MAPREDUCE-2858. Added a WebApp Proxy for applications. Contributed by Robert Evans.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1189036 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -118,6 +118,9 @@ Release 0.23.0 - Unreleased
     MAPREDUCE-2708. Designed and implemented MR Application Master recovery to
     make MR AMs resume their progress after restart. (Sharad Agarwal via vinodkv)
 
+    MAPREDUCE-2858. Added a WebApp Proxy for applications. (Robert Evans via
+    acmurthy) 
+
   IMPROVEMENTS
 
     MAPREDUCE-2187. Reporter sends progress during sort/merge. (Anupam Seth via

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/pom.xml

@@ -41,6 +41,10 @@
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-mapreduce-client-common</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-yarn-server-web-proxy</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-yarn-server-common</artifactId>

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/JobSubmitter.java

@@ -341,6 +341,8 @@ class JobSubmitter {
     Path submitJobDir = new Path(jobStagingArea, jobId.toString());
     JobStatus status = null;
     try {
+      conf.set("hadoop.http.filter.initializers", 
+          "org.apache.hadoop.yarn.server.webproxy.amfilter.AmFilterInitializer");
       conf.set(MRJobConfig.MAPREDUCE_JOB_DIR, submitJobDir.toString());
       LOG.debug("Configuring job " + jobId + " with " + submitJobDir 
           + " as the submit dir");

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/NotRunningJob.java

@@ -77,7 +77,8 @@ public class NotRunningJob implements MRClientProtocol {
     // Setting AppState to NEW and finalStatus to UNDEFINED as they are never used 
     // for a non running job
     return BuilderUtils.newApplicationReport(unknownAppId, "N/A", "N/A", "N/A", "N/A", 0, "", 
-        YarnApplicationState.NEW, "N/A", "N/A", 0, 0, FinalApplicationStatus.UNDEFINED, null);    
+        YarnApplicationState.NEW, "N/A", "N/A", 0, 0, 
+        FinalApplicationStatus.UNDEFINED, null, "N/A");    
   }
 
   NotRunningJob(ApplicationReport applicationReport, JobState jobState) {

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/TestClientServiceDelegate.java

@@ -231,14 +231,14 @@ public class TestClientServiceDelegate {
     return BuilderUtils.newApplicationReport(BuilderUtils.newApplicationId(
         1234, 5), "user", "queue", "appname", "host", 124, null,
         YarnApplicationState.FINISHED, "diagnostics", "url", 0, 0,
-        FinalApplicationStatus.SUCCEEDED, null);
+        FinalApplicationStatus.SUCCEEDED, null, "N/A");
   }
 
   private ApplicationReport getRunningApplicationReport(String host, int port) {
     return BuilderUtils.newApplicationReport(BuilderUtils.newApplicationId(
         1234, 5), "user", "queue", "appname", host, port, null,
         YarnApplicationState.RUNNING, "diagnostics", "url", 0, 0,
-        FinalApplicationStatus.UNDEFINED, null);
+        FinalApplicationStatus.UNDEFINED, null, "N/A");
   }
 
   private ResourceMgrDelegate getRMDelegate() throws YarnRemoteException {

hadoop-mapreduce-project/hadoop-mapreduce-client/pom.xml

@@ -52,6 +52,11 @@
         <version>${project.version}</version>
         <type>pom</type>
       </dependency>
+      <dependency>
+        <groupId>org.apache.hadoop</groupId>
+        <artifactId>hadoop-yarn-server-web-proxy</artifactId>
+        <version>${project.version}</version>
+      </dependency>
       <dependency>
         <groupId>org.apache.hadoop</groupId>
         <artifactId>hadoop-yarn-server-common</artifactId>

hadoop-mapreduce-project/hadoop-yarn/bin/start-all.sh

@@ -30,3 +30,5 @@ bin=`cd "$bin"; pwd`
 "$bin"/yarn-daemons.sh --config $YARN_CONF_DIR  start nodemanager
 # start historyserver
 #"$bin"/yarn-daemon.sh --config $YARN_CONF_DIR  start historyserver
+# start proxyserver
+#"$bin"/yarn-daemon.sh --config $YARN_CONF_DIR  start proxyserver

hadoop-mapreduce-project/hadoop-yarn/bin/stop-all.sh

@@ -30,4 +30,5 @@ bin=`cd "$bin"; pwd`
 "$bin"/yarn-daemons.sh --config $YARN_CONF_DIR  stop nodemanager
 # stop historyServer
 "$bin"/yarn-daemon.sh --config $YARN_CONF_DIR  stop historyserver
-
+# stop proxy server
+"$bin"/yarn-daemon.sh --config $YARN_CONF_DIR  stop proxyserver

hadoop-mapreduce-project/hadoop-yarn/bin/yarn

@@ -206,6 +206,9 @@ elif [ "$COMMAND" = "nodemanager" ] ; then
 elif [ "$COMMAND" = "historyserver" ] ; then
   CLASS=org.apache.hadoop.mapreduce.v2.hs.JobHistoryServer
   YARN_OPTS="$YARN_OPTS $YARN_JOB_HISTORYSERVER_OPTS"
+elif [ "$COMMAND" = "proxyserver" ] ; then
+  CLASS='org.apache.hadoop.yarn.server.webproxy.WebAppProxyServer'
+  YARN_OPTS="$YARN_OPTS $YARN_PROXYSERVER_OPTS"
 elif [ "$COMMAND" = "version" ] ; then
   CLASS=org.apache.hadoop.util.VersionInfo
   YARN_OPTS="$YARN_OPTS $YARN_CLIENT_OPTS"

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/ApplicationConstants.java

@@ -60,6 +60,14 @@ public interface ApplicationConstants {
 
   public static final String LOCAL_DIR_ENV = "YARN_LOCAL_DIRS";
 
+  /**
+   * The environmental variable for APPLICATION_WEB_PROXY_BASE. Set in 
+   * ApplicationMaster's environment only. This states that for all non-relative
+   * web URLs in the app masters web UI what base should they have.
+   */
+  public static final String APPLICATION_WEB_PROXY_BASE_ENV = 
+    "APPLICATION_WEB_PROXY_BASE";
+
   public static final String LOG_DIR_EXPANSION_VAR = "<LOG_DIR>";
 
   public static final String STDERR = "stderr";

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/ApplicationReport.java

@@ -174,6 +174,19 @@ public interface ApplicationReport {
   @Private
   @Unstable
   void setTrackingUrl(String url);
+  
+  /**
+   * Get the original not-proxied <em>tracking url</em> for the application.
+   * This is intended to only be used by the proxy itself.
+   * @return the original not-proxied <em>tracking url</em> for the application
+   */
+  @Private
+  @Unstable
+  String getOriginalTrackingUrl();
+
+  @Private
+  @Unstable
+  void setOriginalTrackingUrl(String url);
 
   /**
    * Get the <em>start time</em> of the application.

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/impl/pb/ApplicationReportPBImpl.java

@@ -90,6 +90,15 @@ implements ApplicationReport {
     return p.getTrackingUrl();
   }
 
+  @Override
+  public String getOriginalTrackingUrl() {
+    ApplicationReportProtoOrBuilder p = viaProto ? proto : builder;
+    if (!p.hasOriginalTrackingUrl()) {
+      return null;
+    }
+    return p.getOriginalTrackingUrl();
+  }
+  
   @Override
   public String getName() {
     ApplicationReportProtoOrBuilder p = viaProto ? proto : builder;
@@ -198,6 +207,16 @@ implements ApplicationReport {
     }
     builder.setTrackingUrl(url);
   }
+  
+  @Override
+  public void setOriginalTrackingUrl(String url) {
+    maybeInitBuilder();
+    if (url == null) {
+      builder.clearOriginalTrackingUrl();
+      return;
+    }
+    builder.setOriginalTrackingUrl(url);
+  }
 
   @Override
   public void setName(String name) {

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-api/src/main/proto/yarn_protos.proto

@@ -162,6 +162,7 @@ message ApplicationReportProto {
   optional int64 finishTime = 14;
   optional FinalApplicationStatusProto final_application_status = 15;
   optional ApplicationResourceUsageReportProto app_resource_Usage = 16;
+  optional string originalTrackingUrl = 17;
 }
 
 message NodeIdProto {

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java

@@ -371,6 +371,22 @@ public class YarnConfiguration extends Configuration {
 
   public static final int INVALID_CONTAINER_EXIT_STATUS = -1000;
   public static final int ABORTED_CONTAINER_EXIT_STATUS = -100;
+
+  ////////////////////////////////
+  // Web Proxy Configs
+  ////////////////////////////////
+  public static final String PROXY_PREFIX = "yarn.web-proxy.";
+  
+  /** The kerberos principal for the proxy.*/
+  public static final String PROXY_PRINCIPAL =
+    PROXY_PREFIX + "principal";
+  
+  /** Keytab for Proxy.*/
+  public static final String PROXY_KEYTAB = PROXY_PREFIX + "keytab";
+  
+  /** The address for the web proxy.*/
+  public static final String PROXY_ADDRESS =
+    PROXY_PREFIX + "address";
   
   /**
    * YARN Service Level Authorization
@@ -406,15 +422,27 @@ public class YarnConfiguration extends Configuration {
     }
   }
 
-  public static String getRMWebAppURL(Configuration conf) {
+  public static String getProxyHostAndPort(Configuration conf) {
+    String addr = conf.get(PROXY_ADDRESS);
+    if(addr == null || addr.isEmpty()) {
+      addr = getRMWebAppHostAndPort(conf);
+    }
+    return addr;
+  }
+  
+  public static String getRMWebAppHostAndPort(Configuration conf) {
     String addr = conf.get(YarnConfiguration.RM_WEBAPP_ADDRESS,
-                           YarnConfiguration.DEFAULT_RM_WEBAPP_ADDRESS);
+        YarnConfiguration.DEFAULT_RM_WEBAPP_ADDRESS);
     Iterator<String> it = ADDR_SPLITTER.split(addr).iterator();
     it.next(); // ignore the bind host
     String port = it.next();
     // Use apps manager address to figure out the host for webapp
     addr = conf.get(YarnConfiguration.RM_ADDRESS, YarnConfiguration.DEFAULT_RM_ADDRESS);
     String host = ADDR_SPLITTER.split(addr).iterator().next();
-    return JOINER.join("http://", host, ":", port);
+    return JOINER.join(host, ":", port);
+  }
+  
+  public static String getRMWebAppURL(Configuration conf) {
+    return JOINER.join("http://", getRMWebAppHostAndPort(conf));
   }
 }

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/BuilderUtils.java

@@ -281,7 +281,8 @@ public class BuilderUtils {
       ApplicationId applicationId, String user, String queue, String name,
       String host, int rpcPort, String clientToken, YarnApplicationState state,
       String diagnostics, String url, long startTime, long finishTime,
-      FinalApplicationStatus finalStatus, ApplicationResourceUsageReport appResources) {
+      FinalApplicationStatus finalStatus, ApplicationResourceUsageReport appResources,
+      String origTrackingUrl) {
     ApplicationReport report = recordFactory
         .newRecordInstance(ApplicationReport.class);
     report.setApplicationId(applicationId);
@@ -298,6 +299,7 @@ public class BuilderUtils {
     report.setFinishTime(finishTime);
     report.setFinalApplicationStatus(finalStatus);
     report.setApplicationResourceUsageReport(appResources);
+    report.setOriginalTrackingUrl(origTrackingUrl);
     return report;
   }
 

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/StringHelper.java

@@ -154,15 +154,24 @@ public final class StringHelper {
         if (part.startsWith("#") || isAbsUrl(part)) {
           sb.append(part);
         } else {
-          sb.append('/').append(pathPrefix).append('/').append(part);
+          uappend(sb, pathPrefix);
+          uappend(sb, part);
         }
       } else {
-        sb.append('/').append(part);
+        uappend(sb, part);
       }
     }
     return sb.toString();
   }
-
+  
+  private static void uappend(StringBuilder sb, String part) {
+    if((sb.length() <= 0 || sb.charAt(sb.length() - 1) != '/') 
+        && !part.startsWith("/")) {
+      sb.append('/');
+    }
+    sb.append(part);
+  }
+  
   public static String percent(double value) {
     return String.format("%.2f", value * 100);
   }

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/View.java

@@ -32,6 +32,7 @@ import javax.servlet.http.HttpServletResponse;
 
 import static org.apache.hadoop.yarn.util.StringHelper.*;
 
+import org.apache.hadoop.yarn.api.ApplicationConstants;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -175,8 +176,20 @@ public abstract class View implements Params {
     moreParams().put(key, value);
   }
 
+  public String root() {
+    String root = System.getenv(ApplicationConstants.APPLICATION_WEB_PROXY_BASE_ENV);
+    if(root == null || root.isEmpty()) {
+      root = "/";
+    }
+    return root;
+  }
+  
   public String prefix() {
-    return context().rc.prefix;
+    if(context().rc.prefix == null) {
+      return root();
+    } else {
+      return ujoin(root(), context().rc.prefix);
+    }
   }
 
   public void setTitle(String title) {
@@ -188,6 +201,16 @@ public abstract class View implements Params {
     set(TITLE_LINK, url);
   }
 
+  /**
+   * Create an url from url components
+   * @param parts components to join
+   * @return an url string
+   */
+  public String root_url(String... parts) {
+    return ujoin(root(), parts);
+  }
+
+  
   /**
    * Create an url from url components
    * @param parts components to join

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/WebApps.java

@@ -18,23 +18,27 @@
 
 package org.apache.hadoop.yarn.webapp;
 
-import static com.google.common.base.Preconditions.*;
-import com.google.inject.AbstractModule;
-import com.google.inject.Guice;
-import com.google.inject.Injector;
-import com.google.inject.Module;
-import com.google.inject.servlet.GuiceFilter;
+import static com.google.common.base.Preconditions.checkNotNull;
 
 import java.net.ConnectException;
 import java.net.URL;
-import org.apache.commons.lang.StringUtils;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
 
+import javax.servlet.http.HttpServlet;
+
+import org.apache.commons.lang.StringUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.http.HttpServer;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.google.inject.AbstractModule;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.google.inject.servlet.GuiceFilter;
+
 /**
  * Helpers to create an embedded webapp.
  *
@@ -59,6 +63,12 @@ public class WebApps {
   static final Logger LOG = LoggerFactory.getLogger(WebApps.class);
 
   public static class Builder<T> {
+    static class ServletStruct {
+      public Class<? extends HttpServlet> clazz;
+      public String name;
+      public String spec;
+    }
+    
     final String name;
     final Class<T> api;
     final T application;
@@ -67,6 +77,8 @@ public class WebApps {
     boolean findPort = false;
     Configuration conf;
     boolean devMode = false;
+    private final HashSet<ServletStruct> servlets = new HashSet<ServletStruct>();
+    private final HashMap<String, Object> attributes = new HashMap<String, Object>();
 
     Builder(String name, Class<T> api, T application) {
       this.name = name;
@@ -93,6 +105,21 @@ public class WebApps {
       return this;
     }
 
+    public Builder<T> withAttribute(String key, Object value) {
+      attributes.put(key, value);
+      return this;
+    }
+    
+    public Builder<T> withServlet(String name, String pathSpec, 
+        Class<? extends HttpServlet> servlet) {
+      ServletStruct struct = new ServletStruct();
+      struct.clazz = servlet;
+      struct.name = name;
+      struct.spec = pathSpec;
+      servlets.add(struct);
+      return this;
+    }
+    
     public Builder<T> with(Configuration conf) {
       this.conf = conf;
       return this;
@@ -152,6 +179,12 @@ public class WebApps {
         HttpServer server =
             new HttpServer(name, bindAddress, port, findPort, conf, 
             webapp.getServePathSpecs());
+        for(ServletStruct struct: servlets) {
+          server.addServlet(struct.name, struct.spec, struct.clazz);
+        }
+        for(Map.Entry<String, Object> entry : attributes.entrySet()) {
+          server.setAttribute(entry.getKey(), entry.getValue());
+        }
         server.addGlobalFilter("guice", GuiceFilter.class.getName(), null);
         webapp.setConf(conf);
         webapp.setHttpServer(server);

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/view/ErrorPage.java

@@ -34,7 +34,7 @@ public class ErrorPage extends HtmlPage {
     String title = "Sorry, got error "+ status();
     html.
       title(title).
-      link("/static/yarn.css").
+      link(root_url("static","yarn.css")).
       _(JQueryUI.class). // an embedded sub-view
       style("#msg { margin: 1em auto; width: 88%; }",
             "#msg h1 { padding: 0.2em 1.5em; font: bold 1.3em serif; }").

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/view/JQueryUI.java

@@ -81,12 +81,12 @@ public class JQueryUI extends HtmlBlock {
     html.
       link(join("https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.9/themes/",
                 getTheme(), "/jquery-ui.css")).
-      link("/static/dt-1.7.5/css/jui-dt.css").
+      link(root_url("static/dt-1.7.5/css/jui-dt.css")).
       script("https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js").
       script("https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.9/jquery-ui.min.js").
-      script("/static/dt-1.7.5/js/jquery.dataTables.min.js").
-      script("/static/yarn.dt.plugins.js").
-      script("/static/themeswitcher.js").
+      script(root_url("static/dt-1.7.5/js/jquery.dataTables.min.js")).
+      script(root_url("static/yarn.dt.plugins.js")).
+      script(root_url("static/themeswitcher.js")).
       style("#jsnotice { padding: 0.2em; text-align: center; }",
             ".ui-progressbar { height: 1em; min-width: 5em }"); // required
 

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/view/TwoColumnCssLayout.java

@@ -35,7 +35,7 @@ public class TwoColumnCssLayout extends HtmlPage {
     preHead(html);
     html.
       title($("title")).
-      link("/static/yarn.css").
+      link(root_url("static","yarn.css")).
       style(".main { min-height: 100%; height: auto !important; height: 100%;",
             "  margin: 0 auto -4em; border: 0; }",
             ".footer, .push { height: 4em; clear: both; border: 0 }",

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/view/TwoColumnLayout.java

@@ -41,7 +41,7 @@ public class TwoColumnLayout extends HtmlPage {
     preHead(html);
     html.
       title($(TITLE)).
-      link("/static/yarn.css").
+      link(root_url("static","yarn.css")).
       style("#layout { height: 100%; }",
             "#layout thead td { height: 3em; }",
             "#layout #navcell { width: 11em; padding: 0 1em; }",

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/MockApps.java

@@ -89,6 +89,7 @@ public class MockApps {
       @Override public YarnApplicationState getYarnApplicationState() { return state; }
       @Override public String getQueue() { return queue; }
       @Override public String getTrackingUrl() { return ""; }
+      @Override public String getOriginalTrackingUrl() { return ""; }
       @Override public FinalApplicationStatus getFinalApplicationStatus() { return finishState; }
       @Override
       public ApplicationResourceUsageReport getApplicationResourceUsageReport() {
@@ -103,6 +104,7 @@ public class MockApps {
         // TODO Auto-generated method stub
 
       }
+      @Override public void setOriginalTrackingUrl(String url) { }
       @Override
       public void setApplicationResourceUsageReport(ApplicationResourceUsageReport appResources) {
         this.appUsageReport = appResources;

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/resources/yarn-default.xml

@@ -376,4 +376,27 @@
     <name>mapreduce.job.hdfs-servers</name>
     <value>${fs.default.name}</value>
   </property>
+
+  <!-- WebAppProxy Configuration-->
+  
+  <property>
+    <description>The kerberos principal for the proxy, if the proxy is not
+    running as part of the RM.</description>
+    <name>yarn.web-proxy.principal</name>
+    <value/>
+  </property>
+  
+  <property>
+    <description>Keytab for WebAppProxy, if the proxy is not running as part of 
+    the RM.</description>
+    <name>yarn.web-proxy.keytab</name>
+  </property>
+  
+  <property>
+    <description>The address for the web proxy as HOST:PORT, if this is not
+     given or if it matches yarn.resourcemanager.address then the proxy will
+     run as part of the RM</description>
+     <name>yarn.web-proxy.address</name>
+     <value/>
+  </property>
 </configuration>

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/pom.xml

@@ -34,6 +34,10 @@
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-yarn-server-common</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-yarn-server-web-proxy</artifactId>
+    </dependency>
   </dependencies>
 
   <build>

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java

@@ -66,11 +66,16 @@ import org.apache.hadoop.yarn.server.resourcemanager.security.DelegationTokenRen
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.RMWebApp;
 import org.apache.hadoop.yarn.server.security.ApplicationACLsManager;
 import org.apache.hadoop.yarn.server.security.ContainerTokenSecretManager;
+import org.apache.hadoop.yarn.server.webproxy.AppReportFetcher;
+import org.apache.hadoop.yarn.server.webproxy.WebAppProxy;
+import org.apache.hadoop.yarn.server.webproxy.WebAppProxyServlet;
+import org.apache.hadoop.yarn.server.webproxy.ProxyUriUtils;
 import org.apache.hadoop.yarn.service.AbstractService;
 import org.apache.hadoop.yarn.service.CompositeService;
 import org.apache.hadoop.yarn.service.Service;
 import org.apache.hadoop.yarn.webapp.WebApp;
 import org.apache.hadoop.yarn.webapp.WebApps;
+import org.apache.hadoop.yarn.webapp.WebApps.Builder;
 
 /**
  * The ResourceManager is the main class that is a set of components.
@@ -406,11 +411,18 @@ public class ResourceManager extends CompositeService implements Recoverable {
   }
 
   protected void startWepApp() {
-    webApp = WebApps.$for("cluster", masterService).at(
-        this.conf.get(YarnConfiguration.RM_WEBAPP_ADDRESS,
-        YarnConfiguration.DEFAULT_RM_WEBAPP_ADDRESS)).
-      start(new RMWebApp(this));
-
+    Builder<ApplicationMasterService> builder = 
+      WebApps.$for("cluster", masterService).at(
+          this.conf.get(YarnConfiguration.RM_WEBAPP_ADDRESS,
+          YarnConfiguration.DEFAULT_RM_WEBAPP_ADDRESS)); 
+    if(YarnConfiguration.getRMWebAppHostAndPort(conf).
+        equals(YarnConfiguration.getProxyHostAndPort(conf))) {
+      AppReportFetcher fetcher = new AppReportFetcher(conf, getClientRMService());
+      builder.withServlet(ProxyUriUtils.PROXY_SERVLET_NAME, 
+          ProxyUriUtils.PROXY_PATH_SPEC, WebAppProxyServlet.class);
+      builder.withAttribute(WebAppProxy.FETCHER_ATTRIBUTE, fetcher);
+    }
+    webApp = builder.start(new RMWebApp(this));
   }
 
   @Override

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/amlauncher/AMLauncher.java

@@ -187,6 +187,8 @@ public class AMLauncher implements Runnable {
       throws IOException {
     Map<String, String> environment = container.getEnvironment();
 
+    environment.put(ApplicationConstants.APPLICATION_WEB_PROXY_BASE_ENV,
+        application.getWebProxyBase());
     // Set the AppAttemptId, containerId, NMHTTPAdress, AppSubmitTime to be
     // consumable by the AM.
     environment.put(ApplicationConstants.AM_CONTAINER_ID_ENV, container

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java

@@ -331,11 +331,13 @@ public class RMAppImpl implements RMApp {
       String clientToken = "N/A";
       String trackingUrl = "N/A";
       String host = "N/A";
+      String origTrackingUrl = "N/A";
       int rpcPort = -1;
       ApplicationResourceUsageReport appUsageReport = null;
       FinalApplicationStatus finishState = getFinalApplicationStatus();
       if (this.currentAttempt != null) {
         trackingUrl = this.currentAttempt.getTrackingUrl();
+        origTrackingUrl = this.currentAttempt.getOriginalTrackingUrl();
         clientToken = this.currentAttempt.getClientToken();
         host = this.currentAttempt.getHost();
         rpcPort = this.currentAttempt.getRpcPort();
@@ -345,7 +347,8 @@ public class RMAppImpl implements RMApp {
           this.queue, this.name, host, rpcPort, clientToken,
           createApplicationState(this.stateMachine.getCurrentState()),
           this.diagnostics.toString(), trackingUrl,
-          this.startTime, this.finishTime, finishState, appUsageReport);
+          this.startTime, this.finishTime, finishState, appUsageReport,
+          origTrackingUrl);
     } finally {
       this.readLock.unlock();
     }
@@ -381,7 +384,7 @@ public class RMAppImpl implements RMApp {
   @Override
   public String getTrackingUrl() {
     this.readLock.lock();
-
+    
     try {
       if (this.currentAttempt != null) {
         return this.currentAttempt.getTrackingUrl();
@@ -439,7 +442,7 @@ public class RMAppImpl implements RMApp {
 
     RMAppAttempt attempt = new RMAppAttemptImpl(appAttemptId,
         clientTokenStr, rmContext, scheduler, masterService,
-        submissionContext);
+        submissionContext, YarnConfiguration.getProxyHostAndPort(conf));
     attempts.put(appAttemptId, attempt);
     currentAttempt = attempt;
     handler.handle(

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttempt.java

@@ -71,6 +71,22 @@ public interface RMAppAttempt extends EventHandler<RMAppAttemptEvent> {
    */
   String getTrackingUrl();
 
+  /**
+   * The original url at which the status of the application attempt can be 
+   * accessed. This url is not fronted by a proxy. This is only intended to be
+   * used by the proxy.
+   * @return the url at which the status of the attempt can be accessed and is
+   * not fronted by a proxy.
+   */
+  String getOriginalTrackingUrl();
+
+  /**
+   * The base to be prepended to web URLs that are not relative, and the user
+   * has been checked.
+   * @return the base URL to be prepended to web URLs that are not relative.
+   */
+  String getWebProxyBase();
+
   /**
    * The token required by the clients to talk to the application attempt
    * @return the token required by the clients to talk to the application attempt

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java

@@ -18,6 +18,8 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt;
 
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -67,6 +69,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerAppRepor
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.YarnScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.event.AppAddedSchedulerEvent;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.event.AppRemovedSchedulerEvent;
+import org.apache.hadoop.yarn.server.webproxy.ProxyUriUtils;
 import org.apache.hadoop.yarn.state.InvalidStateTransitonException;
 import org.apache.hadoop.yarn.state.MultipleArcTransition;
 import org.apache.hadoop.yarn.state.SingleArcTransition;
@@ -114,12 +117,16 @@ public class RMAppAttemptImpl implements RMAppAttempt {
   private float progress = 0;
   private String host = "N/A";
   private int rpcPort;
-  private String trackingUrl = "N/A";
+  private String origTrackingUrl = "N/A";
+  private String proxiedTrackingUrl = "N/A";
+  
   // Set to null initially. Will eventually get set 
   // if an RMAppAttemptUnregistrationEvent occurs
   private FinalApplicationStatus finalStatus = null;
   private final StringBuilder diagnostics = new StringBuilder();
 
+  private final String proxy;
+
   private static final StateMachineFactory<RMAppAttemptImpl,
                                            RMAppAttemptState,
                                            RMAppAttemptEventType,
@@ -250,8 +257,10 @@ public class RMAppAttemptImpl implements RMAppAttempt {
   public RMAppAttemptImpl(ApplicationAttemptId appAttemptId,
       String clientToken, RMContext rmContext, YarnScheduler scheduler,
       ApplicationMasterService masterService,
-      ApplicationSubmissionContext submissionContext) {
+      ApplicationSubmissionContext submissionContext,
+      String proxy) {
 
+    this.proxy = proxy;
     this.applicationAttemptId = appAttemptId;
     this.rmContext = rmContext;
     this.eventHandler = rmContext.getDispatcher().getEventHandler();
@@ -322,9 +331,46 @@ public class RMAppAttemptImpl implements RMAppAttempt {
   @Override
   public String getTrackingUrl() {
     this.readLock.lock();
-
     try {
-      return this.trackingUrl;
+      return this.proxiedTrackingUrl;
+    } finally {
+      this.readLock.unlock();
+    }
+  }
+  
+  @Override
+  public String getOriginalTrackingUrl() {
+    this.readLock.lock();
+    try {
+      return this.origTrackingUrl;
+    } finally {
+      this.readLock.unlock();
+    }    
+  }
+  
+  @Override
+  public String getWebProxyBase() {
+    this.readLock.lock();
+    try {
+      return ProxyUriUtils.getPath(applicationAttemptId.getApplicationId());
+    } finally {
+      this.readLock.unlock();
+    }    
+  }
+  
+  private String generateProxyUriWithoutScheme(
+      final String trackingUriWithoutScheme) {
+    this.readLock.lock();
+    try {
+      URI trackingUri = ProxyUriUtils.getUriFromAMUrl(trackingUriWithoutScheme);
+      URI proxyUri = ProxyUriUtils.getUriFromAMUrl(proxy);
+      URI result = ProxyUriUtils.getProxyUri(trackingUri, proxyUri, 
+          applicationAttemptId.getApplicationId());
+      //We need to strip off the scheme to have it match what was there before
+      return result.toASCIIString().substring(7);
+    } catch (URISyntaxException e) {
+      LOG.warn("Could not proxify "+trackingUriWithoutScheme,e);
+      return trackingUriWithoutScheme;
     } finally {
       this.readLock.unlock();
     }
@@ -691,7 +737,9 @@ public class RMAppAttemptImpl implements RMAppAttempt {
           = (RMAppAttemptRegistrationEvent) event;
       appAttempt.host = registrationEvent.getHost();
       appAttempt.rpcPort = registrationEvent.getRpcport();
-      appAttempt.trackingUrl = registrationEvent.getTrackingurl();
+      appAttempt.origTrackingUrl = registrationEvent.getTrackingurl();
+      appAttempt.proxiedTrackingUrl = 
+        appAttempt.generateProxyUriWithoutScheme(appAttempt.origTrackingUrl);
 
       // Let the app know
       appAttempt.eventHandler.handle(new RMAppEvent(appAttempt
@@ -787,7 +835,9 @@ public class RMAppAttemptImpl implements RMAppAttempt {
       RMAppAttemptUnregistrationEvent unregisterEvent
         = (RMAppAttemptUnregistrationEvent) event;
       appAttempt.diagnostics.append(unregisterEvent.getDiagnostics());
-      appAttempt.trackingUrl = unregisterEvent.getTrackingUrl();
+      appAttempt.origTrackingUrl = unregisterEvent.getTrackingUrl();
+      appAttempt.proxiedTrackingUrl = 
+        appAttempt.generateProxyUriWithoutScheme(appAttempt.origTrackingUrl);
       appAttempt.finalStatus = unregisterEvent.getFinalApplicationStatus();
 
       // Tell the app and the scheduler
@@ -837,7 +887,8 @@ public class RMAppAttemptImpl implements RMAppAttempt {
          * NOTE: don't set trackingUrl to 'null'. That will cause null-pointer exceptions
          * in the generated proto code.
          */
-        appAttempt.trackingUrl = "";
+        appAttempt.origTrackingUrl = "";
+        appAttempt.proxiedTrackingUrl = "";
 
         new FinalTransition(RMAppAttemptState.FAILED).transition(
             appAttempt, containerFinishedEvent);

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/TestRMAppAttemptTransitions.java

@@ -178,7 +178,7 @@ public class TestRMAppAttemptTransitions {
     application = mock(RMApp.class);
     applicationAttempt = 
         new RMAppAttemptImpl(applicationAttemptId, null, rmContext, scheduler, 
-            masterService, submissionContext);
+            masterService, submissionContext, null);
     when(application.getCurrentAppAttempt()).thenReturn(applicationAttempt);
     when(application.getApplicationId()).thenReturn(applicationId);
     
@@ -328,7 +328,9 @@ public class TestRMAppAttemptTransitions {
     assertEquals(container, applicationAttempt.getMasterContainer());
     assertEquals(host, applicationAttempt.getHost());
     assertEquals(rpcPort, applicationAttempt.getRpcPort());
-    assertEquals(trackingUrl, applicationAttempt.getTrackingUrl());
+    assertEquals(trackingUrl, applicationAttempt.getOriginalTrackingUrl());
+    assertEquals("null/proxy/"+applicationAttempt.getAppAttemptId().
+        getApplicationId()+"/", applicationAttempt.getTrackingUrl());
     
     // TODO - need to add more checks relevant to this state
   }
@@ -343,7 +345,9 @@ public class TestRMAppAttemptTransitions {
     assertEquals(RMAppAttemptState.FINISHED, 
         applicationAttempt.getAppAttemptState());
     assertEquals(diagnostics, applicationAttempt.getDiagnostics());
-    assertEquals(trackingUrl, applicationAttempt.getTrackingUrl());
+    assertEquals(trackingUrl, applicationAttempt.getOriginalTrackingUrl());
+    assertEquals("null/proxy/"+applicationAttempt.getAppAttemptId().
+        getApplicationId()+"/", applicationAttempt.getTrackingUrl());
     assertEquals(0,applicationAttempt.getJustFinishedContainers().size());
     assertEquals(container, applicationAttempt.getMasterContainer());
     assertEquals(finalStatus, applicationAttempt.getFinalApplicationStatus());

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/pom.xml

@@ -0,0 +1,67 @@
+<?xml version="1.0"?>
+<!--
+  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. See accompanying LICENSE file.
+-->
+<project>
+  <parent>
+    <artifactId>hadoop-yarn-server</artifactId>
+    <groupId>org.apache.hadoop</groupId>
+    <version>0.24.0-SNAPSHOT</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>org.apache.hadoop</groupId>
+  <artifactId>hadoop-yarn-server-web-proxy</artifactId>
+  <version>0.24.0-SNAPSHOT</version>
+  <name>hadoop-yarn-server-web-proxy</name>
+
+  <properties>
+    <install.file>${project.artifact.file}</install.file>
+    <yarn.basedir>${project.parent.parent.basedir}</yarn.basedir>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>servlet-api</artifactId>
+      <scope>compile</scope>
+      <version>2.5</version>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-yarn-server-common</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-yarn-common</artifactId>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+
+      <!-- Publish tests jar -->
+      <plugin>
+        <artifactId>maven-jar-plugin</artifactId>
+        <executions>
+          <execution>
+            <goals>
+              <goal>test-jar</goal>
+            </goals>
+            <phase>test-compile</phase>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/AppReportFetcher.java

@@ -0,0 +1,93 @@
+/**
+* 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.yarn.server.webproxy;
+
+import java.net.InetSocketAddress;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.net.NetUtils;
+import org.apache.hadoop.yarn.api.ClientRMProtocol;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportRequest;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportResponse;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.ApplicationReport;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.exceptions.YarnRemoteException;
+import org.apache.hadoop.yarn.factories.RecordFactory;
+import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
+import org.apache.hadoop.yarn.ipc.YarnRPC;
+
+/**
+ * This class abstracts away how ApplicationReports are fetched.
+ */
+public class AppReportFetcher {
+  private static final Log LOG = LogFactory.getLog(AppReportFetcher.class);
+  private final Configuration conf;
+  private final ClientRMProtocol applicationsManager;
+  private final RecordFactory recordFactory = RecordFactoryProvider.getRecordFactory(null);
+  
+  /**
+   * Create a new Connection to the RM to fetch Application reports.
+   * @param conf the conf to use to know where the RM is.
+   */
+  public AppReportFetcher(Configuration conf) {
+    this.conf = conf;
+    YarnRPC rpc = YarnRPC.create(this.conf);
+    InetSocketAddress rmAddress =
+        NetUtils.createSocketAddr(this.conf.get(
+            YarnConfiguration.RM_ADDRESS,
+            YarnConfiguration.DEFAULT_RM_ADDRESS));
+    LOG.info("Connecting to ResourceManager at " + rmAddress);
+    applicationsManager =
+        (ClientRMProtocol) rpc.getProxy(ClientRMProtocol.class,
+            rmAddress, this.conf);
+    LOG.info("Connected to ResourceManager at " + rmAddress);  
+  }
+  
+  /**
+   * Just call directly into the applicationsManager given instead of creating
+   * a remote connection to it.  This is mostly for when the Proxy is running
+   * as part of the RM already.
+   * @param conf the configuration to use
+   * @param applicationsManager what to use to get the RM reports.
+   */
+  public AppReportFetcher(Configuration conf, ClientRMProtocol applicationsManager) {
+    this.conf = conf;
+    this.applicationsManager = applicationsManager;
+  }
+  
+  /**
+   * Get a report for the specified app.
+   * @param appId the id of the application to get. 
+   * @return the ApplicationReport for that app.
+   * @throws YarnRemoteException on any error.
+   */
+  public ApplicationReport getApplicationReport(ApplicationId appId)
+  throws YarnRemoteException {
+    GetApplicationReportRequest request = recordFactory
+        .newRecordInstance(GetApplicationReportRequest.class);
+    request.setApplicationId(appId);
+    
+    GetApplicationReportResponse response = applicationsManager
+        .getApplicationReport(request);
+    return response.getApplicationReport();
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/ProxyUriUtils.java

@@ -0,0 +1,143 @@
+/**
+* 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.yarn.server.webproxy;
+
+import static org.apache.hadoop.yarn.util.StringHelper.ujoin;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URLEncoder;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+
+public class ProxyUriUtils {
+  @SuppressWarnings("unused")
+  private static final Log LOG = LogFactory.getLog(ProxyUriUtils.class);
+  
+  /**Name of the servlet to use when registering the proxy servlet. */
+  public static final String PROXY_SERVLET_NAME = "proxy";
+  /**Base path where the proxy servlet will handle requests.*/
+  public static final String PROXY_BASE = "/proxy/";
+  /**Path Specification for the proxy servlet.*/
+  public static final String PROXY_PATH_SPEC = PROXY_BASE+"*";
+  /**Query Parameter indicating that the URI was approved.*/
+  public static final String PROXY_APPROVAL_PARAM = "proxyapproved";
+  
+  private static String uriEncode(Object o) {
+    try {
+      assert (o != null) : "o canot be null";
+      return URLEncoder.encode(o.toString(), "UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      //This should never happen
+      throw new RuntimeException("UTF-8 is not supported by this system?", e);
+    }
+  }
+  
+  /**
+   * Get the proxied path for an application.
+   * @param id the application id to use.
+   * @return the base path to that application through the proxy.
+   */
+  public static String getPath(ApplicationId id) {
+    if(id == null) {
+      throw new IllegalArgumentException("Application id cannot be null ");
+    }
+    return ujoin(PROXY_BASE, uriEncode(id));
+  }
+
+  /**
+   * Get the proxied path for an application.
+   * @param id the application id to use.
+   * @param path the rest of the path to the application.
+   * @return the base path to that application through the proxy.
+   */
+  public static String getPath(ApplicationId id, String path) {
+    if(path == null) {
+      return getPath(id);
+    } else {
+      return ujoin(getPath(id), path);
+    }
+  }
+  
+  /**
+   * Get the proxied path for an application
+   * @param id the id of the application
+   * @param path the path of the application.
+   * @param query the query parameters
+   * @param approved true if the user has approved accessing this app.
+   * @return the proxied path for this app.
+   */
+  public static String getPathAndQuery(ApplicationId id, String path, 
+      String query, boolean approved) {
+    StringBuilder newp = new StringBuilder();
+    newp.append(getPath(id, path));
+    boolean first = appendQuery(newp, query, true);
+    if(approved) {
+      first = appendQuery(newp, PROXY_APPROVAL_PARAM+"=true", first);
+    }
+    return newp.toString();
+  }
+  
+  private static boolean appendQuery(StringBuilder builder, String query, 
+      boolean first) {
+    if(query != null && !query.isEmpty()) {
+      if(first && !query.startsWith("?")) {
+        builder.append('?');
+      }
+      if(!first && !query.startsWith("&")) {
+        builder.append('&');
+      }
+      builder.append(query);
+      return false;
+    }
+    return first;
+  }
+  
+  /**
+   * Get a proxied URI for the original URI.
+   * @param originalUri the original URI to go through the proxy
+   * @param proxyUri the URI of the proxy itself, scheme, host and port are used.
+   * @param id the id of the application
+   * @return the proxied URI
+   */
+  public static URI getProxyUri(URI originalUri, URI proxyUri,
+      ApplicationId id) {
+    try {
+      String path = getPath(id, originalUri.getPath());
+      return new URI(proxyUri.getScheme(), proxyUri.getAuthority(), path,
+          originalUri.getQuery(), originalUri.getFragment());
+    } catch (URISyntaxException e) {
+      throw new RuntimeException("Could not proxify "+originalUri,e);
+    }
+  }
+  
+  /**
+   * Create a URI form a no scheme Url, such as is returned by the AM.
+   * @param noSchemeUrl the URL formate returned by an AM
+   * @return a URI with an http scheme
+   * @throws URISyntaxException if the url is not formatted correctly.
+   */
+  public static URI getUriFromAMUrl(String noSchemeUrl) 
+    throws URISyntaxException {
+    return new URI("http://"+noSchemeUrl);
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/WebAppProxy.java

@@ -0,0 +1,111 @@
+/**
+* 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.yarn.server.webproxy;
+
+import java.io.IOException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.http.HttpServer;
+import org.apache.hadoop.security.authorize.AccessControlList;
+import org.apache.hadoop.util.StringUtils;
+import org.apache.hadoop.yarn.YarnException;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.service.AbstractService;
+
+import org.apache.hadoop.fs.CommonConfigurationKeys;
+
+public class WebAppProxy extends AbstractService {
+  public static final String FETCHER_ATTRIBUTE= "AppUrlFetcher";
+  public static final String IS_SECURITY_ENABLED_ATTRIBUTE = "IsSecurityEnabled";
+  private static final Log LOG = LogFactory.getLog(WebAppProxy.class);
+  
+  private HttpServer proxyServer = null;
+  private String bindAddress = null;
+  private int port = 0;
+  private AccessControlList acl = null;
+  private AppReportFetcher fetcher = null;
+  private boolean isSecurityEnabled = false;
+  
+  public WebAppProxy() {
+    super(WebAppProxy.class.getName());
+  }
+  
+  @Override
+  public void init(Configuration conf) {
+    String auth =  conf.get(CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION);
+    if (auth == null || "simple".equals(auth)) {
+      isSecurityEnabled = false;
+    } else if ("kerberos".equals(auth)) {
+      isSecurityEnabled = true;
+    } else {
+      LOG.warn("Unrecongized attribute value for " +
+          CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION +
+          " of " + auth);
+    }
+
+    fetcher = new AppReportFetcher(conf);
+    bindAddress = conf.get(YarnConfiguration.PROXY_ADDRESS);
+    if(bindAddress == null || bindAddress.isEmpty()) {
+      throw new YarnException(YarnConfiguration.PROXY_ADDRESS + 
+          " is not set so the proxy will not run.");
+    }
+    LOG.info("Instantiating Proxy at " + bindAddress);
+    String[] parts = StringUtils.split(bindAddress, ':');
+    port = 0;
+    if (parts.length == 2) {
+      bindAddress = parts[0];
+      port = Integer.parseInt(parts[1]);
+    }
+    acl = new AccessControlList(conf.get(YarnConfiguration.YARN_ADMIN_ACL, 
+        YarnConfiguration.DEFAULT_YARN_ADMIN_ACL));
+    super.init(conf);
+  }
+  
+  @Override
+  public void start() {
+    try {
+      proxyServer = new HttpServer("proxy", bindAddress, port,
+          port == 0, getConfig(), acl);
+      proxyServer.addServlet(ProxyUriUtils.PROXY_SERVLET_NAME, 
+          ProxyUriUtils.PROXY_PATH_SPEC, WebAppProxyServlet.class);
+      proxyServer.setAttribute(FETCHER_ATTRIBUTE, fetcher);
+      proxyServer.setAttribute(IS_SECURITY_ENABLED_ATTRIBUTE, isSecurityEnabled);
+      proxyServer.start();
+    } catch (IOException e) {
+      LOG.fatal("Could not start proxy web server",e);
+      throw new YarnException("Could not start proxy web server",e);
+    }
+    super.start();
+  }
+  
+  @Override
+  public void stop() {
+    if(proxyServer != null) {
+      try {
+        proxyServer.stop();
+      } catch (Exception e) {
+        LOG.fatal("Error stopping proxy web server", e);
+        throw new YarnException("Error stopping proxy web server",e);
+      }
+    }
+    super.stop();
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/WebAppProxyServer.java

@@ -0,0 +1,83 @@
+/**
+* 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.yarn.server.webproxy;
+
+import java.io.IOException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.security.SecurityUtil;
+import org.apache.hadoop.util.StringUtils;
+import org.apache.hadoop.yarn.YarnException;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.service.CompositeService;
+
+/**
+ * ProxyServer will sit in between the end user and AppMaster
+ * web interfaces. 
+ */
+public class WebAppProxyServer extends CompositeService {
+  private static final Log LOG = LogFactory.getLog(WebAppProxyServer.class);
+  
+  private WebAppProxy proxy = null;
+  
+  public WebAppProxyServer() {
+    super(WebAppProxyServer.class.getName());
+  }
+
+  @Override
+  public synchronized void init(Configuration conf) {
+    Configuration config = new YarnConfiguration(conf);
+    try {
+      doSecureLogin(conf);      
+    } catch(IOException ie) {
+      throw new YarnException("Proxy Server Failed to login", ie);
+    }
+    proxy = new WebAppProxy();
+    addService(proxy);
+    super.init(config);
+  }
+
+  /**
+   * Log in as the Kerberose principal designated for the proxy
+   * @param conf the configuration holding this information in it.
+   * @throws IOException on any error.
+   */
+  protected void doSecureLogin(Configuration conf) throws IOException {
+    SecurityUtil.login(conf, YarnConfiguration.PROXY_KEYTAB,
+        YarnConfiguration.PROXY_PRINCIPAL);
+  }
+
+  public static void main(String[] args) {
+    StringUtils.startupShutdownMessage(WebAppProxyServer.class, args, LOG);
+    try {
+      WebAppProxyServer proxy = new WebAppProxyServer();
+      Runtime.getRuntime().addShutdownHook(
+          new CompositeServiceShutdownHook(proxy));
+      YarnConfiguration conf = new YarnConfiguration();
+      proxy.init(conf);
+      proxy.start();
+    } catch (Throwable t) {
+      LOG.fatal("Error starting Proxy server", t);
+      System.exit(-1);
+    }
+  }
+
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/WebAppProxyServlet.java

@@ -0,0 +1,275 @@
+/**
+* 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.yarn.server.webproxy;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URLEncoder;
+import java.util.Arrays;
+import java.util.EnumSet;
+import java.util.Enumeration;
+import java.util.HashSet;
+
+import javax.servlet.http.Cookie;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.commons.httpclient.Header;
+import org.apache.commons.httpclient.HttpClient;
+import org.apache.commons.httpclient.HttpMethod;
+import org.apache.commons.httpclient.methods.GetMethod;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.io.IOUtils;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.ApplicationReport;
+import org.apache.hadoop.yarn.util.Apps;
+import org.apache.hadoop.yarn.util.StringHelper;
+import org.apache.hadoop.yarn.webapp.MimeType;
+import org.apache.hadoop.yarn.webapp.hamlet.Hamlet;
+
+public class WebAppProxyServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
+  private static final Log LOG = LogFactory.getLog(WebAppProxyServlet.class);
+  private static final HashSet<String> passThroughHeaders = 
+    new HashSet<String>(Arrays.asList("User-Agent", "Accept", "Accept-Encoding",
+        "Accept-Language", "Accept-Charset"));
+  
+  public static final String PROXY_USER_COOKIE_NAME = "proxy-user";
+  
+  
+  private static class _ implements Hamlet._ {
+    //Empty
+  }
+  
+  private static class Page extends Hamlet {
+    Page(PrintWriter out) {
+      super(out, 0, false);
+    }
+  
+    public HTML<WebAppProxyServlet._> html() {
+      return new HTML<WebAppProxyServlet._>("html", null, EnumSet.of(EOpt.ENDTAG));
+    }
+  }
+
+  /**
+   * Output 404 with appropriate message.
+   * @param resp the http response.
+   * @param message the message to include on the page.
+   * @throws IOException on any error.
+   */
+  private static void notFound(HttpServletResponse resp, String message) 
+    throws IOException {
+    resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
+    resp.setContentType(MimeType.HTML);
+    Page p = new Page(resp.getWriter());
+    p.html().
+      h1(message).
+    _();
+  }
+  
+  /**
+   * Warn the user that the link may not be safe!
+   * @param resp the http response
+   * @param link the link to point to
+   * @param user the user that owns the link.
+   * @throws IOException on any error.
+   */
+  private static void warnUserPage(HttpServletResponse resp, String link, 
+      String user, ApplicationId id) throws IOException {
+    //Set the cookie when we warn which overrides the query parameter
+    //This is so that if a user passes in the approved query parameter without
+    //having first visited this page then this page will still be displayed 
+    resp.addCookie(makeCheckCookie(id, false));
+    resp.setContentType(MimeType.HTML);
+    Page p = new Page(resp.getWriter());
+    p.html().
+      h1("WARNING: The following page may not be safe!").h3().
+      _("click ").a(link, "here").
+      _(" to continue to an Application Master web interface owned by ", user).
+      _().
+    _();
+  }
+  
+  /**
+   * Download link and have it be the response.
+   * @param req the http request
+   * @param resp the http response
+   * @param link the link to download
+   * @param c the cookie to set if any
+   * @throws IOException on any error.
+   */
+  private static void proxyLink(HttpServletRequest req, 
+      HttpServletResponse resp, URI link,Cookie c) throws IOException {
+    org.apache.commons.httpclient.URI uri = 
+      new org.apache.commons.httpclient.URI(link.toString(), false);
+    HttpClient client = new HttpClient();
+    HttpMethod method = new GetMethod(uri.getEscapedURI());
+
+    @SuppressWarnings("unchecked")
+    Enumeration<String> names = req.getHeaderNames();
+    while(names.hasMoreElements()) {
+      String name = names.nextElement();
+      if(passThroughHeaders.contains(name)) {
+        String value = req.getHeader(name);
+        LOG.debug("REQ HEADER: "+name+" : "+value);
+        method.setRequestHeader(name, value);
+      }
+    }
+
+    String user = req.getRemoteUser();
+    if(user != null && !user.isEmpty()) {
+      method.setRequestHeader("Cookie",PROXY_USER_COOKIE_NAME+"="+
+          URLEncoder.encode(user, "ASCII"));
+    }
+    OutputStream out = resp.getOutputStream();
+    try {
+      resp.setStatus(client.executeMethod(method));
+      for(Header header : method.getResponseHeaders()) {
+        resp.setHeader(header.getName(), header.getValue());
+      }
+      if(c != null) {
+        resp.addCookie(c);
+      }
+      InputStream in = method.getResponseBodyAsStream();
+      if(in != null) {
+        IOUtils.copyBytes(in, out, 4096, true);
+      }
+    } finally {
+      method.releaseConnection();
+    }
+  }
+  
+  private static String getCheckCookieName(ApplicationId id){
+    return "checked_"+id;
+  }
+  
+  private static Cookie makeCheckCookie(ApplicationId id, boolean isSet) {
+    Cookie c = new Cookie(getCheckCookieName(id),String.valueOf(isSet));
+    c.setPath(ProxyUriUtils.getPath(id));
+    c.setMaxAge(60 * 60 * 2); //2 hours in seconds
+    return c;
+  }
+  
+  private boolean isSecurityEnabled() {
+    Boolean b = (Boolean) getServletContext()
+        .getAttribute(WebAppProxy.IS_SECURITY_ENABLED_ATTRIBUTE);
+    if(b != null) return b;
+    return false;
+  }
+  
+  private ApplicationReport getApplicationReport(ApplicationId id) throws IOException {
+    return ((AppReportFetcher) getServletContext()
+        .getAttribute(WebAppProxy.FETCHER_ATTRIBUTE)).getApplicationReport(id);
+  }
+  
+  @Override
+  protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
+  throws IOException{
+    try {
+      String userApprovedParamS = 
+        req.getParameter(ProxyUriUtils.PROXY_APPROVAL_PARAM);
+      boolean userWasWarned = false;
+      boolean userApproved = 
+        (userApprovedParamS != null && Boolean.valueOf(userApprovedParamS));
+      boolean securityEnabled = isSecurityEnabled();
+      final String remoteUser = req.getRemoteUser();
+      final String pathInfo = req.getPathInfo();
+
+      String parts[] = pathInfo.split("/", 3);
+      if(parts.length < 2) {
+        LOG.warn(remoteUser+" Gave an invalid proxy path "+pathInfo);
+        notFound(resp, "Your path appears to be formatted incorrectly.");
+        return;
+      }
+      //parts[0] is empty because path info always starts with a /
+      String appId = parts[1];
+      String rest = parts.length > 2 ? parts[2] : "";
+      ApplicationId id = Apps.toAppID(appId);
+      if(id == null) {
+        LOG.warn(req.getRemoteUser()+" Attempting to access "+appId+
+        " that is invalid");
+        notFound(resp, appId+" appears to be formatted incorrectly.");
+        return;
+      }
+      
+      if(securityEnabled) {
+        String cookieName = getCheckCookieName(id); 
+        for(Cookie c: req.getCookies()) {
+          if(cookieName.equals(c.getName())) {
+            userWasWarned = true;
+            userApproved = userApproved || Boolean.valueOf(c.getValue());
+            break;
+          }
+        }
+      }
+      
+      boolean checkUser = securityEnabled && (!userWasWarned || !userApproved);
+
+      ApplicationReport applicationReport = getApplicationReport(id);
+      if(applicationReport == null) {
+        LOG.warn(req.getRemoteUser()+" Attempting to access "+id+
+            " that was not found");
+        notFound(resp, "Application "+appId+" could not be found, " +
+        		"please try the history server");
+        return;
+      }
+      URI trackingUri = ProxyUriUtils.getUriFromAMUrl(
+          applicationReport.getOriginalTrackingUrl());
+      
+      String runningUser = applicationReport.getUser();
+      if(checkUser && !runningUser.equals(remoteUser)) {
+        LOG.info("Asking "+remoteUser+" if they want to connect to the " +
+            "app master GUI of "+appId+" owned by "+runningUser);
+        warnUserPage(resp, ProxyUriUtils.getPathAndQuery(id, rest, 
+            req.getQueryString(), true), runningUser, id);
+        return;
+      }
+      
+      URI toFetch = new URI(req.getScheme(), 
+          trackingUri.getAuthority(),
+          StringHelper.ujoin(trackingUri.getPath(), rest), req.getQueryString(),
+          null);
+      
+      LOG.info(req.getRemoteUser()+" is accessing unchecked "+toFetch+
+          " which is the app master GUI of "+appId+" owned by "+runningUser);
+
+      switch(applicationReport.getYarnApplicationState()) {
+      case KILLED:
+      case FINISHED:
+      case FAILED:
+        resp.sendRedirect(resp.encodeRedirectURL(toFetch.toString()));
+        return;
+      }
+      Cookie c = null;
+      if(userWasWarned && userApproved) {
+        c = makeCheckCookie(id, true);
+      }
+      proxyLink(req, resp, toFetch, c);
+
+    } catch(URISyntaxException e) {
+      throw new IOException(e); 
+    }
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/amfilter/AmFilterInitializer.java

@@ -0,0 +1,45 @@
+/**
+* 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.yarn.server.webproxy.amfilter;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.http.FilterContainer;
+import org.apache.hadoop.http.FilterInitializer;
+import org.apache.hadoop.yarn.api.ApplicationConstants;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+
+public class AmFilterInitializer extends FilterInitializer {
+  private static final String FILTER_NAME = "AM_PROXY_FILTER";
+  private static final String FILTER_CLASS = AmIpFilter.class.getCanonicalName();
+  
+  @Override
+  public void initFilter(FilterContainer container, Configuration conf) {
+    Map<String, String> params = new HashMap<String, String>();
+    String proxy = YarnConfiguration.getProxyHostAndPort(conf);
+    String[] parts = proxy.split(":");
+    params.put(AmIpFilter.PROXY_HOST, parts[0]);
+    params.put(AmIpFilter.PROXY_URI_BASE, "http://"+proxy+
+        System.getenv(ApplicationConstants.APPLICATION_WEB_PROXY_BASE_ENV));
+    container.addFilter(FILTER_NAME, FILTER_CLASS, params);
+  }
+
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/amfilter/AmIpFilter.java

@@ -0,0 +1,117 @@
+/**
+* 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.yarn.server.webproxy.amfilter;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.Cookie;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.yarn.server.webproxy.WebAppProxyServlet;
+
+public class AmIpFilter implements Filter {
+  private static final Log LOG = LogFactory.getLog(AmIpFilter.class);
+  
+  public static final String PROXY_HOST = "PROXY_HOST";
+  public static final String PROXY_URI_BASE = "PROXY_URI_BASE";
+  //update the proxy IP list about every 5 min
+  private static final long updateInterval = 5 * 60 * 1000;
+  
+  private String proxyHost;
+  private Set<String> proxyAddresses = null;
+  private long lastUpdate;
+  private String proxyUriBase;
+  
+  @Override
+  public void init(FilterConfig conf) throws ServletException {
+    proxyHost = conf.getInitParameter(PROXY_HOST);
+    proxyUriBase = conf.getInitParameter(PROXY_URI_BASE);
+  }
+  
+  private Set<String> getProxyAddresses() throws ServletException {
+    long now = System.currentTimeMillis();
+    if(proxyAddresses == null || (lastUpdate + updateInterval) >= now) {
+      synchronized(this) {
+        try {
+          proxyAddresses = new HashSet<String>();
+          for(InetAddress add : InetAddress.getAllByName(proxyHost)) {
+            proxyAddresses.add(add.getHostAddress());
+          }
+          lastUpdate = now;
+        } catch (UnknownHostException e) {
+          throw new ServletException("Could not locate "+proxyHost, e);
+        }
+      }
+    }
+    return proxyAddresses;
+  }
+
+  @Override
+  public void destroy() {
+    //Empty
+  }
+
+  @Override
+  public void doFilter(ServletRequest req, ServletResponse resp,
+      FilterChain chain) throws IOException, ServletException {
+    if(!(req instanceof HttpServletRequest)) {
+      throw new ServletException("This filter only works for HTTP/HTTPS");
+    }
+    
+    HttpServletRequest httpReq = (HttpServletRequest)req;
+    HttpServletResponse httpResp = (HttpServletResponse)resp;
+    if(!getProxyAddresses().contains(httpReq.getRemoteAddr())) {
+      String redirectUrl = httpResp.encodeRedirectURL(proxyUriBase + 
+          httpReq.getRequestURI());
+      httpResp.sendRedirect(redirectUrl);
+      return;
+    }
+    
+    String user = null;
+    for(Cookie c: httpReq.getCookies()) {
+      if(WebAppProxyServlet.PROXY_USER_COOKIE_NAME.equals(c.getName())){
+        user = c.getValue();
+        break;
+      }
+    }
+    if(user == null) {
+      LOG.warn("Could not find "+WebAppProxyServlet.PROXY_USER_COOKIE_NAME
+          +" cookie, so user will not be set");
+      chain.doFilter(req, resp);
+    } else {
+      final AmIpPrincipal principal = new AmIpPrincipal(user);
+      ServletRequest requestWrapper = new AmIpServletRequestWrapper(httpReq, 
+          principal);
+      chain.doFilter(requestWrapper, resp);
+    }
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/amfilter/AmIpPrincipal.java

@@ -0,0 +1,34 @@
+/**
+* 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.yarn.server.webproxy.amfilter;
+
+import java.security.Principal;
+
+public class AmIpPrincipal implements Principal {
+  private final String name;
+  
+  public AmIpPrincipal(String name) {
+    this.name = name;
+  }
+  
+  @Override
+  public String getName() {
+    return name;
+  }
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/amfilter/AmIpServletRequestWrapper.java

@@ -0,0 +1,51 @@
+/**
+* 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.yarn.server.webproxy.amfilter;
+
+import java.security.Principal;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletRequestWrapper;
+
+public class AmIpServletRequestWrapper extends HttpServletRequestWrapper {
+  private final AmIpPrincipal principal;
+
+  public AmIpServletRequestWrapper(HttpServletRequest request, 
+      AmIpPrincipal principal) {
+    super(request);
+    this.principal = principal;
+  }
+
+  @Override
+  public Principal getUserPrincipal() {
+    return principal;
+  }
+
+  @Override
+  public String getRemoteUser() {
+    return principal.getName();
+  }
+
+  @Override
+  public boolean isUserInRole(String role) {
+    //No role info so far
+    return false;
+  }
+
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/test/java/org/apache/hadoop/yarn/server/webproxy/TestProxyUriUtils.java

@@ -0,0 +1,104 @@
+/**
+* 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.yarn.server.webproxy;
+
+import static org.junit.Assert.*;
+
+import java.net.URI;
+
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.junit.Test;
+
+public class TestProxyUriUtils {
+  public static class TestAppId extends ApplicationId {
+    private long timestamp;
+    private int id;
+
+    public TestAppId(int id, long timestamp) {
+      setId(id);
+      setClusterTimestamp(timestamp);
+    }
+    @Override
+    public int getId() {
+      return id;
+    }
+
+    @Override
+    public void setId(int id) {
+      this.id = id;
+    }
+
+    @Override
+    public long getClusterTimestamp() {
+      return timestamp;
+    }
+
+    @Override
+    public void setClusterTimestamp(long clusterTimestamp) {
+      this.timestamp = clusterTimestamp;
+    }
+  }
+  
+  @Test
+  public void testGetPathApplicationId() {
+    assertEquals("/proxy/application_100_0001", 
+        ProxyUriUtils.getPath(new TestAppId(1, 100l)));
+    assertEquals("/proxy/application_6384623_0005", 
+        ProxyUriUtils.getPath(new TestAppId(5, 6384623l)));
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testGetPathApplicationIdBad() {
+    ProxyUriUtils.getPath(null);
+  }
+  
+  @Test
+  public void testGetPathApplicationIdString() {
+    assertEquals("/proxy/application_6384623_0005", 
+        ProxyUriUtils.getPath(new TestAppId(5, 6384623l), null));
+    assertEquals("/proxy/application_6384623_0005/static/app",
+        ProxyUriUtils.getPath(new TestAppId(5, 6384623l), "/static/app"));
+    assertEquals("/proxy/application_6384623_0005/", 
+        ProxyUriUtils.getPath(new TestAppId(5, 6384623l), "/"));
+    assertEquals("/proxy/application_6384623_0005/some/path", 
+        ProxyUriUtils.getPath(new TestAppId(5, 6384623l), "some/path"));
+  }
+  
+  @Test 
+  public void testGetPathAndQuery() {
+    assertEquals("/proxy/application_6384623_0005/static/app?foo=bar",
+    ProxyUriUtils.getPathAndQuery(new TestAppId(5, 6384623l), "/static/app", 
+        "?foo=bar", false));
+    
+    assertEquals("/proxy/application_6384623_0005/static/app?foo=bar&bad=good&proxyapproved=true",
+        ProxyUriUtils.getPathAndQuery(new TestAppId(5, 6384623l), "/static/app", 
+            "foo=bar&bad=good", true));
+  }
+
+  @Test
+  public void testGetProxyUri() throws Exception {
+    URI originalUri = new URI("http://host.com/static/foo?bar=bar");
+    URI proxyUri = new URI("http://proxy.net:8080/");
+    TestAppId id = new TestAppId(5, 6384623l);
+    URI expected = new URI("http://proxy.net:8080/proxy/application_6384623_0005/static/foo?bar=bar");
+    URI result = ProxyUriUtils.getProxyUri(originalUri, proxyUri, id);
+    assertEquals(expected, result);
+  }
+
+}

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/pom.xml

@@ -37,6 +37,7 @@
   <modules>
     <module>hadoop-yarn-server-common</module>
     <module>hadoop-yarn-server-nodemanager</module>
+    <module>hadoop-yarn-server-web-proxy</module>
     <module>hadoop-yarn-server-resourcemanager</module>
     <module>hadoop-yarn-server-tests</module>
   </modules>

hadoop-mapreduce-project/hadoop-yarn/pom.xml

@@ -334,6 +334,11 @@
         <artifactId>hadoop-yarn-server-common</artifactId>
         <version>${project.version}</version>
       </dependency>
+      <dependency>
+        <groupId>org.apache.hadoop</groupId>
+        <artifactId>hadoop-yarn-server-web-proxy</artifactId>
+        <version>${project.version}</version>
+      </dependency>
       <dependency>
         <groupId>org.apache.hadoop</groupId>
         <artifactId>hadoop-yarn-server-resourcemanager</artifactId>