Heartbeat healthcheck

healthCheck.go

func health() {
	dowork := func(done <-chan interface{}, pulseInterval time.Duration) (<-chan interface{}, <-chan time.Time) {
		hearthbeat := make(chan interface{})
		results := make(chan time.Time)
		go func() {
			defer close(hearthbeat)
			defer close(results)

			pulse := time.Tick(pulseInterval)
			workGen := time.Tick(2 * pulseInterval)

			sendPulse := func() {
				select {
				case hearthbeat <- struct{}{}:
				default:

				}
			}

			sendResult := func(r time.Time) {
				for {
					select {
					case <-done:
						return
					case <-pulse:
						sendPulse()
					case results <- r:
						return
					}
				}
			}

			for {
				select {
				case <-done:
					return
				case <-pulse:
					sendPulse()
				case r := <-workGen:
					sendResult(r)
				}
			}
		}()
		return hearthbeat, results
	}

	done := make(chan interface{})
	time.AfterFunc(10*time.Second, func() {
		close(done)
	})

	const timeout = 2 * time.Second
	heartbeat, results := dowork(done, timeout/2)
	for {
		select {
		case _, ok := <-heartbeat:
			if ok == false {
				return
			}
			fmt.Println("pulse")
		case r, ok := <-results:
			if ok == false {
				return
			}
			fmt.Printf("results %v \n", r.Second())
		case <-time.After(timeout):
			return
		}

	}
}