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org.apache.curator.ConnectionState Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.curator;
import org.apache.curator.utils.CloseableUtils;
import org.apache.curator.drivers.TracerDriver;
import org.apache.curator.ensemble.EnsembleProvider;
import org.apache.curator.utils.DebugUtils;
import org.apache.curator.utils.ZookeeperFactory;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.Closeable;
import java.io.IOException;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
class ConnectionState implements Watcher, Closeable
{
private static final int MAX_BACKGROUND_EXCEPTIONS = 10;
private static final boolean LOG_EVENTS = Boolean.getBoolean(DebugUtils.PROPERTY_LOG_EVENTS);
private final Logger log = LoggerFactory.getLogger(getClass());
private final HandleHolder zooKeeper;
private final AtomicBoolean isConnected = new AtomicBoolean(false);
private final EnsembleProvider ensembleProvider;
private final int sessionTimeoutMs;
private final int connectionTimeoutMs;
private final AtomicReference tracer;
private final Queue backgroundExceptions = new ConcurrentLinkedQueue();
private final Queue parentWatchers = new ConcurrentLinkedQueue();
private final AtomicLong instanceIndex = new AtomicLong();
private volatile long connectionStartMs = 0;
ConnectionState(ZookeeperFactory zookeeperFactory, EnsembleProvider ensembleProvider, int sessionTimeoutMs, int connectionTimeoutMs, Watcher parentWatcher, AtomicReference tracer, boolean canBeReadOnly)
{
this.ensembleProvider = ensembleProvider;
this.sessionTimeoutMs = sessionTimeoutMs;
this.connectionTimeoutMs = connectionTimeoutMs;
this.tracer = tracer;
if ( parentWatcher != null )
{
parentWatchers.offer(parentWatcher);
}
zooKeeper = new HandleHolder(zookeeperFactory, this, ensembleProvider, sessionTimeoutMs, canBeReadOnly);
}
ZooKeeper getZooKeeper() throws Exception
{
if ( SessionFailRetryLoop.sessionForThreadHasFailed() )
{
throw new SessionFailRetryLoop.SessionFailedException();
}
Exception exception = backgroundExceptions.poll();
if ( exception != null )
{
log.error("Background exception caught", exception);
tracer.get().addCount("background-exceptions", 1);
throw exception;
}
boolean localIsConnected = isConnected.get();
if ( !localIsConnected )
{
checkTimeouts();
}
return zooKeeper.getZooKeeper();
}
boolean isConnected()
{
return isConnected.get();
}
void start() throws Exception
{
log.debug("Starting");
ensembleProvider.start();
reset();
}
@Override
public void close() throws IOException
{
log.debug("Closing");
CloseableUtils.closeQuietly(ensembleProvider);
try
{
zooKeeper.closeAndClear();
}
catch ( Exception e )
{
throw new IOException(e);
}
finally
{
isConnected.set(false);
}
}
void addParentWatcher(Watcher watcher)
{
parentWatchers.offer(watcher);
}
void removeParentWatcher(Watcher watcher)
{
parentWatchers.remove(watcher);
}
long getInstanceIndex()
{
return instanceIndex.get();
}
@Override
public void process(WatchedEvent event)
{
if ( LOG_EVENTS )
{
log.debug("ConnectState watcher: " + event);
}
for ( Watcher parentWatcher : parentWatchers )
{
TimeTrace timeTrace = new TimeTrace("connection-state-parent-process", tracer.get());
parentWatcher.process(event);
timeTrace.commit();
}
boolean wasConnected = isConnected.get();
boolean newIsConnected = wasConnected;
if ( event.getType() == Watcher.Event.EventType.None )
{
newIsConnected = checkState(event.getState(), wasConnected);
}
if ( newIsConnected != wasConnected )
{
isConnected.set(newIsConnected);
connectionStartMs = System.currentTimeMillis();
}
}
EnsembleProvider getEnsembleProvider()
{
return ensembleProvider;
}
private synchronized void checkTimeouts() throws Exception
{
int minTimeout = Math.min(sessionTimeoutMs, connectionTimeoutMs);
long elapsed = System.currentTimeMillis() - connectionStartMs;
if ( elapsed >= minTimeout )
{
if ( zooKeeper.hasNewConnectionString() )
{
handleNewConnectionString();
}
else
{
int maxTimeout = Math.max(sessionTimeoutMs, connectionTimeoutMs);
if ( elapsed > maxTimeout )
{
if ( !Boolean.getBoolean(DebugUtils.PROPERTY_DONT_LOG_CONNECTION_ISSUES) )
{
log.warn(String.format("Connection attempt unsuccessful after %d (greater than max timeout of %d). Resetting connection and trying again with a new connection.", elapsed, maxTimeout));
}
reset();
}
else
{
KeeperException.ConnectionLossException connectionLossException = new CuratorConnectionLossException();
if ( !Boolean.getBoolean(DebugUtils.PROPERTY_DONT_LOG_CONNECTION_ISSUES) )
{
log.error(String.format("Connection timed out for connection string (%s) and timeout (%d) / elapsed (%d)", zooKeeper.getConnectionString(), connectionTimeoutMs, elapsed), connectionLossException);
}
tracer.get().addCount("connections-timed-out", 1);
throw connectionLossException;
}
}
}
}
private synchronized void reset() throws Exception
{
log.debug("reset");
instanceIndex.incrementAndGet();
isConnected.set(false);
connectionStartMs = System.currentTimeMillis();
zooKeeper.closeAndReset();
zooKeeper.getZooKeeper(); // initiate connection
}
private boolean checkState(Event.KeeperState state, boolean wasConnected)
{
boolean isConnected = wasConnected;
boolean checkNewConnectionString = true;
switch ( state )
{
default:
case Disconnected:
{
isConnected = false;
break;
}
case SyncConnected:
case ConnectedReadOnly:
{
isConnected = true;
break;
}
case AuthFailed:
{
isConnected = false;
log.error("Authentication failed");
break;
}
case Expired:
{
isConnected = false;
checkNewConnectionString = false;
handleExpiredSession();
break;
}
case SaslAuthenticated:
{
// NOP
break;
}
}
if ( checkNewConnectionString && zooKeeper.hasNewConnectionString() )
{
handleNewConnectionString();
}
return isConnected;
}
private void handleNewConnectionString()
{
log.info("Connection string changed");
tracer.get().addCount("connection-string-changed", 1);
try
{
reset();
}
catch ( Exception e )
{
queueBackgroundException(e);
}
}
private void handleExpiredSession()
{
log.warn("Session expired event received");
tracer.get().addCount("session-expired", 1);
try
{
reset();
}
catch ( Exception e )
{
queueBackgroundException(e);
}
}
@SuppressWarnings({"ThrowableResultOfMethodCallIgnored"})
private void queueBackgroundException(Exception e)
{
while ( backgroundExceptions.size() >= MAX_BACKGROUND_EXCEPTIONS )
{
backgroundExceptions.poll();
}
backgroundExceptions.offer(e);
}
}
