Build an Event-Driven Integration

TimeUnder 10 minutes

What you'll buildAn event-driven integration that consumes messages from Orders queue in RabbitMQ broker and processes them.

Event integrations are designed for reactive workflows triggered by messages from a broker. This quick start demonstrates the complete flow: creating a RabbitMQ message listener, adding an event handler to process messages, and implementing the integration logic executed when a message is received.

Prerequisites

A working WSO2 Integrator environment.

Local setup

Install and launch WSO2 Integrator on your machine.

WSO2 Cloud Account

For AI assisted development and WSO2 Cloud deployments.

Also required, a running RabbitMQ instance. To start one with Docker, run:

docker run -d -p 5672:5672 -p 15672:15672 rabbitmq:4.2-management

Step 1: Create the integration

Note

If you're using the cloud editor, a project is already open, so you can skip this step and go directly to Step 2: Add a RabbitMQ event listener.

1. Open WSO2 Integrator.

2. Click Create in the Create a Project card.

   

3. Set Project name to event-integration.

4. Set Integration name to OrderProcessor.

5. Click Create.

   

Step 2: Add a RabbitMQ event listener

1. Select your integration from the project overview canvas.

2. In the design view, click Add Artifact manually.

   

3. Select RabbitMQ under Event Integration.

   

4. Set Host to localhost and Port to 5672 (update these if your RabbitMQ instance runs elsewhere).

5. Set Queue Name to Orders.

6. Click Create.

   

Step 3: Add onMessage event handler

1. In the RabbitMQ service design view, click + Add Handler.

2. Set Format to On Message.

3. Click Save.

   

Step 4: Add message processing logic

1. Click + inside the onMessage flow.

2. Select Call Function under Statement.

   

3. Select printInfo under log.

   

4. Set Msg to Received order.

5. Click Save.

   

Step 5: Run and test the integration

1. Click Run.

2. The integration starts and listens for messages on the Orders queue.

3. Open the RabbitMQ Management UI at http://localhost:15672 (default credentials: guest/guest).

   • Go to Queues and Streams → Orders → Publish message, enter any text as the payload, and click Publish message.
   • Confirm the integration log displays Received order.
   

Step 6: Deploy to WSO2 Cloud

Before you deploy, set Host and Port to a RabbitMQ broker that WSO2 Cloud can reach; localhost doesn't resolve to your local broker there.

Deploy your integration to WSO2 Cloud - Integration Platform in any of the following ways:

• If you're using the cloud editor, see Save and deploy.
• If you're using WSO2 Integrator on your machine, see Deploy from WSO2 Integrator.

Skip ahead: deploy a ready-made sample

Rather not build it yourself? One-click deploy the OrderProcessor sample straight to WSO2 Cloud.

Source code

View the generated Ballerina code

The steps above generate the following complete, runnable Ballerina program:

import ballerina/log;
import ballerinax/rabbitmq;

listener rabbitmq:Listener rabbitmqListener = new ("localhost", 5672);

service "Orders" on rabbitmqListener {
   remote function onMessage(rabbitmq:AnydataMessage message, rabbitmq:Caller caller) returns error? {
       do {
           log:printInfo("Received order");
       } on fail error err {
           // handle error
           return error("unhandled error", err);
       }
   }
}

Supported event sources

Broker	Ballerina Package
Apache Kafka	ballerinax/kafka
RabbitMQ	ballerinax/rabbitmq
MQTT	ballerina/mqtt
Azure Service Bus	ballerinax/asb
Salesforce	ballerinax/salesforce
GitHub Webhooks	ballerinax/trigger.github

What's next

• Kafka — Consume and produce Kafka messages
• Azure Service Bus — Integrate with Azure Service Bus queues and topics
• RabbitMQ — Full RabbitMQ listener and publisher reference
• MQTT — Handle MQTT messages from IoT and messaging devices
• CDC for PostgreSQL — React to database changes with change data capture