Golanggoroutine数量控制与限制技巧

func worker(id int, jobChan <-chan int, done chan<- bool, sem chan struct{}) {
    sem <- struct{}{} // 获取信号
    defer func() { <-sem }() // 释放信号
<pre class='brush:php;toolbar:false;'>for job := range jobChan {
    fmt.Printf("Worker %d processing job %d\n", id, job)
    time.Sleep(100 * time.Millisecond) // 模拟处理
}
done <- true

// 启动固定数量worker
for i := 0; i < maxGoroutines; i++ {
    go worker(i, jobChan, done, sem)
}

// 发送任务
for i := 0; i < 20; i++ {
    jobChan <- i
}
close(jobChan)

// 等待所有worker完成
for i := 0; i < maxGoroutines; i++ {
    <-done
}

ctx := context.Background()
g, ctx := errgroup.WithContext(ctx)
<p>for i := 0; i < 100; i++ {
i := i
g.Go(func() error {
select {
case <-time.After(500 * time.Millisecond):
if i == 50 {
return fmt.Errorf("task %d failed", i)
}
fmt.Printf("Task %d done\n", i)
return nil
case <-ctx.Done():
return ctx.Err()
}
})
}</p><p>if err := g.Wait(); err != nil {
fmt.Printf("Error: %v\n", err)
}</p>

fmt.Printf("Current goroutines: %d\n", runtime.NumGoroutine())