YARN-11367. [Federation] Fix DefaultRequestInterceptorREST Client NPE. (#5100)

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

@@ -19,6 +19,10 @@
 package org.apache.hadoop.yarn.server.router.webapp;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
+
+import java.io.IOException;
 
 /**
  * Extends the RequestInterceptor class and provides common functionality which
@@ -29,6 +33,7 @@ public abstract class AbstractRESTRequestInterceptor
 
   private Configuration conf;
   private RESTRequestInterceptor nextInterceptor;
+  private UserGroupInformation user = null;
 
   /**
    * Sets the {@link RESTRequestInterceptor} in the chain.
@@ -62,9 +67,10 @@ public abstract class AbstractRESTRequestInterceptor
    * Initializes the {@link RESTRequestInterceptor}.
    */
   @Override
-  public void init(String user) {
+  public void init(String userName) {
+    setupUser(userName);
     if (this.nextInterceptor != null) {
-      this.nextInterceptor.init(user);
+      this.nextInterceptor.init(userName);
     }
   }
 
@@ -86,4 +92,35 @@ public abstract class AbstractRESTRequestInterceptor
     return this.nextInterceptor;
   }
 
+  /**
+   * Set User information.
+   *
+   * If the username is empty, we will use the Yarn Router user directly.
+   * Do not create a proxy user if user name matches the user name on current UGI.
+   * @param userName userName.
+   */
+  private void setupUser(final String userName) {
+    try {
+      if (userName == null || userName.isEmpty()) {
+        user = UserGroupInformation.getCurrentUser();
+      } else if (UserGroupInformation.isSecurityEnabled()) {
+        user = UserGroupInformation.createProxyUser(userName, UserGroupInformation.getLoginUser());
+      } else if (userName.equalsIgnoreCase(UserGroupInformation.getCurrentUser().getUserName())) {
+        user = UserGroupInformation.getCurrentUser();
+      } else {
+        user = UserGroupInformation.createProxyUser(userName,
+            UserGroupInformation.getCurrentUser());
+      }
+    } catch (IOException e) {
+      String message = "Error while creating Router RMAdmin Service for user:";
+      if (user != null) {
+        message += ", user: " + user;
+      }
+      throw new YarnRuntimeException(message, e);
+    }
+  }
+
+  public UserGroupInformation getUser() {
+    return user;
+  }
 }

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

@@ -28,6 +28,7 @@ import javax.servlet.http.HttpServletResponse;
 import javax.ws.rs.core.Response;
 
 import com.sun.jersey.api.client.Client;
+import org.apache.hadoop.classification.VisibleForTesting;
 import org.apache.hadoop.security.authorize.AuthorizationException;
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
@@ -603,6 +604,11 @@ public class DefaultRequestInterceptorREST
             null, getConf(), client);
   }
 
+  @VisibleForTesting
+  public Client getClient() {
+    return client;
+  }
+
   @Override
   public NodeLabelsInfo getRMNodeLabels(HttpServletRequest hsr) {
     return RouterWebServiceUtil.genericForward(webAppAddress, hsr,

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

@@ -152,6 +152,9 @@ public class FederationInterceptorREST extends AbstractRESTRequestInterceptor {
 
   @Override
   public void init(String user) {
+
+    super.init(user);
+
     federationFacade = FederationStateStoreFacade.getInstance();
     rand = new Random();
 
@@ -239,7 +242,8 @@ public class FederationInterceptorREST extends AbstractRESTRequestInterceptor {
           .isAssignableFrom(interceptorClass)) {
         interceptorInstance = (DefaultRequestInterceptorREST) ReflectionUtils
             .newInstance(interceptorClass, conf);
-
+        String userName = getUser().getUserName();
+        interceptorInstance.init(userName);
       } else {
         throw new YarnRuntimeException(
             "Class: " + interceptorClassName + " not instance of "

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

@@ -1257,4 +1257,23 @@ public class TestFederationInterceptorREST extends BaseRouterWebServicesTest {
     when(mockHsr.getUserPrincipal()).thenReturn(principal);
     return mockHsr;
   }
+
+  @Test
+  public void testCheckFederationInterceptorRESTClient() {
+    SubClusterId subClusterId = SubClusterId.newInstance("SC-1");
+    String webAppSocket = "SC-1:WebAddress";
+    String webAppAddress = "http://" + webAppSocket;
+
+    Configuration configuration = new Configuration();
+    FederationInterceptorREST rest = new FederationInterceptorREST();
+    rest.setConf(configuration);
+    rest.init("router");
+
+    DefaultRequestInterceptorREST interceptorREST =
+        rest.getOrCreateInterceptorForSubCluster(subClusterId, webAppSocket);
+
+    Assert.assertNotNull(interceptorREST);
+    Assert.assertNotNull(interceptorREST.getClient());
+    Assert.assertEquals(webAppAddress, interceptorREST.getWebAppAddress());
+  }
 }