jvmroutebindervalve.java

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/*
 * Copyright 1999,2004-2005 The Apache Software Foundation.
 * 
 * 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 org.apache.catalina.ha.session;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;

import org.apache.catalina.Container;
import org.apache.catalina.Context;
import org.apache.catalina.Engine;
import org.apache.catalina.Globals;
import org.apache.catalina.Host;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.Manager;
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.ha.ClusterValve;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.session.ManagerBase;
import org.apache.catalina.util.LifecycleSupport;
import org.apache.catalina.util.StringManager;
import org.apache.catalina.valves.ValveBase;

/**
 * Valve to handle Tomcat jvmRoute takeover using mod_jk module after node
 * failure. After a node crashed the next request going to other cluster node.
 * Now the answering from apache is slower ( make some error handshaking. Very
 * bad with apache at my windows.). We rewrite now the cookie jsessionid
 * information to the backup cluster node. After the next response all client
 * request goes direct to the backup node. The change sessionid send also to all
 * other cluster nodes. Well, now the session stickyness work directly to the
 * backup node and traffic don't go back too restarted cluster nodes!
 * 
 * At all cluster node you must configure the as ClusterListener since 5.5.10
 * {@link org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener JvmRouteSessionIDBinderListener}
 * or before with
 * org.apache.catalina.ha.session.JvmRouteSessionIDBinderListenerLifecycle.
 * 
 * Add this Valve to your host definition at conf/server.xml .
 * 
 * Since 5.5.10 as direct cluster valve:<br/>
 * <pre>
 *  &lt;Cluster&gt;
 *  &lt;Valve className=&quot;org.apache.catalina.ha.session.JvmRouteBinderValve&quot; /&gt;  
 *  &lt;/Cluster&gt;
 * </pre>
 * <br />
 * Before 5.5.10 as Host element:<br/>
 * <pre>
 *  &lt;Hostr&gt;
 *  &lt;Valve className=&quot;org.apache.catalina.ha.session.JvmRouteBinderValve&quot; /&gt;  
 *  &lt;/Hostr&gt;
 * </pre>
 * 
 * Trick:<br/>
 * You can enable this mod_jk turnover mode via JMX before you drop a node to all backup nodes!
 * Set enable true on all JvmRouteBinderValve backups, disable worker at mod_jk 
 * and then drop node and restart it! Then enable mod_jk Worker and disable JvmRouteBinderValves again. 
 * This use case means that only requested session are migrated.
 * 
 * @author Peter Rossbach
 * @version $Revision: 326110 $ $Date: 2005-10-18 09:08:36 -0500 (Tue, 18 Oct 2005) $
 */
public class JvmRouteBinderValve extends ValveBase implements ClusterValve, Lifecycle {

    /*--Static Variables----------------------------------------*/
    public static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory
            .getLog(JvmRouteBinderValve.class);

    /**
     * The descriptive information about this implementation.
     */
    protected static final String info = "org.apache.catalina.ha.session.JvmRouteBinderValve/1.2";

    /*--Instance Variables--------------------------------------*/

    /**
     * the cluster
     */
    protected CatalinaCluster cluster;

    /**
     * The string manager for this package.
     */
    protected StringManager sm = StringManager.getManager(Constants.Package);

    /**
     * Has this component been started yet?
     */
    protected boolean started = false;

    /**
     * enabled this component
     */
    protected boolean enabled = true;

    /**
     * number of session that no at this tomcat instanz hosted
     */
    protected long numberOfSessions = 0;

    protected String sessionIdAttribute = "org.apache.catalina.ha.session.JvmRouteOrignalSessionID";

    /**
     * The lifecycle event support for this component.
     */
    protected LifecycleSupport lifecycle = new LifecycleSupport(this);

    /*--Logic---------------------------------------------------*/

    /**
     * Return descriptive information about this implementation.
     */
    public String getInfo() {

        return (info);

    }

    /**
     * set session id attribute to failed node for request.
     * 
     * @return Returns the sessionIdAttribute.
     */
    public String getSessionIdAttribute() {
        return sessionIdAttribute;
    }

    /**
     * get name of failed reqeust session attribute
     * 
     * @param sessionIdAttribute
     *            The sessionIdAttribute to set.
     */
    public void setSessionIdAttribute(String sessionIdAttribute) {
        this.sessionIdAttribute = sessionIdAttribute;
    }

    /**
     * @return Returns the number of migrated sessions.
     */
    public long getNumberOfSessions() {
        return numberOfSessions;
    }

    /**
     * @return Returns the enabled.
     */
    public boolean getEnabled() {
        return enabled;
    }

    /**
     * @param enabled
     *            The enabled to set.
     */
    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }

    /**
     * Detect possible the JVMRoute change at cluster backup node..
     * 
     * @param request
     *            tomcat request being processed
     * @param response
     *            tomcat response being processed
     * @exception IOException
     *                if an input/output error has occurred
     * @exception ServletException
     *                if a servlet error has occurred
     */
    public void invoke(Request request, Response response) throws IOException,
            ServletException {

         if (getEnabled() 
             && getCluster() != null
             && request.getContext() != null
             && request.getContext().getDistributable() ) {
             // valve cluster can access manager - other cluster handle turnover 
             // at host level - hopefully!
             Manager manager = request.getContext().getManager();
             if (manager != null && manager instanceof ClusterManager
                     && getCluster().getManager(((ClusterManager)manager).getName()) != null)
                 handlePossibleTurnover(request, response);
        }
        // Pass this request on to the next valve in our pipeline
        getNext().invoke(request, response);
    }

    /**
     * handle possible session turn over.
     * 
     * @see JvmRouteBinderValve#handleJvmRoute(Request, Response, String, String)
     * @param request current request
     * @param response current response
     */
    protected void handlePossibleTurnover(Request request, Response response) {
        Session session = request.getSessionInternal(false);
        if (session != null) {
            long t1 = System.currentTimeMillis();
            String jvmRoute = getLocalJvmRoute(request);
            if (jvmRoute == null) {
                if (log.isWarnEnabled())
                    log.warn(sm.getString("jvmRoute.missingJvmRouteAttribute"));
                return;
            }
            handleJvmRoute( request, response,session.getIdInternal(), jvmRoute);
            if (log.isDebugEnabled()) {
                long t2 = System.currentTimeMillis();
                long time = t2 - t1;
                log.debug(sm.getString("jvmRoute.turnoverInfo", new Long(time)));
            }
        }
    }

    /**
     * get jvmroute from engine
     * 
     * @param request current request
     * @return return jvmRoute from ManagerBase or null
     */
    protected String getLocalJvmRoute(Request request) {
        Manager manager = getManager(request);
        if(manager instanceof ManagerBase)
            return ((ManagerBase) manager).getJvmRoute();
        return null ;
    }

    /**
     * get Cluster DeltaManager
     * 
     * @param request current request
     * @return manager or null
     */
    protected Manager getManager(Request request) {
        Manager manager = request.getContext().getManager();
        if (log.isDebugEnabled()) {
            if(manager != null)
                log.debug(sm.getString("jvmRoute.foundManager", manager,  request.getContext().getName()));
            else 
                log.debug(sm.getString("jvmRoute.notFoundManager", manager,  request.getContext().getName()));
        }
        return manager;
    }

    /**
     * @return Returns the cluster.
     */
    public CatalinaCluster getCluster() {
        return cluster;
    }