We have a project that partially uses DDD. When changing / creating an entity, we throw an event inside the entity. Next, the Doctrine Event Subscriber takes all the events and forwards them to the EventBus.
Let's say we have a MissionCreatedEvent event. I want to make routing key mission.event.created for it and tie it into 2 queues: new_mission_notification_to_part_time_employee and new_mission_area_notification_to_manager.
This is what the config looks like:
transports:
async_new_mission_notification_to_part_time_employee:
dsn: '%env(MESSENGER_TRANSPORT_DSN)%'
options:
exchange:
name: mission
type: topic
queues:
new_mission_notification_to_part_time_employee:
binding_keys: ['mission.event.created']
retry_strategy:
max_retries: 0
async_new_mission_area_notification_to_manager:
dsn: '%env(MESSENGER_TRANSPORT_DSN)%'
options:
exchange:
name: mission
type: topic
queues:
new_mission_area_notification_to_manager:
binding_keys: ['mission.event.created']
retry_strategy:
max_retries: 0
routing:
'App\Domain\Mission\Event\MissionCreatedEvent':
- async_new_mission_notification_to_part_time_employee
- async_new_mission_area_notification_to_manager
The problem is that Symfony Messenger first runs on transports and only then pushes the message into exchange. Since we have 2 transports, it turns out that the event with routing key mission.event.created is triggered twice. Because of this, my Message handlers run 2 times.
There is an option not to use routing key mission.event.created. But use similar to mission.cmd.notify_part_time_employee_about_new_mission
and mission.cmd.notify_manager_about_new_mission_in_area for each transport with direct exchange.
This will help solve duplication problems, but I can’t use all the features that RabbitMQ gives me :(