Go by Example - Worker Pools

翻译自 https://gobyexample.com/

Go by Example

Go is an open source programming language designed for building simple, fast, and reliable software.

Go by Example is a hands-on introduction to Go using annotated example programs. Check out the first example or browse the full list below.

Go by Example: Worker Pools

这节探索如何使用goroutine和channel实现工作池的功能。

package main

import "fmt"
import "time"

// 这个是工作进程，用来执行并发的任务
// 每个进程都会从管道jobs接受工作，并且将相应发送至管道results
// 每个工作我们都会睡眠一秒用以模拟一项耗时的任务
func worker(id int, jobs <-chan int, results chan<- int) {
    for j := range jobs {
        fmt.Println("worker", id, "started job", j)
        time.Sleep(time.Second)
        fmt.Println("worker", id, "finished job", j)
        results <- j * 2
    }
}

func main() {
    // 初始化两个管道用以给工作进程分配任务及接收结果
    jobs := make(chan int, 100)
    results := make(chan int, 100)

    // 启动三个工作进程
    // 此时它们是阻塞的，因为管道jobs是空的
    for w:= 1; w <= 3; w++ {
        go worker(w, jobs, results)
    }

    // 初始化5个任务
    // 关闭管道jobs，标识没有多余的任务了
    for j:= 1; j <= 5; j++ {
        jobs <- j
    }
    close(jobs)

    // 收集所有任务的结果
    for a := 1; a <= 5; a++ {
        <-results
    }
}

tashuo:golang ta_shuo$ go run worker-pool.go
worker 3 started job 1
worker 2 started job 3
worker 1 started job 2
worker 3 finished job 1
worker 3 started job 4
worker 2 finished job 3
worker 1 finished job 2
worker 2 started job 5
worker 2 finished job 5
worker 3 finished job 4

通过输出可以看出5个任务被多个工作进程执行。程序只消耗了2秒多而不是5秒，是因为所有的任务被3个工作进程并发处理。

原文链接：Go by Example: Worker Pools