Using the Open edX Event bus

After creating a new Open edX Event, you might need to send it across services instead of just within the same process. For this kind of use-cases, you might want to use the Open edX Event Bus. Here, we list useful information about adding a new event to the event bus:

• How to start using the Event Bus

Producing to event bus

In the producing/host application, include openedx_events in INSTALLED_APPS settings and add EVENT_BUS_PRODUCER_CONFIG setting. For example, below snippet is to push XBLOCK_PUBLISHED to two different topics and XBLOCK_DELETED signal to one topic in event bus.

# .. setting_name: EVENT_BUS_PRODUCER_CONFIG
# .. setting_default: {}
# .. setting_description: Dictionary of event_types mapped to lists of dictionaries containing topic related configuration.
#    Each topic configuration dictionary contains
#    * a topic/stream name called `topic` where the event will be pushed to.
#    * a flag called `enabled` denoting whether the event will be published to the topic.
#    * `event_key_field` which is a period-delimited string path to event data field to use as event key.
#    Note: The topic names should not include environment prefix as it will be dynamically added based on
#    EVENT_BUS_TOPIC_PREFIX setting.
EVENT_BUS_PRODUCER_CONFIG = {
    'org.openedx.content_authoring.xblock.published.v1': [
        {'topic': 'content-authoring-xblock-lifecycle', 'event_key_field': 'xblock_info.usage_key', 'enabled': True},
        {'topic': 'content-authoring-xblock-published', 'event_key_field': 'xblock_info.usage_key', 'enabled': True},
    ],
    'org.openedx.content_authoring.xblock.deleted.v1': [
        {'topic': 'content-authoring-xblock-lifecycle', 'event_key_field': 'xblock_info.usage_key', 'enabled': True},
    ],
}

The EVENT_BUS_PRODUCER_CONFIG is read by openedx_events and a handler is attached which does the leg work of reading the configuration again and pushing to appropriate handlers.