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  • references
  • www.rabbitmq.com/tutorials
  • https://chatgpt.com/c/67532c74-a6d8-800d-8ad3-13afd07dcd8e
  • https://docs.spring.io/spring-boot/reference/messaging/amqp.html#messaging.amqp
  • https://www.rabbitmq.com/tutorials/tutorial-two-java-stream - stream
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    • using Kafka

RabbitMQ

  • Producer --> Exchange >> binding >> Queue --> consumer
  • open-source message broker system
  • use-case : Distributed system, microservices, etc
  • message persistence
  • acknowledgments
  • Scalability:

A install (docker)

docker run -d --hostname my-rabbit --name my-rabbit -p 5672:5672 -p 15672:15672  rabbitmq:3-management -e ssl_options.verify:verify_none rabbitmq:latest
>> console : guest/guest http://localhost:15672/

B Exchange

  • Type:
  • Direct** : Routes messages to queues based on message routing key.
  • Topic : Routes messages to queues based on "wildcard matching" of the routing key.
  • Fanout : Routes messages to all queues bound to it.
  • Headers : Uses message headers for routing.
  • Binding: relationship between an exchange and a queue

Queues:

  • Buffers that store messages until consumed

1. Standard Queue

  • Description: Basic FIFO (First In, First Out) queue.
  • Features:
  • Messages are delivered in the order they arrive.
  • Messages are removed once consumed (unless re-queued).
  • Use Case: General-purpose message processing.

2. Priority Queue

  • Description: Messages are prioritized based on a priority level assigned during publishing.
  • Features:
  • Higher-priority messages are delivered first.
  • Configured using the x-max-priority argument.
  • Use Case: Scenarios requiring prioritization, such as alerting systems.

3. Lazy Queue

  • Description: Stores messages on disk rather than in memory.
  • Features:
  • Designed for handling large queues.
  • Reduces memory usage but increases disk I/O.
  • Use Case: High-volume message storage where memory efficiency is critical.
  • Description: A distributed queue type for high availability and data integrity.
  • Features:
  • Uses the Raft consensus algorithm.
  • Replaces classic mirrored queues.
  • Supports leader elections and replication across nodes.
  • Use Case: Applications needing high reliability and fault tolerance.

5. Classic Mirrored Queue (Deprecated in RabbitMQ 3.9+)

  • Description: Replicates messages across multiple nodes for high availability.
  • Features:
  • Each node has a mirror of the queue.
  • Message replication can cause performance overhead.
  • Use Case: Legacy setups requiring HA before quorum queues were available.

6. TTL Queue

  • Description: Messages in this queue expire after a specified time-to-live (TTL).
  • Features:
  • Set TTL per queue or message using the x-message-ttl argument.
  • Expired messages are dropped or moved to a dead-letter exchange.
  • Use Case: Temporary message holding, like caching.

7. Dead Letter Queue (DLQ)

  • Description: A queue to which messages are routed if they are rejected or expired.
  • Features:
  • Helps capture unprocessable messages.
  • Configured using dead-letter exchanges.
  • Use Case: Error handling and debugging.

8. Exclusive Queue

  • Description: A queue limited to a single connection.
  • Features:
  • Automatically deleted when the connection closes.
  • Private to the declaring consumer.
  • Use Case: Temporary or session-specific tasks.

99 Key Differences Between Queue Types

Queue Type Message Storage High Availability Priority Support Order Guarantee
Standard Memory/Disk No No Yes
Priority Memory/Disk No Yes No (priority-based)
Lazy Disk No No Yes
Quorum Disk Yes No Yes
Classic Mirrored Memory/Disk Yes No Yes
TTL Memory/Disk Optional No Yes
Dead Letter Memory/Disk Optional No Yes
Exclusive Memory/Disk No No Yes

C Scalability

  • Supports clustering

D Plugins