Golang学习笔记-zerolog

zerolog是一个高性能，支持日志等级，钩子的结构化日志库。log的Print()和Printf()方法默认输出到os.Stderr，默认日志等级为debug，用法和官方log库相同。

package main

import (
    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
)


func main(){
    zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
    log.Print("hello world")
}

{"level":"debug","time":1576398679,"message":"hello world"}

日志等级

zerolog有下面几种日志等级，调用zerolog.SetGlobalLevel()设置日志等级。

• panic (zerolog.PanicLevel, 5)
• fatal (zerolog.FatalLevel, 4)
• error (zerolog.ErrorLevel, 3)
• warn (zerolog.WarnLevel, 2)
• info (zerolog.InfoLevel, 1)
• debug (zerolog.DebugLevel, 0)
• trace (zerolog.TraceLevel, -1)

添加数据到上下文

zerolog可以将数据以key-value对的形式添加到一条日志事件的上下文中，重复的key-value对不会删除。调用Msg方法输出日志，也可以调用Send方法输出日志，其本质是调用Msg("")。

package main

import (
    "github.com/rs/zerolog/log"
)


func main(){
    log.Debug().
        Str("name", "xy").
        Str("name", "xy").
        Float64("height", 100.0).
        Msg("create object")
}

{"level":"debug","name":"xy","name":"xy","height":100,"time":"2019-12-15T17:17:46+08:00","message":"create object"}

自定义字段名

package main

import (
    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
)


func main(){
    zerolog.TimestampFieldName = "t"
    zerolog.LevelFieldName = "l"
    zerolog.MessageFieldName = "m"
    log.Debug().
        Str("name", "xy").
        Float64("height", 100.0).
        Msg("create object")
}

{"l":"debug","name":"xy","height":100,"t":"2019-12-15T17:04:24+08:00","m":"create object"}

添加文件名和代码行

package main

import (
    "github.com/rs/zerolog/log"
)


func main(){
    log.Logger = log.With().Caller().Logger()
    log.Info().Msg("hello world")
}

{"level":"info","time":"2019-12-15T17:13:02+08:00","caller":"C:/Users/Administrator/go/src/studygo/main.go:10","message":"hello world"}

logger

zerolog可以创建不同的logger实例来输出日志，下面代码创建了一个新的logger替换了log的logger，其中zerolog.ConsoleWriter可以使输出的日志更加友好，日志等级变为彩色的。

package main

import (
    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
    "os"
)


func main(){
    log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr,TimeFormat: "2006-01-02 15:04:05.000"})
    log.Info().Msg("hello world")
}

钩子

利用钩子可以拦截日志事件，从而实现各种扩展功能，例如将日志输出到文件。

package main

import (
    "fmt"
    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
)

type LogHook struct{}

func (hook LogHook) Run(e *zerolog.Event, level zerolog.Level, msg string) {
    fmt.Println(msg)
}

func main(){
    log.Logger=log.Hook(LogHook{})
    log.Info().Msg("hello world")
}

hello world
{"level":"info","time":"2019-12-15T17:28:58+08:00","message":"hello world"}