Michael,
Not a problem. It looks like you are calling session.read() but passing it a
null FlowFile.
My guess is that in your processor you're doing something like this:
FlowFile flowFile = session.get();
...
session.read(flowFile, new InputStreamCallback() {...});
It's important to always check if the FlowFile returned from session.get() is
null or not. Because
NiFi allows for multi-threading and allows Processors to be run without
incoming connections,
session.get() may well return null.
If that is not the case, please let us know, and we will continue to help you
investigate.
Thanks!
-Mark
> On Nov 17, 2015, at 11:42 AM, Michael De Courci <[email protected]> wrote:
>
> Hi
> Thanks for your speedy reply.
> I have just done a retest and changed the code to handle exceptions by
> calling context.yield
>
> and I now get, the following stack trace forever repeating, still my custom
> plugin is never yielded.
>
> What I am trying to develop is a stable nifi plugin that does not consume
> resource when an exception occurs - Can you help with that also?
>
> 015-11-17 16:26:50,476 INFO [NiFi Web Server-26]
> c.s.j.s.i.application.WebApplicationImpl Initiating Jersey application,
> version 'Jersey: 1.19 02/11/2015 03:25 AM'
> 2015-11-17 16:27:08,462 INFO [Flow Service Tasks Thread-2]
> o.a.nifi.controller.StandardFlowService Saved flow controller
> org.apache.nifi.controller.FlowController@54c2b852 // Another save pending =
> false
> 2015-11-17 16:27:17,676 INFO [pool-35-thread-4]
> o.a.n.c.s.TimerDrivenSchedulingAgent Scheduled
> PutFile[id=5135b041-66ff-43ab-9e71-f1848dcef4f6] to run with 1 threads
> 2015-11-17 16:27:17,676 INFO [pool-35-thread-2]
> o.a.n.c.s.TimerDrivenSchedulingAgent Scheduled
> GetFile[id=2886b8ff-1f82-4aa3-b42d-1f4f4c9f03f8] to run with 1 threads
> 2015-11-17 16:27:17,676 INFO [pool-35-thread-3]
> o.a.n.c.s.TimerDrivenSchedulingAgent Scheduled
> SampleErrorHandlerProcessor[id=8e8f80eb-552a-471c-8ffd-f2509d71fd2e] to run
> with 1 threads
> 2015-11-17 16:27:17,691 INFO [Timer-Driven Process Thread-2]
> o.a.nifi.processors.standard.GetFile
> GetFile[id=2886b8ff-1f82-4aa3-b42d-1f4f4c9f03f8] added
> StandardFlowFileRecord[uuid=6a1800eb-03ca-4aad-9e2c-f96df41252e6,claim=StandardContentClaim
> [resourceClaim=StandardResourceClaim[id=1447777637680-1, container=default,
> section=1], offset=0,
> length=15658],offset=0,name=162700882642440.json,size=15658] to flow
> 2015-11-17 16:27:17,743 ERROR [Timer-Driven Process Thread-5]
> c.b.n.p.SampleErrorHandlerProcessor
> [SampleErrorHandlerProcessor[id=8e8f80eb-552a-471c-8ffd-f2509d71fd2e]] ---
> Encountered process exception
> org.apache.nifi.processor.exception.FlowFileHandlingException: null is not
> known in this session (StandardProcessSession[id=35])
> at
> org.apache.nifi.controller.repository.StandardProcessSession.validateRecordState(StandardProcessSession.java:2345)
> ~[nifi-framework-core-0.3.0.jar:0.3.0]
> at
> org.apache.nifi.controller.repository.StandardProcessSession.read(StandardProcessSession.java:1773)
> ~[nifi-framework-core-0.3.0.jar:0.3.0]
> at
> com.barclays.nifi.processor.SampleErrorHandlerProcessor.doTrigger(SampleErrorHandlerProcessor.scala:49)
> [poc-1.0-SNAPSHOT-nifiPlugins.nar-unpacked/:na]
> at
> com.barclays.nifi.processor.ErrorHandlerAdapterProcessor$class.onTrigger(ErrorHandlerAdapterProcessor.scala:24)
> ~[poc-1.0-SNAPSHOT-nifiPlugins.nar-unpacked/:na]
> at
> com.barclays.nifi.processor.SampleErrorHandlerProcessor.onTrigger(SampleErrorHandlerProcessor.scala:26)
> [poc-1.0-SNAPSHOT-nifiPlugins.nar-unpacked/:na]
> at
> org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27)
> [nifi-api-0.3.0.jar:0.3.0]
> at
> org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1077)
> [nifi-framework-core-0.3.0.jar:0.3.0]
> at
> org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:127)
> [nifi-framework-core-0.3.0.jar:0.3.0]
> at
> org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:49)
> [nifi-framework-core-0.3.0.jar:0.3.0]
> at
> org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:119)
> [nifi-framework-core-0.3.0.jar:0.3.0]
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> [na:1.8.0_51]
> at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
> [na:1.8.0_51]
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
> [na:1.8.0_51]
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
> [na:1.8.0_51]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> [na:1.8.0_51]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> [na:1.8.0_51]
> at java.lang.Thread.run(Thread.java:745) [na:1.8.0_51]
> 2015-11-17 16:27:17,743 ERROR [Timer-Driven Process Thread-5]
> c.b.n.p.SampleErrorHandlerProcessor
> SampleErrorHandlerProcessor[id=8e8f80eb-552a-471c-8ffd-f2509d71fd2e]
> SampleErrorHandlerProcessor[id=8e8f80eb-552a-471c-8ffd-f2509d71fd2e] failed
> to process due to
> org.apache.nifi.processor.exception.FlowFileHandlingException:
> StandardFlowFileRecord[uuid=6a1800eb-03ca-4aad-9e2c-f96df41252e6,claim=StandardContentClaim
> [resourceClaim=StandardResourceClaim[id=1447777637680-1, container=default,
> section=1], offset=0,
> length=15658],offset=0,name=162700882642440.json,size=15658] is not known in
> this session
>
>
>> On 17 Nov 2015, at 16:19, Mark Payne <[email protected]> wrote:
>>
>> Michael,
>>
>> Hello. First, thanks for your interest in NiFi! I'm very happy to see that
>> you're already starting to dig in pretty deep here!
>>
>> I admit that the wording here can be a little confusing. Let me try to
>> explain what's going on here and how yielding
>> works. When you are developing a Processor in NiFi, especially if reaching
>> out to some external resource,
>> a common occurrence is to realize that there is no work that can really be
>> done at this point in time (for
>> example, because the remote resource is not accessible). In that case, the
>> processor can call ProcessContext.yield()
>> and as a result, the framework will stop scheduling that processor to run
>> for the configured amount of time, so that
>> we aren't wasting resources when we know there is nothing that we can
>> accomplish. This is where the configured
>> Yield Duration comes in.
>>
>> There is, however, a concept of "administratively yielding" a processor. The
>> idea here is that the Processor throws
>> some unexpected exception. Since the Exception was not of type
>> ProcessException, the framework considers this
>> a bug and will perform an administrative yield to avoid continually
>> triggering a processor that may be in a bad state.
>>
>> Perhaps using the term "administratively yielding" was a bad idea, as it can
>> clearly lead to confusion.
>> If you feel that something is not behaving properly, though, or you believe
>> that the user experience can be improved
>> in some way, please do let us know, as we strive to continually improve the
>> user experience.
>>
>> Thanks
>> -Mark
>>
>>
>>> On Nov 17, 2015, at 10:34 AM, Michael De Courci <[email protected]> wrote:
>>>
>>> FYI
>>>
>>>> Begin forwarded message:
>>>>
>>>> From: Michael De Courci <[email protected]>
>>>> Date: 16 November 2015 at 15:41:27 GMT
>>>> To: [email protected], [email protected], Kefah
>>>> Issa <[email protected]>
>>>> Subject: NiFI Custom Plugin - Yield Duration Ignored
>>>>
>>>> I wrote a NAR custom plugin to verify NoFi Exception handling. - version;
>>>> nifi-0.3.0
>>>>
>>>> The plugin was written to always through a RunTimeException for any
>>>> exception including ProcessException.
>>>>
>>>> I created a simple flow; GetFile->MyPlugin->PutFile
>>>>
>>>> and set the Yield duration to 60 seconds.
>>>>
>>>> The log shows that the yield duration is always 1 sec
>>>>
>>>> I debugged the NiFi framework code and see that the yield duration always
>>>> defaults to 1 sec;
>>>> See;
>>>> org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent
>>>>
>>>> Setting the duration updates the class
>>>> org.apache.nifi.controller.StandardProcessorNode
>>>> but this does not communicate the change to TimerDrivenSchedulingAgent
>>>>
>>>> Evidence from log;
>>>>
>>>> 80eb-552a-471c-8ffd-f2509d71fd2e] failed to process session due to
>>>> java.lang.RuntimeException: java.lang.RuntimeException
>>>>
>>>> 2015-11-15 16:17:58,417 WARN [Timer-Driven Process Thread-7]
>>>> c.b.n.p.SampleErrorHandlerProcessor
>>>> SampleErrorHandlerProcessor[id=8e8f80eb-552a-471c-8ffd-f2509d71fd2e]
>>>> Processor Administratively Yielded for 1 sec due to processing failure
>>>>
>>>> 2015-11-15 16:17:58,417 WARN [Timer-Driven Process Thread-7]
>>>> o.a.n.c.t.ContinuallyRunProcessorTask Administratively Yielding
>>>> SampleErrorHandlerProcessor[id=8e8f80eb-552a-471c-8ffd-f2509d71fd2e] due
>>>> to uncaught Exception: java.lang.RuntimeException
>>>>
>>>> 2015-11-15 16:17:58,419 WARN [Timer-Driven Process Thread-7]
>>>> o.a.n.c.t.ContinuallyRunProcessorTask
>>>>
>>>> java.lang.RuntimeException: null
>>>>
>>>> at
>>>> com.barclays.nifi.processor.SampleErrorHandlerProcessor.onTrigger(SampleErrorHandlerProcessor.scala:103)
>>>> ~[na:na]
>>>>
>>>>
>>>>
>>>> With Kind Regards
>>>> Michael de Courci
>>>
>>
>
