YARN-11121:Check GetClusterMetrics Request parameter is null

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/clientrm/FederationClientInterceptor.java

@@ -703,6 +703,12 @@ public GetApplicationsResponse getApplications(GetApplicationsRequest request)
   @Override
   public GetClusterMetricsResponse getClusterMetrics(
       GetClusterMetricsRequest request) throws YarnException, IOException {
+    if(request == null) {
+      routerMetrics.incrGetClusterMetricsFailedRetrieved();
+      RouterServerUtil.logAndThrowException(
+              "Missing getClusterMetrics request.",
+              null);
+    }
     long startTime = clock.getTime();
     Map<SubClusterId, SubClusterInfo> subclusters =
         federationFacade.getSubClusters(true);

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/clientrm/TestFederationClientInterceptor.java

@@ -516,14 +516,14 @@ public void testGetApplicationAttemptEmptyRequest()
 
 
   @Test
-  public void testGetClusterMetricsRequest() throws YarnException, IOException {
+  public void testGetClusterMetricsRequest() throws Exception {
     LOG.info("Test FederationClientInterceptor : Get Cluster Metrics request");
     // null request
-    GetClusterMetricsResponse response = interceptor.getClusterMetrics(null);
-    Assert.assertEquals(subClusters.size(),
-        response.getClusterMetrics().getNumNodeManagers());
+    LambdaTestUtils.intercept(YarnException.class,
+            "Missing getClusterMetrics request.", () -> interceptor.getClusterMetrics(null));
+
     // normal request.
-    response =
+    GetClusterMetricsResponse response =
         interceptor.getClusterMetrics(GetClusterMetricsRequest.newInstance());
     Assert.assertEquals(subClusters.size(),
         response.getClusterMetrics().getNumNodeManagers());
@@ -641,4 +641,25 @@ public void testGetApplicationsApplicationStateNotExists() throws Exception{
     Assert.assertNotNull(responseGet);
     Assert.assertTrue(responseGet.getApplicationList().isEmpty());
   }
+
+  /**
+   * This test validates that if the request is null,
+   * calling the interface for obtaining cluster metrics should throw an exception,
+   * verifying that the exception is as expected.
+   *
+   * @throws YarnException
+   * @throws IOException
+   */
+  @Test
+  public void testGetClusterMetricsRequestNull() throws YarnException, IOException {
+    LOG.info(
+            "Test FederationClientInterceptor: GetClusterMetrics - Empty");
+    try {
+      interceptor.getClusterMetrics(null);
+      Assert.fail();
+    } catch (YarnException e) {
+      Assert.assertTrue(
+              e.getMessage().startsWith("Missing getClusterMetrics request"));
+    }
+  }
 }