -364,10 +443,12 @@ func TestLevelWriter(t *testing.T) {
 		{InfoLevel, `{"level":"info","message":"2"}` + "\n"},
 		{WarnLevel, `{"level":"warn","message":"3"}` + "\n"},
 		{ErrorLevel, `{"level":"error","message":"4"}` + "\n"},
+		{NoLevel, `{"message":"nolevel-1"}` + "\n"},
 		{DebugLevel, `{"level":"debug","message":"5"}` + "\n"},
 		{InfoLevel, `{"level":"info","message":"6"}` + "\n"},
 		{WarnLevel, `{"level":"warn","message":"7"}` + "\n"},
 		{ErrorLevel, `{"level":"error","message":"8"}` + "\n"},
+		{NoLevel, `{"message":"nolevel-2"}` + "\n"},
 	}
 	if got := lw.ops; !reflect.DeepEqual(got, want) {
 		t.Errorf("invalid ops:\ngot:\n%v\nwant:\n%v", got, want)
@@ -385,7 +466,7 @@ func TestContextTimestamp(t *testing.T) {
 	log := New(out).With().Timestamp().Str("foo", "bar").Logger()
 	log.Log().Msg("hello world")
 
-	if got, want := out.String(), `{"time":"2001-02-03T04:05:06Z","foo":"bar","message":"hello world"}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"foo":"bar","time":"2001-02-03T04:05:06Z","message":"hello world"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }
@@ -401,7 +482,35 @@ func TestEventTimestamp(t *testing.T) {
 	log := New(out).With().Str("foo", "bar").Logger()
 	log.Log().Timestamp().Msg("hello world")
 
-	if got, want := out.String(), `{"foo":"bar","time":"2001-02-03T04:05:06Z","message":"hello world"}`+"\n"; got != want {
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"foo":"bar","time":"2001-02-03T04:05:06Z","message":"hello world"}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestOutputWithoutTimestamp(t *testing.T) {
+	ignoredOut := &bytes.Buffer{}
+	out := &bytes.Buffer{}
+	log := New(ignoredOut).Output(out).With().Str("foo", "bar").Logger()
+	log.Log().Msg("hello world")
+
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"foo":"bar","message":"hello world"}`+"\n"; got != want {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+}
+
+func TestOutputWithTimestamp(t *testing.T) {
+	TimestampFunc = func() time.Time {
+		return time.Date(2001, time.February, 3, 4, 5, 6, 7, time.UTC)
+	}
+	defer func() {
+		TimestampFunc = time.Now
+	}()
+	ignoredOut := &bytes.Buffer{}
+	out := &bytes.Buffer{}
+	log := New(ignoredOut).Output(out).With().Timestamp().Str("foo", "bar").Logger()
+	log.Log().Msg("hello world")
+
+	if got, want := decodeIfBinaryToString(out.Bytes()), `{"foo":"bar","time":"2001-02-03T04:05:06Z","message":"hello world"}`+"\n"; got != want {
 		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
 	}
 }

sampler.go

@@ -0,0 +1,126 @@
+package zerolog
+
+import (
+	"math/rand"
+	"sync/atomic"
+	"time"
+)
+
+var (
+	// Often samples log every ~ 10 events.
+	Often = RandomSampler(10)
+	// Sometimes samples log every ~ 100 events.
+	Sometimes = RandomSampler(100)
+	// Rarely samples log every ~ 1000 events.
+	Rarely = RandomSampler(1000)
+)
+
+// Sampler defines an interface to a log sampler.
+type Sampler interface {
+	// Sample returns true if the event should be part of the sample, false if
+	// the event should be dropped.
+	Sample(lvl Level) bool
+}
+
+// RandomSampler use a PRNG to randomly sample an event out of N events,
+// regardless of their level.
+type RandomSampler uint32
+
+// Sample implements the Sampler interface.
+func (s RandomSampler) Sample(lvl Level) bool {
+	if s <= 0 {
+		return false
+	}
+	if rand.Intn(int(s)) != 0 {
+		return false
+	}
+	return true
+}
+
+// BasicSampler is a sampler that will send every Nth events, regardless of
+// there level.
+type BasicSampler struct {
+	N       uint32
+	counter uint32
+}
+
+// Sample implements the Sampler interface.
+func (s *BasicSampler) Sample(lvl Level) bool {
+	c := atomic.AddUint32(&s.counter, 1)
+	return c%s.N == 0
+}
+
+// BurstSampler lets Burst events pass per Period then pass the decision to
+// NextSampler. If Sampler is not set, all subsequent events are rejected.
+type BurstSampler struct {
+	// Burst is the maximum number of event per period allowed before calling
+	// NextSampler.
+	Burst uint32
+	// Period defines the burst period. If 0, NextSampler is always called.
+	Period time.Duration
+	// NextSampler is the sampler used after the burst is reached. If nil,
+	// events are always rejected after the burst.
+	NextSampler Sampler
+
+	counter uint32
+	resetAt int64
+}
+
+// Sample implements the Sampler interface.
+func (s *BurstSampler) Sample(lvl Level) bool {
+	if s.Burst > 0 && s.Period > 0 {
+		if s.inc() <= s.Burst {
+			return true
+		}
+	}
+	if s.NextSampler == nil {
+		return false
+	}
+	return s.NextSampler.Sample(lvl)
+}
+
+func (s *BurstSampler) inc() uint32 {
+	now := time.Now().UnixNano()
+	resetAt := atomic.LoadInt64(&s.resetAt)
+	var c uint32
+	if now > resetAt {
+		c = 1
+		atomic.StoreUint32(&s.counter, c)
+		newResetAt := now + s.Period.Nanoseconds()
+		reset := atomic.CompareAndSwapInt64(&s.resetAt, resetAt, newResetAt)
+		if !reset {
+			// Lost the race with another goroutine trying to reset.
+			c = atomic.AddUint32(&s.counter, 1)
+		}
+	} else {
+		c = atomic.AddUint32(&s.counter, 1)
+	}
+	return c
+}
+
+// LevelSampler applies a different sampler for each level.
+type LevelSampler struct {
+	DebugSampler, InfoSampler, WarnSampler, ErrorSampler Sampler
+}
+
+func (s LevelSampler) Sample(lvl Level) bool {
+	switch lvl {
+	case DebugLevel:
+		if s.DebugSampler != nil {
+			return s.DebugSampler.Sample(lvl)
+		}
+	case InfoLevel:
+		if s.InfoSampler != nil {
+			return s.InfoSampler.Sample(lvl)
+		}
+	case WarnLevel:
+		if s.WarnSampler != nil {
+			return s.WarnSampler.Sample(lvl)
+		}
+	case ErrorLevel:
+		if s.ErrorSampler != nil {
+			return s.ErrorSampler.Sample(lvl)
+		}
+	}
+	return true
+}

sampler_test.go

@@ -0,0 +1,77 @@
+// +build !binary_log
+
+package zerolog
+
+import (
+	"testing"
+	"time"
+)
+
+var samplers = []struct {
+	name    string
+	sampler func() Sampler
+	total   int
+	wantMin int
+	wantMax int
+}{
+	{
+		"BasicSampler",
+		func() Sampler {
+			return &BasicSampler{N: 5}
+		},
+		100, 20, 20,
+	},
+	{
+		"RandomSampler",
+		func() Sampler {
+			return RandomSampler(5)
+		},
+		100, 10, 30,
+	},
+	{
+		"BurstSampler",
+		func() Sampler {
+			return &BurstSampler{Burst: 20, Period: time.Second}
+		},
+		100, 20, 20,
+	},
+	{
+		"BurstSamplerNext",
+		func() Sampler {
+			return &BurstSampler{Burst: 20, Period: time.Second, NextSampler: &BasicSampler{N: 5}}
+		},
+		120, 40, 40,
+	},
+}
+
+func TestSamplers(t *testing.T) {
+	for i := range samplers {
+		s := samplers[i]
+		t.Run(s.name, func(t *testing.T) {
+			sampler := s.sampler()
+			got := 0
+			for t := s.total; t > 0; t-- {
+				if sampler.Sample(0) {
+					got++
+				}
+			}
+			if got < s.wantMin || got > s.wantMax {
+				t.Errorf("%s.Sample(0) == true %d on %d, want [%d, %d]", s.name, got, s.total, s.wantMin, s.wantMax)
+			}
+		})
+	}
+}
+
+func BenchmarkSamplers(b *testing.B) {
+	for i := range samplers {
+		s := samplers[i]
+		b.Run(s.name, func(b *testing.B) {
+			sampler := s.sampler()
+			b.RunParallel(func(pb *testing.PB) {
+				for pb.Next() {
+					sampler.Sample(0)
+				}
+			})
+		})
+	}
+}

syslog.go

@@ -1,8 +1,11 @@
 // +build !windows
+// +build !binary_log
 
 package zerolog
 
-import "io"
+import (
+	"io"
+)
 
 // SyslogWriter is an interface matching a syslog.Writer struct.
 type SyslogWriter interface {
@@ -44,6 +47,8 @@ func (sw syslogWriter) WriteLevel(level Level, p []byte) (n int, err error) {
 		err = sw.w.Emerg(string(p))
 	case PanicLevel:
 		err = sw.w.Crit(string(p))
+	case NoLevel:
+		err = sw.w.Info(string(p))
 	default:
 		panic("invalid level")
 	}

syslog_test.go

@@ -1,3 +1,6 @@
+// +build !binary_log
+// +build !windows
+
 package zerolog
 
 import "testing"
@@ -46,11 +49,13 @@ func TestSyslogWriter(t *testing.T) {
 	log.Info().Msg("info")
 	log.Warn().Msg("warn")
 	log.Error().Msg("error")
+	log.Log().Msg("nolevel")
 	want := []syslogEvent{
 		{"Debug", `{"level":"debug","message":"debug"}` + "\n"},
 		{"Info", `{"level":"info","message":"info"}` + "\n"},
 		{"Warning", `{"level":"warn","message":"warn"}` + "\n"},
 		{"Err", `{"level":"error","message":"error"}` + "\n"},
+		{"Info", `{"message":"nolevel"}` + "\n"},
 	}
 	if got := sw.events; !reflect.DeepEqual(got, want) {
 		t.Errorf("Invalid syslog message routing: want %v, got %v", want, got)

writer_test.go

@@ -1,3 +1,6 @@
+// +build !binary_log
+// +build !windows
+
 package zerolog
 
 import (
@@ -12,11 +15,13 @@ func TestMultiSyslogWriter(t *testing.T) {
 	log.Info().Msg("info")
 	log.Warn().Msg("warn")
 	log.Error().Msg("error")
+	log.Log().Msg("nolevel")
 	want := []syslogEvent{
 		{"Debug", `{"level":"debug","message":"debug"}` + "\n"},
 		{"Info", `{"level":"info","message":"info"}` + "\n"},
 		{"Warning", `{"level":"warn","message":"warn"}` + "\n"},
 		{"Err", `{"level":"error","message":"error"}` + "\n"},
+		{"Info", `{"message":"nolevel"}` + "\n"},
 	}
 	if got := sw.events; !reflect.DeepEqual(got, want) {
 		t.Errorf("Invalid syslog message routing: want %v, got %v", want, got)