log

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 Go to latest Published: Jan 25, 2024 License: MIT Imports: 26 Imported by: 0

README

phuslog - High performance structured logging

godoc goreport build stability-stable

Features

  • Dependency Free
  • Simple and Clean Interface
  • Consistent Writer
    • IOWriter, io.Writer wrapper
    • ConsoleWriter, colorful & formatting
    • FileWriter, rotating & effective
    • MultiLevelWriter, multiple level dispatch
    • SyslogWriter, memory efficient syslog
    • JournalWriter, linux systemd logging
    • EventlogWriter, windows system event
    • AsyncWriter, asynchronously writing
  • Stdlib Log Adapter
    • Logger.Std, transform to std log instances
    • Logger.Slog, transform to log/slog instances
  • Third-party Logger Interceptor
    • logr, logr interceptor
    • gin, gin logging middleware
    • gorm, gorm logger interface
    • fiber, fiber logging handler
    • grpc, grpc logger interceptor
    • grpcgateway, grpcgateway logger interceptor
  • Useful utility function
    • Goid(), the goroutine id matches stack trace
    • NewXID(), create a tracing id
    • Fastrandn(n uint32), fast pseudorandom uint32 in [0,n)
    • IsTerminal(fd uintptr), isatty for golang
    • Printf(fmt string, a ...interface{}), printf logging
  • High Performance

Interfaces

Logger
// DefaultLogger is the global logger.
var DefaultLogger = Logger{
	Level:      DebugLevel,
	Caller:     0,
	TimeField:  "",
	TimeFormat: "",
	Writer:     &IOWriter{os.Stderr},
}

// A Logger represents an active logging object that generates lines of JSON output to an io.Writer.
type Logger struct {
	// Level defines log levels.
	Level Level

	// Caller determines if adds the file:line of the "caller" key.
	// If Caller is negative, adds the full /path/to/file:line of the "caller" key.
	Caller int

	// TimeField defines the time filed name in output.  It uses "time" in if empty.
	TimeField string

	// TimeFormat specifies the time format in output. It uses RFC3339 with millisecond if empty.
	// If set with `TimeFormatUnix/TimeFormatUnixMs/TimeFormatUnixWithMs`, timestamps are formated.
	TimeFormat string

	// Writer specifies the writer of output. It uses a wrapped os.Stderr Writer in if empty.
	Writer Writer
}
ConsoleWriter
// ConsoleWriter parses the JSON input and writes it in a colorized, human-friendly format to Writer.
// IMPORTANT: Don't use ConsoleWriter on critical path of a high concurrency and low latency application.
//
// Default output format:
//     {Time} {Level} {Goid} {Caller} > {Message} {Key}={Value} {Key}={Value}
type ConsoleWriter struct {
	// ColorOutput determines if used colorized output.
	ColorOutput bool

	// QuoteString determines if quoting string values.
	QuoteString bool

	// EndWithMessage determines if output message in the end of line.
	EndWithMessage bool

	// Writer is the output destination. using os.Stderr if empty.
	Writer io.Writer

	// Formatter specifies an optional text formatter for creating a customized output,
	// If it is set, ColorOutput, QuoteString and EndWithMessage will be ignored.
	Formatter func(w io.Writer, args *FormatterArgs) (n int, err error)
}

// FormatterArgs is a parsed sturct from json input
type FormatterArgs struct {
	Time      string // "2019-07-10T05:35:54.277Z"
	Message   string // "a structure message"
	Level     string // "info"
	Caller    string // "main.go:123"
	Goid      string // "1"
	Stack     string // "<stack string>"
	KeyValues []struct {
		Key       string // "foo"
		Value     string // "bar"
	}
}
FileWriter
// FileWriter is an Writer that writes to the specified filename.
type FileWriter struct {
	// Filename is the file to write logs to.  Backup log files will be retained
	// in the same directory.
	Filename string

	// FileMode represents the file's mode and permission bits.  The default
	// mode is 0644
	FileMode os.FileMode

	// MaxSize is the maximum size in bytes of the log file before it gets rotated.
	MaxSize int64

	// MaxBackups is the maximum number of old log files to retain.  The default
	// is to retain all old log files
	MaxBackups int

	// TimeFormat specifies the time format of filename, uses `2006-01-02T15-04-05` as default format.
	// If set with `TimeFormatUnix`, `TimeFormatUnixMs`, times are formated as UNIX timestamp.
	TimeFormat string

	// LocalTime determines if the time used for formatting the timestamps in
	// log files is the computer's local time.  The default is to use UTC time.
	LocalTime bool

	// HostName determines if the hostname used for formatting in log files.
	HostName bool

	// ProcessID determines if the pid used for formatting in log files.
	ProcessID bool

	// EnsureFolder ensures the file directory creation before writing.
	EnsureFolder bool

	// Header specifies an optional header function of log file after rotation,
	Header func(fileinfo os.FileInfo) []byte

	// Cleaner specifies an optional cleanup function of log backups after rotation,
	// if not set, the default behavior is to delete more than MaxBackups log files.
	Cleaner func(filename string, maxBackups int, matches []os.FileInfo)
}

Highlights:

  • FileWriter implements log.Writer and io.Writer interfaces both, it is a recommended alternative to lumberjack.
  • FileWriter creates a symlink to the current logging file, it requires administrator privileges on Windows.
  • FileWriter does not rotate if you define a broad TimeFormat value(daily or monthly) then reach its MaxSize.

Getting Started

Simple Logging Example

An out of box example. playground

package main

import (
	"github.com/fabricatorsltd/logstack"
)

func main() {
	log.Info().Str("foo", "bar").Int("number", 42).Msg("hi, phuslog")
	log.Info().Msgf("foo=%s number=%d error=%+v", "bar", 42, "an error")
}

// Output:
//   {"time":"2020-03-22T09:58:41.828Z","level":"info","foo":"bar","number":42,"message":"hi, phuslog"}
//   {"time":"2020-03-22T09:58:41.828Z","level":"info","message":"foo=bar number=42 error=an error"}

Note: By default log writes to os.Stderr

Customize the configuration and formatting:

To customize logger filed name and format. playground

package main

import (
	"github.com/fabricatorsltd/logstack"
)

func main() {
	log.DefaultLogger = log.Logger{
		Level:      log.InfoLevel,
		Caller:     1,
		TimeField:  "date",
		TimeFormat: "2006-01-02",
		Writer:     &log.IOWriter{os.Stdout},
	}

	log.Info().Str("foo", "bar").Msgf("hello %s", "world")

	logger := log.Logger{
		Level:      log.InfoLevel,
		TimeField:  "ts",
		TimeFormat: log.TimeFormatUnixMs,
	}

	logger.Log().Str("foo", "bar").Msg("")
}

// Output:
//    {"date":"2019-07-04","level":"info","caller":"prog.go:16","foo":"bar","message":"hello world"}
//    {"ts":1257894000000,"foo":"bar"}
Pretty Console Writer

To log a human-friendly, colorized output, use ConsoleWriter. playground

if log.IsTerminal(os.Stderr.Fd()) {
	log.DefaultLogger = log.Logger{
		TimeFormat: "15:04:05",
		Caller:     1,
		Writer: &log.ConsoleWriter{
			ColorOutput:    true,
			QuoteString:    true,
			EndWithMessage: true,
		},
	}
}

log.Debug().Int("everything", 42).Str("foo", "bar").Msg("hello world")
log.Info().Int("everything", 42).Str("foo", "bar").Msg("hello world")
log.Warn().Int("everything", 42).Str("foo", "bar").Msg("hello world")
log.Error().Err(errors.New("an error")).Msg("hello world")

Pretty logging

Note: pretty logging also works on windows console

Formatting Console Writer

To log with user-defined format(e.g. glog), using ConsoleWriter.Formatter. playground

package main

import (
	"fmt"
	"io"

	"github.com/fabricatorsltd/logstack"
)

type Glog struct {
	Logger log.Logger
}

func (l *Glog) Infof(fmt string, a ...any) { l.Logger.Info().Msgf(fmt, a...) }

func (l *Glog) Warnf(fmt string, a ...any) { l.Logger.Warn().Msgf(fmt, a...) }

func (l *Glog) Errorf(fmt string, a ...any) { l.Logger.Error().Msgf(fmt, a...) }

var glog = &Glog{log.Logger{
	Level:      log.InfoLevel,
	Caller:     1,
	TimeFormat: "0102 15:04:05.999999",
	Writer: &log.ConsoleWriter{Formatter: func(w io.Writer, a *log.FormatterArgs) (int, error) {
		return fmt.Fprintf(w, "%c%s %s %s] %s\n%s", a.Level[0]-32, a.Time, a.Goid, a.Caller, a.Message, a.Stack)
	}},
}}

func main() {
	glog.Infof("hello glog %s", "Info")
	glog.Warnf("hello glog %s", "Warn")
	glog.Errorf("hello glog %s", "Error")
}

// Output:
// I0725 09:59:57.503246 19 console_test.go:183] hello glog Info
// W0725 09:59:57.504247 19 console_test.go:184] hello glog Warn
// E0725 09:59:57.504247 19 console_test.go:185] hello glog Error
Formatting Logfmt output

To log with logfmt format, also using ConsoleWriter.Formatter. playground

package main

import (
	"io"
	"os"

	"github.com/fabricatorsltd/logstack"
)

func main() {
	log.DefaultLogger = log.Logger{
		Level:      log.InfoLevel,
		Caller:     1,
		TimeField:  "ts",
		TimeFormat: log.TimeFormatUnixWithMs,
		Writer: &log.ConsoleWriter{
			Formatter: log.LogfmtFormatter{"ts"}.Formatter,
			Writer:    io.MultiWriter(os.Stdout, os.Stderr),
		},
	}

	log.Info().Str("foo", "bar").Int("no", 42).Msgf("a logfmt %s", "info")
}

// Output:
// ts=1257894000.000 level=info goid=1 caller="prog.go:20" foo="bar" no=42 "a logfmt info"
// ts=1257894000.000 level=info goid=1 caller="prog.go:20" foo="bar" no=42 "a logfmt info"
Rotating File Writer

To log to a daily-rotating file, use FileWriter. playground

package main

import (
	"os"
	"path/filepath"
	"time"

	"github.com/fabricatorsltd/logstack"
	"github.com/robfig/cron/v3"
)

func main() {
	logger := log.Logger{
		Level: log.ParseLevel("info"),
		Writer: &log.FileWriter{
			Filename:     "logs/main.log",
			FileMode:     0600,
			MaxSize:      100 * 1024 * 1024,
			MaxBackups:   7,
			EnsureFolder: true,
			LocalTime:    true,
		},
	}

	runner := cron.New(cron.WithLocation(time.Local))
	runner.AddFunc("0 0 * * *", func() { logger.Writer.(*log.FileWriter).Rotate() })
	go runner.Run()

	for {
		time.Sleep(time.Second)
		logger.Info().Msg("hello world")
	}
}
Rotating File Writer within a total size

To rotating log file hourly and keep in a total size, use FileWriter.Cleaner.

package main

import (
	"os"
	"path/filepath"
	"time"

	"github.com/fabricatorsltd/logstack"
	"github.com/robfig/cron/v3"
)

func main() {
	logger := log.Logger{
		Level: log.ParseLevel("info"),
		Writer: &log.FileWriter{
			Filename: "main.log",
			MaxSize:  500 * 1024 * 1024,
			Cleaner:  func(filename string, maxBackups int, matches []os.FileInfo) {
				var dir = filepath.Dir(filename)
				var total int64
				for i := len(matches) - 1; i >= 0; i-- {
					total += matches[i].Size()
					if total > 5*1024*1024*1024 {
						os.Remove(filepath.Join(dir, matches[i].Name()))
					}
				}
			},
		},
	}

	runner := cron.New(cron.WithLocation(time.UTC))
	runner.AddFunc("0 * * * *", func() { logger.Writer.(*log.FileWriter).Rotate() })
	go runner.Run()

	for {
		time.Sleep(time.Second)
		logger.Info().Msg("hello world")
	}
}
Rotating File Writer with compression

To rotating log file hourly and compressing after rotation, use FileWriter.Cleaner.

package main

import (
	"os"
	"os/exec"
	"path/filepath"
	"time"

	"github.com/fabricatorsltd/logstack"
	"github.com/robfig/cron/v3"
)

func main() {
	logger := log.Logger{
		Level: log.ParseLevel("info"),
		Writer: &log.FileWriter{
			Filename: "main.log",
			MaxSize:  500 * 1024 * 1024,
			Cleaner:  func(filename string, maxBackups int, matches []os.FileInfo) {
				var dir = filepath.Dir(filename)
				for i, fi := range matches {
					filename := filepath.Join(dir, fi.Name())
					switch {
					case i > maxBackups:
						os.Remove(filename)
					case !strings.HasSuffix(filename, ".gz"):
						go exec.Command("nice", "gzip", filename).Run()
					}
				}
			},
		},
	}

	runner := cron.New(cron.WithLocation(time.UTC))
	runner.AddFunc("0 * * * *", func() { logger.Writer.(*log.FileWriter).Rotate() })
	go runner.Run()

	for {
		time.Sleep(time.Second)
		logger.Info().Msg("hello world")
	}
}
Random Sample Logger:

To logging only 5% logs, use below idiom.

if log.Fastrandn(100) < 5 {
	log.Log().Msg("hello world")
}
Multiple Dispatching Writer

To log to different writers by different levels, use MultiLevelWriter.

log.DefaultLogger.Writer = &log.MultiLevelWriter{
	InfoWriter:    &log.FileWriter{Filename: "main.INFO", MaxSize: 100<<20},
	WarnWriter:    &log.FileWriter{Filename: "main.WARNING", MaxSize: 100<<20},
	ErrorWriter:   &log.FileWriter{Filename: "main.ERROR", MaxSize: 100<<20},
	ConsoleWriter: &log.ConsoleWriter{ColorOutput: true},
	ConsoleLevel:  log.ErrorLevel,
}

log.Info().Int("number", 42).Str("foo", "bar").Msg("a info log")
log.Warn().Int("number", 42).Str("foo", "bar").Msg("a warn log")
log.Error().Int("number", 42).Str("foo", "bar").Msg("a error log")
Multiple Entry Writer

To log to different writers, use MultiEntryWriter.

log.DefaultLogger.Writer = &log.MultiEntryWriter{
	&log.ConsoleWriter{ColorOutput: true},
	&log.FileWriter{Filename: "main.log", MaxSize: 100<<20},
	&log.EventlogWriter{Source: ".NET Runtime", ID: 1000},
}

log.Info().Int("number", 42).Str("foo", "bar").Msg("a info log")
Multiple IO Writer

To log to multiple io writers like io.MultiWriter, use below idiom. playground

log.DefaultLogger.Writer = &log.MultiIOWriter{
	os.Stdout,
	&log.FileWriter{Filename: "main.log", MaxSize: 100<<20},
}

log.Info().Int("number", 42).Str("foo", "bar").Msg("a info log")
Multiple Combined Logger:

To logging to different logger as you want, use below idiom. playground

package main

import (
	"github.com/fabricatorsltd/logstack"
)

var logger = struct {
	Console log.Logger
	Access  log.Logger
	Data    log.Logger
}{
	Console: log.Logger{
		TimeFormat: "15:04:05",
		Caller:     1,
		Writer: &log.ConsoleWriter{
			ColorOutput:    true,
			EndWithMessage: true,
		},
	},
	Access: log.Logger{
		Level: log.InfoLevel,
		Writer: &log.FileWriter{
			Filename:   "access.log",
			MaxSize:    50 * 1024 * 1024,
			MaxBackups: 7,
			LocalTime:  false,
		},
	},
	Data: log.Logger{
		Level: log.InfoLevel,
		Writer: &log.FileWriter{
			Filename:   "data.log",
			MaxSize:    50 * 1024 * 1024,
			MaxBackups: 7,
			LocalTime:  false,
		},
	},
}

func main() {
	logger.Console.Info().Msgf("hello world")
	logger.Access.Log().Msgf("handle request")
	logger.Data.Log().Msgf("some data")
}
SyslogWriter

SyslogWriter is a memory-efficient, cross-platform, dependency-free syslog writer, outperforms all other structured logging libraries.

package main

import (
	"net"
	"time"

	"github.com/fabricatorsltd/logstack"
)

func main() {
	go func() {
		ln, _ := net.Listen("tcp", "127.0.0.1:1601")
		for {
			conn, _ := ln.Accept()
			go func(c net.Conn) {
				b := make([]byte, 8192)
				n, _ := conn.Read(b)
				println(string(b[:n]))
			}(conn)
		}
	}()

	syslog := log.Logger{
		Level:      log.InfoLevel,
		TimeField:  "ts",
		TimeFormat: log.TimeFormatUnixMs,
		Writer: &log.SyslogWriter{
			Network: "tcp",            // "unixgram",
			Address: "127.0.0.1:1601", // "/run/systemd/journal/syslog",
			Tag:     "",
			Marker:  "@cee:",
			Dial:    net.Dial,
		},
	}

	syslog.Info().Str("foo", "bar").Int("an", 42).Msg("a syslog info")
	syslog.Warn().Str("foo", "bar").Int("an", 42).Msg("a syslog warn")
	time.Sleep(2)
}

// Output:
// <6>2022-07-24T18:48:15+08:00 127.0.0.1:59277 [11516]: @cee:{"ts":1658659695428,"level":"info","foo":"bar","an":42,"message":"a syslog info"}
// <4>2022-07-24T18:48:15+08:00 127.0.0.1:59277 [11516]: @cee:{"ts":1658659695429,"level":"warn","foo":"bar","an":42,"message":"a syslog warn"}
JournalWriter

To log to linux systemd journald, using JournalWriter.

log.DefaultLogger.Writer = &log.JournalWriter{
	JournalSocket: "/run/systemd/journal/socket",
}

log.Info().Int("number", 42).Str("foo", "bar").Msg("hello world")
EventlogWriter

To log to windows system event, using EventlogWriter.

log.DefaultLogger.Writer = &log.EventlogWriter{
	Source: ".NET Runtime",
	ID:     1000,
}

log.Info().Int("number", 42).Str("foo", "bar").Msg("hello world")
AsyncWriter

To logging asynchronously for performance stability, use AsyncWriter.

logger := log.Logger{
	Level:  log.InfoLevel,
	Writer: &log.AsyncWriter{
		ChannelSize: 100,
		Writer:      &log.FileWriter{
			Filename:   "main.log",
			FileMode:   0600,
			MaxSize:    50*1024*1024,
			MaxBackups: 7,
			LocalTime:  false,
		},
	},
}

logger.Info().Int("number", 42).Str("foo", "bar").Msg("a async info log")
logger.Warn().Int("number", 42).Str("foo", "bar").Msg("a async warn log")
logger.Writer.(io.Closer).Close()

Note: To flush data and quit safely, call AsyncWriter.Close() explicitly.

Stdlib Log Adapter

Using wrapped loggers for stdlog. playground

package main

import (
	stdlog "log"
	"os"

	"github.com/fabricatorsltd/logstack"
)

func main() {
	var logger *stdlog.Logger = (&log.Logger{
		Level:      log.InfoLevel,
		TimeField:  "date",
		TimeFormat: "2006-01-02",
		Caller:     1,
		Context:    log.NewContext(nil).Str("logger", "mystdlog").Int("myid", 42).Value(),
		Writer:     &log.IOWriter{os.Stdout},
	}).Std("", 0)

	logger.Print("hello from stdlog Print")
	logger.Println("hello from stdlog Println")
	logger.Printf("hello from stdlog %s", "Printf")
}
log/slog Adapter

Using wrapped loggers for log/slog. playground

package main

import (
	"log/slog"

	"github.com/fabricatorsltd/logstack"
)

func main() {
	slog.SetDefault((&log.Logger{
		Level:      log.InfoLevel,
		TimeField:  "date",
		TimeFormat: "2006-01-02",
		Caller:     1,
		Context:    log.NewContext(nil).Str("logger", "my_slog").Int("myid", 42).Value(),
	}).Slog())

	slog.Debug("hello from slog Info")
	slog.Info("hello from slog Info")
	slog.Warn("hello from slog Warn")
	slog.Error("hello from slog Error")
}
Third-party Logger Interceptor
Logger Interceptor
logr https://github.com/fabricatorsltd/logstack-contrib/tree/master/logr
gin https://github.com/fabricatorsltd/logstack-contrib/tree/master/gin
fiber https://github.com/fabricatorsltd/logstack-contrib/tree/master/fiber
gorm https://github.com/fabricatorsltd/logstack-contrib/tree/master/gorm
grpc https://github.com/fabricatorsltd/logstack-contrib/tree/master/grpc
grpcgateway https://github.com/fabricatorsltd/logstack-contrib/tree/master/grpcgateway
User-defined Data Structure

To log with user-defined struct effectively, implements MarshalObject. playground

package main

import (
	"github.com/fabricatorsltd/logstack"
)

type User struct {
	ID   int
	Name string
	Pass string
}

func (u *User) MarshalObject(e *log.Entry) {
	e.Int("id", u.ID).Str("name", u.Name).Str("password", "***")
}

func main() {
	log.Info().Object("user", &User{1, "neo", "123456"}).Msg("")
	log.Info().EmbedObject(&User{2, "john", "abc"}).Msg("")
}

// Output:
//   {"time":"2020-07-12T05:03:43.949Z","level":"info","user":{"id":1,"name":"neo","password":"***"}}
//   {"time":"2020-07-12T05:03:43.949Z","level":"info","id":2,"name":"john","password":"***"}
Contextual Fields

To add preserved key:value pairs to each entry, use NewContext. playground

logger := log.Logger{
	Level:   log.InfoLevel,
	Context: log.NewContext(nil).Str("ctx", "some_ctx").Value(),
}

logger.Debug().Int("no0", 0).Msg("zero")
logger.Info().Int("no1", 1).Msg("first")
logger.Info().Int("no2", 2).Msg("second")

// Output:
//   {"time":"2020-07-12T05:03:43.949Z","level":"info","ctx":"some_ctx","no1":1,"message":"first"}
//   {"time":"2020-07-12T05:03:43.949Z","level":"info","ctx":"some_ctx","no2":2,"message":"second"}

You can make a copy of log and add contextual fields. playground

package main

import (
	"github.com/fabricatorsltd/logstack"
)

func main() {
	sublogger := log.DefaultLogger
	sublogger.Level = log.InfoLevel
	sublogger.Context = log.NewContext(nil).Str("ctx", "some_ctx").Value()

	sublogger.Debug().Int("no0", 0).Msg("zero")
	sublogger.Info().Int("no1", 1).Msg("first")
	sublogger.Info().Int("no2", 2).Msg("second")
	log.Debug().Int("no3", 3).Msg("no context")
}

// Output:
//   {"time":"2021-06-14T06:36:42.904+02:00","level":"info","ctx":"some_ctx","no1":1,"message":"first"}
//   {"time":"2021-06-14T06:36:42.905+02:00","level":"info","ctx":"some_ctx","no2":2,"message":"second"}
//   {"time":"2021-06-14T06:36:42.906+02:00","level":"debug","no3":3,"message":"no context"}
High Performance

The most common benchmarks(disable/normal/interface/printf/caller) with zap/zerolog, which runs on github actions:

// go test -v -cpu=4 -run=none -bench=. -benchtime=10s -benchmem log_test.go
package main

import (
  "io"
  "os"
  "testing"

  log "github.com/fabricatorsltd/logstack"
  "github.com/rs/zerolog"
  "go.uber.org/zap"
  "go.uber.org/zap/zapcore"
)

const msg = "The quick brown fox jumps over the lazy dog"

var obj = struct {
  Rate string
  Low  int
  High float32
}{"15", 16, 123.2}

func BenchmarkDisableZap(b *testing.B) {
  logger := zap.New(zapcore.NewCore(
    zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
    zapcore.AddSync(io.Discard),
    zapcore.InfoLevel,
  ))
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Debug(msg, zap.String("rate", "15"), zap.Int("low", 16), zap.Float32("high", 123.2))
  }
}

func BenchmarkDisableZeroLog(b *testing.B) {
  zerolog.SetGlobalLevel(zerolog.InfoLevel)
  logger := zerolog.New(io.Discard).With().Timestamp().Logger()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Debug().Str("rate", "15").Int("low", 16).Float32("high", 123.2).Msg(msg)
  }
}

func BenchmarkDisablePhusLog(b *testing.B) {
  logger := log.Logger{Level: log.InfoLevel, Writer: log.IOWriter{io.Discard}}
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Debug().Str("rate", "15").Int("low", 16).Float32("high", 123.2).Msg(msg)
  }
}

func BenchmarkNormalZap(b *testing.B) {
  logger := zap.New(zapcore.NewCore(
    zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
    zapcore.AddSync(io.Discard),
    zapcore.InfoLevel,
  ))
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info(msg, zap.String("rate", "15"), zap.Int("low", 16), zap.Float32("high", 123.2))
  }
}

func BenchmarkNormalZeroLog(b *testing.B) {
  logger := zerolog.New(io.Discard).With().Timestamp().Logger()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Str("rate", "15").Int("low", 16).Float32("high", 123.2).Msg(msg)
  }
}

func BenchmarkNormalPhusLog(b *testing.B) {
  logger := log.Logger{Writer: log.IOWriter{io.Discard}}
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Str("rate", "15").Int("low", 16).Float32("high", 123.2).Msg(msg)
  }
}

func BenchmarkInterfaceZap(b *testing.B) {
  logger := zap.New(zapcore.NewCore(
    zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
    zapcore.AddSync(io.Discard),
    zapcore.InfoLevel,
  )).Sugar()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Infow(msg, "object", &obj)
  }
}

func BenchmarkInterfaceZeroLog(b *testing.B) {
  logger := zerolog.New(io.Discard).With().Timestamp().Logger()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Interface("object", &obj).Msg(msg)
  }
}

func BenchmarkInterfacePhusLog(b *testing.B) {
  logger := log.Logger{Writer: log.IOWriter{io.Discard}}
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Interface("object", &obj).Msg(msg)
  }
}

func BenchmarkPrintfZap(b *testing.B) {
  logger := zap.New(zapcore.NewCore(
    zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
    zapcore.AddSync(io.Discard),
    zapcore.InfoLevel,
  )).Sugar()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Infof("rate=%s low=%d high=%f msg=%s", "15", 16, 123.2, msg)
  }
}

func BenchmarkPrintfZeroLog(b *testing.B) {
  logger := zerolog.New(io.Discard).With().Timestamp().Logger()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Msgf("rate=%s low=%d high=%f msg=%s", "15", 16, 123.2, msg)
  }
}

func BenchmarkPrintfPhusLog(b *testing.B) {
  logger := log.Logger{Writer: log.IOWriter{io.Discard}}
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Msgf("rate=%s low=%d high=%f msg=%s", "15", 16, 123.2, msg)
  }
}

func BenchmarkCallerZap(b *testing.B) {
  logger := zap.New(zapcore.NewCore(
    zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
    zapcore.AddSync(io.Discard),
    zapcore.InfoLevel),
    zap.AddCaller(),
  )
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info(msg, zap.String("rate", "15"), zap.Int("low", 16), zap.Float32("high", 123.2))
  }
}

func BenchmarkCallerZeroLog(b *testing.B) {
  logger := zerolog.New(io.Discard).With().Caller().Timestamp().Logger()
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Str("rate", "15").Int("low", 16).Float32("high", 123.2).Msg(msg)
  }
}

func BenchmarkCallerPhusLog(b *testing.B) {
  logger := log.Logger{Caller: 1, Writer: log.IOWriter{io.Discard}}
  tokenErr := setBSToken(&logger)
  if tokenErr != "" {
    b.Fatal(tokenErr)
  }
  for i := 0; i < b.N; i++ {
    logger.Info().Str("rate", "15").Int("low", 16).Float32("high", 123.2).Msg(msg)
  }
}

func setBSToken(l *log.Logger) string {
  bsToken := os.Getenv("BETTERSTACK_TOKEN")
  if bsToken == "" {
    return "please set BETTERSTACK_TOKEN env"
  }

  l.SetToken(bsToken)
  l.GoSync = true

  return ""
}

A Performance result as below, for daily benchmark results see github actions

BenchmarkDisableZap-4         	86193418	       142.8 ns/op	     192 B/op	       1 allocs/op
BenchmarkDisableZeroLog-4     	1000000000	        11.58 ns/op	       0 B/op	       0 allocs/op
BenchmarkDisablePhusLog-4     	1000000000	        11.93 ns/op	       0 B/op	       0 allocs/op

BenchmarkNormalZap-4          	 9152504	      1331 ns/op	     192 B/op	       1 allocs/op
BenchmarkNormalZeroLog-4      	14775375	       812.3 ns/op	       0 B/op	       0 allocs/op
BenchmarkNormalPhusLog-4      	27574824	       435.5 ns/op	       0 B/op	       0 allocs/op

BenchmarkInterfaceZap-4       	 6488127	      1850 ns/op	     208 B/op	       2 allocs/op
BenchmarkInterfaceZeroLog-4   	10102683	      1199 ns/op	      48 B/op	       1 allocs/op
BenchmarkInterfacePhusLog-4   	13968078	       858.7 ns/op	       0 B/op	       0 allocs/op

BenchmarkPrintfZap-4          	 7066578	      1687 ns/op	      80 B/op	       1 allocs/op
BenchmarkPrintfZeroLog-4      	 9119858	      1317 ns/op	      80 B/op	       1 allocs/op
BenchmarkPrintfPhusLog-4      	14854870	       808.7 ns/op	       0 B/op	       0 allocs/op

BenchmarkCallerZap-4          	 2931970	      4038 ns/op	     424 B/op	       3 allocs/op
BenchmarkCallerZeroLog-4      	 3029824	      3947 ns/op	     272 B/op	       4 allocs/op
BenchmarkCallerPhusLog-4      	 8405709	      1406 ns/op	     216 B/op	       2 allocs/op

This library uses the following special techniques to achieve better performance,

  1. handwriting time formatting
  2. manual inlining
  3. unrolled functions

A Real World Example

The example starts a geoip http server which supports change log level dynamically

package main

import (
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"os"

	"github.com/phuslu/iploc"
	"github.com/fabricatorsltd/logstack"
)

type Config struct {
	Listen struct {
		Tcp string
	}
	Log struct {
		Level   string
		Maxsize int64
		Backups int
	}
}

type Handler struct {
	Config       *Config
	AccessLogger log.Logger
}

func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	reqID := log.NewXID()
	remoteIP, _, _ := net.SplitHostPort(req.RemoteAddr)
	geo := iploc.Country(net.ParseIP(remoteIP))

	h.AccessLogger.Log().
		Xid("req_id", reqID).
		Str("host", req.Host).
		Bytes("geo", geo).
		Str("remote_ip", remoteIP).
		Str("request_uri", req.RequestURI).
		Str("user_agent", req.UserAgent()).
		Str("referer", req.Referer()).
		Msg("access log")

	switch req.RequestURI {
	case "/debug", "/info", "/warn", "/error":
		log.DefaultLogger.SetLevel(log.ParseLevel(req.RequestURI[1:]))
	default:
		fmt.Fprintf(rw, `{"req_id":"%s","ip":"%s","geo":"%s"}`, reqID, remoteIP, geo)
	}
}

func main() {
	config := new(Config)
	err := json.Unmarshal([]byte(`{
		"listen": {
			"tcp": ":8080"
		},
		"log": {
			"level": "debug",
			"maxsize": 1073741824,
			"backups": 5
		}
	}`), config)
	if err != nil {
		log.Fatal().Msgf("json.Unmarshal error: %+v", err)
	}

	handler := &Handler{
		Config: config,
		AccessLogger: log.Logger{
			Writer: &log.FileWriter{
				Filename:   "access.log",
				MaxSize:    config.Log.Maxsize,
				MaxBackups: config.Log.Backups,
				LocalTime:  true,
			},
		},
	}

	if log.IsTerminal(os.Stderr.Fd()) {
		log.DefaultLogger = log.Logger{
			Level:      log.ParseLevel(config.Log.Level),
			Caller:     1,
			TimeFormat: "15:04:05",
			Writer: &log.ConsoleWriter{
				ColorOutput:    true,
				EndWithMessage: true,
			},
		}
		handler.AccessLogger = log.DefaultLogger
	} else {
		log.DefaultLogger = log.Logger{
			Level: log.ParseLevel(config.Log.Level),
			Writer: &log.FileWriter{
				Filename:   "main.log",
				MaxSize:    config.Log.Maxsize,
				MaxBackups: config.Log.Backups,
				LocalTime:  true,
			},
		}
	}

	server := &http.Server{
		Addr:     config.Listen.Tcp,
		ErrorLog: log.DefaultLogger.Std(log.ErrorLevel, nil, "", 0),
		Handler:  handler,
	}

	log.Fatal().Err(server.ListenAndServe()).Msg("listen failed")
}

Acknowledgment

This log is heavily inspired by zerolog, glog, gjson and lumberjack.

Documentation

Index

Constants

View Source 
const ErrInvalidXID = xidError("xid: invalid XID")

ErrInvalidXID is returned when trying to parse an invalid XID

View Source 
const TimeFormatUnix = "\x01"

TimeFormatUnix defines a time format that makes time fields to be serialized as Unix timestamp integers.

View Source 
const TimeFormatUnixMs = "\x02"

TimeFormatUnixMs defines a time format that makes time fields to be serialized as Unix timestamp integers in milliseconds.

View Source 
const TimeFormatUnixWithMs = "\x03"

TimeFormatUnixWithMs defines a time format that makes time fields to be serialized as Unix timestamp timestamp floats.

Variables

View Source 
var DefaultLogger = Logger{
	Level:            DebugLevel,
	Caller:           0,
	TimeField:        "",
	TimeFormat:       "",
	Writer:           IOWriter{os.Stderr},
	BetterStackToken: "",
}

DefaultLogger is the global logger.

Functions

func Fastrandn 

func Fastrandn(x uint32) uint32

Fastrandn returns a pseudorandom uint32 in [0,n).

func Goid 

func Goid() int64

Goid returns the current goroutine id. It exactly matches goroutine id of the stack trace.

func IsTerminal 

func IsTerminal(fd uintptr) bool

IsTerminal returns whether the given file descriptor is a terminal.

func Printf 

func Printf(format string, v ...interface{})

Printf sends a log entry without extra field. Arguments are handled in the manner of fmt.Printf.

Types

type AsyncWriter 

type AsyncWriter struct {
	// ChannelSize is the size of the data channel, the default size is 1.
	ChannelSize uint

	// Writer specifies the writer of output.
	Writer Writer
	// contains filtered or unexported fields
}

AsyncWriter is an Writer that writes asynchronously.

func (*AsyncWriter) Close 

func (w *AsyncWriter) Close() (err error)

Close implements io.Closer, and closes the underlying Writer.

func (*AsyncWriter) WriteEntry 

func (w *AsyncWriter) WriteEntry(e *Entry) (int, error)

WriteEntry implements Writer.

type ConsoleWriter 

type ConsoleWriter struct {
	// ColorOutput determines if used colorized output.
	ColorOutput bool

	// QuoteString determines if quoting string values.
	QuoteString bool

	// EndWithMessage determines if output message in the end.
	EndWithMessage bool

	// Formatter specifies an optional text formatter for creating a customized output,
	// If it is set, ColorOutput, QuoteString and EndWithMessage will be ignore.
	Formatter func(w io.Writer, args *FormatterArgs) (n int, err error)

	// Writer is the output destination. using os.Stderr if empty.
	Writer io.Writer
}

ConsoleWriter parses the JSON input and writes it in a colorized, human-friendly format to Writer. IMPORTANT: Don't use ConsoleWriter on critical path of a high concurrency and low latency application.

Default output format: 

{Time} {Level} {Goid} {Caller} > {Message} {Key}={Value} {Key}={Value}

Note: The performance of ConsoleWriter is not good enough, because it will parses JSON input into structured records, then output in a specific order. Roughly 2x faster than logrus.TextFormatter, 0.8x fast as zap.ConsoleEncoder, and 5x faster than zerolog.ConsoleWriter.

func (*ConsoleWriter) Close 

func (w *ConsoleWriter) Close() (err error)

Close implements io.Closer, will closes the underlying Writer if not empty.

func (*ConsoleWriter) WriteEntry 

func (w *ConsoleWriter) WriteEntry(e *Entry) (int, error)

WriteEntry implements Writer.

type Context 

type Context []byte

Context represents contextual fields.

type Entry 

type Entry struct {
	Level Level `json:"level"`

	Dt      string                   `json:"dt"`
	Message string                   `json:"message"`
	Data    []map[string]interface{} `json:"-"`
	// contains filtered or unexported fields
}

Entry represents a log entry. It is instanced by one of the level method of Logger and finalized by the Msg or Msgf method.

func Debug 

func Debug() (e *Entry)

Debug starts a new message with debug level.

func Error 

func Error() (e *Entry)

Error starts a new message with error level.

func Fatal 

func Fatal() (e *Entry)

Fatal starts a new message with fatal level.

func Info 

func Info() (e *Entry)

Info starts a new message with info level.

func NewContext 

func NewContext(dst []byte) (e *Entry)

NewContext starts a new contextual entry.

func Panic 

func Panic() (e *Entry)

Panic starts a new message with panic level.

func Trace 

func Trace() (e *Entry)

Trace starts a new message with trace level.

func Warn 

func Warn() (e *Entry)

Warn starts a new message with warning level.

func (*Entry) AnErr 

func (e *Entry) AnErr(key string, err error) *Entry

AnErr adds the field key with serialized err to the logger context.

func (*Entry) Any 

func (e *Entry) Any(key string, value interface{}) *Entry

Any adds the field key with f as an any value to the entry.

func (*Entry) Bool 

func (e *Entry) Bool(key string, b bool) *Entry

Bool append append the val as a bool to the entry.

func (*Entry) Bools 

func (e *Entry) Bools(key string, b []bool) *Entry

Bools adds the field key with val as a []bool to the entry.

func (*Entry) Byte 

func (e *Entry) Byte(key string, val byte) *Entry

Byte adds the field key with val as a byte to the entry.

func (*Entry) Bytes 

func (e *Entry) Bytes(key string, val []byte) *Entry

Bytes adds the field key with val as a string to the entry.

func (*Entry) BytesOrNil 

func (e *Entry) BytesOrNil(key string, val []byte) *Entry

BytesOrNil adds the field key with val as a string or nil to the entry.

func (*Entry) Caller 

func (e *Entry) Caller(depth int) *Entry

Caller adds the file:line of the "caller" key. If depth is negative, adds the full /path/to/file:line of the "caller" key.

func (*Entry) Context 

func (e *Entry) Context(ctx Context) *Entry

Context sends the contextual fields to entry.

func (*Entry) Dict 

func (e *Entry) Dict(key string, ctx Context) *Entry

Dict sends the contextual fields with key to entry.

func (*Entry) Discard 

func (e *Entry) Discard() *Entry

Discard disables the entry so Msg(f) won't print it.

func (*Entry) Dur 

func (e *Entry) Dur(key string, d time.Duration) *Entry

Dur adds the field key with duration d to the entry.

func (*Entry) Durs 

func (e *Entry) Durs(key string, d []time.Duration) *Entry

Durs adds the field key with val as a []time.Duration to the entry.

func (*Entry) EmbedObject 

func (e *Entry) EmbedObject(obj ObjectMarshaler) *Entry

EmbedObject marshals and Embeds an object that implement the ObjectMarshaler interface.

func (*Entry) Enabled 

func (e *Entry) Enabled() bool

Enabled return false if the entry is going to be filtered out by log level.

func (*Entry) Err 

func (e *Entry) Err(err error) *Entry

Err adds the field "error" with serialized err to the entry.

func (*Entry) Errs 

func (e *Entry) Errs(key string, errs []error) *Entry

Errs adds the field key with errs as an array of serialized errors to the entry.

func (*Entry) Fields 

func (e *Entry) Fields(fields Fields) *Entry

Fields is a helper function to use a map to set fields using type assertion.

func (*Entry) Float32 

func (e *Entry) Float32(key string, f float32) *Entry

Float32 adds the field key with f as a float32 to the entry.

func (*Entry) Float64 

func (e *Entry) Float64(key string, f float64) *Entry

Float64 adds the field key with f as a float64 to the entry.

func (*Entry) Floats32 

func (e *Entry) Floats32(key string, f []float32) *Entry

Floats32 adds the field key with f as a []float32 to the entry.

func (*Entry) Floats64 

func (e *Entry) Floats64(key string, f []float64) *Entry

Floats64 adds the field key with f as a []float64 to the entry.

func (*Entry) Func 

func (e *Entry) Func(f func(e *Entry)) *Entry

Func allows an anonymous func to run only if the entry is enabled.

func (*Entry) GoStringer 

func (e *Entry) GoStringer(key string, val fmt.GoStringer) *Entry

GoStringer adds the field key with val.GoStringer() to the entry.

func (*Entry) Hex 

func (e *Entry) Hex(key string, val []byte) *Entry

Hex adds the field key with val as a hex string to the entry.

func (*Entry) IPAddr 

func (e *Entry) IPAddr(key string, ip net.IP) *Entry

IPAddr adds IPv4 or IPv6 Address to the entry.

func (*Entry) IPPrefix 

func (e *Entry) IPPrefix(key string, pfx net.IPNet) *Entry

IPPrefix adds IPv4 or IPv6 Prefix (address and mask) to the entry.

func (*Entry) Int 

func (e *Entry) Int(key string, i int) *Entry

Int adds the field key with i as a int to the entry.

func (*Entry) Int16 

func (e *Entry) Int16(key string, i int16) *Entry

Int16 adds the field key with i as a int16 to the entry.

func (*Entry) Int32 

func (e *Entry) Int32(key string, i int32) *Entry

Int32 adds the field key with i as a int32 to the entry.

func (*Entry) Int64 

func (e *Entry) Int64(key string, i int64) *Entry

Int64 adds the field key with i as a int64 to the entry.

func (*Entry) Int8 

func (e *Entry) Int8(key string, i int8) *Entry

Int8 adds the field key with i as a int8 to the entry.

func (*Entry) Interface 

func (e *Entry) Interface(key string, i interface{}) *Entry

Interface adds the field key with i marshaled using reflection.

func (*Entry) Ints 

func (e *Entry) Ints(key string, a []int) *Entry

Ints adds the field key with i as a []int to the entry.

func (*Entry) Ints16 

func (e *Entry) Ints16(key string, a []int16) *Entry

Ints16 adds the field key with i as a []int16 to the entry.

func (*Entry) Ints32 

func (e *Entry) Ints32(key string, a []int32) *Entry

Ints32 adds the field key with i as a []int32 to the entry.

func (*Entry) Ints64 

func (e *Entry) Ints64(key string, a []int64) *Entry

Ints64 adds the field key with i as a []int64 to the entry.

func (*Entry) Ints8 

func (e *Entry) Ints8(key string, a []int8) *Entry

Ints8 adds the field key with i as a []int8 to the entry.

func (*Entry) KeysAndValues 

func (e *Entry) KeysAndValues(keysAndValues ...interface{}) *Entry

KeysAndValues sends keysAndValues to Entry

func (*Entry) MACAddr 

func (e *Entry) MACAddr(key string, ha net.HardwareAddr) *Entry

MACAddr adds MAC address to the entry.

func (*Entry) Msg 

func (e *Entry) Msg(msg string)

Msg sends the entry with msg added as the message field if not empty.

func (*Entry) Msgf 

func (e *Entry) Msgf(format string, v ...interface{})

Msgf sends the entry with formatted msg added as the message field if not empty.

func (*Entry) Msgs 

func (e *Entry) Msgs(args ...interface{})

Msgs sends the entry with msgs added as the message field if not empty.

func (*Entry) NetIPAddr 

func (e *Entry) NetIPAddr(key string, ip netip.Addr) *Entry

NetIPAddr adds IPv4 or IPv6 Address to the entry.

func (*Entry) NetIPAddrPort 

func (e *Entry) NetIPAddrPort(key string, ipPort netip.AddrPort) *Entry

NetIPAddrPort adds IPv4 or IPv6 with Port Address to the entry.

func (*Entry) NetIPPrefix 

func (e *Entry) NetIPPrefix(key string, pfx netip.Prefix) *Entry

NetIPPrefix adds IPv4 or IPv6 Prefix (address and mask) to the entry.

func (*Entry) Object 

func (e *Entry) Object(key string, obj ObjectMarshaler) *Entry

Object marshals an object that implement the ObjectMarshaler interface.

func (*Entry) RawJSON 

func (e *Entry) RawJSON(key string, b []byte) *Entry

RawJSON adds already encoded JSON to the log line under key.

func (*Entry) RawJSONStr 

func (e *Entry) RawJSONStr(key string, s string) *Entry

RawJSONStr adds already encoded JSON String to the log line under key.

func (*Entry) Stack 

func (e *Entry) Stack() *Entry

Stack enables stack trace printing for the error passed to Err().

func (*Entry) Str 

func (e *Entry) Str(key string, val string) *Entry

Str adds the field key with val as a string to the entry.

func (*Entry) StrInt 

func (e *Entry) StrInt(key string, val int64) *Entry

StrInt adds the field key with integer val as a string to the entry.

func (*Entry) Stringer 

func (e *Entry) Stringer(key string, val fmt.Stringer) *Entry

Stringer adds the field key with val.String() to the entry.

func (*Entry) Strs 

func (e *Entry) Strs(key string, vals []string) *Entry

Strs adds the field key with vals as a []string to the entry.

func (*Entry) Time 

func (e *Entry) Time(key string, t time.Time) *Entry

Time append append t formated as string using time.RFC3339Nano.

func (*Entry) TimeDiff 

func (e *Entry) TimeDiff(key string, t time.Time, start time.Time) *Entry

TimeDiff adds the field key with positive duration between time t and start. If time t is not greater than start, duration will be 0. Duration format follows the same principle as Dur().

func (*Entry) TimeFormat 

func (e *Entry) TimeFormat(key string, timefmt string, t time.Time) *Entry

TimeFormat append append t formated as string using timefmt.

func (*Entry) Times 

func (e *Entry) Times(key string, a []time.Time) *Entry

Times append append a formated as string array using time.RFC3339Nano.

func (*Entry) TimesFormat 

func (e *Entry) TimesFormat(key string, timefmt string, a []time.Time) *Entry

TimesFormat append append a formated as string array using timefmt.

func (*Entry) Type 

func (e *Entry) Type(key string, v interface{}) *Entry

Type adds type of the key using reflection to the entry.

func (*Entry) Uint 

func (e *Entry) Uint(key string, i uint) *Entry

Uint adds the field key with i as a uint to the entry.

func (*Entry) Uint16 

func (e *Entry) Uint16(key string, i uint16) *Entry

Uint16 adds the field key with i as a uint16 to the entry.

func (*Entry) Uint32 

func (e *Entry) Uint32(key string, i uint32) *Entry

Uint32 adds the field key with i as a uint32 to the entry.

func (*Entry) Uint64 

func (e *Entry) Uint64(key string, i uint64) *Entry

Uint64 adds the field key with i as a uint64 to the entry.

func (*Entry) Uint8 

func (e *Entry) Uint8(key string, i uint8) *Entry

Uint8 adds the field key with i as a uint8 to the entry.

func (*Entry) Uints 

func (e *Entry) Uints(key string, a []uint) *Entry

Uints adds the field key with i as a []uint to the entry.

func (*Entry) Uints16 

func (e *Entry) Uints16(key string, a []uint16) *Entry

Uints16 adds the field key with i as a []uint16 to the entry.

func (*Entry) Uints32 

func (e *Entry) Uints32(key string, a []uint32) *Entry

Uints32 adds the field key with i as a []uint32 to the entry.

func (*Entry) Uints64 

func (e *Entry) Uints64(key string, a []uint64) *Entry

Uints64 adds the field key with i as a []uint64 to the entry.

func (*Entry) Uints8 

func (e *Entry) Uints8(key string, a []uint8) *Entry

Uints8 adds the field key with i as a []uint8 to the entry.

func (*Entry) Value 

func (e *Entry) Value() Context

Value builds the contextual fields.

func (*Entry) Xid 

func (e *Entry) Xid(key string, xid [12]byte) *Entry

Xid adds the field key with xid.ID as a base32 string to the entry.

type Fields 

type Fields map[string]interface{}

Fields type, used to pass to `Fields`.

type FileWriter 

type FileWriter struct {
	// Filename is the file to write logs to.  Backup log files will be retained
	// in the same directory.
	Filename string

	// MaxSize is the maximum size in bytes of the log file before it gets rotated.
	MaxSize int64

	// MaxBackups is the maximum number of old log files to retain.  The default
	// is to retain all old log files
	MaxBackups int

	// FileMode represents the file's mode and permission bits.  The default
	// mode is 0644
	FileMode os.FileMode

	// TimeFormat specifies the time format of filename, uses `2006-01-02T15-04-05` as default format.
	// If set with `TimeFormatUnix`, `TimeFormatUnixMs`, times are formated as UNIX timestamp.
	TimeFormat string

	// LocalTime determines if the time used for formatting the timestamps in
	// log files is the computer's local time.  The default is to use UTC time.
	LocalTime bool

	// HostName determines if the hostname used for formatting in log files.
	HostName bool

	// ProcessID determines if the pid used for formatting in log files.
	ProcessID bool

	// EnsureFolder ensures the file directory creation before writing.
	EnsureFolder bool

	// Header specifies an optional header function of log file after rotation,
	Header func(fileinfo os.FileInfo) []byte

	// Cleaner specifies an optional cleanup function of log backups after rotation,
	// if not set, the default behavior is to delete more than MaxBackups log files.
	Cleaner func(filename string, maxBackups int, matches []os.FileInfo)
	// contains filtered or unexported fields
}

FileWriter is an Writer that writes to the specified filename.

Backups use the log file name given to FileWriter, in the form `name.timestamp.ext` where name is the filename without the extension, timestamp is the time at which the log was rotated formatted with the time.Time format of `2006-01-02T15-04-05` and the extension is the original extension. For example, if your FileWriter.Filename is `/var/log/foo/server.log`, a backup created at 6:30pm on Nov 11 2016 would use the filename `/var/log/foo/server.2016-11-04T18-30-00.log`

Cleaning Up Old Log Files

Whenever a new logfile gets created, old log files may be deleted. The most recent files according to filesystem modified time will be retained, up to a number equal to MaxBackups (or all of them if MaxBackups is 0). Note that the time encoded in the timestamp is the rotation time, which may differ from the last time that file was written to.

func (*FileWriter) Close 

func (w *FileWriter) Close() (err error)

Close implements io.Closer, and closes the current logfile.

func (*FileWriter) Rotate 

func (w *FileWriter) Rotate() (err error)

Rotate causes Logger to close the existing log file and immediately create a new one. This is a helper function for applications that want to initiate rotations outside of the normal rotation rules, such as in response to SIGHUP. After rotating, this initiates compression and removal of old log files according to the configuration.

func (*FileWriter) Write 

func (w *FileWriter) Write(p []byte) (n int, err error)

Write implements io.Writer. If a write would cause the log file to be larger than MaxSize, the file is closed, rotate to include a timestamp of the current time, and update symlink with log name file to the new file.

func (*FileWriter) WriteEntry 

func (w *FileWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements Writer. If a write would cause the log file to be larger than MaxSize, the file is closed, rotate to include a timestamp of the current time, and update symlink with log name file to the new file.

type FormatterArgs 

type FormatterArgs struct {
	Time      string // "2019-07-10T05:35:54.277Z"
	Level     string // "info"
	Caller    string // "prog.go:42"
	Goid      string // "123"
	Stack     string // "<stack string>"
	Message   string // "a structure message"
	KeyValues []struct {
		Key       string // "foo"
		Value     string // "bar"
		ValueType byte   // 's'
	}
}

FormatterArgs is a parsed sturct from json input

func (*FormatterArgs) Get 

func (args *FormatterArgs) Get(key string) (value string)

Get gets the value associated with the given key.

type IOWriteCloser 

type IOWriteCloser struct {
	io.WriteCloser
}

IOWriteCloser wraps an io.IOWriteCloser to Writer.

func (IOWriteCloser) Close 

func (w IOWriteCloser) Close() (err error)

Close implements Writer.

func (IOWriteCloser) WriteEntry 

func (w IOWriteCloser) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements Writer.

type IOWriter 

type IOWriter struct {
	io.Writer
}

IOWriter wraps an io.Writer to Writer.

func (IOWriter) WriteEntry 

func (w IOWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements Writer.

type JournalWriter 

type JournalWriter struct {
	// JournalSocket specifies socket name, using `/run/systemd/journal/socket` if empty.
	JournalSocket string
	// contains filtered or unexported fields
}

JournalWriter is an Writer that writes logs to journald.

func (*JournalWriter) Close 

func (w *JournalWriter) Close() (err error)

Close implements io.Closer.

func (*JournalWriter) WriteEntry 

func (w *JournalWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements Writer.

type Level 

type Level uint32

Level defines log levels. 

const (
	// TraceLevel defines trace log level.
	TraceLevel Level = 1
	// DebugLevel defines debug log level.
	DebugLevel Level = 2
	// InfoLevel defines info log level.
	InfoLevel Level = 3
	// WarnLevel defines warn log level.
	WarnLevel Level = 4
	// ErrorLevel defines error log level.
	ErrorLevel Level = 5
	// FatalLevel defines fatal log level.
	FatalLevel Level = 6
	// PanicLevel defines panic log level.
	PanicLevel Level = 7
)

func ParseLevel 

func ParseLevel(s string) (level Level)

ParseLevel converts a level string into a log Level value.

func (Level) String 

func (l Level) String() (s string)

String return lowe case string of Level

type LogfmtFormatter 

type LogfmtFormatter struct {
	TimeField string
}

func (LogfmtFormatter) Formatter 

func (f LogfmtFormatter) Formatter(out io.Writer, args *FormatterArgs) (n int, err error)

type Logger 

type Logger struct {
	// Level defines log levels.
	Level Level

	// Caller determines if adds the file:line of the "caller" key.
	// If Caller is negative, adds the full /path/to/file:line of the "caller" key.
	Caller int

	// TimeField defines the time filed name in output.  It uses "time" in if empty.
	TimeField string

	// TimeFormat specifies the time format in output. It uses time.RFC3339 with milliseconds if empty.
	// If set with `TimeFormatUnix`, `TimeFormatUnixMs`, times are formated as UNIX timestamp.
	TimeFormat string

	// Context specifies an optional context of logger.
	Context Context

	// Writer specifies the writer of output. It uses a wrapped os.Stderr Writer in if empty.
	Writer Writer

	// BetterStackToken specifies the token to use for BetterStack API.
	BetterStackToken string

	// GoSync specifies if the call to BetterStack should run in routine
	GoSync bool
}

A Logger represents an active logging object that generates lines of JSON output to an io.Writer.

func (*Logger) Debug 

func (l *Logger) Debug() (e *Entry)

Debug starts a new message with debug level.

func (*Logger) Err 

func (l *Logger) Err(err error) (e *Entry)

Err starts a new message with error level with err as a field if not nil or with info level if err is nil.

func (*Logger) Error 

func (l *Logger) Error() (e *Entry)

Error starts a new message with error level.

func (*Logger) Fatal 

func (l *Logger) Fatal() (e *Entry)

Fatal starts a new message with fatal level.

func (*Logger) Info 

func (l *Logger) Info() (e *Entry)

Info starts a new message with info level.

func (*Logger) Log 

func (l *Logger) Log() (e *Entry)

Log starts a new message with no level.

func (*Logger) Panic 

func (l *Logger) Panic() (e *Entry)

Panic starts a new message with panic level.

func (*Logger) Printf 

func (l *Logger) Printf(format string, v ...interface{})

Printf sends a log entry without extra field. Arguments are handled in the manner of fmt.Printf.

func (*Logger) SetLevel 

func (l *Logger) SetLevel(level Level)

SetLevel changes logger default level.

func (*Logger) SetToken 

func (l *Logger) SetToken(token string)

SetToken sets the BetterStack token to use.

func (*Logger) Slog 

func (l *Logger) Slog() *slog.Logger

Slog wraps the Logger to provide *slog.Logger

func (*Logger) Std 

func (l *Logger) Std(prefix string, flag int) *stdLog.Logger

Std wraps the Logger to provide *stdLog.Logger

func (*Logger) Trace 

func (l *Logger) Trace() (e *Entry)

Trace starts a new message with trace level.

func (*Logger) Warn 

func (l *Logger) Warn() (e *Entry)

Warn starts a new message with warning level.

func (*Logger) WithLevel 

func (l *Logger) WithLevel(level Level) (e *Entry)

WithLevel starts a new message with level.

type MultiEntryWriter 

type MultiEntryWriter []Writer

MultiEntryWriter is an array Writer that log to different writers

func (*MultiEntryWriter) Close 

func (w *MultiEntryWriter) Close() (err error)

Close implements io.Closer, and closes the underlying MultiEntryWriter.

func (*MultiEntryWriter) WriteEntry 

func (w *MultiEntryWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements entryWriter.

type MultiIOWriter 

type MultiIOWriter []io.Writer

MultiIOWriter is an array io.Writer that log to different writers

func (*MultiIOWriter) Close 

func (w *MultiIOWriter) Close() (err error)

Close implements io.Closer, and closes the underlying MultiIOWriter.

func (*MultiIOWriter) WriteEntry 

func (w *MultiIOWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements entryWriter.

type MultiLevelWriter 

type MultiLevelWriter struct {
	// InfoWriter specifies all the level logs writes to
	InfoWriter Writer

	// WarnWriter specifies the level greater than or equal to WarnLevel writes to
	WarnWriter Writer

	// WarnWriter specifies the level greater than or equal to ErrorLevel writes to
	ErrorWriter Writer

	// ConsoleWriter specifies the console writer
	ConsoleWriter Writer

	// ConsoleLevel specifies the level greater than or equal to it also writes to
	ConsoleLevel Level
}

MultiLevelWriter is an Writer that log to different writers by different levels

func (*MultiLevelWriter) Close 

func (w *MultiLevelWriter) Close() (err error)

Close implements io.Closer, and closes the underlying LeveledWriter.

func (*MultiLevelWriter) WriteEntry 

func (w *MultiLevelWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements entryWriter.

type MultiWriter 

type MultiWriter = MultiLevelWriter

MultiWriter is an alias for MultiLevelWriter

type ObjectMarshaler 

type ObjectMarshaler interface {
	MarshalObject(e *Entry)
}

ObjectMarshaler provides a strongly-typed and encoding-agnostic interface to be implemented by types used with Entry's Object methods.

type SyslogWriter 

type SyslogWriter struct {
	// Network specifies network of the syslog server
	Network string

	// Address specifies address of the syslog server
	Address string

	// Hostname specifies hostname of the syslog message
	Hostname string

	// Tag specifies tag of the syslog message
	Tag string

	// Marker specifies prefix of the syslog message, e.g. `@cee:`
	Marker string

	// Dial specifies the dial function for creating TCP/TLS connections.
	Dial func(network, addr string) (net.Conn, error)
	// contains filtered or unexported fields
}

SyslogWriter is an Writer that writes logs to a syslog server..

func (*SyslogWriter) Close 

func (w *SyslogWriter) Close() (err error)

Close closes a connection to the syslog server.

func (*SyslogWriter) WriteEntry 

func (w *SyslogWriter) WriteEntry(e *Entry) (n int, err error)

WriteEntry implements Writer, sends logs with priority to the syslog server.

type TSVEntry 

type TSVEntry struct {
	// contains filtered or unexported fields
}

TSVEntry represents a tsv log entry. It is instanced by one of TSVLogger and finalized by the Msg method.

func (*TSVEntry) Bool 

func (e *TSVEntry) Bool(b bool) *TSVEntry

Bool append the b as a bool to the entry, the value of output bool is 0 or 1.

func (*TSVEntry) BoolString 

func (e *TSVEntry) BoolString(b bool) *TSVEntry

BoolString append the b as a bool to the entry, the value of output bool is false or true.

func (*TSVEntry) Byte 

func (e *TSVEntry) Byte(b byte) *TSVEntry

Byte append the b as a byte to the entry.

func (*TSVEntry) Bytes 

func (e *TSVEntry) Bytes(val []byte) *TSVEntry

Bytes adds a bytes as string to the entry.

func (*TSVEntry) Caller 

func (e *TSVEntry) Caller(depth int) *TSVEntry

Caller adds the file:line of to the entry.

func (*TSVEntry) Float32 

func (e *TSVEntry) Float32(f float32) *TSVEntry

Float32 adds a float32 to the entry.

func (*TSVEntry) Float64 

func (e *TSVEntry) Float64(f float64) *TSVEntry

Float64 adds a float64 to the entry.

func (*TSVEntry) IPAddr 

func (e *TSVEntry) IPAddr(ip net.IP) *TSVEntry

IPAddr adds IPv4 or IPv6 Address to the entry.

func (*TSVEntry) Int 

func (e *TSVEntry) Int(i int) *TSVEntry

Int adds a int to the entry.

func (*TSVEntry) Int16 

func (e *TSVEntry) Int16(i int16) *TSVEntry

Int16 adds a int16 to the entry.

func (*TSVEntry) Int32 

func (e *TSVEntry) Int32(i int32) *TSVEntry

Int32 adds a int32 to the entry.

func (*TSVEntry) Int64 

func (e *TSVEntry) Int64(i int64) *TSVEntry

Int64 adds a int64 to the entry.

func (*TSVEntry) Int8 

func (e *TSVEntry) Int8(i int8) *TSVEntry

Int8 adds a int8 to the entry.

func (*TSVEntry) Msg 

func (e *TSVEntry) Msg()

Msg sends the entry.

func (*TSVEntry) NetIPAddr 

func (e *TSVEntry) NetIPAddr(ip netip.Addr) *TSVEntry

NetIPAddr adds IPv4 or IPv6 Address to the entry.

func (*TSVEntry) NetIPAddrPort 

func (e *TSVEntry) NetIPAddrPort(ipPort netip.AddrPort) *TSVEntry

NetIPAddrPort adds IPv4 or IPv6 with Port Address to the entry.

func (*TSVEntry) NetIPPrefix 

func (e *TSVEntry) NetIPPrefix(pfx netip.Prefix) *TSVEntry

NetIPPrefix adds IPv4 or IPv6 Prefix (address and mask) to the entry.

func (*TSVEntry) Str 

func (e *TSVEntry) Str(val string) *TSVEntry

Str adds a string to the entry.

func (*TSVEntry) Timestamp 

func (e *TSVEntry) Timestamp() *TSVEntry

Timestamp adds the current time as UNIX timestamp

func (*TSVEntry) TimestampMS 

func (e *TSVEntry) TimestampMS() *TSVEntry

TimestampMS adds the current time with milliseconds as UNIX timestamp

func (*TSVEntry) Uint 

func (e *TSVEntry) Uint(i uint) *TSVEntry

Uint adds a uint to the entry.

func (*TSVEntry) Uint16 

func (e *TSVEntry) Uint16(i uint16) *TSVEntry

Uint16 adds a uint16 to the entry.

func (*TSVEntry) Uint32 

func (e *TSVEntry) Uint32(i uint32) *TSVEntry

Uint32 adds a uint32 to the entry.

func (*TSVEntry) Uint64 

func (e *TSVEntry) Uint64(i uint64) *TSVEntry

Uint64 adds a uint64 to the entry.

func (*TSVEntry) Uint8 

func (e *TSVEntry) Uint8(i uint8) *TSVEntry

Uint8 adds a uint8 to the entry.

type TSVLogger 

type TSVLogger struct {
	Separator byte
	Writer    io.Writer
}

TSVLogger represents an active logging object that generates lines of TSV output to an io.Writer.

func (*TSVLogger) New 

func (l *TSVLogger) New() (e *TSVEntry)

New starts a new tsv message.

type Writer 

type Writer interface {
	WriteEntry(*Entry) (int, error)
}

Writer defines an entry writer interface.

type XID 

type XID [12]byte

XID represents a unique request id

func NewXID 

func NewXID() XID

NewXID generates a globally unique XID

func NewXIDWithTime 

func NewXIDWithTime(timestamp int64) (x XID)

NewXIDWithTime generates a globally unique XID with unix timestamp

func ParseXID 

func ParseXID(s string) (x XID, err error)

ParseXID parses an XID from its string representation

func (XID) Counter 

func (x XID) Counter() uint32

Counter returns the incrementing value part of the id.

func (XID) Machine 

func (x XID) Machine() []byte

Machine returns the 3-byte machine id part of the id.

func (XID) MarshalJSON 

func (x XID) MarshalJSON() (dst []byte, err error)

MarshalJSON implements encoding/json Marshaler interface

func (XID) MarshalText 

func (x XID) MarshalText() (dst []byte, err error)

MarshalText implements encoding/text TextMarshaler interface

func (XID) Pid 

func (x XID) Pid() uint16

Pid returns the process id part of the id.

func (XID) String 

func (x XID) String() string

String returns a base32 hex lowercased representation of the id.

func (XID) Time 

func (x XID) Time() time.Time

Time returns the timestamp part of the id.

func (*XID) UnmarshalJSON 

func (x *XID) UnmarshalJSON(b []byte) (err error)

UnmarshalJSON implements encoding/json Unmarshaler interface

func (*XID) UnmarshalText 

func (x *XID) UnmarshalText(text []byte) (err error)

UnmarshalText implements encoding/text TextUnmarshaler interface

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