📬Key Takeaways
- 1Point-to-point: one producer, one consumer per message (task queues, job processing)
- 2Pub/Sub: one message delivered to all subscribers (event broadcasting, notifications)
- 3Dead Letter Queue (DLQ): failed messages are moved to a separate queue for investigation
- 4Priority and delayed queues enable scheduling and importance-based processing
Core Messaging Patterns
Message queues support different delivery patterns depending on whether a message should be processed by one consumer (competing consumers) or broadcast to all consumers (pub/sub). Understanding these patterns is critical for designing event-driven architectures.
Messaging Patterns
Each message is consumed by exactly one consumer. Multiple consumers compete for messages (competing consumers pattern).
Use case: Task/job queues (image processing, email sending). Each job should be processed exactly once.
Examples: SQS queues, RabbitMQ queues, Celery tasks.
Advantages
- •Flexible patterns for different use cases
- •DLQ prevents message loss
- •Fan-out enables event-driven architecture
Disadvantages
- •Choosing the wrong pattern leads to data inconsistency
- •Pub/Sub can create message storms
- •Request-reply adds complexity
🧪 Test Your Understanding
Knowledge Check1/1
When should you use Pub/Sub instead of Point-to-Point?