Dlmuthu, This explains your need. Could you please point me to the code? I was wondering, where and how are we registering callbacks for the participants?
On Thu, Nov 16, 2017 at 7:16 PM, DImuthu Upeksha <dimuthu.upeks...@gmail.com > wrote: > Adding Helix Dev > > Hi Ajinkya > > Thank you for the explanation. > > Let me explain my requirement. [1] is the correct task registry > configuration in a working participant code. All the transition call backs > are registered in this code. The problem here is, we have to bundle > binaries of all the tasks into a single Participant. If we want to change > one task, we need to rebuild the participant with other tasks as well. What > I thought is, why can't we build Participants that only do specific set of > tasks. For example, in the cluster there are 3 participants, Participant 1 > [2], Participant 2 [3] and Participant 3 [4]. If we want to change the > DataCollecting task, we only need to re build Participant 2. I got above > error, once I run 3 participants in above configuration. I can understand > this is due to the missing transition callback of CommandTask in > Participant 1 as I have purposely commented out it. What I need to know is > that, is this configuration allowed in Helix architecture or do we have to > implement Participants that contain all the task implementations as in [1]. > Workflow configuration for both scenarios is here [5]. > > [1] https://gist.github.com/DImuthuUpe/41c0db579e7d86d101d112f07ed6ea00 > [2] https://gist.github.com/DImuthuUpe/ec72df1ec3207ce2dce88ff7f1756da4 > [3] https://gist.github.com/DImuthuUpe/4d193a3dff3008315efa2e31f6209cac > [4] https://gist.github.com/DImuthuUpe/872c432935b8d33944dd571b3ac4207b > [5] https://gist.github.com/DImuthuUpe/f61851b68b685b8d6744689dc130babd > > Thanks > Dimuthu > > On Fri, Nov 17, 2017 at 3:21 AM, Ajinkya Dhamnaskar <adham...@umail.iu.edu > > wrote: > >> Hey Dlmuthu, >> >> Not an expert in Helix, but from exceptions it seems, system is entering >> in a state not expected by reflection. I feel https://github.com/apache >> /helix/blob/master/helix-core/src/main/java/org/apache/helix >> /messaging/handling/HelixStateTransitionHandler.java#L295 is triggering >> this exception. >> As mentioned in the later part of the stack trace and from Helix Apache >> Docs <http://helix.apache.org/0.7.1-docs/tutorial_agent.html> *("Helix >> is built on the following assumption: if your distributed resource is >> modeled by a finite state machine, then Helix can tell participants when >> they should transition between states. In the Java API, this means >> implementing transition callbacks. In the Helix agent API, this means >> providing commands than can run for each transition"),* did you >> implement *transition callback* for these tasks? >> >> On Thu, Nov 16, 2017 at 10:01 AM, DImuthu Upeksha < >> dimuthu.upeks...@gmail.com> wrote: >> >>> Hi Devs, >>> >>> I'm working on the technology evaluation to re architecture Apache >>> Airavata task execution framework and Helix seems like a good candidate for >>> that as it has an in built distributed generic workflow execution >>> capability. After going through several tutorials, I tried to implement a >>> simple workflow on Helix to demonstrate following transition >>> >>> Data Collecting Job -> Command Executing Job -> Data Uploading Job >>> >>> I managed to implement this using a Participant node that includes all >>> the tasks required for above workflow. However my goal is to implement >>> specialized Participants for each Job type. For example, Participant 1 >>> knows only about the tasks to perform Data Collecting Job and Participant >>> knows only about the task to perform Command Executing Job. When I tried to >>> implement such Participants, I got following error from Participant 1. I >>> can share the code samples that I have tried but before that I need to know >>> whether my approach is compatible with Helix's design? Does Helix require >>> all the Participants to be homogeneous? >>> >>> Executing data collecting >>> 675892 [pool-2-thread-8] ERROR org.apache.helix.messaging.han >>> dling.HelixStateTransitionHandler - Exception while executing a state >>> transition task Airavata_Workflow_commandExecuteJob_0 >>> java.lang.reflect.InvocationTargetException >>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) >>> at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAcce >>> ssorImpl.java:62) >>> at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMe >>> thodAccessorImpl.java:43) >>> at java.lang.reflect.Method.invoke(Method.java:498) >>> at org.apache.helix.messaging.handling.HelixStateTransitionHand >>> ler.invoke(HelixStateTransitionHandler.java:344) >>> at org.apache.helix.messaging.handling.HelixStateTransitionHand >>> ler.handleMessage(HelixStateTransitionHandler.java:290) >>> at org.apache.helix.messaging.handling.HelixTask.call(HelixTask.java:84) >>> at org.apache.helix.messaging.handling.HelixTask.call(HelixTask.java:41) >>> at java.util.concurrent.FutureTask.run(FutureTask.java:266) >>> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPool >>> Executor.java:1149) >>> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoo >>> lExecutor.java:624) >>> at java.lang.Thread.run(Thread.java:748) >>> Caused by: java.lang.IllegalStateException: No callback implemented for >>> task COMMAND >>> at org.apache.helix.task.TaskStateModel.startTask(TaskStateMode >>> l.java:302) >>> at org.apache.helix.task.TaskStateModel.onBecomeRunningFromInit >>> (TaskStateModel.java:69) >>> ... 12 more >>> 675900 [pool-2-thread-8] ERROR >>> org.apache.helix.participant.statemachine.StateModel >>> - Default rollback method invoked on error. Error Code: ERROR >>> 675908 [pool-2-thread-8] ERROR org.apache.helix.messaging.handling.HelixTask >>> - Message execution failed. msgId: 8d9a08c9-0ae7-419a-8940-6b8e6e7c1ecb, >>> errorMsg: java.lang.reflect.InvocationTargetException >>> 675922 [pool-2-thread-8] ERROR org.apache.helix.messaging.han >>> dling.HelixStateTransitionHandler - Skip internal error. errCode: >>> ERROR, errMsg: null >>> >>> Thanks >>> Dimuthu >>> >> >> >> >> -- >> Thanks and regards, >> >> Ajinkya Dhamnaskar >> Student ID : 0003469679 >> Masters (CS) >> +1 (812) 369- 5416 <(812)%20369-5416> >> > > -- Thanks and regards, Ajinkya Dhamnaskar Student ID : 0003469679 Masters (CS) +1 (812) 369- 5416
