Golang zerolog 範例

Go的三方log套件zerolog的使用範例。

zerolog的特色是以JSON為輸出的日誌格式。

範例環境：

• Go 1.19

安裝

專案根目錄輸入go get -u github.com/rs/zerolog/log安裝。

範例

main.go

package main

import (
    "errors"
    "os"

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

func main() {
    // default
    log.Print("hello world") // {"level":"debug","time":"2023-11-03T18:36:38+08:00","message":"hello world"}

    // level loggin/ only print log above [Info] level
    zerolog.SetGlobalLevel(zerolog.InfoLevel)
    log.Trace().Msg("trace") // below [Info] level, no print
    log.Debug().Msg("debug") // below [Info] level, no print
    log.Info().Msg("info")   // {"level":"info","time":"2023-11-03T18:36:38+08:00","message":"info"}
    log.Warn().Msg("warn")   // {"level":"warn","time":"2023-11-03T18:36:38+08:00","message":"warn"}
    log.Error().Msg("error") // {"level":"error","time":"2023-11-03T18:36:38+08:00","message":"error"}

    // log.Fatal().Msg("fetal message") // will exit
    // log.Panic().Msg("panic message") // will panic

    // contextual logging (with other fields)
    log.Info().Str("id", "1").Msg("with id") // {"level":"info","id":"1","time":"2023-11-03T18:36:38+08:00","message":"with id"}

    log.Log().Msg("without level") // {"time":"2023-11-03T18:36:38+08:00","message":"without level"}

    // error logging (with "error" field)
    log.Err(errors.New("Error!!")).Msg("error message") // {"level":"error","error":"Error!!","time":"2023-11-03T18:36:38+08:00","message":"error message"}

    // sub logger
    logger := log.With().Str("env", "dev").Logger()
    logger.Info().Str("id", "2").Msg("sub log") // {"level":"info","env":"dev","id":"2","time":"2023-11-03T18:36:38+08:00","message":"sub log"}

    // pretty logging
    log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
    log.Info().Msg("pretty") // 6:36PM INF pretty

    // stardard logging
    log.Logger = log.Output(os.Stdout)

    // sub dictionary
    log.Info().Str("env", "test").
        Dict("dict", zerolog.Dict().Str("sub", "11").Int("amt", 100)).
        Msg("with dict")
        // {"level":"info","env":"test","dict":{"sub":"11","amt":100},"time":"2023-11-03T18:36:38+08:00","message":"with dict"}

    // caller
    logger = log.With().Caller().Logger()
    logger.Info().Msg("with caller") // {"level":"info","time":"2023-11-03T18:36:38+08:00","caller":"/../go-demo/main.go:50","message":"with caller"}

    // add contextual fields to global logger
    log.Logger = log.With().Str("env", "qat").Logger()
    log.Info().Msg("message") // {"level":"info","env":"qat","time":"2023-11-03T18:36:38+08:00","message":"message"}

}

github

測試

執行程式後輸出以下：

{"level":"debug","time":"2023-11-03T18:36:38+08:00","message":"hello world"}
{"level":"info","time":"2023-11-03T18:36:38+08:00","message":"info"}
{"level":"warn","time":"2023-11-03T18:36:38+08:00","message":"warn"}
{"level":"error","time":"2023-11-03T18:36:38+08:00","message":"error"}
{"level":"info","id":"1","time":"2023-11-03T18:36:38+08:00","message":"with id"}
{"time":"2023-11-03T18:36:38+08:00","message":"log without level"}
{"level":"error","error":"Error!!","time":"2023-11-03T18:36:38+08:00","message":"error message"}
{"level":"info","env":"dev","id":"2","time":"2023-11-03T18:36:38+08:00","message":"sub log"}
6:36PM INF pretty info message
{"level":"info","env":"test","dict":{"sub":"11","amt":100},"time":"2023-11-03T18:36:38+08:00","message":"info message with dict"}
{"level":"info","time":"2023-11-03T18:36:38+08:00","caller":"/Users/leo.hung/Documents/projects/go-demo/main.go:50","message":"with caller"}
{"level":"info","env":"qat","time":"2023-11-03T18:36:38+08:00","message":"message"}

• Golang log Logger日誌工具簡介