Description (required on creation)

This endpoint is required for #27409, to read the message name and correlation key when a message intermediate event is selected in the BPMN diagram.

The idea is to create an endpoint that returns message subscriptions and can be filtered by element instance key. It should use the operate-event index (that stores the information today).

Note: This index also contains data for flow node instances, incidents, and jobs. This will change with #33498.

Endpoint: POST /v2/message-subscriptions/search

Acceptance Criteria (required on creation)

• Rename the POJO from EventEntity to MessageSubscriptionEntity
• Create the message subscription RDBMS table and query it from the RDBMS search client.
• To be clarified:
  • The exact API request/response properties
  • A solution for migrated data: Before migrating to a Camunda version with Focus ES/OS operate-event index on messages only #33498 implemented, this index will still receive documents that are not message subscriptions. The API endpoints should (most likely) not return these documents.
    • Idea (to be validated): The operate-event index tracks the eventSourceType. In that field, we match for PROCESS_MESSAGE_SUBSCRIPTION to filter only for message subscription events. This should happen in the ES and OS search clients in a hardwired way. The user does not provide this.

Links

• Related issue to focus the ES/OS index on messages: Focus ES/OS operate-event index on messages only #33498