RESP 3 push model requires polling

[nihohit]

Currently sync & async connections only receive RESP3 disconnect push messages when a request is sent on the connection, because the incoming TCP traffic isn't polled independently. This means that for pubsub / monitor / client side caching works, but can't report issues - the user will only receive updates when they send on the message, not when the user is inactive.

[nihohit]

@jaymell I think that this should be a blocker to the next release. Either that, or we hide the push manager behind a beta feature branch.

[altanozlu]

It could only be a problem if user just subscribes to certain channels and then never subs/unsubs again or sending any commands.
It could be solved by a heartbeat PING command every x seconds, but I'm not sure if it's a blocker.

[jaymell]

How are other clients handling this situation?

[altanozlu]

I tried with rueidis and it also didn't gave an error when server is crashed, but we can fix this in multiplexed easily(tested it), with sync you always have to call get_message in pubsub, which should raise PushKind::Disconnection (didn't test it).

rueidis code:

client, err := rueidis.NewClient(rueidis.ClientOption{InitAddress: []string{"127.0.0.1:6379"}})
	if err != nil {
		panic(err)
	}
	defer client.Close()
	log.Println("connected")
	err = client.Receive(context.Background(), client.B().Subscribe().Channel("ch1", "ch2").Build(), func(msg rueidis.PubSubMessage) {
		log.Println(msg)
	})
	log.Println(err)