[jira] [Work logged] (GOBBLIN-1078) Coordination between task cancel and task initialization in Helix

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GOBBLIN-1078?focusedWorklogId=401027&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-401027 ]

ASF GitHub Bot logged work on GOBBLIN-1078:
-------------------------------------------

                Author: ASF GitHub Bot
            Created on: 10/Mar/20 22:42
            Start Date: 10/Mar/20 22:42
    Worklog Time Spent: 10m 
      Work Description: autumnust commented on pull request #2919: [GOBBLIN-1078] Coordination between task cancel and initialization in Helix Task
URL: https://github.com/apache/incubator-gobblin/pull/2919
 
 
   Dear Gobblin maintainers,
   
   Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!
   
   
   ### JIRA
   - https://issues.apache.org/jira/browse/GOBBLIN-1078
   
   
   ### Description
   The task cancel and task.run is called in different thread from helix side, which introduced problems when: 
   - Task get cancelled for some reasons from Helix side, therefore calling `SingleTask#cancel `
   - However, TaskAttempt object within SingleTask has not been initialized, therefore it didn't pass the non-null checking and only prints a log. After that, the run method in different thread start to run and never get cancelled. 
   
   This sequence could result in violation of helix quota in each participant: While helix believe there's no partition assigned to a participant and assign a new partition, the previous not-yet-cancelled partition is still running. 
   
   We added a barrier in cancel method to ensure cancel is blocked if taskAttempt object is not yet being initialized. Added unit test to simulate the sequence as well. 
   
   
   ### Tests
   - [ ] My PR adds the following unit tests __OR__ does not need testing for this extremely good reason:
   
   
   ### Commits
   - [ ] My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "[How to write a good git commit message](http://chris.beams.io/posts/git-commit/)":
       1. Subject is separated from body by a blank line
       2. Subject is limited to 50 characters
       3. Subject does not end with a period
       4. Subject uses the imperative mood ("add", not "adding")
       5. Body wraps at 72 characters
       6. Body explains "what" and "why", not "how"
   
   
 
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Issue Time Tracking
-------------------

            Worklog Id:     (was: 401027)
    Remaining Estimate: 0h
            Time Spent: 10m

> Coordination between task cancel and task initialization in Helix
> -----------------------------------------------------------------
>
>                 Key: GOBBLIN-1078
>                 URL: https://issues.apache.org/jira/browse/GOBBLIN-1078
>             Project: Apache Gobblin
>          Issue Type: Improvement
>            Reporter: Lei Sun
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>




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