Description
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 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.
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)
Below is an example of an exception I see when closing a leader selector and then closing the curator framework.
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)
Attachments
Issue Links
- relates to
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CURATOR-337 LeaderSelector logs stack trace with "The leader threw an exception" message erroneously
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- Closed
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- links to
