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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