Logos: like log4j, but for golang.

Features

This project is a wrapper around the excellent logging framework zap.

• Dependency
  • go.uber.org/zap for logging
  • github.com/elastic/go-ucfg for config logging system
• Simple and Clean Interface
• One log manager for all logs
• Hot config update from file or env
• Appenders
  • Console, write to console
  • File, any log file
  • GelfUpd, greylog logger
  • RollingFile, rolling file writing & compress
• Encoders
  • Console, colorful & formatting text for console
  • Gelf, gelf for greylog
  • Json, standard json encoder
• Useful utility function
  • Setlevel(LogName string, level int), hot update logger level
  • UpdateLogger(LogName string, logger *zap.Logger*), hot update core logger
  • RedirectStdLog(), redirect standard log package
• High Performance
  • Significantly faster json loggers.

How to use

Quick start

package main

import (
  
  "github.com/khorevaa/logos"
)

func main() {

  log := logos.New("<your-package-name>") // like github.com/khorevaa/logos
  log.Info("This is me first log. Hello world logging systems")


}

Setup config

Logos loads configuration file from system environment variable LOGOS_CONFIG_FILE. If the variable is unset, then Logos will try to load the configuration file from current work directory, the file name is "logos.yaml" or "logos.yml".

Additionally, the configuration is loaded from the environment variable LOGOS_CONFIG adn connects to the configuration obtained from the file and takes precedence over its data.

From file

appenders:
  console:
    - name: CONSOLE
      target: stdout
      encoder:
        console:
          
  file:
    - name: FILE
      file_name: /tmp/app.log
      encoder:
        json:
  gelf_udp:
    - name: GRAYLOG
      host: 127.0.0.1
      port: 12201
      compression_type: none
      encoder:
        gelf:
          key_value_pairs:
            - key: env
              value: ${ENV:dev}
            - key: app
              value: ${APPNAME:demo}
            - key: file
              value: app.log
  rolling_file:
    - name: GELF_FILE
      file_name: /tmp/app_gelf.log
      max_size: 100
      encoder:
        gelf:
          key_value_pairs:
            - key: env
              value: ${ENV:dev}
            - key: app
              value: ${APPNAME:demo}
            - key: file
              value: app.log
loggers:
  root:
    level: info
    appender_refs:
      - CONSOLE
  logger:
    - name: helloworld
      appender_refs:
        - CONSOLE
        - FILE
        - GELF_FILE
        - GRAYLOG
      level: debug      

From ENV

# Setup all logs level DEBUG
export LOGOS_CONFIG=loggers.root.level=debug

# Add new appender and setup it to logger
export LOGOS_CONFIG="appenders.console.0.name=CONSOLE_TEST;
appenders.console.0.target=stdout;
appenders.console.0.no_color=true;
appenders.console.0.encoder.console;
loggers.logger.0.add_caller=true;
loggers.logger.0.level=debug;
loggers.logger.0.name=github.com/khorevaa/logos;
loggers.logger.0.appender_refs.0=CONSOLE_TEST"

Json Writer

To log a machine-friendly, use json.

package main

import (
  "errors"
  "github.com/khorevaa/logos"
)

func main() {
	
	rawConfig := `
appenders:
  console:
    - name: CONSOLE
      target: stdout
      encoder:
        json:

loggers:
  root:
    level: info
    appender_refs:
      - CONSOLE
`
	
    logos.InitWithConfigContent(rawConfig)	
	
    log := logos.New("<your-package-name>") // like github.com/khorevaa/logos
    log.Info("This is me first log. Hello world logging systems")


}

Pretty Console Writer

To log a human-friendly, colorized output, use Console.

package main

import (
  "errors"
  "github.com/khorevaa/logos"
)

func main() {

  rawConfig := `
appenders:
  console:
    - name: CONSOLE
      target: stdout
      encoder:
        console:
          color_scheme:
            info_level: blue+b
            debug_level: green+b

loggers:
  root:
    level: debug
    appender_refs:
      - CONSOLE
`

  logos.InitWithConfigContent(rawConfig)

  log := logos.New("<your-package-name>") // like github.com/khorevaa/logos
  log.Info("This is me first log. Hello world logging systems")

  err := errors.New("log system error")
  log.Debug("This is me first error", logos.Any("err", err))

}

Note: pretty logging also works on windows console

High Performance

A quick and simple benchmark 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/ioutil"
	"testing"

	"github.com/khorevaa/logos"
	"github.com/phuslu/log"
	"github.com/rs/zerolog"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

var fakeMessage = "Test logging, but use a somewhat realistic message length. "

func BenchmarkLogos(b *testing.B) {

	const newConfig = `
appenders:
  console:
    - name: CONSOLE
      target: discard
      encoder:
        console:
loggers:
  root:
    level: info
    appender_refs:
      - CONSOLE
`
	err := logos.InitWithConfigContent(newConfig)
	if err != nil {
		panic(err)
	}

	logger := logos.New("benchmark")
	for i := 0; i < b.N; i++ {
		logger.Info(fakeMessage, zap.String("foo", "bar"), zap.Int("int", 42))
	}
}

func BenchmarkZap(b *testing.B) {
	logger := zap.New(zapcore.NewCore(
		zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
		zapcore.AddSync(ioutil.Discard),
		zapcore.InfoLevel,
	))
	for i := 0; i < b.N; i++ {
		logger.Info(fakeMessage, zap.String("foo", "bar"), zap.Int("int", 42))
	}
}

func BenchmarkZeroLog(b *testing.B) {
	logger := zerolog.New(ioutil.Discard).With().Timestamp().Logger()
	for i := 0; i < b.N; i++ {
		logger.Info().Str("foo", "bar").Int("int", 42).Msg(fakeMessage)
	}
}

func BenchmarkPhusLog(b *testing.B) {
	logger := log.Logger{
		TimeFormat: "", // uses rfc3339 by default
		Writer:     log.IOWriter{ioutil.Discard},
	}
	for i := 0; i < b.N; i++ {
		logger.Info().Str("foo", "bar").Int("int", 42).Msg(fakeMessage)
	}
}

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