event-bus.md

RedisSMQ / Docs / EventBus

EventBus

The RedisSMQ EventBus enables your applications to subscribe to various system events using a Publish-Subscribe (PubSub) architecture.

By default, most events in RedisSMQ are not published to the EventBus. To utilize the EventBus, you must first enable it in your RedisSMQ Configuration.

For detailed information, refer to the EventBus API.

Supported EventBus Events

RedisSMQ supports several events that you can subscribe to:

• TConsumerEvent
• TConsumerHeartbeatEvent
• TConsumerMessageHandlerRunnerEvent
• TConsumerMessageHandlerEvent
• TConsumerConsumeMessageEvent
• TConsumerDequeueMessageEvent
• TProducerEvent
• TQueueEvent

Usage

Configuration

To enable the EventBus, add the following configuration:

const { Configuration } = require('redis-smq');

const config = {
  eventBus: {
    enabled: true,
  }
}

Configuration.getSetConfig(config);

For more details on configuration, see RedisSMQ Configuration.

Creating an EventBus Instance

To create an instance of the EventBus, use the following code:

import { EventBus } from 'redis-smq';

EventBus.getSetInstance((err, eventBus) => {
  if (err) {
    console.error('Failed to create EventBus instance:', err);
  } else {
    console.log('EventBus instance created successfully');
    // You can now use the eventBus instance
  }
});

Subscribing to Events

The example below demonstrates how to subscribe to a TConsumerConsumeMessageEvent:

eventBus.on('consumer.consumeMessage.messageAcknowledged', (messageId, queue, messageHandlerId, consumerId) => {
    console.log(`Message acknowledged: ${messageId} from queue: ${queue} handled by: ${messageHandlerId}, consumed by: ${consumerId}`);
    // Add your event handling logic here
});

Shutting Down the EventBus Instance

To properly shut down the EventBus instance, call the shutDown method:

EventBus.shutDown((err) => {
  if (err) {
    console.error('Error shutting down EventBus:', err);
  } else {
    console.log('EventBus shut down successfully');
  }
});

By following these steps, you can effectively integrate the RedisSMQ EventBus into your applications, allowing for streamlined event handling and improved communication between system components.