【Go语言入门学习笔记】Part18.工作池与WaitGroup（也即协程池）

一、前言

两个功能相似的多个同类协程使用同类资源时候需要用到的协程池，满足并发工作需求。

二、学习代码

工作池：用result通道来收集完成情况

package main

import (
	"fmt"
	"time"
)

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() {
	const numJobs = 5
	jobs := make(chan int, numJobs)
	results := make(chan int, numJobs)
	for w := 1; w <= 3; w++ {
		go worker(w, jobs, results)
	}
	for j := 1; j <= numJobs; j++ {
		jobs <- j
	}
	close(jobs)
	for a := 1; a <= numJobs; a++ { //用循环模拟等待全部工人完成工作
		<-results
	}

}

WaitGroup：用特殊的WaitGroup变量来对协程进行处理。

package main

import (
	"fmt"
	"sync"
	"time"
)

func worker(id int, jobs <-chan int, wg *sync.WaitGroup) {
	defer wg.Done()
	for j := range jobs {
		fmt.Println("worker", id, "started  job", j)
		time.Sleep(time.Second)
		fmt.Println("worker", id, "finished job", j)
	}
	//wg.Done()
}
func main() {
	const numJobs = 5
	const numWorkers = 3
	var wg sync.WaitGroup
	wg.Add(numWorkers)
	jobs := make(chan int, numJobs)
	for w := 1; w <= numWorkers; w++ {
		go worker(w, jobs, &wg)
	}
	for j := 1; j <= numJobs; j++ {
		jobs <- j
	}
	close(jobs)
	wg.Wait()
}