Message bus is a library (or a collection of libraries) used by Dáme jídlo for separating different layers and contexts within it's monolithic backend application.
In Dáme jídlo the main purpose was to
- create an application layer with commands/handlers (e.g. "place order") to separate domain logic from the rest of the application
- get rid of tight coupling of different contexts by using asynchronous event subscribers for secondary tasks (e.g. send notification to customer on order placed)
The core is a general message bus. It can be used in different ways:
- as a command bus, handling commands synchronously
- as a event dispatching system, with the ability to plug-in asynchronous ways to handle events in different subscribers
The message bus functionality can be enhanced with middleware, e.g.:
- logging
- transaction management
- sync/async handling
Pending :) See tests/Integration for basic use case examples.