Send events even if no service is registered in the Service Registry

[mathiasmoeller]

Is your feature request related to a problem? Please describe.
I am building a system of micro services that broadcast events. One of the services will be a Moleculer service.
Even with disableBalancer: true Moleculer will only publish events to the transporter (NATS in my case) if another Moleculer service is registered in the Service Registry of Moleculer. If not no events will be broadcasted.
If you use Moleculer together with other frameworks they will not receive any events unless one of them is a Moleculer service.

Describe the solution you'd like
It would be great to have an option that forces Moleculer to send events to the transporter no matter if another service is registered in the Service Registry or not. This is crucial to be able to use Moleculer in an diverse micro service environment.

I created a small project to show the issue:
https://github.com/mathiasmoeller/moleculer-publish-subscribe-demo

[icebob]

The problem is here:

moleculer/src/service-broker.js

Lines 1080 to 1081 in 6e76848

	if (groups.length == 0)
	return;

But there are other problems too. The broker.broadcast doesn't work correctly with disableBalancer option.

[icebob]

Hi mathias,

The broker.emit works just you should use groups always.
E.g.

broker.start().then(() => {
    setInterval(() => {
        broker.emit("test.event", { ddata: "this is test data" }, ["group"]);
    }, 2000);
});


nats.subscribe("MOL.EVENTB.group.test.event", { queue: "group" }, message => {
    broker.logger.info("nodejs-subscriber: Test event received with payload:", message);
});

I will fix the broker.broadcast too, but I can't do this with broker.call. The action calling is very different. The broker always looks up the action definition from registry. And it is not easy to skip this parts.

[mathiasmoeller]

Thanks! I will try this approach ASAP.

[mathiasmoeller]

It seems to work! Thanks a lot. Should I leave my demo project public so you can use it to test the broker.broadcast issue?

[icebob]

Not need it. I've created a simple dev example to demonstrate it: https://github.com/moleculerjs/moleculer/blob/fix-426/dev/no-balancer.js