DeadLetterChannel handle option

[Wang Yan <wy...@gmail.com>]

Hello All,

based on below document
if handle =false the message will be propagated to caller when exception
happened
if handle=true, the message will not be propagated to caller but somewhere
else as you can
define . is my understanding correct?

http://camel.apache.org/dead-letter-channel.html
The *DeadLetterChannel* lets you control behaviors including redelivery,
whether to propagate the thrown Exception to the caller (the *handled* option),
and where the (failed) Exchange should now be routed to.

RE: DeadLetterChannel handle option

[Valdis Andersons <va...@vhi.ie>]

Hey,

That's pretty much how I would understand it was well. Though I'm not setting the handled option explicitly anywhere in my route builders. To make the exchange go somewhere else in case of an exception you'd really just have to specify the deadLetterChannel in the errorHandler of your route builder:

errorHandler(deadLetterChannel(deadLetterQueue));

Optionally you can also define a retry strategy on some exceptions while not on others:

onException(RecoverableException.class)
					.maximumRedeliveries(redeliverable.maximumRedeliveries())
					.redeliveryDelay(redeliverable.redeliveryDelay())
					.logExhaustedMessageHistory(true)
					.retryAttemptedLogLevel(LoggingLevel.WARN)
					.useOriginalMessage();

Or whatever fits your use case and requirements.

To get the log output for an exception that isn't specified for the retry (in the onException configuration) I had to configure my logging properties this way:

logging:
    level:
        org:
            apache:
                camel: ERROR
                processor:
                    DeadLetterChannel: DEBUG

That will print a line in the logs every time something gets dead-lettered due to an exception that hasn't been handled in the code.


Cheers,
Valdis

-----Original Message-----
From: Wang Yan [mailto:wyanbox@gmail.com] 
Sent: 06 March 2019 13:17
To: users@camel.apache.org
Subject: DeadLetterChannel handle option

Hello All,

based on below document
if handle =false the message will be propagated to caller when exception happened if handle=true, the message will not be propagated to caller but somewhere else as you can define . is my understanding correct?

http://scanmail.trustwave.com/?c=6600&d=2sj_3M0KVwaA2voGn_01oHSf2lEMV672cpA88z2Sww&s=33&u=http%3a%2f%2fcamel%2eapache%2eorg%2fdead-letter-channel%2ehtml
The *DeadLetterChannel* lets you control behaviors including redelivery, whether to propagate the thrown Exception to the caller (the *handled* option), and where the (failed) Exchange should now be routed to.

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