/*
* 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.catalina.tribes.membership;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import org.apache.catalina.tribes.MembershipListener;
import java.util.Arrays;
import java.net.SocketTimeoutException;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.Channel;
import java.net.InetSocketAddress;
/**
* A <b>membership</b> implementation using simple multicast.
* This is the representation of a multicast membership service.
* This class is responsible for maintaining a list of active cluster nodes in the cluster.
* If a node fails to send out a heartbeat, the node will be dismissed.
* This is the low level implementation that handles the multicasting sockets.
* Need to fix this, could use java.nio and only need one thread to send and receive, or
* just use a timeout on the receive
* @author Filip Hanik
* @version $Revision: 467222 $, $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
*/
public class McastServiceImpl
{
private static org.apache.juli.logging.Log log =
org.apache.juli.logging.LogFactory.getLog( McastService.class );
protected static int MAX_PACKET_SIZE = 65535;
/**
* Internal flag used for the listen thread that listens to the multicasting socket.
*/
protected boolean doRunSender = false;
protected boolean doRunReceiver = false;
protected int startLevel = 0;
/**
* Socket that we intend to listen to
*/
protected MulticastSocket socket;
/**
* The local member that we intend to broad cast over and over again
*/
protected MemberImpl member;
/**
* The multicast address
*/
protected InetAddress address;
/**
* The multicast port
*/
protected int port;
/**
* The time it takes for a member to expire.
*/
protected long timeToExpiration;
/**
* How often to we send out a broadcast saying we are alive, must be smaller than timeToExpiration
*/
protected long sendFrequency;
/**
* Reuse the sendPacket, no need to create a new one everytime
*/
protected DatagramPacket sendPacket;
/**
* Reuse the receivePacket, no need to create a new one everytime
*/
protected DatagramPacket receivePacket;
/**
* The membership, used so that we calculate memberships when they arrive or don't arrive
*/
protected Membership membership;
/**
* The actual listener, for callback when shits goes down
*/
protected MembershipListener service;
/**
* Thread to listen for pings
*/
protected ReceiverThread receiver;
/**
* Thread to send pings
*/
protected SenderThread sender;
/**
* When was the service started
*/
protected long serviceStartTime = System.currentTimeMillis();
/**
* Time to live for the multicast packets that are being sent out
*/
protected int mcastTTL = -1;
/**
* Read timeout on the mcast socket
*/
protected int mcastSoTimeout = -1;
/**
* bind address
*/
protected InetAddress mcastBindAddress = null;
/**
* Create a new mcast service impl
* @param member - the local member
* @param sendFrequency - the time (ms) in between pings sent out
* @param expireTime - the time (ms) for a member to expire
* @param port - the mcast port
* @param bind - the bind address (not sure this is used yet)
* @param mcastAddress - the mcast address
* @param service - the callback service
* @throws IOException
*/
public McastServiceImpl(
MemberImpl member,
long sendFrequency,
long expireTime,
int port,
InetAddress bind,
InetAddress mcastAddress,
int ttl,
int soTimeout,
MembershipListener service)
throws IOException {
this.member = member;
this.address = mcastAddress;
this.port = port;
this.mcastSoTimeout = soTimeout;
this.mcastTTL = ttl;
this.mcastBindAddress = bind;
this.timeToExpiration = expireTime;
this.service = service;
this.sendFrequency = sendFrequency;
setupSocket();
sendPacket = new DatagramPacket(new byte[MAX_PACKET_SIZE],MAX_PACKET_SIZE);
sendPacket.setAddress(address);
sendPacket.setPort(port);
receivePacket = new DatagramPacket(new byte[MAX_PACKET_SIZE],MAX_PACKET_SIZE);
receivePacket.setAddress(address);
receivePacket.setPort(port);
membership = new Membership(member);
}
protected void setupSocket() throws IOException {
if (mcastBindAddress != null) socket = new MulticastSocket(new InetSocketAddress(mcastBindAddress, port));
else socket = new MulticastSocket(port);
socket.setLoopbackMode(false); //hint that we don't need loop back messages
if (mcastBindAddress != null) {
if(log.isInfoEnabled())
log.info("Setting multihome multicast interface to:" +mcastBindAddress);
socket.setInterface(mcastBindAddress);
} //end if
//force a so timeout so that we don't block forever
if ( mcastSoTimeout <= 0 ) mcastSoTimeout = (int)sendFrequency;
if(log.isInfoEnabled())
log.info("Setting cluster mcast soTimeout to "+mcastSoTimeout);
socket.setSoTimeout(mcastSoTimeout);
if ( mcastTTL >= 0 ) {
if(log.isInfoEnabled())
log.info("Setting cluster mcast TTL to " + mcastTTL);
socket.setTimeToLive(mcastTTL);
}
}
/**
* Start the service
* @param level 1 starts the receiver, level 2 starts the sender
* @throws IOException if the service fails to start
* @throws IllegalStateException if the service is already started
*/
public synchronized void start(int level) throws IOException {
boolean valid = false;
if ( (level & Channel.MBR_RX_SEQ)==Channel.MBR_RX_SEQ ) {
if ( receiver != null ) throw new IllegalStateException("McastService.receive already running.");
if ( sender == null ) socket.joinGroup(address);
doRunReceiver = true;
receiver = new ReceiverThread();
receiver.setDaemon(true);
receiver.start();
valid = true;
}
if ( (level & Channel.MBR_TX_SEQ)==Channel.MBR_TX_SEQ ) {
if ( sender != null ) throw new IllegalStateException("McastService.send already running.");
if ( receiver == null ) socket.joinGroup(address);
//make sure at least one packet gets out there
send(false);
doRunSender = true;
serviceStartTime = System.currentTimeMillis();
sender = new SenderThread(sendFrequency);
sender.setDaemon(true);
sender.start();
//we have started the receiver, but not yet waited for membership to establish
valid = true;
}
if (!valid) {
throw new IllegalArgumentException("Invalid start level. Only acceptable levels are Channel.MBR_RX_SEQ and Channel.MBR_TX_SEQ");
}
//pause, once or twice
waitForMembers(level);
startLevel = (startLevel | level);
}
private void waitForMembers(int level) {
long memberwait = sendFrequency*2;
if(log.isInfoEnabled())
log.info("Sleeping for "+memberwait+" milliseconds to establish cluster membership, start level:"+level);
try {Thread.sleep(memberwait);}catch (InterruptedException ignore){}
if(log.isInfoEnabled())
log.info("Done sleeping, membership established, start level:"+level);
}
/**
* Stops the service
* @throws IOException if the service fails to disconnect from the sockets
*/
public synchronized boolean stop(int level) throws IOException {
boolean valid = false;
if ( (level & Channel.MBR_RX_SEQ)==Channel.MBR_RX_SEQ ) {
valid = true;
doRunReceiver = false;
if ( receiver !=null ) receiver.interrupt();
receiver = null;
}
if ( (level & Channel.MBR_TX_SEQ)==Channel.MBR_TX_SEQ ) {
valid = true;
doRunSender = false;
if ( sender != null )sender.interrupt();
sender = null;
}
if (!valid) {
throw new IllegalArgumentException("Invalid stop level. Only acceptable levels are Channel.MBR_RX_SEQ and Channel.MBR_TX_SEQ");
}
startLevel = (startLevel & (~level));
//we're shutting down, send a shutdown message and close the socket
if ( startLevel == 0 ) {
//send a stop message
member.setCommand(Member.SHUTDOWN_PAYLOAD);
member.getData(true, true);
send(false);
//leave mcast group
try {socket.leaveGroup(address);}catch ( Exception ignore){}
serviceStartTime = Long.MAX_VALUE;
}
return (startLevel == 0);
}
/**
* Receive a datagram packet, locking wait
* @throws IOException
*/
public void receive() throws IOException {
try {
socket.receive(receivePacket);
if(receivePacket.getLength() > MAX_PACKET_SIZE) {
log.error("Multicast packet received was too long, dropping package:"+receivePacket.getLength());
} else {
byte[] data = new byte[receivePacket.getLength()];
System.arraycopy(receivePacket.getData(), receivePacket.getOffset(), data, 0, data.length);
final MemberImpl m = MemberImpl.getMember(data);
if (log.isTraceEnabled()) log.trace("Mcast receive ping from member " + m);
Thread t = null;
if (Arrays.equals(m.getCommand(), Member.SHUTDOWN_PAYLOAD)) {
if (log.isDebugEnabled()) log.debug("Member has shutdown:" + m);
membership.removeMember(m);
t = new Thread() {
public void run() {
service.memberDisappeared(m);
}
};
} else if (membership.memberAlive(m)) {
if (log.isDebugEnabled()) log.debug("Mcast add member " + m);
t = new Thread() {
public void run() {
service.memberAdded(m);
}
};
} //end if
if ( t != null ) t.start();
}
} catch (SocketTimeoutException x ) {
//do nothing, this is normal, we don't want to block forever
//since the receive thread is the same thread
//that does membership expiration
}
checkExpired();
}
protected Object expiredMutex = new Object();
protected void checkExpired() {
synchronized (expiredMutex) {
MemberImpl[] expired = membership.expire(timeToExpiration);
for (int i = 0; i < expired.length; i++) {
final MemberImpl member = expired[i];
if (log.isDebugEnabled())
log.debug("Mcast exipre member " + expired[i]);
try {
Thread t = new Thread() {
public void run() {
service.memberDisappeared(member);
}
};
t.start();
} catch (Exception x) {
log.error("Unable to process member disappeared message.", x);
}
}
}
}
/**
* Send a ping
* @throws Exception
*/
public void send(boolean checkexpired) throws IOException{
//ignore if we haven't started the sender
//if ( (startLevel&Channel.MBR_TX_SEQ) != Channel.MBR_TX_SEQ ) return;
member.inc();
if(log.isTraceEnabled())
log.trace("Mcast send ping from member " + member);
byte[] data = member.getData();
DatagramPacket p = new DatagramPacket(data,data.length);
p.setAddress(address);
p.setPort(port);
socket.send(p);
if ( checkexpired ) checkExpired();
}
public long getServiceStartTime() {
return this.serviceStartTime;
}
public class ReceiverThread extends Thread {
public ReceiverThread() {
super();
setName("Cluster-MembershipReceiver");
}
public void run() {
while ( doRunReceiver ) {
try {
receive();
} catch ( ArrayIndexOutOfBoundsException ax ) {
//we can ignore this, as it means we have an invalid package
//but we will log it to debug
if ( log.isDebugEnabled() )
log.debug("Invalid member mcast package.",ax);
} catch ( Exception x ) {
log.warn("Error receiving mcast package. Sleeping 500ms",x);
try { Thread.sleep(500); } catch ( Exception ignore ){}
}
}
}
}//class ReceiverThread
public class SenderThread extends Thread {
long time;
public SenderThread(long time) {
this.time = time;
setName("Cluster-MembershipSender");
}
public void run() {
while ( doRunSender ) {
try {
send(true);
} catch ( Exception x ) {
log.warn("Unable to send mcast message.",x);
}
try { Thread.sleep(time); } catch ( Exception ignore ) {}
}
}
}//class SenderThread
}
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