Overview
Flow
Components
- Corporation
- Service A
- RabbitMQ
- Service B
- Core Banking
- DLQ
- Message
- Idempotency
- Consumers
Execution
How it works
- Dashed arc at top represents ACK loop - invisible feedback driving system
- Service B sends ACK, broker deletes message, gives B next message
- ACK loop ensures overall system safety
- NACK arrow routes from broker down to DLQ instead of directly from Service B - because Service B instructs broker to NACK and broker performs routing
- Service B never accesses DLQ directly
Best practices
- Diagram functions as checklist for implementation practice
- Checklist flow: Corp → Producer (declare topology, basic_publish, delivery_mode=2) → Broker (exchange, queue, DLQ binding, routing key match) → Consumer (prefetch=1, auto_ack=False, idempotency check, ACK/NACK) → Core Banking
- Build components in specified sequence to achieve production-safe payment queue