Golang用time.Ticker控制任务执行频率

ticker := time.NewTicker(500 * time.Millisecond)
defer ticker.Stop()
<p>for {
select {
case <-ticker.C:
go func() {
// 并发执行任务
fetchData()
}()
}
}</p>

semaphore := make(chan struct{}, 3) // 最多3个并发
<p>ticker := time.NewTicker(200 * time.Millisecond)
defer ticker.Stop()</p><p>for {
select {
case <-ticker.C:
select {
case semaphore <- struct{}{}: // 获取许可
go func() {
defer func() { <-semaphore }() // 释放许可
fetchData()
}()
default:
// 并发已达上限，跳过本次执行或排队
log.Println("too many concurrent tasks, skip")
}
}
}</p>

ctx, cancel := context.WithCancel(context.Background())
ticker := time.NewTicker(1 * time.Second)
<p>go func() {
time.Sleep(5 * time.Second)
cancel() // 5秒后停止
}()</p><p>for {
select {
case <-ctx.Done():
ticker.Stop()
return
case <-ticker.C:
select {
case semaphore <- struct{}{}:
go func() {
defer func() { <-semaphore }()
if err := doWork(ctx); err != nil {
log.Printf("work failed: %v", err)
}
}()
default:
log.Println("concurrent limit reached, skip")
}
}
}</p>