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/*
* 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.ha.session;
import java.io.IOException;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleState;
import org.apache.catalina.Session;
import org.apache.catalina.ha.CatalinaCluster;
import org.apache.catalina.ha.ClusterManager;
import org.apache.catalina.ha.ClusterMessage;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.realm.GenericPrincipal;
import org.apache.catalina.session.StandardManager;
import org.apache.catalina.tribes.io.ReplicationStream;
import org.apache.catalina.util.LifecycleBase;
import java.io.ByteArrayInputStream;
import org.apache.catalina.Loader;
/**
* Title: Tomcat Session Replication for Tomcat 4.0
* Description: A very simple straight forward implementation of
* session replication of servers in a cluster.
* This session replication is implemented "live". By live
* I mean, when a session attribute is added into a session on Node A
* a message is broadcasted to other messages and setAttribute is called on the
* replicated sessions.
* A full description of this implementation can be found under
* Filip's Tomcat Page
*
* Copyright: See apache license
* Company: www.filip.net
*
* Description: The InMemoryReplicationManager is a session manager that replicated
* session information in memory.
*
* The InMemoryReplicationManager extends the StandardManager hence it allows for us
* to inherit all the basic session management features like expiration, session listeners etc
*
* To communicate with other nodes in the cluster, the InMemoryReplicationManager sends out 7 different type of multicast messages
* all defined in the SessionMessage class.
* When a session is replicated (not an attribute added/removed) the session is serialized into
* a byte array using the StandardSession.readObjectData, StandardSession.writeObjectData methods.
*
* @author Filip Hanik
* @author Bela Ban (modifications for synchronous replication)
* @version 1.0 for TC 4.0
*/
public class SimpleTcpReplicationManager extends StandardManager implements ClusterManager
{
public static final org.apache.juli.logging.Log log = org.apache.juli.logging.LogFactory.getLog( SimpleTcpReplicationManager.class );
//the channel configuration
protected String mChannelConfig = null;
//the group name
protected String mGroupName = "TomcatReplication";
//log to screen
protected boolean mPrintToScreen = true;
protected boolean defaultMode = false;
/** Use synchronous rather than asynchronous replication. Every session modification (creation, change, removal etc)
* will be sent to all members. The call will then wait for max milliseconds, or forever (if timeout is 0) for
* all responses.
*/
protected boolean synchronousReplication=true;
/** Set to true if we don't want the sessions to expire on shutdown */
protected boolean mExpireSessionsOnShutdown = true;
protected boolean useDirtyFlag = false;
protected String name;
protected boolean distributable = true;
protected CatalinaCluster cluster;
protected java.util.HashMap invalidatedSessions =
new java.util.HashMap();
/**
* Flag to keep track if the state has been transferred or not
* Assumes false.
*/
protected boolean stateTransferred = false;
private boolean notifyListenersOnReplication;
private boolean sendClusterDomainOnly = true ;
/**
* Constructor, just calls super()
*
*/
public SimpleTcpReplicationManager()
{
super();
}
public boolean doDomainReplication() {
return sendClusterDomainOnly;
}
/**
* @param sendClusterDomainOnly The sendClusterDomainOnly to set.
*/
public void setDomainReplication(boolean sendClusterDomainOnly) {
this.sendClusterDomainOnly = sendClusterDomainOnly;
}
/**
* @return Returns the defaultMode.
*/
public boolean isDefaultMode() {
return defaultMode;
}
/**
* @param defaultMode The defaultMode to set.
*/
public void setDefaultMode(boolean defaultMode) {
this.defaultMode = defaultMode;
}
public void setUseDirtyFlag(boolean usedirtyflag)
{
this.useDirtyFlag = usedirtyflag;
}
public void setExpireSessionsOnShutdown(boolean expireSessionsOnShutdown)
{
mExpireSessionsOnShutdown = expireSessionsOnShutdown;
}
public void setCluster(CatalinaCluster cluster) {
if(log.isDebugEnabled())
log.debug("Cluster associated with SimpleTcpReplicationManager");
this.cluster = cluster;
}
public boolean getExpireSessionsOnShutdown()
{
return mExpireSessionsOnShutdown;
}
public void setPrintToScreen(boolean printtoscreen)
{
if(log.isDebugEnabled())
log.debug("Setting screen debug to:"+printtoscreen);
mPrintToScreen = printtoscreen;
}
public void setSynchronousReplication(boolean flag)
{
synchronousReplication=flag;
}
/**
* Override persistence since they don't go hand in hand with replication for now.
*/
@Override
public void unload() throws IOException {
if ( !getDistributable() ) {
super.unload();
}
}
/**
* Creates a HTTP session.
* Most of the code in here is copied from the StandardManager.
* This is not pretty, yeah I know, but it was necessary since the
* StandardManager had hard coded the session instantiation to the a
* StandardSession, when we actually want to instantiate a ReplicatedSession
* If the call comes from the Tomcat servlet engine, a SessionMessage goes out to the other
* nodes in the cluster that this session has been created.
* @param notify - if set to true the other nodes in the cluster will be notified.
* This flag is needed so that we can create a session before we deserialize
* a replicated one
*
* @see ReplicatedSession
*/
protected Session createSession(String sessionId, boolean notify, boolean setId)
{
//inherited from the basic manager
if ((getMaxActiveSessions() >= 0) &&
(sessions.size() >= getMaxActiveSessions()))
throw new IllegalStateException(sm.getString("standardManager.createSession.ise"));
Session session = new ReplicatedSession(this);
// Initialize the properties of the new session and return it
session.setNew(true);
session.setValid(true);
session.setCreationTime(System.currentTimeMillis());
session.setMaxInactiveInterval(this.maxInactiveInterval);
if(sessionId == null)
sessionId = generateSessionId();
if ( setId ) session.setId(sessionId);
if ( notify && (cluster!=null) ) {
((ReplicatedSession)session).setIsDirty(true);
}
return (session);
}//createSession
//=========================================================================
// OVERRIDE THESE METHODS TO IMPLEMENT THE REPLICATION
//=========================================================================
/**
* Construct and return a new session object, based on the default
* settings specified by this Manager's properties. The session
* id will be assigned by this method, and available via the getId()
* method of the returned session. If a new session cannot be created
* for any reason, return null.
*
* @exception IllegalStateException if a new session cannot be
* instantiated for any reason
*/
@Override
public Session createSession(String sessionId)
{
//create a session and notify the other nodes in the cluster
Session session = createSession(sessionId,getDistributable(),true);
add(session);
return session;
}
public void sessionInvalidated(String sessionId) {
synchronized ( invalidatedSessions ) {
invalidatedSessions.put(sessionId, sessionId);
}
}
public String[] getInvalidatedSessions() {
synchronized ( invalidatedSessions ) {
String[] result = new String[invalidatedSessions.size()];
invalidatedSessions.values().toArray(result);
return result;
}
}
public ClusterMessage requestCompleted(String sessionId)
{
if ( !getDistributable() ) {
log.warn("Received requestCompleted message, although this context["+
getName()+"] is not distributable. Ignoring message");
return null;
}
try
{
if ( invalidatedSessions.get(sessionId) != null ) {
synchronized ( invalidatedSessions ) {
invalidatedSessions.remove(sessionId);
SessionMessage msg = new SessionMessageImpl(name,
SessionMessage.EVT_SESSION_EXPIRED,
null,
sessionId,
sessionId);
return msg;
}
} else {
ReplicatedSession session = (ReplicatedSession) findSession(
sessionId);
if (session != null) {
//return immediately if the session is not dirty
if (useDirtyFlag && (!session.isDirty())) {
//but before we return doing nothing,
//see if we should send
//an updated last access message so that
//sessions across cluster dont expire
long interval = session.getMaxInactiveInterval();
long lastaccdist = System.currentTimeMillis() -
session.getLastAccessWasDistributed();
if ( ((interval*1000) / lastaccdist)< 3 ) {
SessionMessage accmsg = new SessionMessageImpl(name,
SessionMessage.EVT_SESSION_ACCESSED,
null,
sessionId,
sessionId);
session.setLastAccessWasDistributed(System.currentTimeMillis());
return accmsg;
}
return null;
}
session.setIsDirty(false);
if (log.isDebugEnabled()) {
try {
log.debug("Sending session to cluster=" + session);
}
catch (Exception ignore) {}
}
SessionMessage msg = new SessionMessageImpl(name,
SessionMessage.EVT_SESSION_CREATED,
writeSession(session),
session.getIdInternal(),
session.getIdInternal());
return msg;
} //end if
}//end if
}
catch (Exception x )
{
log.error("Unable to replicate session",x);
}
return null;
}
/**
* Serialize a session into a byte array
* This method simple calls the writeObjectData method on the session
* and returns the byte data from that call
* @param session - the session to be serialized
* @return a byte array containing the session data, null if the serialization failed
*/
protected byte[] writeSession( Session session )
{
try
{
java.io.ByteArrayOutputStream session_data = new java.io.ByteArrayOutputStream();
java.io.ObjectOutputStream session_out = new java.io.ObjectOutputStream(session_data);
session_out.flush();
boolean hasPrincipal = session.getPrincipal() != null;
session_out.writeBoolean(hasPrincipal);
if ( hasPrincipal )
{
session_out.writeObject(SerializablePrincipal.createPrincipal((GenericPrincipal)session.getPrincipal()));
}//end if
((ReplicatedSession)session).writeObjectData(session_out);
return session_data.toByteArray();
}
catch ( Exception x )
{
log.error("Failed to serialize the session!",x);
}
return null;
}
/**
* Open Stream and use correct ClassLoader (Container) Switch
* ThreadClassLoader
*
* @param data
* @return The object input stream
* @throws IOException
*/
public ReplicationStream getReplicationStream(byte[] data) throws IOException {
return getReplicationStream(data,0,data.length);
}
public ReplicationStream getReplicationStream(byte[] data, int offset, int length) throws IOException {
ByteArrayInputStream fis =null;
ReplicationStream ois = null;
Loader loader = null;
ClassLoader classLoader = null;
//fix to be able to run the DeltaManager
//stand alone without a container.
//use the Threads context class loader
if (container != null)
loader = container.getLoader();
if (loader != null)
classLoader = loader.getClassLoader();
else
classLoader = Thread.currentThread().getContextClassLoader();
//end fix
fis = new ByteArrayInputStream(data, offset, length);
if ( classLoader == Thread.currentThread().getContextClassLoader() ) {
ois = new ReplicationStream(fis, new ClassLoader[] {classLoader});
} else {
ois = new ReplicationStream(fis, new ClassLoader[] {classLoader,Thread.currentThread().getContextClassLoader()});
}
return ois;
}
/**
* Reinstantiates a serialized session from the data passed in.
* This will first call createSession() so that we get a fresh instance with all
* the managers set and all the transient fields validated.
* Then it calls Session.readObjectData(byte[]) to deserialize the object
* @param data - a byte array containing session data
* @return a valid Session object, null if an error occurs
*
*/
protected Session readSession( byte[] data, String sessionId )
{
try
{
ReplicationStream session_in = getReplicationStream(data);
Session session = sessionId!=null?this.findSession(sessionId):null;
boolean isNew = (session==null);
//clear the old values from the existing session
if ( session!=null ) {
ReplicatedSession rs = (ReplicatedSession)session;
rs.expire(false); //cleans up the previous values, since we are not doing removes
session = null;
}//end if
if (session==null) {
session = createSession(null,false, false);
sessions.remove(session.getIdInternal());
}
boolean hasPrincipal = session_in.readBoolean();
SerializablePrincipal p = null;
if ( hasPrincipal )
p = (SerializablePrincipal)session_in.readObject();
((ReplicatedSession)session).readObjectData(session_in);
if ( hasPrincipal )
session.setPrincipal(p.getPrincipal());
((ReplicatedSession)session).setId(sessionId,isNew);
ReplicatedSession rsession = (ReplicatedSession)session;
rsession.setAccessCount(1);
session.setManager(this);
session.setValid(true);
rsession.setLastAccessedTime(System.currentTimeMillis());
rsession.setThisAccessedTime(System.currentTimeMillis());
((ReplicatedSession)session).setAccessCount(0);
session.setNew(false);
if(log.isTraceEnabled())
log.trace("Session loaded id="+sessionId +
" actualId="+session.getId()+
" exists="+this.sessions.containsKey(sessionId)+
" valid="+rsession.isValid());
return session;
}
catch ( Exception x )
{
log.error("Failed to deserialize the session!",x);
}
return null;
}
@Override
public String getName() {
return this.name;
}
/**
* Start this component and implement the requirements
* of {@link LifecycleBase#startInternal()}.
*
* Starts the cluster communication channel, this will connect with the
* other nodes in the cluster, and request the current session state to be
* transferred to this node.
*
* @exception LifecycleException if this component detects a fatal error
* that prevents this component from being used
*/
@Override
protected synchronized void startInternal() throws LifecycleException {
try {
if(log.isInfoEnabled())
log.info("Starting clustering manager...:"+getName());
if ( cluster == null ) {
log.error("Starting... no cluster associated with this context:"+getName());
setState(LifecycleState.FAILED);
return;
}
cluster.registerManager(this);
if (cluster.getMembers().length > 0) {
Member mbr = cluster.getMembers()[0];
SessionMessage msg =
new SessionMessageImpl(this.getName(),
SessionMessage.EVT_GET_ALL_SESSIONS,
null,
"GET-ALL",
"GET-ALL-"+this.getName());
cluster.send(msg, mbr);
if(log.isWarnEnabled())
log.warn("Manager["+getName()+"], requesting session state from "+mbr+
". This operation will timeout if no session state has been received within "+
"60 seconds");
long reqStart = System.currentTimeMillis();
long reqNow = 0;
boolean isTimeout=false;
do {
try {
Thread.sleep(100);
}catch ( Exception sleep) {}
reqNow = System.currentTimeMillis();
isTimeout=((reqNow-reqStart)>(1000*60));
} while ( (!isStateTransferred()) && (!isTimeout));
if ( isTimeout || (!isStateTransferred()) ) {
log.error("Manager["+getName()+"], No session state received, timing out.");
}else {
if(log.isInfoEnabled())
log.info("Manager["+getName()+"], session state received in "+(reqNow-reqStart)+" ms.");
}
} else {
if(log.isInfoEnabled())
log.info("Manager["+getName()+"], skipping state transfer. No members active in cluster group.");
}//end if
super.startInternal();
} catch ( Exception x ) {
log.error("Unable to start SimpleTcpReplicationManager",x);
setState(LifecycleState.FAILED);
}
}
/**
* Stop this component and implement the requirements
* of {@link LifecycleBase#stopInternal()}.
*
* This will disconnect the cluster communication channel and stop the
* listener thread.
*
* @exception LifecycleException if this component detects a fatal error
* that prevents this component from being used
*/
@Override
protected synchronized void stopInternal() throws LifecycleException {
super.stopInternal();
try
{
this.sessions.clear();
cluster.removeManager(this);
}
catch ( Exception x )
{
log.error("Unable to stop SimpleTcpReplicationManager",x);
}
}
@Override
public void setDistributable(boolean dist) {
this.distributable = dist;
}
@Override
public boolean getDistributable() {
return distributable;
}
/**
* This method is called by the received thread when a SessionMessage has
* been received from one of the other nodes in the cluster.
* @param msg - the message received
* @param sender - the sender of the message, this is used if we receive a
* EVT_GET_ALL_SESSION message, so that we only reply to
* the requesting node
*/
protected void messageReceived( SessionMessage msg, Member sender ) {
try {
if(log.isInfoEnabled()) {
log.debug("Received SessionMessage of type="+msg.getEventTypeString());
log.debug("Received SessionMessage sender="+sender);
}
switch ( msg.getEventType() ) {
case SessionMessage.EVT_GET_ALL_SESSIONS: {
//get a list of all the session from this manager
Object[] sessions = findSessions();
java.io.ByteArrayOutputStream bout = new java.io.ByteArrayOutputStream();
java.io.ObjectOutputStream oout = new java.io.ObjectOutputStream(bout);
oout.writeInt(sessions.length);
for (int i=0; i
