Federico Mariani created CAMEL-24070:
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Summary: camel-spring-rabbitmq - SpringRabbitMQProducer lazy
template creation is not thread-safe and can leak started AsyncRabbitTemplates
Key: CAMEL-24070
URL: https://issues.apache.org/jira/browse/CAMEL-24070
Project: Camel
Issue Type: Bug
Components: camel-spring-rabbitmq
Affects Versions: 4.22.0
Reporter: Federico Mariani
{{SpringRabbitMQProducer}} lazily creates its templates without synchronization:
{code:java}
public RabbitTemplate getInOnlyTemplate() {
if (inOnlyTemplate == null) {
inOnlyTemplate = getEndpoint().createInOnlyTemplate();
}
return inOnlyTemplate;
}
public AsyncRabbitTemplate getInOutTemplate() {
if (inOutTemplate == null) {
inOutTemplate = getEndpoint().createInOutTemplate();
}
inOutTemplate.start();
return inOutTemplate;
}
{code}
A producer is a singleton that is invoked concurrently by route threads, so
concurrent first messages can each create their own template; all but the last
assignment are dropped without being stopped. In the InOut case each racing
thread also *starts* its template, so the losers are leaked in started state.
{{EndpointMessageListener.getTemplate()}} in the same component guards the
identical lazy-init pattern with a {{ReentrantLock}} - the producer should do
the same.
Two related nits in the same methods:
* {{getInOutTemplate()}} calls {{start()}} on every message instead of only
when the template is created (or better: in {{doStart()}}).
* {{processInOnly}} compares {{Boolean.FALSE == sent}} on a primitive boolean.
Attached reproducer (no broker needed) calls {{getInOnlyTemplate()}} from 8
threads behind a barrier and fails immediately on current main:
{noformat}
concurrent getInOnlyTemplate() must always return the same template (round 0)
==> expected: <1> but was: <8>
{noformat}
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_This issue was found during an AI-assisted code review of
camel-spring-rabbitmq: Claude Code on behalf of Federico Mariani (fmariani). A
failing unit test reproducing the issue is attached._
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