在golang中同步goroutine有2种方法,要么使用channel,要么使用sync.WaitGroup,本文就是介绍如何通过channel来同步goroutine。先看代码。
1 package main
2
3 import (
4 "os"
5 "os/signal"
6 "runtime"
7 "log"
8 "syscall"
9 )
10
11 const NUM_OF_QUIT int = 100
12
13 func main() {
14 runtime.GOMAXPROCS(runtime.NumCPU())
15 done := make(chan bool)
16 receive_channel := make(chan chan bool)
17 finish := make(chan bool)
18
19
20 for i := 0; i < NUM_OF_QUIT; i++ {
21 go do_while_select(i, receive_channel, finish)
22 }
23
24 go handle_exit(done, receive_channel, finish)
25
26 <-done
27 os.Exit(0)
28
29 }
30 func handle_exit(done chan bool, receive_channel chan chan bool, finish chan bool) {
31 sigs := make(chan os.Signal, 1)
32 signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
33 chan_slice := make([]chan bool, 0)
34 for {
35 select {
36 case <-sigs:
37 for _, v := range chan_slice {
38 v <- true
39 }
40 for i := 0; i < len(chan_slice); i++ {
41 <-finish
42 }
43 done <- true
44 runtime.Goexit()
45 case single_chan := <-receive_channel:
46 log.Println("the single_chan is ", single_chan)
47 chan_slice = append(chan_slice, single_chan)
48 }
49 }
50 }
51 func do_while_select(num int, rece chan chan bool, done chan bool) {
52 quit := make(chan bool)
53 rece <- quit
54 for {
55 select {
56 case <-quit:
57 done <- true
58 runtime.Goexit()
59 default:
60 //简单输出
61 log.Println("the ", num, "is running")
62 }
63 }
64 }
上面的代码保存为example.go,通过gotool编译代码:
go build example.go
在当前目录下有example文件,在终端运行这个文件
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
2013/03/19 21:17:14 the 0 is running
......
上面不断输出goroutine中的数字,等待退出信号。
新打开一个终端,通过ps找到这个进程名,通过kill工具干掉这个进程:
$ps aux | grep example
user 4026 77.9 0.0 39436 1716 pts/1 Sl+ 21:19 0:17 ./example
$kill 4026
不久就可以看到在第一个终端里面不再打印,至此演示完毕。
代码思想:
新建NUM_OF_QUIT个goroutine,这些个goroutine里面新建1个chan bool,通过这个channel来接受退出的信号,这些channel在新建的时候,已经发给了handle_exit。在handle_exit这个goroutine里面,1方面监控由系统发过来的退出信号,然后再通知其他的goroutin优雅地退出;另一方面通过slice收集其他goroutine发过来的channel。handle_exit通知其他的goroutine优雅退出后,再发信号给main进程主动退出。
可以修改NUM_OF_QUIT值,例如改为10000,这个时候,kill命令发出去后,要等待相当长的一段时间才能看到第一个终端停止打印。
参考:
Go by Example: Signals
https://gobyexample.com/signals
转贴请注明来自:格通
转载于:https://my.oschina.net/u/191928/blog/618675