com.netflix.curator.test.KillSession Maven / Gradle / Ivy
/*
*
* Copyright 2011 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package com.netflix.curator.test;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
/**
*
* Utility to simulate a ZK session dying. See: ZooKeeper FAQ
*
*
*
* In the case of testing we want to cause a problem, so to explicitly expire a session an
* application connects to ZooKeeper, saves the session id and password, creates another
* ZooKeeper handle with that id and password, and then closes the new handle. Since both
* handles reference the same session, the close on second handle will invalidate the session
* causing a SESSION_EXPIRED on the first handle.
*
*/
public class KillSession
{
/**
* Kill the given ZK session
*
* @param client the client to kill
* @param connectString server connection string
* @throws Exception errors
*/
public static void kill(ZooKeeper client, String connectString) throws Exception
{
kill(client, connectString, new Timing().forWaiting().milliseconds());
}
/**
* Kill the given ZK session
*
* @param client the client to kill
* @param connectString server connection string
* @param maxMs max time ms to wait for kill
* @throws Exception errors
*/
public static void kill(ZooKeeper client, String connectString, int maxMs) throws Exception
{
long startTicks = System.currentTimeMillis();
final CountDownLatch sessionLostLatch = new CountDownLatch(1);
Watcher sessionLostWatch = new Watcher()
{
@Override
public void process(WatchedEvent event)
{
sessionLostLatch.countDown();
}
};
client.exists("/___CURATOR_KILL_SESSION___" + System.nanoTime(), sessionLostWatch);
final CountDownLatch connectionLatch = new CountDownLatch(1);
Watcher connectionWatcher = new Watcher()
{
@Override
public void process(WatchedEvent event)
{
if ( event.getState() == Event.KeeperState.SyncConnected )
{
connectionLatch.countDown();
}
}
};
ZooKeeper zk = new ZooKeeper(connectString, maxMs, connectionWatcher, client.getSessionId(), client.getSessionPasswd());
try
{
if ( !connectionLatch.await(maxMs, TimeUnit.MILLISECONDS) )
{
throw new Exception("KillSession could not establish duplicate session");
}
try
{
zk.close();
}
finally
{
zk = null;
}
while ( client.getState().isConnected() && !sessionLostLatch.await(100, TimeUnit.MILLISECONDS) )
{
long elapsed = System.currentTimeMillis() - startTicks;
if ( elapsed > maxMs )
{
throw new Exception("KillSession timed out waiting for session to expire");
}
}
}
finally
{
if ( zk != null )
{
zk.close();
}
}
}
}