java/org/apache/catalina/valves/LoadBalancerDrainingValve.java - tomcat - Git at Google

 /*
  * 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.valves;

 import java.io.IOException;

 import jakarta.servlet.ServletException;
 import jakarta.servlet.SessionCookieConfig;
 import jakarta.servlet.http.Cookie;
 import jakarta.servlet.http.HttpServletResponse;

 import org.apache.catalina.connector.Request;
 import org.apache.catalina.connector.Response;
 import org.apache.catalina.util.SessionConfig;

 /**
  * <p>
  * A Valve to detect situations where a load-balanced node receiving a request has been deactivated by the load balancer
  * (JK_LB_ACTIVATION=DIS) and the incoming request has no valid session.
  * </p>
  * <p>
  * In these cases, the user's session cookie should be removed if it exists, any ";jsessionid" parameter should be
  * removed from the request URI, and the client should be redirected to the same URI. This will cause the load-balanced
  * to re-balance the client to another server.
  * </p>
  * <p>
  * All this work is required because when the activation state of a node is DISABLED, the load-balancer will still send
  * requests to the node if they appear to have a session on that node. Since mod_jk doesn't actually know whether the
  * session id is valid, it will send the request blindly to the disabled node, which makes it take much longer to drain
  * the node than strictly necessary.
  * </p>
  * <p>
  * For testing purposes, a special cookie can be configured and used by a client to ignore the normal behavior of this
  * Valve and allow a client to get a new session on a DISABLED node. See {@link #setIgnoreCookieName} and
  * {@link #setIgnoreCookieValue} to configure those values.
  * </p>
  * <p>
  * This Valve should be installed earlier in the Valve pipeline than any authentication valves, as the redirection
  * should take place before an authentication valve would save a request to a protected resource.
  * </p>
  *
  * @see <a href="https://tomcat.apache.org/connectors-doc/generic_howto/loadbalancers.html">Load balancer
  *          documentation</a>
  */
 public class LoadBalancerDrainingValve extends ValveBase {

     /**
      * The request attribute key where the load-balancer's activation state can be found.
      */
     public static final String ATTRIBUTE_KEY_JK_LB_ACTIVATION = "JK_LB_ACTIVATION";

     /**
      * The HTTP response code that will be used to redirect the request back to the load-balancer for re-balancing.
      * Defaults to 307 (TEMPORARY_REDIRECT). HTTP status code 305 (USE_PROXY) might be an option, here. too.
      */
     private int _redirectStatusCode = HttpServletResponse.SC_TEMPORARY_REDIRECT;

     /**
      * The name of the cookie which can be set to ignore the "draining" action of this Filter. This will allow a client
      * to contact the server without being re-balanced to another server. The expected cookie value can be set in the
      * {@link #_ignoreCookieValue}. The cookie name and value must match to avoid being re-balanced.
      */
     private String _ignoreCookieName;

     /**
      * The value of the cookie which can be set to ignore the "draining" action of this Filter. This will allow a client
      * to contact the server without being re-balanced to another server. The expected cookie name can be set in the
      * {@link #_ignoreCookieName}. The cookie name and value must match to avoid being re-balanced.
      */
     private String _ignoreCookieValue;

     public LoadBalancerDrainingValve() {
         super(true); // Supports async
     }

     //
     // Configuration parameters
     //

     /**
      * Sets the HTTP response code that will be used to redirect the request back to the load-balancer for re-balancing.
      * Defaults to 307 (TEMPORARY_REDIRECT).
      *
      * @param code The code to use for the redirect
      */
     public void setRedirectStatusCode(int code) {
         _redirectStatusCode = code;
     }

     /**
      * Gets the name of the cookie that can be used to override the re-balancing behavior of this Valve when the current
      * node is in the DISABLED activation state.
      *
      * @return The cookie name used to ignore normal processing rules.
      *
      * @see #setIgnoreCookieValue
      */
     public String getIgnoreCookieName() {
         return _ignoreCookieName;
     }

     /**
      * Sets the name of the cookie that can be used to override the re-balancing behavior of this Valve when the current
      * node is in the DISABLED activation state. There is no default value for this setting: the ability to override the
      * re-balancing behavior of this Valve is <i>disabled</i> by default.
      *
      * @param cookieName The cookie name to use to ignore normal processing rules.
      *
      * @see #getIgnoreCookieValue
      */
     public void setIgnoreCookieName(String cookieName) {
         _ignoreCookieName = cookieName;
     }

     /**
      * Gets the expected value of the cookie that can be used to override the re-balancing behavior of this Valve when
      * the current node is in the DISABLED activation state.
      *
      * @return The cookie value used to ignore normal processing rules.
      *
      * @see #setIgnoreCookieValue
      */
     public String getIgnoreCookieValue() {
         return _ignoreCookieValue;
     }

     /**
      * Sets the expected value of the cookie that can be used to override the re-balancing behavior of this Valve when
      * the current node is in the DISABLED activation state. The "ignore" cookie's value <b>must</b> be exactly equal to
      * this value in order to allow the client to override the re-balancing behavior.
      *
      * @param cookieValue The cookie value to use to ignore normal processing rules.
      *
      * @see #getIgnoreCookieValue
      */
     public void setIgnoreCookieValue(String cookieValue) {
         _ignoreCookieValue = cookieValue;
     }

     @Override
     public void invoke(Request request, Response response) throws IOException, ServletException {
         if ("DIS".equals(request.getAttribute(ATTRIBUTE_KEY_JK_LB_ACTIVATION)) &&
                 !request.isRequestedSessionIdValid()) {

             if (containerLog.isDebugEnabled()) {
                 containerLog.debug(sm.getString("loadBalancerDrainingValve.draining"));
             }

             boolean ignoreRebalance = false;
             Cookie sessionCookie = null;

             final Cookie[] cookies = request.getCookies();

             final String sessionCookieName = SessionConfig.getSessionCookieName(request.getContext());

             if (null != cookies) {
                 for (Cookie cookie : cookies) {
                     final String cookieName = cookie.getName();
                     if (containerLog.isTraceEnabled()) {
                         containerLog.trace("Checking cookie " + cookieName + "=" + cookie.getValue());
                     }

                     if (sessionCookieName.equals(cookieName) &&
                             request.getRequestedSessionId().equals(cookie.getValue())) {
                         sessionCookie = cookie;
                     } else if (null != _ignoreCookieName && _ignoreCookieName.equals(cookieName) &&
                             null != _ignoreCookieValue && _ignoreCookieValue.equals(cookie.getValue())) {
                         // The client presenting a valid ignore-cookie value?
                         ignoreRebalance = true;
                     }
                 }
             }

             if (ignoreRebalance) {
                 if (containerLog.isDebugEnabled()) {
                     containerLog.debug(sm.getString("loadBalancerDrainingValve.skip", _ignoreCookieName));
                 }

                 getNext().invoke(request, response);

                 return;
             }

             // Kill any session cookie that was found
             // TODO: Consider implications of SSO cookies
             if (null != sessionCookie) {
                 sessionCookie.setPath(SessionConfig.getSessionCookiePath(request.getContext()));
                 sessionCookie.setMaxAge(0); // Delete
                 sessionCookie.setValue(""); // Purge the cookie's value
                 // Replicate logic used to set secure attribute for session cookies
                 SessionCookieConfig sessionCookieConfig =
                         request.getContext().getServletContext().getSessionCookieConfig();
                 sessionCookie.setSecure(request.isSecure() || sessionCookieConfig.isSecure());
                 response.addCookie(sessionCookie);
             }

             // Re-write the URI if it contains a ;jsessionid parameter
             String uri = request.getRequestURI();
             String sessionURIParamName = SessionConfig.getSessionUriParamName(request.getContext());
             if (uri.contains(";" + sessionURIParamName + "=")) {
                 uri = uri.replaceFirst(";" + sessionURIParamName + "=[^&?]*", "");
             }

             String queryString = request.getQueryString();

             if (null != queryString) {
                 uri = uri + "?" + queryString;
             }

             // NOTE: Do not call response.encodeRedirectURL or the bad
             // sessionid will be restored
             response.setHeader("Location", uri);
             response.setStatus(_redirectStatusCode);
         } else {
             getNext().invoke(request, response);
         }
     }
 }
	/*
	* 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.valves;

	import java.io.IOException;

	import jakarta.servlet.ServletException;
	import jakarta.servlet.SessionCookieConfig;
	import jakarta.servlet.http.Cookie;
	import jakarta.servlet.http.HttpServletResponse;

	import org.apache.catalina.connector.Request;
	import org.apache.catalina.connector.Response;
	import org.apache.catalina.util.SessionConfig;

	/**
	* <p>
	* A Valve to detect situations where a load-balanced node receiving a request has been deactivated by the load balancer
	* (JK_LB_ACTIVATION=DIS) and the incoming request has no valid session.
	* </p>
	* <p>
	* In these cases, the user's session cookie should be removed if it exists, any ";jsessionid" parameter should be
	* removed from the request URI, and the client should be redirected to the same URI. This will cause the load-balanced
	* to re-balance the client to another server.
	* </p>
	* <p>
	* All this work is required because when the activation state of a node is DISABLED, the load-balancer will still send
	* requests to the node if they appear to have a session on that node. Since mod_jk doesn't actually know whether the
	* session id is valid, it will send the request blindly to the disabled node, which makes it take much longer to drain
	* the node than strictly necessary.
	* </p>
	* <p>
	* For testing purposes, a special cookie can be configured and used by a client to ignore the normal behavior of this
	* Valve and allow a client to get a new session on a DISABLED node. See {@link #setIgnoreCookieName} and
	* {@link #setIgnoreCookieValue} to configure those values.
	* </p>
	* <p>
	* This Valve should be installed earlier in the Valve pipeline than any authentication valves, as the redirection
	* should take place before an authentication valve would save a request to a protected resource.
	* </p>
	*
	* @see <a href="https://tomcat.apache.org/connectors-doc/generic_howto/loadbalancers.html">Load balancer
	* documentation</a>
	*/
	public class LoadBalancerDrainingValve extends ValveBase {

	/**
	* The request attribute key where the load-balancer's activation state can be found.
	*/
	public static final String ATTRIBUTE_KEY_JK_LB_ACTIVATION = "JK_LB_ACTIVATION";

	/**
	* The HTTP response code that will be used to redirect the request back to the load-balancer for re-balancing.
	* Defaults to 307 (TEMPORARY_REDIRECT). HTTP status code 305 (USE_PROXY) might be an option, here. too.
	*/
	private int _redirectStatusCode = HttpServletResponse.SC_TEMPORARY_REDIRECT;

	/**
	* The name of the cookie which can be set to ignore the "draining" action of this Filter. This will allow a client
	* to contact the server without being re-balanced to another server. The expected cookie value can be set in the
	* {@link #_ignoreCookieValue}. The cookie name and value must match to avoid being re-balanced.
	*/
	private String _ignoreCookieName;

	/**
	* The value of the cookie which can be set to ignore the "draining" action of this Filter. This will allow a client
	* to contact the server without being re-balanced to another server. The expected cookie name can be set in the
	* {@link #_ignoreCookieName}. The cookie name and value must match to avoid being re-balanced.
	*/
	private String _ignoreCookieValue;

	public LoadBalancerDrainingValve() {
	super(true); // Supports async
	}

	//
	// Configuration parameters
	//

	/**
	* Sets the HTTP response code that will be used to redirect the request back to the load-balancer for re-balancing.
	* Defaults to 307 (TEMPORARY_REDIRECT).
	*
	* @param code The code to use for the redirect
	*/
	public void setRedirectStatusCode(int code) {
	_redirectStatusCode = code;
	}

	/**
	* Gets the name of the cookie that can be used to override the re-balancing behavior of this Valve when the current
	* node is in the DISABLED activation state.
	*
	* @return The cookie name used to ignore normal processing rules.
	*
	* @see #setIgnoreCookieValue
	*/
	public String getIgnoreCookieName() {
	return _ignoreCookieName;
	}

	/**
	* Sets the name of the cookie that can be used to override the re-balancing behavior of this Valve when the current
	* node is in the DISABLED activation state. There is no default value for this setting: the ability to override the
	* re-balancing behavior of this Valve is <i>disabled</i> by default.
	*
	* @param cookieName The cookie name to use to ignore normal processing rules.
	*
	* @see #getIgnoreCookieValue
	*/
	public void setIgnoreCookieName(String cookieName) {
	_ignoreCookieName = cookieName;
	}

	/**
	* Gets the expected value of the cookie that can be used to override the re-balancing behavior of this Valve when
	* the current node is in the DISABLED activation state.
	*
	* @return The cookie value used to ignore normal processing rules.
	*
	* @see #setIgnoreCookieValue
	*/
	public String getIgnoreCookieValue() {
	return _ignoreCookieValue;
	}

	/**
	* Sets the expected value of the cookie that can be used to override the re-balancing behavior of this Valve when
	* the current node is in the DISABLED activation state. The "ignore" cookie's value <b>must</b> be exactly equal to
	* this value in order to allow the client to override the re-balancing behavior.
	*
	* @param cookieValue The cookie value to use to ignore normal processing rules.
	*
	* @see #getIgnoreCookieValue
	*/
	public void setIgnoreCookieValue(String cookieValue) {
	_ignoreCookieValue = cookieValue;
	}

	@Override
	public void invoke(Request request, Response response) throws IOException, ServletException {
	if ("DIS".equals(request.getAttribute(ATTRIBUTE_KEY_JK_LB_ACTIVATION)) &&
	!request.isRequestedSessionIdValid()) {

	if (containerLog.isDebugEnabled()) {
	containerLog.debug(sm.getString("loadBalancerDrainingValve.draining"));
	}

	boolean ignoreRebalance = false;
	Cookie sessionCookie = null;

	final Cookie[] cookies = request.getCookies();

	final String sessionCookieName = SessionConfig.getSessionCookieName(request.getContext());

	if (null != cookies) {
	for (Cookie cookie : cookies) {
	final String cookieName = cookie.getName();
	if (containerLog.isTraceEnabled()) {
	containerLog.trace("Checking cookie " + cookieName + "=" + cookie.getValue());
	}

	if (sessionCookieName.equals(cookieName) &&
	request.getRequestedSessionId().equals(cookie.getValue())) {
	sessionCookie = cookie;
	} else if (null != _ignoreCookieName && _ignoreCookieName.equals(cookieName) &&
	null != _ignoreCookieValue && _ignoreCookieValue.equals(cookie.getValue())) {
	// The client presenting a valid ignore-cookie value?
	ignoreRebalance = true;
	}
	}
	}

	if (ignoreRebalance) {
	if (containerLog.isDebugEnabled()) {
	containerLog.debug(sm.getString("loadBalancerDrainingValve.skip", _ignoreCookieName));
	}

	getNext().invoke(request, response);

	return;
	}

	// Kill any session cookie that was found
	// TODO: Consider implications of SSO cookies
	if (null != sessionCookie) {
	sessionCookie.setPath(SessionConfig.getSessionCookiePath(request.getContext()));
	sessionCookie.setMaxAge(0); // Delete
	sessionCookie.setValue(""); // Purge the cookie's value
	// Replicate logic used to set secure attribute for session cookies
	SessionCookieConfig sessionCookieConfig =
	request.getContext().getServletContext().getSessionCookieConfig();
	sessionCookie.setSecure(request.isSecure() \|\| sessionCookieConfig.isSecure());
	response.addCookie(sessionCookie);
	}

	// Re-write the URI if it contains a ;jsessionid parameter
	String uri = request.getRequestURI();
	String sessionURIParamName = SessionConfig.getSessionUriParamName(request.getContext());
	if (uri.contains(";" + sessionURIParamName + "=")) {
	uri = uri.replaceFirst(";" + sessionURIParamName + "=[^&?]*", "");
	}

	String queryString = request.getQueryString();

	if (null != queryString) {
	uri = uri + "?" + queryString;
	}

	// NOTE: Do not call response.encodeRedirectURL or the bad
	// sessionid will be restored
	response.setHeader("Location", uri);
	response.setStatus(_redirectStatusCode);
	} else {
	getNext().invoke(request, response);
	}
	}
	}