Implement Pub/Sub pattern for RabbitMQ

[derevnjuk]

Each event type has a related channel to get events from RabbitMQ. You can then have as many event handlers per channel and event type as needed.

The register method accepts a type of EventHandler, adding that event handler to the list of handlers that each event can have. If the bus is not subscribed to the event, it creates a new channel with a routing key using an event type so it can receive events when that event is published from any other service.

type IssueFoundHandler struct {}

func (h *IssueFoundHandler) Handle(message Message) (any, error) {
    // implementation
}

// ...

eventBus.Register("IssueFound", &IssueFoundHandler{})

Once it is done, the bus will register corresponding handlers to listen to particular events. When any message of the expected type arrives, the bus invokes the handle method of the event handler that is passed to it.

Make sure that a single handler can handle multiple different events, and multiple different handlers can handle events.