Spring AMQP (RabbitMQ) - Quick Reference

Full Reference: See advanced.md for exchange types (topic, fanout), consumer patterns (multi-method, request-reply), error handling, DLQ processing, and testing.

Deep Knowledge: Use mcp__documentation__fetch_docs with technology: rabbitmq for comprehensive documentation.

Dependencies

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
</dependency>

Configuration

spring:
  rabbitmq:
    host: localhost
    port: 5672
    username: guest
    password: guest
    listener:
      simple:
        acknowledge-mode: manual
        concurrency: 3
        max-concurrency: 10
        prefetch: 10

Exchange, Queue, Binding Setup

@Configuration
public class RabbitMQConfig {

    public static final String EXCHANGE = "orders.exchange";
    public static final String QUEUE = "orders.queue";
    public static final String ROUTING_KEY = "orders.created";

    @Bean
    public DirectExchange ordersExchange() {
        return new DirectExchange(EXCHANGE);
    }

    @Bean
    public Queue ordersQueue() {
        return QueueBuilder.durable(QUEUE)
            .withArgument("x-dead-letter-exchange", "orders.dlx")
            .withArgument("x-dead-letter-routing-key", "dead")
            .build();
    }

    @Bean
    public Binding ordersBinding() {
        return BindingBuilder.bind(ordersQueue()).to(ordersExchange()).with(ROUTING_KEY);
    }

    @Bean
    public Jackson2JsonMessageConverter messageConverter() {
        return new Jackson2JsonMessageConverter();
    }
}

Producer

@Service
@RequiredArgsConstructor
public class OrderProducer {

    private final RabbitTemplate rabbitTemplate;

    public void sendOrder(OrderEvent event) {
        rabbitTemplate.convertAndSend(EXCHANGE, ROUTING_KEY, event);
    }

    public void sendWithHeaders(OrderEvent event, String correlationId) {
        rabbitTemplate.convertAndSend(EXCHANGE, ROUTING_KEY, event, message -> {
            message.getMessageProperties().setCorrelationId(correlationId);
            message.getMessageProperties().setDeliveryMode(MessageDeliveryMode.PERSISTENT);
            return message;
        });
    }
}

Consumer

@Service
public class OrderConsumer {

    @RabbitListener(queues = "orders.queue")
    public void consume(
            @Payload OrderEvent event,
            @Header(AmqpHeaders.DELIVERY_TAG) long deliveryTag,
            @Header(AmqpHeaders.CORRELATION_ID) String correlationId,
            Channel channel) throws IOException {

        try {
            processOrder(event);
            channel.basicAck(deliveryTag, false);
        } catch (Exception e) {
            channel.basicNack(deliveryTag, false, false); // Send to DLQ
        }
    }
}

Best Practices

| Do | Don't | |----|-------| | Use manual acknowledgment | Auto-ack without processing | | Configure DLX/DLQ | Silently lose failed messages | | Set message TTL | Keep messages forever | | Use persistent delivery | Transient for important messages | | Configure prefetch | Unbounded prefetch |

When NOT to Use This Skill

Raw RabbitMQ - Use rabbitmq skill for server configuration
Kafka integration - Use spring-kafka skill
Generic messaging patterns - Consult messaging-expert

Anti-Patterns

| Anti-Pattern | Problem | Solution | |--------------|---------|----------| | Auto-ack without processing | Message loss | Use manual acknowledgment | | No DLQ configured | Lost failed messages | Configure dead letter exchange | | Unbounded prefetch | Memory issues | Set appropriate prefetch count | | Blocking in listener | Thread exhaustion | Use async processing | | No retry policy | Temporary failures cause loss | Configure retry with backoff |

Quick Troubleshooting

| Problem | Diagnostic | Fix | |---------|------------|-----| | Connection refused | Check RabbitMQ running | Verify host/port | | Message not consumed | Check queue binding | Verify routing key | | Messages in DLQ | Check x-death header | Fix processing error | | Consumer not starting | Check @RabbitListener | Verify queue exists | | Serialization error | Check message type | Configure Jackson converter |

Production Checklist

[ ] Connection factory configured
[ ] Manual acknowledgment mode
[ ] DLX/DLQ configured
[ ] Retry policy set
[ ] Message converter configured
[ ] Publisher confirms enabled
[ ] Prefetch count optimized
[ ] Error handler implemented
[ ] Message TTL set
[ ] Monitoring enabled

Reference Documentation

Spring AMQP Reference