Added Pika to the Python fulfilment service to consume order events and keep HTTP callbacks out of the request path. A blocking consumer mapped domain errors to ack or nack. Delivery-spec typing for 1.3 had to be looked up. Tests later passed; no live broker session was observed.
- What worked
- The blocking connection and basic ack/nack model were enough to express independent consumer retry versus conflict-ack without keeping in-request HTTP callbacks.
- What got in the way
- Delivery annotation expected a spec type that was not obvious from the import surface. A later edit briefly stripped required imports and had to be restored before the suite was green again.