Kumiko, In general you shouldn't have to create threads in your processors, with the exception of some special cases. The framework has a thread pool and it takes one of those threads and calls the onTrigger method of your processor.
If you want multiple threads to call onTrigger, then each processor has a Concurrent Tasks property in the UI on the scheduling tab, which equates to the number of threads that will concurrently call onTrigger. A processor developer needs to only worry about the business logic in the onTrigger method, and needs to ensure thread-safe access to any member variables or state stored in the processor. Hope that helps. -Bryan On Thu, Jun 9, 2016 at 2:11 PM, Kumiko Yada <kumiko.y...@ds-iq.com> wrote: > Microsoft found this is an issue with the SDK, they are working on a fix, > they do not have the ETA for the fix. To workaround this issue, I’m trying > to create the multiple threads in using AbstractSessionFactoryProcessor and > handle the Create a file in a single thread. I’m having a problem that > the single thread is not working correctly. The processor is still acting > like a single thread. > > > > When I create a thread to handle the create a file, do I have to call this > method using java.util.concurrent.ExecutorService? > > > > Are there any sample processors that I can take a look? > > > > Thanks > > Kumiko > > > > *From:* Kumiko Yada [mailto:kumiko.y...@ds-iq.com] > *Sent:* Sunday, June 5, 2016 6:28 PM > *To:* users@nifi.apache.org > *Cc:* Ki Kang <ki.k...@ds-iq.com>; Kevin Verhoeven < > kevin.verhoe...@ds-iq.com> > *Subject:* RE: Custom processor is failing for concurrency > > > > Thank you, Bryan. I’m working with Microsoft on this issue. Will keep > you guys updated. > > > > Thanks > > Kumiko > > > > *From:* Bryan Bende [mailto:bbe...@gmail.com <bbe...@gmail.com>] > *Sent:* Friday, June 3, 2016 2:32 PM > *To:* users@nifi.apache.org > *Subject:* Re: Custom processor is failing for concurrency > > > > It is hard to say for sure, but I think your NiFi processor is generally > ok regarding thread safety, but I think there could be a problem in the > Azure SDK code... > > > > RequestFactory has an instance of BaseUrl and every time > RequestFactory.create() is called, it calls BaseUrl.url(). > > > > The implementation of BaseUrl is the following (according to my IntelliJ > attaching the sources...): > > > > public class AutoRestBaseUrl implements BaseUrl { > /** A template based URL with variables wrapped in {}s. */ > private String template; > /** a mapping from {} wrapped variables in the template and their actual > values. */ > private Map<CharSequence, String> mappings; > > @Override > public HttpUrl url() { > String url = template; > for (Map.Entry<CharSequence, String> entry : mappings.entrySet()) { > url = url.replace(entry.getKey(), entry.getValue()); > } > mappings.clear(); > return HttpUrl.parse(url); > } > > /** > * Creates an instance of a template based URL. > * > * @param url the template based URL to use. > */ > public AutoRestBaseUrl(String url) { > this.template = url; > this.mappings = new HashMap<>(); > } > > /** > * Sets the value for the {} wrapped variables in the template URL. > * @param matcher the {} wrapped variable to replace. > * @param value the value to set for the variable. > */ > public void set(CharSequence matcher, String value) { > this.mappings.put(matcher, value); > } > } > > > > The exception is coming from the line where it is looping over the > entryset: > > > > for (Map.Entry<CharSequence, String> entry : mappings.entrySet()) { > > > > Right after that loop it calls mappings.clear() so if the RequestFactory > is shared by multiple threads (which I think it is), then one thread could > be iterating over the set, which another calls mappings.clear(). > > > > > > On Fri, Jun 3, 2016 at 5:09 PM, Oleg Zhurakousky < > ozhurakou...@hortonworks.com> wrote: > > Kumiko > > > > It appears that the current state of the source you linked in is not in > sync with what is in the stack trace. Perhaps you have made some code > modifications (e.g., line 218 is an empty line in code while it has a > pointer in the star trace). > > In any event, from what I can see the error is coming from Azure libraries > (not NiFi). Specifically ‘com.microsoft.rest.AutoRestBaseUrl.url(..)’ seems > to be doing some iteration where I presume the remove is called. Perhaps it > is not a thread safe class after all. What does Microsoft documentation > says? Have you looked at the source to see what’s going on there? If its > open please link and we can tale a look. > > > > Cheers > > Oleg > > > > On Jun 3, 2016, at 4:58 PM, Kumiko Yada <kumiko.y...@ds-iq.com> wrote: > > > > Here is the code, https://github.com/kyada1/PutFileAzureDLStore. > > > > Thanks > > Kumiko > > > > *From:* Bryan Bende [mailto:bbe...@gmail.com <bbe...@gmail.com>] > *Sent:* Friday, June 3, 2016 12:57 PM > *To:* users@nifi.apache.org > *Subject:* Re: Custom processor is failing for the custom processor > > > > Hello, > > > > Would you be able to share your code for PutFileAzureDLStore so we can > help identify if there is a concurrency problem? > > > > -Bryan > > > > On Fri, Jun 3, 2016 at 3:39 PM, Kumiko Yada <kumiko.y...@ds-iq.com> wrote: > > Hello, > > > > I wrote the following custom service control and processor. When the > custom processor is running concurrently, it’s failing often with several > different errors. Are there any special handlings for concurrently that I > need to add in the custom processor? I wrote the sample Java program which > does the same thing as the custom processor (authenticate every time the > file is created/create a file, create 2 threads and run concurrently), it’s > working fine. The custom processor also fine when this is not running > concurrently. > > > > *Custom service control – set the properties for the Microsoft Azure > Datalake Store* > > *Custom processor – authenticate, then create a file in Microsoft Azure > Datalake Store* > > > > Error1: > > 2016-06-03 12:29:31,942 INFO [pool-2815-thread-1] > c.m.aad.adal4j.AuthenticationAuthority [Correlation ID: > 64c89876-2f7b-4fbb-8e6f-fb395a47aa87] Instance discovery was successful > > 2016-06-03 12:29:31,946 ERROR [Timer-Driven Process Thread-10] > n.a.d.processors.PutFileAzureDLStore > > java.util.ConcurrentModificationException: null > > at > java.util.HashMap$HashIterator.nextNode(HashMap.java:1429) ~[na:1.8.0_77] > > at java.util.HashMap$EntryIterator.next(HashMap.java:1463) > ~[na:1.8.0_77] > > at java.util.HashMap$EntryIterator.next(HashMap.java:1461) > ~[na:1.8.0_77] > > at > com.microsoft.rest.AutoRestBaseUrl.url(AutoRestBaseUrl.java:28) ~[na:na] > > at retrofit2.RequestFactory.create(RequestFactory.java:50) > ~[na:na] > > at retrofit2.OkHttpCall.createRawCall(OkHttpCall.java:181) > ~[na:na] > > at retrofit2.OkHttpCall.execute(OkHttpCall.java:165) > ~[na:na] > > at > com.microsoft.azure.management.datalake.store.FileSystemOperationsImpl.create(FileSystemOperationsImpl.java:1432) > ~[na:na] > > at > nifi.azure.dlstore.processors.PutFileAzureDLStore.CreateFile(PutFileAzureDLStore.java:252) > ~[na:na] > > at > nifi.azure.dlstore.processors.PutFileAzureDLStore.onTrigger(PutFileAzureDLStore.java:218) > ~[na:na] > > at > org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27) > ~[nifi-api-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1057) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:136) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:47) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:123) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) > [na:1.8.0_77] > > at > java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) > [na:1.8.0_77] > > at > java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) > [na:1.8.0_77] > > at > java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) > [na:1.8.0_77] > > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) > [na:1.8.0_77] > > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) > [na:1.8.0_77] > > at java.lang.Thread.run(Thread.java:745) [na:1.8.0_77] > > > > Error2: > > 2016-06-03 12:29:24,913 WARN [Timer-Driven Process Thread-5] > o.a.n.c.t.ContinuallyRunProcessorTask Administratively Yielding > PutFileAzureDLStore[id=2133fdad-54b7-46a5-9bcf-958ddd8cfac0] due to > uncaught Exception: com.microsoft.rest.ServiceException: Invalid status > code 403 > > 2016-06-03 12:29:24,915 WARN [Timer-Driven Process Thread-5] > o.a.n.c.t.ContinuallyRunProcessorTask > > com.microsoft.rest.ServiceException: Invalid status code 403 > > at > sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) > ~[na:1.8.0_77] > > at > sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) > ~[na:1.8.0_77] > > at > sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) > ~[na:1.8.0_77] > > at > java.lang.reflect.Constructor.newInstance(Constructor.java:423) > ~[na:1.8.0_77] > > at > com.microsoft.rest.ServiceResponseBuilder.build(ServiceResponseBuilder.java:147) > ~[na:na] > > at > com.microsoft.azure.management.datalake.store.FileSystemOperationsImpl.createDelegate(FileSystemOperationsImpl.java:1491) > ~[na:na] > > at > com.microsoft.azure.management.datalake.store.FileSystemOperationsImpl.create(FileSystemOperationsImpl.java:1432) > ~[na:na] > > at > nifi.azure.dlstore.processors.PutFileAzureDLStore.CreateFile(PutFileAzureDLStore.java:252) > ~[na:na] > > at > nifi.azure.dlstore.processors.PutFileAzureDLStore.onTrigger(PutFileAzureDLStore.java:218) > ~[na:na] > > at > org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27) > ~[nifi-api-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1057) > ~[nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:136) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:47) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:123) > [nifi-framework-core-0.7.0-SNAPSHOT.jar:0.7.0-SNAPSHOT] > > at > java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) > [na:1.8.0_77] > > at > java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) > [na:1.8.0_77] > > at > java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) > [na:1.8.0_77] > > at > java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) > [na:1.8.0_77] > > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) > [na:1.8.0_77] > > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) > [na:1.8.0_77] > > > > Thanks > > Kumiko > > > > >
