Greetings, I have many routes that read from AMQ queues and write to other
AMQ queues. For error handling I have been using the following paradigm:
from("activemq:queue:inbox")
.onException(Exception.class).useOriginalMessage().handled(handled).maximumRedeliveries(0)
.setHeader(Exchange.FAILURE_ROUTE_ID, property(Exchange.FAILURE_ROUTE_ID))
.setHeader(Exchange.EXCEPTION_CAUGHT, simple("${exception.stacktrace}"))
.to(ExchangePattern.InOnly, "activemq:queue:dead").end();
.process(new PreProcessor())
.to("activemq:queue:outbox")
.process(new PostProcessor());
The goal being that if there was any kind of exception, that information
would be noted in the headers on the message before it was sent off to the
DLQ. The problem is this runs into roadblocks when transacted() is added to
the route.
With the code above when the route is transacted and a message fails in
post processing I want the message pulled off the outbox, record
information indicating what the exception was, and have the message sent to
the DLQ. Unfortunately I seem to be in a quandary of how to do this.
The code above simply wont work because the message being sent to the dead
letter queue gets rolled back along with the outbox if I mark the exchange
with rollback() in the exception handler. If I don't mark the message with
rollback() in the handler then the outbox doesn't get rolled back if the
post processor exceptions but the dead letter channel will contain the
correct information. On the other hand if I just let activemq handle the
transaction, it will retry and then eventually send the message to the DLQ
but the message in the DLQ will contain no information about why it failed.
So I want my cake and eat it too. I want to be able to record WHY an
exchange failed but still be able to rollback the outbox at the same time.
I have been plugging away at this a ton and I am out of ideas. What would
not be acceptable would be to require the user to troll through log files
trying to find a reason why an exchange failed. This would be an
operational nightmare. So the message and the reason for the rollback need
to be somewhere accessible and they need to be together.
I would appreciate any suggestions on how I could make this happen.
*Robert Simmons Jr. MSc. - Lead Java Architect @ EA*
*Author of: Hardcore Java (2003) and Maintainable Java (2012)*
*LinkedIn: **http://www.linkedin.com/pub/robert-simmons/40/852/a39
<http://www.linkedin.com/pub/robert-simmons/40/852/a39>*
