Enterprise Service Bus

Overview

The Enterprise Service Bus qBit adds message queue integration to qqq applications. Build event-driven architectures with RabbitMQ, ActiveMQ, or Amazon SQS without writing queue management code.

Features

• Message Queue Integration - Native support for RabbitMQ, ActiveMQ, and Amazon SQS
• Topics & Pub/Sub - Publish events to topics and subscribe multiple consumers
• Dead Letter Queues - Automatic routing of failed messages with retry policies
• Message Serialization - JSON, Avro, and Protobuf with schema registry support
• Async Process Triggers - Trigger qqq processes from queue messages
• Event Sourcing - Publish domain events to message buses
• Content-Based Routing - Route messages based on payload content
• Guaranteed Delivery - At-least-once and exactly-once delivery semantics
• Queue Monitoring - Message counts, consumer lag, and throughput metrics

Use Cases

• Decoupling request handling from processing
• Building event-driven microservice architectures
• Async processing of long-running operations
• Fan-out notifications to multiple consumers
• Integration with external systems via message queues

Installation

qqq install qbit-esb --license YOUR_LICENSE_KEY

Configuration

Configure RabbitMQ as a message backend:

new MessageBusMetaData()
   .withName("orderEvents")
   .withType(MessageBusType.RABBITMQ)
   .withHost("localhost")
   .withExchange("orders")
   .withDeadLetterExchange("orders.dlx");

Publish events from processes:

new QProcessMetaData()
   .withName("createOrder")
   .withPublishEvent(new EventConfig()
      .withBus("orderEvents")
      .withTopic("order.created"));

Subscribe to queue messages:

new QueueSubscriptionMetaData()
   .withQueue("order-notifications")
   .withProcess("sendOrderConfirmation")
   .withRetryPolicy(RetryPolicy.exponentialBackoff(3));

Requirements

• qqq Framework 1.0+
• Java 21+
• RabbitMQ 3.8+, ActiveMQ 5.16+, or Amazon SQS
• QRunIO account with valid license key