## 工作池（Worker Pools） 緩沖信道的重要應用之一就是實現工作池； 工作池就是一組等待任務分配的線程； ### 工作池的實現 工作池的核心功能如下： 創建一個Go協程池，監聽一個等待作業分配的輸入型緩沖信道； 將作業添加到該輸入型緩沖信道中； 作業完成后，再將結果寫入一個輸出型緩沖信道； 從輸出型緩沖信道讀取結果； 示例： ~~~ type Job struct { id int randomno int } type Result struct { job Job sumofdigits int } var jobs = make(chan Job, 10) var results = make(chan Result, 10) func digits(number int) int { sum := 0 no := number for no != 0 { digit := no % 10 sum += digit no /= 10 } time.Sleep(2 * time.Second) return sum } func worker(wg *sync.WaitGroup) { for job := range jobs { output := Result{job, digits(job.randomno)} results <- output } wg.Done() } func createWorkerPool(noOfWorkers int) { var wg sync.WaitGroup for i := 0; i < noOfWorkers; i++ { wg.Add(1) go worker(&wg) } wg.Wait() close(results) } func allocate(noOfJobs int) { for i := 0; i < noOfJobs; i++ { randomno := rand.Intn(999) job := Job{i, randomno} jobs <- job } close(jobs) } func result(done chan bool) { for result := range results { fmt.Printf("Job id %d, input random no %d , sum of digits %d\n", result.job.id, result.job.randomno, result.sumofdigits) } done <- true } func TestWrokPool(t *testing.T) { startTime := time.Now() noOfJobs := 100 go allocate(noOfJobs) done := make(chan bool) go result(done) noOfWorkers := 10 createWorkerPool(noOfWorkers) <-done endTime := time.Now() diff := endTime.Sub(startTime) fmt.Println("total time taken ", diff.Seconds(), "seconds") } ~~~