Golang的日志处理

package main

import (
    "log"
    "os"
    "io/ioutil"
    "io"
)

var (
    Trace   *log.Logger // 记录所有日志
    Info    *log.Logger // 重要的信息
    Warning *log.Logger // 需要注意的信息
    Error   *log.Logger // 致命错误
)

func init() {
    file, err := os.OpenFile("file", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err != nil {
        log.Fatalln("Failed to open error log file:", err)
    }

    Trace = log.New(ioutil.Discard, "TRACE: ", log.Ltime|log.Lshortfile)
    Info = log.New(os.Stdout, "Info: ", log.Ltime|log.Lshortfile)
    Warning = log.New(os.Stdout, "Warning: ", log.Ltime|log.Lshortfile)
    Error = log.New(io.MultiWriter(file, os.Stderr),  "Error", log.Ltime|log.Lshortfile)
}

func main() {
    Trace.Println("I have something standard to say")
    Info.Println("Special Information")
    Warning.Println("There is something you need to know about")
    Error.Println("Something has failed")
}