Spring Integration, WebSphere Application Server and the TopicConnectionFactory in a Cluster (Active-Active)

Spring Integration, WebSphere Application Server and the TopicConnectionFactory in a Cluster (Active-Active)

so, something i recently came across with when setting up a TopicConnectionFactory on WebSphere is the difference between Cluster level and Node level.  when setting up a QueueConnectionFactory, you can set once at the Cluster level, and all the Nodes replicate the setup and it all works fine.  This is not the case with the TopicConnectionFactory.  

The ClientID concept in a TopicConnectionFactory (that is, the unique ID for the subscription side of things) doesn't play nice across the Cluster if set at the Cluster level.  Essentially only one of the Nodes in the Cluster becomes the subscriber and receives messages where the other Nodes throw warnings that the subscription is in use.  (which is true)

To get around this, set the TopicConnectionFactory at the Node level, giving each one a unique ClientID.  All the rest of the settings can stay the same (JMS name, topic string, etc.).  A suggested format for the ClientID is [application].node.[number] to help you easily track and clean up subscriptions.

Remember, this is for an Active-Active cluster where each Node in it is Active and semi-autonomous (can handle their own processing independently).

Spring Integration, Spring JMS, ActiveMQ and testing Topics

Spring Integration, Spring JMS, ActiveMQ and testing Topics

so everyone knows how to test a JMS Queue in JUnit, ActiveMQ and - to make life easy - Spring JmsTemplate.  but, testing a Topic is a slightly different matter.

first, a topic subscriber has to be 'connected' before you can publish the message.  that's a bit of a challenge to setup.  but, with a little Spring Integration to the rescue we can get a subscriber sorted and sne a message via the JmsTemplate.

another catch comes from ActiveMQ.  to test queues, you can setup the ActiveMQConnectionFactory and you're done.  however, with Topics, you'll need the PooledConnectionFactory as well.

first, a couple dependencies for our pom

   
    org.apache.activemq
    activemq-core
    5.6.0
    test
   
   
    org.apache.activemq
    activemq-pool
    5.6.0
    test
   

then a little Spring Integration to listen to the Topic

(i prefer a queue channel, just to make it easier to get the messages off in testing)
so the next part would be the test class

package de.incompleteco.spring.integration.test;

import static org.junit.Assert.assertNotNull;

import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.Session;
import javax.jms.Topic;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.integration.Message;
import org.springframework.integration.core.PollableChannel;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.jms.core.MessageCreator;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:/META-INF/spring/integration-context.xml"})
public class TopicIntegrationTest {

 @Autowired
 private PollableChannel receiveChannel;
 
 @Autowired
 private ConnectionFactory connectionFactory;
 
 @Autowired
 private Topic topic;
 
 private JmsTemplate jmsTemplate;
 
 @Test
 public void test() throws Exception {
  //setup the jmsTemplate and send
  jmsTemplate = new JmsTemplate(connectionFactory);
  jmsTemplate.setDefaultDestination(topic);
  jmsTemplate.setPubSubDomain(true);//it's a topic
  //send
  jmsTemplate.send(new MessageCreator() {

   public javax.jms.Message createMessage(Session session) throws JMSException {
    return session.createTextMessage("hello world");
   } });
  //now grab it off the queue
  Message message = receiveChannel.receive(1000);//let's put a timeout
  //test
  assertNotNull(message);
 }
 
}

and here's the specific apache configuration to support Topics