- Change await to .then() for cdcConsumer.start()
- Allows HTTP endpoints to be accessible during CDC sync
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Root cause: calculateForAdoption uses separate DB connections, which
cannot see uncommitted data in Serializable isolation level, causing
"Adoption not found" errors.
Solution (following Kafka Idempotent Consumer best practice):
- Add TransactionalCDCHandlerWithResult<T> type for handlers with return
- Add withIdempotencyAndCallback() wrapper for post-commit callbacks
- Add registerTransactionalHandlerWithCallback() registration method
- AdoptionSyncedHandler.handle() now returns AdoptionSyncResult
- Contribution calculation runs AFTER transaction commits via callback
Reference: Lydtech Consulting - Kafka Idempotent Consumer Pattern
https://www.lydtechconsulting.com/blog/kafka-idempotent-consumer-transactional-outbox
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implements 100% exactly-once semantics for CDC events from 1.0 databases
(identity-service, planting-service, referral-service) to contribution-service.
Key changes:
- Add ProcessedCdcEvent model with (sourceTopic, offset) unique constraint
- Add withIdempotency() wrapper using Serializable transaction isolation
- Add registerTransactionalHandler() for handlers requiring idempotency
- Modify CDC handlers to accept external transaction client
- All database operations now use the passed transaction client
This ensures that:
1. Each CDC event is processed exactly once
2. Idempotency record and business logic are in the same transaction
3. Any failure causes complete rollback
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
hailin