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https://issues.apache.org/jira/browse/CURATOR-468?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16501269#comment-16501269
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Cameron McKenzie commented on CURATOR-468:
------------------------------------------
Any suggestions for a fix? We can check if the thread is interrupted in the
finally block and abort the clean up if it is. As you've said, the mutex won't
get released if the thread is in an interrupted state anyway.
Alternatively, I guess we could clear the interrupted flag, clean up and then
reset the flag, but I think that this is going to be more error prone.
> Closing an active leader selector always logs spurious error
> ------------------------------------------------------------
>
> Key: CURATOR-468
> URL: https://issues.apache.org/jira/browse/CURATOR-468
> Project: Apache Curator
> Issue Type: Improvement
> Reporter: Keith Turner
> Assignee: Jordan Zimmerman
> Priority: Major
>
> Closing a a leader selector seems to always log spurious error messages.
> This only happens when it has assumed leadership because of CURATOR-337. I
> think this spurious error logging highlights a conceptual problem with the
> code. The primary reason that [LeaderSelector.java line
> 449|https://github.com/apache/curator/blob/ee5d65463b73abb2a2b732fb02729239b183519d/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderSelector.java#L449]
> is executed is because the thread was interrupted. Since the interrupt is
> set for the thread the call to release the mutex will never work, so its a
> bit of a catch-22.
> Below is an example of the exception I am seeing.
> {noformat}
> 2018-05-31 20:23:51,068 [leader.LeaderSelector] ERROR: The leader threw an
> exception
> java.lang.InterruptedException
> at java.lang.Object.wait(Native Method)
> at java.lang.Object.wait(Object.java:502)
> at org.apache.zookeeper.ClientCnxn.submitRequest(ClientCnxn.java:1406)
> at org.apache.zookeeper.ZooKeeper.delete(ZooKeeper.java:871)
> at
> org.apache.curator.framework.imps.DeleteBuilderImpl$5.call(DeleteBuilderImpl.java:250)
> at
> org.apache.curator.framework.imps.DeleteBuilderImpl$5.call(DeleteBuilderImpl.java:244)
> at org.apache.curator.RetryLoop.callWithRetry(RetryLoop.java:109)
> at
> org.apache.curator.framework.imps.DeleteBuilderImpl.pathInForeground(DeleteBuilderImpl.java:241)
> at
> org.apache.curator.framework.imps.DeleteBuilderImpl.forPath(DeleteBuilderImpl.java:225)
> at
> org.apache.curator.framework.imps.DeleteBuilderImpl.forPath(DeleteBuilderImpl.java:35)
> at
> org.apache.curator.framework.recipes.locks.LockInternals.deleteOurPath(LockInternals.java:339)
> at
> org.apache.curator.framework.recipes.locks.LockInternals.releaseLock(LockInternals.java:123)
> at
> org.apache.curator.framework.recipes.locks.InterProcessMutex.release(InterProcessMutex.java:154)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector.doWork(LeaderSelector.java:449)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector.doWorkLoop(LeaderSelector.java:466)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector.access$100(LeaderSelector.java:65)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector$2.call(LeaderSelector.java:246)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector$2.call(LeaderSelector.java:240)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {noformat}
> Below is an example of an exception I see when closing a leader selector and
> then closing the curator framework.
> {noformat}
> 2018-05-31 20:23:49,905 [leader.LeaderSelector] ERROR: The leader threw an
> exception
> java.lang.IllegalStateException: instance must be started before calling this
> method
> at
> org.apache.curator.shaded.com.google.common.base.Preconditions.checkState(Preconditions.java:176)
> at
> org.apache.curator.framework.imps.CuratorFrameworkImpl.delete(CuratorFrameworkImpl.java:359)
> at
> org.apache.curator.framework.recipes.locks.LockInternals.deleteOurPath(LockInternals.java:339)
> at
> org.apache.curator.framework.recipes.locks.LockInternals.releaseLock(LockInternals.java:123)
> at
> org.apache.curator.framework.recipes.locks.InterProcessMutex.release(InterProcessMutex.java:154)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector.doWork(LeaderSelector.java:449)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector.doWorkLoop(LeaderSelector.java:466)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector.access$100(LeaderSelector.java:65)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector$2.call(LeaderSelector.java:246)
> at
> org.apache.curator.framework.recipes.leader.LeaderSelector$2.call(LeaderSelector.java:240)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {noformat}
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