cancel a WithCancel context not work on BLPop?

[zihuyishi]

I want graceful shutdown, so use context to cancel block command, but i found it still block after call cancel()

func main() {
	app = util.NewApplication()
	if app.Redis == nil {
		panic("worker need env REDIS_HOST to connect to redis")
	}
	ctx, cancel := context.WithCancel(context.Background())
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	var wg sync.WaitGroup
	wg.Add(2)
	go func() {
		wait(ctx)
		wg.Done()
	}()
	go func() {
		wait(ctx)
		wg.Done()
	}()
	go func() {
		<-c
		fmt.Println("shutdown")
		cancel()
	}()
	wg.Wait()
}

func wait(ctx context.Context) {
	fmt.Println("run")
	app.Redis.BLPop(ctx, 0, "test")
}

[zihuyishi]

should i write like is?

func wait(ctx context.Context) {
	fmt.Println("run")
	for {
		app.Redis.BLPop(ctx, 5 * time.Second, "test")
		if ctx.Err() != nil {
			break
		}
	}
	fmt.Println("cancel")
}