YARN-8593. Add RM web service endpoint to get user information. Contributed by Akhil PB.

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

@@ -222,6 +222,10 @@ public class ResourceManager extends CompositeService implements Recoverable {
     return clusterTimeStamp;
   }
 
+  public String getRMLoginUser() {
+    return rmLoginUGI.getShortUserName();
+  }
+
   @VisibleForTesting
   protected static void setClusterTimeStamp(long timestamp) {
     clusterTimeStamp = timestamp;

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWSConsts.java

@@ -36,6 +36,9 @@ public final class RMWSConsts {
   /** Path for {@code RMWebServiceProtocol#getClusterInfo}. */
   public static final String INFO = "/info";
 
+  /** Path for {@code RMWebServiceProtocol#getClusterUserInfo}. */
+  public static final String CLUSTER_USER_INFO = "/userinfo";
+
   /** Path for {@code RMWebServiceProtocol#getClusterMetricsInfo}. */
   public static final String METRICS = "/metrics";
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWebServiceProtocol.java

@@ -46,6 +46,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ApplicationSubmi
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.LabelsToNodesInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.NodeInfo;
@@ -88,6 +89,15 @@ public interface RMWebServiceProtocol {
    */
   ClusterInfo getClusterInfo();
 
+
+  /**
+   * This method retrieves the cluster user information, and it is reachable by using
+   * {@link RMWSConsts#CLUSTER_USER_INFO}.
+   *
+   * @return the cluster user information
+   */
+  ClusterUserInfo getClusterUserInfo(HttpServletRequest hsr);
+
   /**
    * This method retrieves the cluster metrics information, and it is reachable
    * by using {@link RMWSConsts#METRICS}.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWebServices.java

@@ -160,6 +160,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.CapacitySchedulerInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.FairSchedulerInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.FifoSchedulerInfo;
@@ -335,6 +336,17 @@ public class RMWebServices extends WebServices implements RMWebServiceProtocol {
     return new ClusterInfo(this.rm);
   }
 
+  @GET
+  @Path(RMWSConsts.CLUSTER_USER_INFO)
+  @Produces({ MediaType.APPLICATION_JSON + "; " + JettyUtils.UTF_8,
+      MediaType.APPLICATION_XML + "; " + JettyUtils.UTF_8 })
+  @Override
+  public ClusterUserInfo getClusterUserInfo(@Context HttpServletRequest hsr) {
+    initForReadableEndpoints();
+    UserGroupInformation callerUGI = getCallerUserGroupInformation(hsr, true);
+    return new ClusterUserInfo(this.rm, callerUGI);
+  }
+
   @GET
   @Path(RMWSConsts.METRICS)
   @Produces({ MediaType.APPLICATION_JSON + "; " + JettyUtils.UTF_8,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/dao/ClusterUserInfo.java

@@ -0,0 +1,64 @@
+/**
+ * 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.resourcemanager.webapp.dao;
+
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.yarn.server.resourcemanager.ResourceManager;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlRootElement;
+
+/**
+ * The YARN UI doesn't have centralized login mechanism. While accessing UI2 from kerberized shell, user who is
+ * placed the request to YARN need to be displayed in UI. Given requests from UI2 is routed via Proxy, only RM can provide
+ * the user who has placed the request. This DAO object help to provide the requested user and also RM logged in user.
+ * the response sent by RM is authenticated user instead of proxy user.
+ * It is always good to display authenticated user in browser which eliminates lot of confusion to end use.
+ */
+@XmlRootElement
+@XmlAccessorType(XmlAccessType.FIELD)
+@InterfaceStability.Unstable
+public class ClusterUserInfo {
+
+    // User who has started the RM
+    protected String rmLoginUser;
+    // User who has placed the request
+    protected String requestedUser;
+
+    public ClusterUserInfo() {
+    }
+
+    public ClusterUserInfo(ResourceManager rm, UserGroupInformation ugi) {
+        this.rmLoginUser = rm.getRMLoginUser();
+        if (ugi != null) {
+            this.requestedUser = ugi.getShortUserName();
+        } else {
+            this.requestedUser = "UNKNOWN_USER";
+        }
+    }
+
+    public String getRmLoginUser() {
+        return rmLoginUser;
+    }
+
+    public String getRequestedUser() {
+        return requestedUser;
+    }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/TestRMWebServices.java

@@ -61,6 +61,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.Capacity
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.fifo.FifoScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.security.ApplicationACLsManager;
 import org.apache.hadoop.yarn.util.AdHocLogDumper;
 import org.apache.hadoop.yarn.util.YarnVersionInfo;
@@ -843,4 +844,24 @@ public class TestRMWebServices extends JerseyTestBase {
     Assert.assertFalse(webSvc.checkUserAccessToQueue("queue", "yarn",
         QueueACL.ADMINISTER_QUEUE.name(), mockHsr).isAllowed());
   }
+
+  @Test
+  public void testClusterUserInfo() throws JSONException, Exception {
+    ResourceManager mockRM = mock(ResourceManager.class);
+    Configuration conf = new YarnConfiguration();
+    HttpServletRequest mockHsr = mockHttpServletRequestByUserName("admin");
+    when(mockRM.getRMLoginUser()).thenReturn("yarn");
+    RMWebServices webSvc =
+            new RMWebServices(mockRM, conf, mock(HttpServletResponse.class));
+    ClusterUserInfo userInfo = webSvc.getClusterUserInfo(mockHsr);
+    verifyClusterUserInfo(userInfo, "yarn", "admin");
+  }
+
+  public void verifyClusterUserInfo(ClusterUserInfo userInfo,
+            String rmLoginUser, String requestedUser) {
+    assertEquals("rmLoginUser doesn't match: ",
+            rmLoginUser, userInfo.getRmLoginUser());
+    assertEquals("requestedUser doesn't match: ",
+            requestedUser, userInfo.getRequestedUser());
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/webapp/DefaultRequestInterceptorREST.java

@@ -46,6 +46,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ApplicationSubmi
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.LabelsToNodesInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.NodeInfo;
@@ -103,6 +104,13 @@ public class DefaultRequestInterceptorREST
         RMWSConsts.RM_WEB_SERVICE_PATH + RMWSConsts.INFO, null, null);
   }
 
+  @Override
+  public ClusterUserInfo getClusterUserInfo(HttpServletRequest hsr) {
+    return RouterWebServiceUtil.genericForward(webAppAddress, hsr,
+            ClusterUserInfo.class, HTTPMethods.GET,
+            RMWSConsts.RM_WEB_SERVICE_PATH + RMWSConsts.CLUSTER_USER_INFO, null, null);
+  }
+
   @Override
   public ClusterMetricsInfo getClusterMetricsInfo() {
     return RouterWebServiceUtil.genericForward(webAppAddress, null,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/webapp/FederationInterceptorREST.java

@@ -72,6 +72,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ApplicationSubmi
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.LabelsToNodesInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.NodeInfo;
@@ -1043,6 +1044,11 @@ public class FederationInterceptorREST extends AbstractRESTRequestInterceptor {
     throw new NotImplementedException("Code is not implemented");
   }
 
+  @Override
+  public ClusterUserInfo getClusterUserInfo(HttpServletRequest hsr) {
+    throw new NotImplementedException("Code is not implemented");
+  }
+
   @Override
   public SchedulerTypeInfo getSchedulerInfo() {
     throw new NotImplementedException("Code is not implemented");

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/webapp/RouterWebServices.java

@@ -68,6 +68,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ApplicationSubmi
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.LabelsToNodesInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.NodeInfo;
@@ -326,6 +327,17 @@ public class RouterWebServices implements RMWebServiceProtocol {
     return pipeline.getRootInterceptor().getClusterInfo();
   }
 
+  @GET
+  @Path(RMWSConsts.CLUSTER_USER_INFO)
+  @Produces({ MediaType.APPLICATION_JSON + "; " + JettyUtils.UTF_8,
+          MediaType.APPLICATION_XML + "; " + JettyUtils.UTF_8 })
+  @Override
+  public ClusterUserInfo getClusterUserInfo(@Context HttpServletRequest hsr) {
+    init();
+    RequestInterceptorChainWrapper pipeline = getInterceptorChain(hsr);
+    return pipeline.getRootInterceptor().getClusterUserInfo(hsr);
+  }
+
   @GET
   @Path(RMWSConsts.METRICS)
   @Produces({ MediaType.APPLICATION_JSON + "; " + JettyUtils.UTF_8,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/webapp/MockRESTRequestInterceptor.java

@@ -43,6 +43,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ApplicationSubmi
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.LabelsToNodesInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.NodeInfo;
@@ -82,6 +83,11 @@ public class MockRESTRequestInterceptor extends AbstractRESTRequestInterceptor {
     return new ClusterInfo();
   }
 
+  @Override
+  public ClusterUserInfo getClusterUserInfo(HttpServletRequest hsr) {
+    return new ClusterUserInfo();
+  }
+
   @Override
   public ClusterMetricsInfo getClusterMetricsInfo() {
     return new ClusterMetricsInfo();

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/webapp/PassThroughRESTRequestInterceptor.java

@@ -41,6 +41,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ApplicationSubmi
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.AppsInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterMetricsInfo;
+import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.ClusterUserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.DelegationToken;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.LabelsToNodesInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.NodeInfo;
@@ -107,6 +108,11 @@ public class PassThroughRESTRequestInterceptor
     return getNextInterceptor().getClusterInfo();
   }
 
+  @Override
+  public ClusterUserInfo getClusterUserInfo(HttpServletRequest hsr) {
+    return getNextInterceptor().getClusterUserInfo(hsr);
+  }
+
   @Override
   public ClusterMetricsInfo getClusterMetricsInfo() {
     return getNextInterceptor().getClusterMetricsInfo();