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https://issues.apache.org/jira/browse/CURATOR-507?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16772386#comment-16772386
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Cameron McKenzie commented on CURATOR-507:
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I don't think it's a race condition. The two paths for initialisationComplete()
to be called seem mutually exclusive to me, but maybe I'm missing something.
Could you write a small unit test to reproduce the problem? It's difficult to
work out what's going on from the code snippets.
> PERSISTENT NODE ISSUE
> ---------------------
>
> Key: CURATOR-507
> URL: https://issues.apache.org/jira/browse/CURATOR-507
> Project: Apache Curator
> Issue Type: Bug
> Components: Recipes
> Affects Versions: 4.1.0
> Reporter: Evaristo
> Priority: Major
>
> Hi there,
> I am using Apache Curator 4.1.0 with Zk 3.4.10 (Open JDK 1.8)
> openjdk version "1.8.0_191"
> I am PersistentNode recipe and I am receiving this exception
>
> java.lang.IllegalStateException: initial create has not been processed. Call
> waitForInitialCreate() to ensure.
> at
> org.apache.curator.shaded.com.google.common.base.Preconditions.checkState(Preconditions.java:444)
> at
> org.apache.curator.framework.recipes.nodes.PersistentNode.setData(PersistentNode.java:392)
> at com.cheva.udr.sm.RemoteReporter.reportToRemote(RemoteReporter.java:67)
> at com.cheva.udr.sm.RemoteReporter.lambda$2(RemoteReporter.java:84)
> at java.util.concurrent.Executors$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)
>
> My class RemoteReporter.java (assumes that PersistentNode is thread safe)
> // The class is final, and the attribute is private final so allow safe
> publication
> private final Persistent pn;
> Constrcutor() {
> ...
> PersistentNode pn = new PersistentNode(cf, CreateMode.EPHEMERAL, false, path,
> dataToReport());
> }
> // Class has also an start method
> start() {
> ...
> 79 pn.start();
> ...
> // Create new thread and execute the follwoing code
> 84 pn.waitForInitialCreate(1000, TimeUnit.DAYS);
> 85 pn.setData("XXx");
> 86 statusCache.getListenable().addListener(listener);
> }
> I was checking the PersistentNode code and the excepction happens because
> nodePath.get()==null variable. I am not 100% sure if the problem is in my
> code or in the recipe...
> - My code is using the waitForinitial as suggested
> - The recipe uses a CountDownLatch, but there are 2 different paths for the
> latch to be countDown (via initalisationComplete() method), and I am not sure
> that one of them assures that nodePath.get() != null
> In this code snippet, you can see that the latch is countDown, but I am not
> sure that nodePath.set(whatever) is called, so I guess there could be a race
> condition
> private final BackgroundCallback setDataCallback = new BackgroundCallback()
> {
> @Override
> public void processResult(CuratorFramework dummy, CuratorEvent event)
> throws Exception
> {
> //If the result is ok then initialisation is complete (if we're still
> initialising)
> //Don't retry on other errors as the only recoverable cases will be
> connection loss
> //and the node not existing, both of which are already handled by other
> watches.
> if ( event.getResultCode() == KeeperException.Code.OK.intValue() )
> {
> //Update is ok, mark initialisation as complete if required.
> initialisationComplete();
> }
> else if ( event.getResultCode() == KeeperException.Code.NOAUTH.intValue() )
> {
> log.warn("Client does not have authorisation to write node at path {}",
> event.getPath());
> authFailure.set(true);
> }
> }
> };
> Thanks in adavance for the help,
> Evaristo
>
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