aholic / ggtimer

cancelable timer(ticker) in golang

ggtimer

Why ggtimer

ggtimer is a cancelable timer(ticker) in golang. A timer(ticker) in standard lib of golang is not cancelable. That is, when you are blocked on a channel of a timer(ticker), you are not able to stop it. The timer.Stop() doesn't close the channel. The following code will result an error.

t := time.NewTimer(3 * time.Second)
done := make(chan bool, 1)

go func() {
    <-t.C
    fmt.Println("after 3 seconds")
    done <- true
}()

t.Stop()
<-done

The implementation of ggtimer is easy, for more information, refer to here

Usgae

The typical usgae of ggtimer, refer to here

eg.

func main() {
	lck := &sync.Mutex{}
	cnt := 0

	tmr := ggtimer.NewTimer(5*time.Second, func(time.Time) {
		lck.Lock()
		defer lck.Unlock()
		cnt++
	})

	time.Sleep(1 * time.Second)
	close(tmr)
	if cnt != 0 {
		fmt.Errorf("expect: %v, actual: %v", 0, cnt)
	}

	cnt = 0
	tmr = ggtimer.NewTimer(1*time.Second, func(time.Time) {
		lck.Lock()
		defer lck.Unlock()
		cnt++
	})
	time.Sleep(3 * time.Second)
	close(tmr)
	if cnt != 1 {
		fmt.Errorf("expect: %v, actual: %v", 1, cnt)
	}
}