request-reply with akka-camel and ActiveMQ

Question

Update: It would seem that an even simpler test case is not working: just trying to send a message from an ActiveMQ producer to an ActiveMQ consumer via the in-process broker. Here is the code:

val brokerURL = "vm://localhost?broker.persistent=false"
val connectionFactory = new ActiveMQConnectionFactory(brokerURL)
val connection = connectionFactory.createConnection()
val session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE)
val queue = session.createQueue("foo.bar")
val producer = session.createProducer(queue)
val consumer = session.createConsumer(queue)
val message = session.createTextMessage("marco")

producer.send(message)
val resp = consumer.receive(2000)
assert(resp != null)

I'm trying to implement a very simple request-reply pattern using akka-camel. Here's my (testbench) code which is trying to use activeMQ directly to send a message and expect a response:

val brokerURL = "vm://localhost?broker.persistent=false"

// create in-process broker, session, queue, etc...
val connectionFactory = new ActiveMQConnectionFactory(brokerURL)
val connection = connectionFactory.createConnection()
val session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE)
val queue = session.createQueue("myapp.somequeue")
val producer = session.createProducer(queue)
val tempDest = session.createTemporaryQueue()
val respConsumer = session.createConsumer(tempDest)
val message = session.createTextMessage("marco")
message.setJMSReplyTo(tempDest)
message.setJMSCorrelationID("myCorrelationID")

// create actor system with CamelExtension
val camel = CamelExtension(system)
val camelContext = camel.context
camelContext.addComponent("activemq", ActiveMQComponent.activeMQComponent(brokerURL))
val listener = system.actorOf(Props[Frontend])

// send a message, expect a response
producer.send(message)
val resp: TextMessage = respConsumer.receive(5000).asInstanceOf[TextMessage]
assert(resp.getText() == "polo")

I've tried two different approaches for the Consumer actor. The first is simpler, which attempts to respond using sender !:

class Frontend extends Actor with Consumer {
  def endpointUri = "activemq:myapp.somequeue"
  override def autoAck = false
  def receive = {
    case msg: CamelMessage => {
      println("received %s" format msg.bodyAs[String])
      sender ! "polo"
    }
  }
}

The second attempts to reply using the CamelTemplate:

class Frontend extends Actor with Consumer {
  def endpointUri = "activemq:myapp.somequeue"
  override def autoAck = false
  def receive = {
    case msg: CamelMessage => {
      println("received %s" format msg.bodyAs[String])
      val replyTo = msg.getHeaderAs("JMSReplyTo", classOf[ActiveMQTempQueue], camelContext)
      val correlationId = msg.getHeaderAs("JMSCorrelationID", classOf[String], camelContext)
      camel.template.sendBodyAndHeader("activemq:"+replyTo.getQueueName(), "polo", "JMSCorrelationID", correlationId)
    }
  }
}

I do see the println() output from my actor's receive method, so the ActiveMQ message is getting into the actor, but I get a timeout on the respConsumer.receive() call in the testbench. I've tried lots of combinations of specifying and not specifying headers in the reply. I've also tried enabling and disabling autoAck.

Thanks in advance.

gnathan gnathan · Accepted Answer · 2014-05-02T19:18:04

1

votes

Turns out I needed to call connection.start() in the JMS code.

request-reply with akka-camel and ActiveMQ

1 Answers