Part 5: Readmodels

When implementing a new EventHandler, users often want to store the results of event processing within the EventHandler itself and make them available to the read side (QueryHandler) or simply respond to specific events (Reactor).

Here, we are presenting the best practices for implementing an EventHandler that handles event processing. Just like with Command, Query, and Aggregate, we create a new package folder named readmodel and create the file domain/aqua/readmodel/readmodel.go within it.

// domain/aqua/readmodel/readmodel.go
package readmodel

type AquaReadmodel struct {
	EventRepository *repo.EventRepository
	state           *state
	metrics         *metrics
	mapByAquaUuid   sync.Map
}

func NewAquaReadModel(EventRepository *repo.EventRepository) *AquaReadmodel {
	rm := &AquaReadmodel{}
	rm.EventRepository = EventRepository
	rm.state = &state{}
	rm.metrics = &metrics{}
	rm.mapByAquaUuid = sync.Map{}
	return rm
}