golang--使用channel来同步goroutine

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

 

posted @ 2013-03-19 21:41  格通  阅读(5687)  评论(0编辑  收藏  举报