विश्वसनीय RabbitMQ consumers के लिए errors और retries को handle करना महत्वपूर्ण है — यह तय करना कि जब message processing fail हो तो क्या करें (retry, dead-letter, या discard)। उचित error handling messages के खो जाने और consumers के अटक जाने को रोकता है।
समस्या
When a consumer fails to process a message (bad data, downstream failure, bug):
→ requeue forever → a "poison" message blocks the queue (retried endlessly)
→ discard → message LOST
→ crash → reprocess, possibly stuck again
→ need a deliberate strategy.
Retry strategies
✓ NACK + REQUEUE → reject and requeue for retry (but limit retries — don't requeue forever)
✓ RETRY WITH BACKOFF → retry transient failures with increasing delays (e.g. via a delayed
retry queue with TTL → requeue after a delay)
✓ RETRY LIMIT → track attempts; after N failures → DEAD LETTER (don't retry forever)
✓ Distinguish TRANSIENT (retry) vs PERMANENT (dead-letter immediately) failures
