polling.go

func polling(interval, maxTime int) error {
	ticker := time.NewTicker(time.Duration(interval) * time.Second)
	timeout := time.NewTimer(time.Duration(maxTime) * time.Second)
	defer timeout.Stop()
	defer ticker.Stop()
	for {
		select {
		case <-timeout.C:
			return errors.New("timeout")
		case <-ticker.C:
			if f() {
				return nil
			}
		}
	}
	return nil
}