[CAMEL-9560] RabbitMQ InOut Producer generates a null body response when a correlationId is used

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.16.2
• Fix Version/s: 2.16.3, 2.17.0
• Component/s: camel-rabbitmq
• Estimated Complexity: Novice
• Assignee: Claus Ibsen
• Reporter: Arnaud CHOTARD
• Created: 02/Feb/16 15:04
• Updated: 04/Feb/16 18:43
• Resolved: 04/Feb/16 18:43

Description

The use case uses a correlationId with RabbitMQ InOut Producer :

from("direct:route")
   .setHeader(RabbitMQConstants.EXCHANGE_NAME, constant("exchange"))
   .setHeader(RabbitMQConstants.CORRELATIONID, constant("123"))
   .inOut("rabbitmq://...")

The response always contains a null out body message.

The problem is located when restoring the original correlation id in org.apache.camel.component.rabbitmq.reply.ReplyManagerSupport :

public void processReply(ReplyHolder holder)

// restore correlation id in case the remote server messed with it
if (holder.getOriginalCorrelationId() != null) {
   if (exchange.getOut() != null) {
      exchange.getOut().setHeader(RabbitMQConstants.CORRELATIONID, 
         holder.getOriginalCorrelationId());
   } else {
      exchange.getIn().setHeader(RabbitMQConstants.CORRELATIONID, 
         holder.getOriginalCorrelationId());
   }
}

The test exchange.getOut() is always successful because of the lazy creation in DefaultExchange.getOut

public Message getOut() {
   // lazy create
   if (out == null) {
      out = (in != null && in instanceof MessageSupport)
      ? ((MessageSupport)in).newInstance() : new DefaultMessage();
      configureMessage(out);
   }
   return out;
}

The in body message contains the correct response from RabbitMQ. However, since the out message will be always created with a null body, the null body response will be returned in the pipeline