Help on how to setup two handlers in two different services, subscribe to the same message without a shared library

[KorpEduardoSikora]

I'm trying to setup my microsservices applications to be indepedent, even of a shared Message library.

I've added a small project to the following repository, describing what I'm trying to accomplish: https://github.com/KorpEduardoSikora/DemoRebusHandlerSameMessage

I guess i'm trying publish a message and subscribe to it's queue by name (the same name as the Type). All the examples I found uses a shared message type library.

Thanks in advance.

[mookid8000]

Hi @KorpEduardoSikora , great question 😄 it's fairly easy to bind two processes together solely by their knowledge of queue names and/or topics – but as you've probably discovered, Rebus encourages you to share a message DLL between your processes, which might not always be what you want.

It's not hard to remove this dependency though, the crux is just to

• lower the level of how much type information JSON.NET puts into the serialized format, and
• maybe add some special handling in the receiving end to help with deserialization

To show how that can be done, I just created the SharedNothing demo, where a publisher and a subscriber communicate without sharing anything but their knowledge of a topic name and a message schema.

I hope you find the demo useful 😄 I'll close this issue for now, but please don't hesitate to write any questions/comments you might have in here.

[EduSikora]

Thanks for your help @mookid8000!

We've implemented this after your answer and example (: Thanks!!

Basically we get all MessageTypes on the Handlers, and subscribe to a Endpoint. If the MessageType has an custom Endpoint attribute, we use that value, otherwise we get the string from the MessageType, and adjust to a IFailed<> if needed.

On the serialization method we basically do the same thing:

Works as a charm (: (for now, on initial tests) hahaha

Now we came across a situation where we need a request/reply... But when we use bus.Send(message, header), we get a error that we did not map the classes to a endpoint..

I didn't quite understand how to implement this Mapping along side the custom subscribe/serialization..

[mookid8000]

When you

await bus.Send(new MyMessage());

Rebus will look through its "endpoint mappings" for a destination queue for messages of type MyMessage.

An endpoint mapping for MyMessage can be configured like this:

Configure.With(...)
    .(...)
    .Routing(r => r.TypeBased().Map<MyMessage>("some-queue"))
    .Start();

The builder returned from TypeBased() can be used to map multiple specific message types to destination queues, and/or be used to map entire assemblies to destination queues.

[mookid8000]

I suggest you read the wiki page about routing – it also describes the difference between send and publish.