go routines 和接收错误或成功的通道

Question

我有一个函数，我想定义最大数量的 go 例程，我有一个列表，我遍历这个列表，然后通过通道向 go 例程发送消息，在这个 go 例程中，我将调用一个函数将得到答案或错误，当它不是错误时我想将返回保存在一个切片中，当它是错误时我想停止 go 例程并进行调用。但我无法做到，当我有错误时，所有的 go 例程都结束，我需要 err 的值

type response struct {

    value string

}

func Testing() []response {

    fakeValues := getFakeValues()

    maxParallel := 25

    wg := &sync.WaitGroup{}

    wg.Add(maxParallel)

    if len(fakeValues) < maxParallel {

        maxParallel = len(fakeValues)

    }

    errReceive := make(chan error, 1)

    defer close(errReceive)

    response := make([]response, 0)

    valuesChan := make(chan string, 1)

    for i := 0; i < maxParallel; i++ {

        go func(valuesChan <-chan string, errReceive chan error) {

            for value := range valuesChan {

                resp, err := getFakeResult(value)

                if err != nil {

                    errReceive <- err

                }

                response = append(response, resp)

            }

            wg.Done()

        }(valuesChan, errReceive)

    }

    for _, val := range fakeValues {

        valuesChan <- val

    }

    close(valuesChan)

    wg.Wait()

    err := <-errReceive

    if err != nil {

        // make any thing

    }

    return response

}

func getFakeValues() []string {

    return []string{"a", "b"}

}

func getFakeResult(val string) (response, error) {

    if val == "a" {

        return response{}, fmt.Errorf("ooh noh:%s", val)

    }

    return response{

        value: val,

    }, nil

}

Answer 1

您可以使用带取消的上下文，并使用它让 go 例程知道它们应该停止。ctx, cancel := context.WithCancel(context.Background())defer cancel()wg := &sync.WaitGroup{}wg.Add(1)go func(ctx context.Context) {&nbsp; &nbsp; defer wg.Done()&nbsp; &nbsp; for {&nbsp; &nbsp; &nbsp; &nbsp; select {&nbsp; &nbsp; &nbsp; &nbsp; case <-ctx.Done():&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fmt.Println("context is done")&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return&nbsp; &nbsp; &nbsp; &nbsp; case <-time.After(time.Second):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fmt.Println("work")&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }}(ctx)time.Sleep(time.Second * 5)cancel()wg.Wait()https://go.dev/play/p/qe2oDppSnaF这是一个示例，可以在您的用例上下文中更好地展示它。type result struct {&nbsp; &nbsp; err error&nbsp; &nbsp; val int}rand.Seed(time.Now().UnixNano())ctx, cancel := context.WithCancel(context.Background())defer cancel()rchan := make(chan result, 5)wg := &sync.WaitGroup{}for i := 0; i < 5; i++ {&nbsp; &nbsp; wg.Add(1)&nbsp; &nbsp; go func(ctx context.Context) {&nbsp; &nbsp; &nbsp; &nbsp; defer wg.Done()&nbsp; &nbsp; &nbsp; &nbsp; for {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; select {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case <-ctx.Done():&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; fmt.Println("context is done")&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case <-time.After(time.Second):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; n := rand.Intn(100)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if n > 90 {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; rchan <- result{err: fmt.Errorf("error %d", n)}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; rchan <- result{val: n}&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }(ctx)}go func() {&nbsp; &nbsp; wg.Wait()&nbsp; &nbsp; close(rchan)}()for res := range rchan {&nbsp; &nbsp; if res.err != nil {&nbsp; &nbsp; &nbsp; &nbsp; fmt.Println(res.err)&nbsp; &nbsp; &nbsp; &nbsp; cancel()&nbsp; &nbsp; &nbsp; &nbsp; break&nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; fmt.Println(res.val)&nbsp; &nbsp; }}https://go.dev/play/p/Z63n1h2A81o