eiffellib 3.0.0

Start RabbitMQ

In order for these examples to work you need a RabbitMQ server:

# From https://hub.docker.com/_/rabbitmq
docker run -d --hostname my-rabbit --name some-rabbit -p 8080:15672 -p 5672:5672 rabbitmq:3-management

Subscribing to an event

import time
from eiffellib.subscribers import RabbitMQSubscriber


def callback(event, context):
    print(event.pretty)

SUBSCRIBER = RabbitMQSubscriber(host="127.0.0.1", port=5672, ssl=False,
                                queue="eiffel", exchange="amq.fanout")
SUBSCRIBER.subscribe("EiffelActivityTriggeredEvent", callback)
SUBSCRIBER.start()
while True:
    time.sleep(0.1)

Publishing an event

from eiffellib.publishers import RabbitMQPublisher
from eiffellib.events import EiffelActivityTriggeredEvent

PUBLISHER = RabbitMQPublisher(host="127.0.0.1", exchange="amq.fanout", ssl=False,
                              port=5672, routing_key=None)
PUBLISHER.start()
ACTIVITY_TRIGGERED = EiffelActivityTriggeredEvent()
ACTIVITY_TRIGGERED.data.add("name", "Test activity")
PUBLISHER.send_event(ACTIVITY_TRIGGERED)
PUBLISHER.wait_for_unpublished_events()

Deprecation of routing key

The “routing_key” argument in the RabbitMQPublisher class has been deprecated.

This deprecation also affects the default value of the “routing_key” argument and you will be getting warnings while running.

The reason for this change is due to a misunderstanding of how routing keys are supposed to be used when eiffellib was first created.

Each event will now be able to generate their own routing key every time the event is sent.

This routing key is by default “eiffel._.$event_type._._” where the different values are “eiffel.$family.$event_type.$tag.$domainid”.

Please refer to https://eiffel-community.github.io/eiffel-sepia/rabbitmq-message-broker.html for more information about routing keys.

To change to the new routing key behavior (and thus removing the warning), please set “routing_key” to “None” when initializing a new RabbitMQPublisher.

PUBLISHER = RabbitMQPublisher(host="127.0.0.1", exchange="amq.fanout", ssl=False,
                              port=5672, routing_key=None)

In order to change “$family”, “$tag” or “$domainid” in the routing key, they have to be set on the events.

PUBLISHER = RabbitMQPublisher(host="127.0.0.1", exchange="amq.fanout", ssl=False,
                              port=5672, routing_key=None)
EVENT = EiffelActivityTriggeredEvent(family="myfamily", tag="mytag", domain_id="mydomain")
PUBLISHER.send_event(EVENT)