Apache camel how to implement an optional consumer for a wire tap - apache-camel

Question

I set up some routes (Camel 2.22.1) that uses wire tap to log some stuff into a Mongo db.
from(DIRECT_NEXT).process(sendFile)
.wireTap( "direct:count-fetch?failIfNoConsumers=false" )
as you see i am using failIfNoConsumers=false.
from(COUNT_FETCH)
.routeId( MONGO_COUNT_FETCH_ROUTEID )
.autoStartup( false )
.process(countFetchProcessor)
.to(persistenceEndpoints.updateImage())
.log(LoggingLevel.DEBUG, "Counted fetch.");
The mongo DB is an optional component, the whole application will run without it.
I am using Mongo'S ServerMonitorListener to check if Mongo is available. I suspend or resume the rout using Camel's ControlBus accordingly.
All is running fine!
My Problem is that Camel tries to send the exchanges to the not running routes for 30s:
...
[DEBUG] 2019-01-03 14:02:45.848 [Camel (camel-1) thread #23 - WireTap] DirectBlockingProducer - Waited 20025 for consumer to be ready
...
Why the producer blocks? The default value for "block" should be false?!
And after it we see of course an exception:
No consumers available on endpoint: direct://count-fetch?failIfNoConsumers=false
What is the best approach to let camel discard the exchange immediately (how to set the time out?) and don't throw any exception (because it is normal application behavior, exception will only slow down)?
UPDATE:
here is the complete exception:
[ERROR] 2019-01-07 10:21:22.702 [Camel (camel-1) thread #4 - WireTap] DefaultErrorHandler - Failed delivery for (MessageId: ID-moritz-1546852848013-0-3 on ExchangeId: ID-moritz-1546852848013-0-2). Exhausted after delivery attempt: 1 caught: org.apache.camel.component.direct.DirectConsumerNotAvailableException: No consumers available on endpoint: direct://update-all?failIfNoConsumers=false. Exchange[ID-moritz-1546852848013-0-2]
Message History
---------------------------------------------------------------------------------------------------------------------------------------
RouteId ProcessorId Processor Elapsed (ms)
[route4 ] [route4 ] [timer://updateAll ] [ 30065]
[route4 ] [log1 ] [log ] [ 1]
[route4 ] [to3 ] [direct:updateAll ] [ 19]
[route5 ] [process2 ] [Processor#0x4e92466a ] [ 9]
[route5 ] [process3 ] [Processor#0x1b29d52b ] [ 7]
[route5 ] [wireTap1 ] [wireTap[direct:update-all?failIfNoConsumers=false] ] [ 1]
Stacktrace
---------------------------------------------------------------------------------------------------------------------------------------
org.apache.camel.component.direct.DirectConsumerNotAvailableException: No consumers available on endpoint: direct://update-all?failIfNoConsumers=false. Exchange[ID-moritz-1546852848013-0-2]
at org.apache.camel.component.direct.DirectBlockingProducer.getConsumer(DirectBlockingProducer.java:67) ~[camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.component.direct.DirectBlockingProducer.process(DirectBlockingProducer.java:53) ~[camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.SendDynamicProcessor$1.doInAsyncProducer(SendDynamicProcessor.java:178) ~[camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.impl.ProducerCache.doInAsyncProducer(ProducerCache.java:445) ~[camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.SendDynamicProcessor.process(SendDynamicProcessor.java:160) ~[camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:548) [camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201) [camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.DelegateAsyncProcessor.process(DelegateAsyncProcessor.java:97) [camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.WireTapProcessor$1.call(WireTapProcessor.java:160) [camel-core-2.22.1.jar:2.22.1]
at org.apache.camel.processor.WireTapProcessor$1.call(WireTapProcessor.java:155) [camel-core-2.22.1.jar:2.22.1]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_181]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_181]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_181]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181]

Answer 1

Make sure to check the document for the version of Camel you use, which is 2.22.x
There you can see the block is default enabled: https://github.com/apache/camel/blob/camel-2.22.x/camel-core/src/main/docs/direct-component.adoc