打印日志

glog

glog原本是google使用C++实现的一个日志模块(glog c++),go语言出来以后,又实现了一个Go版本的glog

代码

glog依赖标准包flag,在调用glog的方法之前,需要调用flag.Parse()

//create: 2017/12/25 14:24:03 change: 2017/12/25 15:08:49 [email protected]
package main

import (
    "flag"
    "github.com/golang/glog"
)

func main() {
    flag.Parse()
    glog.Infof("%s\n", "This is a info")
    glog.Warningf("%s\n", "This is a warning")
    glog.Errorf("%s\n", "This is a error")
    glog.V(1).Infof("%s\n", "This is a v1 log")
    glog.V(2).Infof("%s\n", "This is a v2 log")
    //this call will make the progress exit.
    //glog.Fatalf("%s\n", "This is a fatal")
    //this call will make the progress exit.
    //glog.Exitf("%s\n", "This is a exit")
}

运行

glog支持以下参数。

$ ./glog -h
Usage of ./glog:
  -alsologtostderr
        log to standard error as well as files
  -log_backtrace_at value
        when logging hits line file:N, emit a stack trace
  -log_dir string
        If non-empty, write log files in this directory
  -logtostderr
        log to standard error instead of files
  -stderrthreshold value
        logs at or above this threshold go to stderr
  -v value
        log level for V logs
  -vmodule value
        comma-separated list of pattern=N settings for file-filtered logging

glog将日志以文件的形式写入-log_dir指定的目录,使用-log_dir时只有ERROR日志会打印到标准输出,

$ ./glog -log_dir=./log
E1225 15:19:10.514843   83246 main.go:13] This is a error

生成的日志文件:

lijiaos-MacBook-Pro:glog lijiao$ ls log/
glog.ERROR
glog.INFO
glog.WARNING
glog.lijiaos-MacBook-Pro.lijiao.log.ERROR.20171225-151858.83190
glog.lijiaos-MacBook-Pro.lijiao.log.ERROR.20171225-151910.83246
glog.lijiaos-MacBook-Pro.lijiao.log.INFO.20171225-151858.83190
glog.lijiaos-MacBook-Pro.lijiao.log.INFO.20171225-151910.83246
glog.lijiaos-MacBook-Pro.lijiao.log.WARNING.20171225-151858.83190
glog.lijiaos-MacBook-Pro.lijiao.log.WARNING.20171225-151910.83246

参数-logtostderr将所有日志打印到标准输出,不保存到文件中。

$ ./glog  -logtostderr
I1225 15:22:11.770424   83995 main.go:11] This is a info
W1225 15:22:11.770510   83995 main.go:12] This is a warning
E1225 15:22:11.770513   83995 main.go:13] This is a error

参数-v指定日志的级别,只打印V(x)中,x小于等于-v指定的数值的日志。

$ ./glog  -logtostderr -v 1
I1225 15:28:03.517261   85366 main.go:11] This is a info
W1225 15:28:03.517335   85366 main.go:12] This is a warning
E1225 15:28:03.517339   85366 main.go:13] This is a error
I1225 15:28:03.517342   85366 main.go:14] This is a v1 log

建议

必须要记录的日志使用glog.InfoXglog.WarningXglog.ErrorX等函数打印。

用于开发调试的日志使用glov.V().InfoX打印。

参考

  1. 李佶澳的博客
  2. glog golang
  3. glog c++

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