操作系统： CentOS 6.9_x64
go语言版本： 1.8.3
问题描述
/* golang log example E-Mail : Mike_Zhang@live.com */ package main import ( "log" "os" ) func main() { logFile,err := os.Create("test1.log") defer logFile.Close() @H_404_42@if err != nil { log.Fatalln("open file error!") } logger := log.New(logFile,"[Debug]",log.Ldate | log.Ltime | log.Lshortfile) logger.Println("test debug message") logger.SetPrefix("[Info]") logger.Println("test info message") }
运行效果：
[root@local t2]# go build logTest1.go [root@local t2]# ./logTest1 [root@local t2]# @H_404_42@cat test1.log [Debug]2017/06/13 23:18:36 logTest1.go:19: test debug message [Info]2017/06/13 23:18:36 logTest1.go:21: test @H_404_42@info message [root@local t2]#
go语言的log模块没有提供log rotate接口，但实际开发中我们需要该功能：
我们不希望单个日志过大，否则文本编辑器无法打开，查看比较困难；
更不希望占用太大的存储空间，可以指定最多存多少个日志文件。
解决方案
借助带缓冲的channel来实现。
示例代码如下：
/* golang log rotate example E-Mail : Mike_Zhang@live.com */ package main import ( "fmt" "log" "os" "time" ) @H_404_42@const ( BACKUP_COUNT = 5 MAX_FILE_BYTES = 2 * 1024 ) func doRotate(fPrefix @H_404_42@string) { @H_404_42@for j := BACKUP_COUNT; j >= 1; j-- { curFileName := fmt.Sprintf("%s_%d.log",fPrefix,j) k := j-1 preFileName := fmt.Sprintf("%s_%d.log",k) @H_404_42@if k == 0 { preFileName = fmt.Sprintf("%s.log",fPrefix) } _,err := os.Stat(curFileName) @H_404_42@if err == nil { os.Remove(curFileName) fmt.Println("remove : ",curFileName) } _,err = os.Stat(preFileName) @H_404_42@if err == nil { fmt.Println("rename : ",preFileName," => ",curFileName) err = os.Rename(preFileName,curFileName) @H_404_42@if err != nil { fmt.Println(err) } } } } func NewLogger(fPrefix @H_404_42@string) (*log.Logger,*os.File) { @H_404_42@var logger *log.Logger fileName := fmt.Sprintf("%s.log",fPrefix) fmt.Println("fileName :",fileName) logFile,err := os.OpenFile(fileName,os.O_RDWR|os.O_CREATE|os.O_APPEND,0666) @H_404_42@if err != nil { fmt.Println("open file error!") } @H_404_42@else { logger = log.New(logFile,log.Ldate|log.Ltime|log.Lshortfile) } @H_404_42@return logger,logFile } func logWorker(msgQueue <-chan @H_404_42@string) { fPrefix := "msg" logger,logFile := NewLogger(fPrefix) @H_404_42@for msg := range msgQueue { logger.Println(msg) fi,err2 := logFile.Stat() @H_404_42@if err2 == nil { @H_404_42@if fi.Size() > MAX_FILE_BYTES { logFile.Close() doRotate(fPrefix) logger,logFile = NewLogger(fPrefix) } } } logFile.Close() } func main() { msgQueue := make(chan @H_404_42@string,1000) go logWorker(msgQueue) @H_404_42@for j := 1; j <= 1000; j++ { msgQueue <- fmt.Sprintf("msg_%d",j) time.Sleep(1 * time.Second) } close(msgQueue) @H_404_42@return }
运行效果如下：
[root@local t2]# ./logRotateTest1 fileName : msg.log rename : msg.log => msg_1.log fileName : msg.log rename : msg_1.log => msg_2.log rename : msg.log => msg_1.log fileName : msg.log rename : msg_2.log => msg_3.log rename : msg_1.log => msg_2.log rename : msg.log => msg_1.log fileName : msg.log ^C
讨论
这里只是个简单的示例代码，实现了log rotate，更多功能需自行开发。
好，就这些了，希望对你有帮助。
本文github地址：
https://github.com/mike-zhang/mikeBlogEssays/blob/master/2017/20170614_golang之logRotate.rst
欢迎补充
