如何在Golang中优化HTTP请求重试策略_Golang HTTP重试性能优化实践

func doWithRetry(client *http.Client, req *http.Request, maxRetries int) (*http.Response, error) {
    var resp *http.Response
    var err error
<pre class='brush:php;toolbar:false;'>for i := 0; i <= maxRetries; i++ {
    resp, err = client.Do(req)
    if err == nil && resp.StatusCode < 500 {
        return resp, nil
    }

    if i < maxRetries {
        sleepTime := time.Second * time.Duration(1<<i) // 指数退避：1s, 2s, 4s...
        time.Sleep(sleepTime)
    }
}
return resp, err

jitter := time.Duration(rand.Int63n(1000)) * time.Millisecond
sleepTime := time.Second*time.Duration(1<<i) + jitter
time.Sleep(sleepTime)

type RetryingRoundTripper struct {
    Transport   http.RoundTripper
    MaxRetries  int
}
<p>func (r <em>RetryingRoundTripper) RoundTrip(req </em>http.Request) (<em>http.Response, error) {
var resp </em>http.Response
var err error</p><pre class='brush:php;toolbar:false;'>for i := 0; i <= r.MaxRetries; i++ {
    resp, err = r.Transport.RoundTrip(req)
    if err != nil {
        if i == r.MaxRetries {
            return nil, err
        }
        goto retry
    }

    if resp.StatusCode >= 500 {
        resp.Body.Close()
        goto retry
    }

    return resp, nil

retry:
    if i < r.MaxRetries {
        time.Sleep(backoff(i))
    }
}
return resp, err

client := &http.Client{
    Transport: &RetryingRoundTripper{
        Transport:  http.DefaultTransport,
        MaxRetries: 3,
    },
}

ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
<p>req = req.WithContext(ctx)</p>