[jira] [Created] (CURATOR-345) NPE in EnsembleTracker when starting Curator

["Alex Rankin (JIRA)" <ji...@apache.org>]

Alex Rankin created CURATOR-345:
-----------------------------------

             Summary: NPE in EnsembleTracker when starting Curator
                 Key: CURATOR-345
                 URL: https://issues.apache.org/jira/browse/CURATOR-345
             Project: Apache Curator
          Issue Type: Bug
          Components: Framework
    Affects Versions: 3.2.0, 3.1.0
         Environment: ZooKeeper 3.5.1-alpha
            Reporter: Alex Rankin
            Priority: Minor


We're currently getting a NPE when running Curator 3.1.0 and 3.2.0 in our environment. I don't believe this was occurring before we upgraded to ZooKeeper 3.5.1-alpha and Curator 3.1.0.

{code}
 java.lang.NullPointerException
 	at org.apache.curator.framework.imps.EnsembleTracker.configToConnectionString(EnsembleTracker.java:171) ~[curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.EnsembleTracker.processConfigData(EnsembleTracker.java:186) ~[curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.EnsembleTracker.access$300(EnsembleTracker.java:50) ~[curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.EnsembleTracker$2.processResult(EnsembleTracker.java:144) ~[curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.CuratorFrameworkImpl.sendToBackgroundCallback(CuratorFrameworkImpl.java:835) [curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.CuratorFrameworkImpl.processBackgroundOperation(CuratorFrameworkImpl.java:618) [curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.WatcherRemovalFacade.processBackgroundOperation(WatcherRemovalFacade.java:152) [curator-framework-3.2.0.jar:3.2.0]
	at org.apache.curator.framework.imps.GetConfigBuilderImpl$2.processResult(GetConfigBuilderImpl.java:214) [curator-framework-3.2.0.jar:3.2.0]
	at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:587) [zookeeper-3.5.1-alpha.jar:?]
	at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:499) [zookeeper-3.5.1-alpha.jar:?]
{code}

The problem is that the QuorumServer.clientAddr here is null. This seems to be filled by parsing the ZooKeeper server properties, which look something like:

{quote}
server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888
{quote}

In the QuorumServer constructor, we parse each server line into its respective tasks. The clientAddr, however, is filled by splitting the line around a semicolon and taking the second part:

{code}
String[] serverClientParts = addressStr.split(";");
...
if(serverClientParts.length == 2) {
    String[] e = splitWithLeadingHostname(serverClientParts[1]);
    if(e.length > 2) {
        throw new ConfigException(addressStr + " does not have the form server_config or server_config;client_config where server_config is host:port:port or host:port:port:type and client_config is port or host:port");
    }

    String hostname = e.length == 2?e[0]:"0.0.0.0";
    ...
}
{code}

This suggests that the server string should be followed by a client host/port (or just port), e.g.:

{quote}
server.1=zoo1:2888:3888;2181
server.2=zoo2:2888:3888;2181
server.3=zoo3:2888:3888;localhost:2181
{quote}

I can't find anything in the ZooKeeper documentation about this though, and it isn't mandatory in the properties (so shouldn't throw a NPE).

This occurs every time we start the server, but doesn't affect functionality, hence the Minor flag. It would be nice to know what exactly is expected here though, so we can get rid of the exception.



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