We use the term camunda as a source for all camunda activity instance events. However, there is nothing stopping users having the same term for external events. This makes it difficult to distinguish the source of where a given event came from, particularly in the context of event counting where we would need to know which indices to count. We should prevent event ingestion with this reserved source.
- We prevent the ingestion of external events using camunda as the source property. We should probably reject the whole batch if a single event is found violating this, making user retries easier
- Our upgrade notes state this new restriction
- We consider the migration needed for any existing external events that have camunda as a source. It would be enough to explain the indices that need updating on this ticket