GolangHTTP请求重试实现方法解析

package main
import (
"net/http"
"time"
"log"
)
type RetryingRoundTripper struct {
Transport http.RoundTripper
MaxRetries int
RetryDelay time.Duration
}
func (r RetryingRoundTripper) RoundTrip(req http.Request) (http.Response, error) {
var resp http.Response
var err error
transport := r.Transport
if transport == nil {
transport = http.DefaultTransport
}
for i := 0; i <= r.MaxRetries; i++ {
    resp, err = transport.RoundTrip(req)
    if err == nil {
        break
    }

    // 可在此加入对特定错误的判断，如网络超时、连接拒绝等
    log.Printf("Request failed (attempt %d): %v", i+1, err)

    if i < r.MaxRetries {
        time.Sleep(r.RetryDelay)
    }
}

return resp, err
}

func main() {
    client := &http.Client{
        Transport: &RetryingRoundTripper{
            MaxRetries: 3,
            RetryDelay: time.Second * 2,
        },
    }
resp, err := client.Get("https://httpbin.org/status/500")
if err != nil {
    log.Fatal("All attempts failed:", err)
}
defer resp.Body.Close()

log.Println("Request succeeded with status:", resp.Status)
}

if resp != nil && resp.StatusCode >= 500 {
    resp.Body.Close() // 需关闭旧响应体
    continue
}