go的超时控制

然而如果某个 goroutine 运行时间太长了，那很肯定会拖累主 goroutine 被阻塞住，整个程序就挂起在那儿了。因此我们需要有超时的控制。

通常我们可以通过 select + time.After 来进行超时检查，例如这样，我们增加一个函数 Run() ，在 Run() 中执行 go run() 。并通过 select + time.After 进行超时判断。

package main

import (
    "fmt"
    "time"
)

func Run(task_id, sleeptime, timeout int, ch chan string) {
    ch_run := make(chan string)
    go run(task_id, sleeptime, ch_run)
    select {
    case re := <-ch_run:
        ch <- re
    case <-time.After(time.Duration(timeout) * time.Second):
        re := fmt.Sprintf("task id %d , timeout", task_id)
        ch <- re
    }
}

func run(task_id, sleeptime int, ch chan string) {

    time.Sleep(time.Duration(sleeptime) * time.Second)
    ch <- fmt.Sprintf("task id %d , sleep %d second", task_id, sleeptime)
    return
}

func main() {
    input := []int{3, 2, 1}
    timeout := 2
    chs := make([]chan string, len(input))
    startTime := time.Now()
    fmt.Println("Multirun start")
    for i, sleeptime := range input {
        chs[i] = make(chan string)
        go Run(i, sleeptime, timeout, chs[i])
    }

    for _, ch := range chs {
        fmt.Println(<-ch)
    }
    endTime := time.Now()
    fmt.Printf("Multissh finished. Process time %s. Number of task is %d", endTime.Sub(startTime), len(input))
}