Golang HTTP限流与并发控制技巧

import "golang.org/x/time/rate"
var limiter = rate.NewLimiter(5, 10)
func handler(w http.ResponseWriter, r *http.Request) {
if !limiter.Allow() {
http.Error(w, "Too Many Requests", http.StatusTooManyRequests)
return
}
// 处理业务逻辑
}

var semaphore = make(chan struct{}, 20)
func limitedHandler(w http.ResponseWriter, r *http.Request) {
semaphore <- struct{}{} // 获取许可
defer func() { <-semaphore }() // 释放许可
// 模拟处理时间
time.Sleep(100 * time.Millisecond)
w.Write([]byte("OK"))
}

ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)
resp, err := http.DefaultClient.Do(req)

func fetchAll(urls []string) {
    jobs := make(chan string, len(urls))
    results := make(chan error, len(urls))
for i := 0; i < 10; i++ { // 10个worker
    go func() {
        for url := range jobs {
            ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
            req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)
            _, err := http.DefaultClient.Do(req)
            cancel()
            results <- err
        }
    }()
}

for _, url := range urls {
    jobs <- url
}
close(jobs)

for range urls {
    <-results
}
}