Getting the Wrong Routing Key for AMQP message using RabbitMQ and Apache Camel

Question

I am having an hard time tracking down an issue with my Camel routes. From what Ive been reading, it seems it may be something to do with my routing key header information getting screwed up, but Im not sure how to resolve this. Also, this is a Java OSGi project if thats important, but all the Camel stuffs are currently implemented in XML. Any help is appreciated.

Here's what Im trying to do:

<!-- The first route creates an object with some info in it and drop it on a rabbitmq 
exchange called message.added -->
<route id="directIn">
    <from uri="direct:in" />
    <bean ref="connector" method="handleIncoming" />
    <marshal id="marshal-one" ref="firstObject" />
    <to uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true&amp;routingKey=message.added" />
</route>

<!-- This route listens to message.added, processes the data, creates a new object, and 
drops it on a different rabbitmq exchange called message.rest -->
<route id="addedOne">
    <from uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true&amp;routingKey=message.added" />
    <unmarshal id="unmarshal-one" ref="firstObject" />
    <bean ref="connector" method="processAndConvert" />
    <marshal id="marshal-out" ref="secondObject" />
    <to uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true&amp;routingKey=message.rest" />
</route>

This code seems to have been working fine. The problem arises when we add a new bundle, which is also listening to the message.added rabbitmq message (which I believe you are allowed to do?)

<!-- This route is in a different bundle, also listening to message.added, processing
     the data and creating the same object (from a common bundle) and dropping it
     on the same rabbitmq exchange as before -->
<route id="addedTwo">
    <from uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true&amp;routingKey=message.added" />
    <unmarshal id="unmarshal-two" ref="firstObject" />
    <bean ref="someService" method="processUpdate" />
    <marshal id="marshal-out2" ref="secondObject" />
    <to uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true&amp;routingKey=message.rest" />
</route>

This route fails with an error message that it is trying to unmarshal a secondObject into a firstObject in the addedTwo route.

ERROR | RabbitMQConsumer | DefaultErrorHandler ....
caught: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException:
Unrecognized field "secondObject" (class com.pointer.dangling.FirstObject["secondObject"])

Message History:
RouteId        ProcessorId        Processor
[addedTwo]     [addedTwo]         [                             ]
[addedTwo]     [unmarshal-two]    [unmarshal[ref:firstObject]   ]

Exchange:
Headers: {
    CamelRedelivered=false,
    rabbitmq.DELIVERY_TAG=1,
    rabbitmq.EXCHANGE_NAME=me.ex,
    rabbitmq.ROUTING_KEY=message.added
}
Body: {
    "secondObject": {
        // a bunch of fields for secondObject
    }
}

It appears that a 'secondObject' is, at some point, making its way onto the 'message.added' exchange and being picked up by the 'addedTwo' route which tries to marshal it into a 'firstObject'. But Im not explicitly telling it to do that anywhere in the code - any ideas?

raulk raulk · Accepted Answer · 2016-01-25T13:27:33

In the RabbitMQ Camel component, the routingKey endpoint option only works for Consumers (<from />).

Producers must set their routing key explicitly as a message header before the <to />. Your addedOne route should look like this:

<route id="addedOne">
    <from uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true&amp;routingKey=message.added" />
    <unmarshal id="unmarshal-one" ref="firstObject" />
    <bean ref="connector" method="processAndConvert" />
    <marshal id="marshal-out" ref="secondObject" />
    <setHeader headerName="rabbitmq.ROUTING_KEY">
        <constant>message.rest</constant>
    </setHeader>
    <to uri="rabbitmq://localhost:5672/me.ex?exchangeType=topic&amp;durable=false&amp;autoDelete=true" />
</route>

See https://camel.apache.org/rabbitmq.html for more info.

Getting the Wrong Routing Key for AMQP message using RabbitMQ and Apache Camel

1 Answers