Raul Kripalani created CAMEL-5390:
-------------------------------------
Summary: Option to assign unique correlation ID to JMS messages
Key: CAMEL-5390
URL: https://issues.apache.org/jira/browse/CAMEL-5390
Project: Camel
Issue Type: Improvement
Components: camel-activemq
Affects Versions: 2.10.0
Reporter: Raul Kripalani
Assignee: Raul Kripalani
Fix For: 2.10.1
Imagine a sequential JMS invocation across Camel routes, such as the following:
{code}
<route>
<from uri="timer:foo?fixedRate=true&period=10000" />
<inOut uri="activemq:queue:test1" />
<inOut uri="activemq:queue:test2" />
</route>
{code}
The camel-jms consumer listening on test1 will set the JMSCorrelationID header
to the JMSMessageID for that exchange.
When the response returns to the route and sent to test2, this consumer also
uses the *same* JMSCorrelationID as before.
IMHO, this behaviour is incorrect from the pragmatic perspective. Why should
test2 reuse the Message ID from test1 after all?
Despite that, the correlation works for simple cases, but for complex routing
with parallel JMS exchanges, it doesn't because the correlation ID is not
unique for each exchange. Consider the following splitter:
{code}
<route>
<from uri="timer:foo?fixedRate=true&period=10000" />
<setBody><constant>1,2,3,4,5</constant></setBody>
<inOut uri="activemq:queue:test1" />
<split parallelProcessing="false">
<tokenize token="," />
<inOut uri="activemq:queue:test2" />
</split>
<to uri="log:Finished?showAll=true" />
</route>
{code}
There are several solutions here:
#. Remove the JMSCorrelationID header before each request to test2
#. Enable the useMessageIDAsCorrelationID option to true on both producer and
consumer
#. Create a new option to assign a unique ID to the JMSCorrelationID header
The downside of 2 is that the message ID is only assigned after the JMS
dispatch, so the component updates the correlation map with the final
JMSMessageID after the JMS dispatch. Also, camel-jms is also prepared to handle
cases where the reply comes in before the map update has occurred, by waiting 5
seconds if an unknown correlation ID is received, blocking the receipt of any
further replies. You will agree with me it is not efficient at all.
That's where the upside of 3 lies. By expressly setting a static unique ID as
the correlation ID, we get rid of these race conditions and inefficiencies.
I propose calling this option 'assignUniqueCorrelationID'.
I'm happy to submit a patch for this, targeting 2.10.1.
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