alivanz / go-notify

Notification in Go

Notify Once

func main() {
  once := notify.NewNotifyOnce()
  for i := 0; i < 3; i++ {
    go func(i){
      <-notify.Listen()
      log.Printf("%d first")
      <-notify.Listen()
      log.Printf("%d second")
    }(int i)
  }
  once.Notify()
}

0 first
1 first
2 first
0 second
1 second
2 second

Notify Bytes

func main() {
  bytesNotify := notify.NewBytes([]byte("first"))
  go func() {
    for {
      data, done := bytesNotify.Listen()
      log.Printf("alice got %s", string(data))
      <-done
    }
  }()
  go func() {
    for {
      data, done := bytesNotify.Listen()
      log.Printf("bob got %s", string(data))
      <-done
    }
  }()
  go func() {
    for {
      data, done := bytesNotify.Listen()
      log.Printf("lucy got %s", string(data))
      <-done
    }
  }()
  for i := 0; ; i++ {
    time.Sleep(1 * time.Second)
    bytesNotify.Notify([]byte(fmt.Sprintf("msg#%d", i)))
  }
}

alive got first
bob got first
lucy got first
alive got msg#0
bob got msg#0
lucy got msg#0
alive got msg#1
bob got msg#1
lucy got msg#1
alive got msg#2
bob got msg#2
lucy got msg#2
....

Network notify

Server side

func main() {
	n := notify.NewInterface(nil)
	server, err := ionotify.ListenAndServe("0.0.0.0:6000", n)
	if err != nil {
		log.Fatal(err)
	}
	defer server.Stop()
	// feed data
	ticker := time.NewTicker(1 * time.Second)
	defer ticker.Stop()
	for {
		select {
		case err := <-server.Err():
			log.Fatal(err)
		case <-ticker.C:
		}
		t := time.Now()
		n.Notify(t)
		log.Printf("server notify %v", t.String())
	}
}

Client / Listener side

func main() {
	n := notify.NewInterface(nil)
	subs, err := ionotify.Subscribe("127.0.0.1:6000", reflect.TypeOf(time.Time{}), n)
	if err != nil {
		log.Fatal(err)
	}
	defer subs.Unsubscribe()
	c := notify.Closed()
	for {
		select {
		case err := <-subs.Err():
			log.Fatal(err)
		case <-c:
			var i interface{}
			i, c = n.Listen()
			if i == nil {
				continue
			}
			t := i.(*time.Time)
			log.Printf("server notify %v", t.String())
		}
	}
}