Worker Pools
package main
import "fmt"
import "time"
// 使用goroutine  開啟大小為3的執行緒池
// 其中1個channel為執行做通訊，1個對結果進行儲存
// 建立的worker
func worker(id int, jobs <-chan int, results chan<- int) {
    for j := range jobs {
        fmt.Println("worker", id, "processing job", j)
        time.Sleep(time.Second)
        results <- j * 2
    }
}
func main() {
    // 建立channel
    jobs := make(chan int, 100)
    results := make(chan int, 100)
    // 3個worker作為一個pool
    for w := 1; w <= 3; w++ {
        go worker(w, jobs, results)
    }
    // 傳送9個jobs，然後關閉
    for j := 1; j <= 9; j++ {
        jobs <- j
    }
    close(jobs)
    // 最後收集結果
    for a := 1; a <= 9; a++ {
        <-results
    }
}
 

輸出： worker 1 processing job 1 worker 2 processing job 2 worker 3 processing job 3 worker 1 processing job 4 worker 2 processing job 5 worker 3 processing job 6 worker 1 processing job 7 worker 2 processing job 8 worker 3 processing job 9 real 0m3.149s