/**
*
* 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.hadoop.hbase.client;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.ClusterStatus;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.protobuf.generated.ClusterStatusProtos;
import org.apache.hadoop.hbase.util.Threads;
import org.jboss.netty.bootstrap.ConnectionlessBootstrap;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.channel.socket.DatagramChannel;
import org.jboss.netty.channel.socket.DatagramChannelFactory;
import org.jboss.netty.channel.socket.oio.OioDatagramChannelFactory;
import org.jboss.netty.handler.codec.protobuf.ProtobufDecoder;
import java.io.Closeable;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/**
* A class that receives the cluster status, and provide it as a set of service to the client.
* Today, manages only the dead server list.
* The class is abstract to allow multiple implementations, from ZooKeeper to multicast based.
*/
@InterfaceAudience.Private
class ClusterStatusListener implements Closeable {
private static final Log LOG = LogFactory.getLog(ClusterStatusListener.class);
private final List<ServerName> deadServers = new ArrayList<ServerName>();
private final DeadServerHandler deadServerHandler;
private final Listener listener;
/**
* The implementation class to use to read the status. Default is null.
*/
public static final String STATUS_LISTENER_CLASS = "hbase.status.listener.class";
public static final Class<? extends Listener> DEFAULT_STATUS_LISTENER_CLASS = null;
/**
* Class to be extended to manage a new dead server.
*/
public interface DeadServerHandler {
/**
* Called when a server is identified as dead. Called only once even if we receive the
* information multiple times.
*
* @param sn - the server name
*/
public void newDead(ServerName sn);
}
/**
* The interface to be implented by a listener of a cluster status event.
*/
static interface Listener extends Closeable {
/**
* Called to close the resources, if any. Cannot throw an exception.
*/
@Override
public void close();
/**
* Called to connect.
*
* @param conf Configuration to use.
* @throws IOException
*/
public void connect(Configuration conf) throws IOException;
}
public ClusterStatusListener(DeadServerHandler dsh, Configuration conf,
Class<? extends Listener> listenerClass) throws IOException {
this.deadServerHandler = dsh;
try {
Constructor<? extends Listener> ctor =
listenerClass.getConstructor(ClusterStatusListener.class);
this.listener = ctor.newInstance(this);
} catch (InstantiationException e) {
throw new IOException("Can't create listener " + listenerClass.getName(), e);
} catch (IllegalAccessException e) {
throw new IOException("Can't create listener " + listenerClass.getName(), e);
} catch (NoSuchMethodException e) {
throw new IllegalStateException();
} catch (InvocationTargetException e) {
throw new IllegalStateException();
}
this.listener.connect(conf);
}
/**
* Acts upon the reception of a new cluster status.
*
* @param ncs the cluster status
*/
public void receive(ClusterStatus ncs) {
if (ncs.getDeadServerNames() != null) {
for (ServerName sn : ncs.getDeadServerNames()) {
if (!isDeadServer(sn)) {
LOG.info("There is a new dead server: " + sn);
deadServers.add(sn);
if (deadServerHandler != null) {
deadServerHandler.newDead(sn);
}
}
}
}
}
@Override
public void close() {
listener.close();
}
/**
* Check if we know if a server is dead.
*
* @param sn the server name to check.
* @return true if we know for sure that the server is dead, false otherwise.
*/
public boolean isDeadServer(ServerName sn) {
if (sn.getStartcode() <= 0) {
return false;
}
for (ServerName dead : deadServers) {
if (dead.getStartcode() >= sn.getStartcode() &&
dead.getPort() == sn.getPort() &&
dead.getHostname().equals(sn.getHostname())) {
return true;
}
}
return false;
}
/**
* An implementation using a multicast message between the master & the client.
*/
class MultiCastListener implements Listener {
private DatagramChannel channel;
private final ExecutorService service = Executors.newSingleThreadExecutor(
Threads.newDaemonThreadFactory("hbase-client-clusterStatus-multiCastListener"));
public MultiCastListener() {
}
public void connect(Configuration conf) throws IOException {
// Can't be NiO with Netty today => not implemented in Netty.
DatagramChannelFactory f = new OioDatagramChannelFactory(service);
ConnectionlessBootstrap b = new ConnectionlessBootstrap(f);
b.setPipeline(Channels.pipeline(
new ProtobufDecoder(ClusterStatusProtos.ClusterStatus.getDefaultInstance()),
new ClusterStatusHandler()));
String mcAddress = conf.get(HConstants.STATUS_MULTICAST_ADDRESS,
HConstants.DEFAULT_STATUS_MULTICAST_ADDRESS);
int port = conf.getInt(HConstants.STATUS_MULTICAST_PORT,
HConstants.DEFAULT_STATUS_MULTICAST_PORT);
channel = (DatagramChannel) b.bind(new InetSocketAddress(mcAddress, port));
channel.getConfig().setReuseAddress(true);
InetAddress ina;
try {
ina = InetAddress.getByName(mcAddress);
} catch (UnknownHostException e) {
throw new IOException("Can't connect to " + mcAddress, e);
}
channel.joinGroup(ina);
}
@Override
public void close() {
if (channel != null) {
channel.close();
channel = null;
}
service.shutdown();
}
/**
* Class, conforming to the Netty framework, that manages the message received.
*/
private class ClusterStatusHandler extends SimpleChannelUpstreamHandler {
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
ClusterStatusProtos.ClusterStatus csp = (ClusterStatusProtos.ClusterStatus) e.getMessage();
ClusterStatus ncs = ClusterStatus.convert(csp);
receive(ncs);
}
/**
* Invoked when an exception was raised by an I/O thread or a
* {@link org.jboss.netty.channel.ChannelHandler}.
*/
@Override
public void exceptionCaught(
ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
LOG.error("Unexpected exception, continuing.", e.getCause());
}
}
}
}