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The pipeline publishes event notifications after each destination loader completes. Notifications are sent to an ActiveMQ Virtual Topic and can be consumed by any number of independent subscribers.

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How It Works

The pipeline uses ActiveMQ’s Virtual Destinations pattern:
  1. Each destination loader (PostgreSQL, MongoDB, Kafka, ActiveMQ, Object Store, REST) publishes a notification to VirtualTopic.{environment}-pipeline-notification
  2. Consumers subscribe by creating a queue named Consumer.{name}.VirtualTopic.{environment}-pipeline-notification
  3. ActiveMQ automatically copies topic messages to all matching consumer queues
  4. Each consumer gets its own independent queue with its own message cursor
No subscription API is needed — consumers simply connect to their named queue.

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Consuming Notifications

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Queue Naming Convention

Consumer.{consumer-name}.VirtualTopic.{environment}-pipeline-notification
For example, with environment oss:
  • Consumer.analytics.VirtualTopic.oss-pipeline-notification
  • Consumer.audit-log.VirtualTopic.oss-pipeline-notification
  • Consumer.dashboard.VirtualTopic.oss-pipeline-notification
Each consumer queue receives a copy of every notification independently.

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Quick Start: Python Consumer (Minimal)

import stomp
import json

class NotificationListener(stomp.ConnectionListener):
    def on_message(self, frame):
        notification = json.loads(frame.body)
        print(f"Pipeline: {notification['pipeline']}, Destination: {notification['destination']}")

conn = stomp.Connection([('localhost', 61613)])
conn.set_listener('', NotificationListener())
conn.connect('admin', 'admin', wait=True)
conn.subscribe(
    destination='/queue/Consumer.myapp.VirtualTopic.oss-pipeline-notification',
    id=1,
    ack='auto'
)
Note: This is a minimal snippet. For a production-ready consumer with automatic reconnect, heartbeats, graceful shutdown, and configurable virtual topic support, see examples/topic-subscriber/.

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Example: Java/JMS Consumer

ConnectionFactory factory = new ActiveMQConnectionFactory("tcp://localhost:61616");
Connection connection = factory.createConnection("admin", "admin");
connection.start();
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
Queue queue = session.createQueue("Consumer.myapp.VirtualTopic.oss-pipeline-notification");
MessageConsumer consumer = session.createConsumer(queue);
consumer.setMessageListener(message -> {
    TextMessage text = (TextMessage) message;
    System.out.println("Notification: " + text.getText());
});

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Message Filtering

Notifications include JMS message properties that can be used with JMS selectors for filtering:
PropertyDescription
pipelinePipeline name
destinationDestination type (postgres, objectStore, kafka, mongodb, activemq)
schemaDatabase schema (database destinations)
databaseDatabase name (database destinations)
tableTable name (database destinations)
topicKafka topic (Kafka destinations)
queueNameQueue name (ActiveMQ destinations)
prefixKeyObject store prefix (object store destinations)
To filter, use a JMS selector when creating the consumer: 
MessageConsumer consumer = session.createConsumer(queue, "pipeline = 'sales_data' AND destination = 'postgres'");

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Notification Payload

{
  "pipeline": "sales_data",
  "publisherToken": "publisher-123",
  "pipelineToken": "pt-abc12345-...",
  "destination": "postgres",
  "prefixKey": null,
  "objectStoreUrl": null,
  "objectStoreTemporaryUrl": null,
  "schema": "public",
  "database": "analytics",
  "table": "sales",
  "topic": null,
  "queueName": null
}
Fields are populated based on the destination type. Unused fields are null.

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Enabling Notifications

Notifications are enabled by default in application.yaml: 
sendPipelineNotifications: "true"
Set to "false" to disable all notifications.