YARN-5929. Missing scheduling policy in the FS queue metric. (Contributed by Yufei Gu via Daniel Templeton)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSQueueMetrics.java

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair;
 
+import com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.metrics2.MetricsSystem;
 import org.apache.hadoop.metrics2.annotation.Metric;
@@ -169,6 +170,12 @@ public class FSQueueMetrics extends QueueMetrics {
     amResourceUsageVCores.set(resource.getVirtualCores());
   }
 
+  /**
+   * Get the scheduling policy.
+   *
+   * @return the scheduling policy
+   */
+  @Metric("Scheduling policy")
   public String getSchedulingPolicy() {
     return schedulingPolicy;
   }
@@ -181,21 +188,38 @@ public class FSQueueMetrics extends QueueMetrics {
   static FSQueueMetrics forQueue(String queueName, Queue parent,
       boolean enableUserMetrics, Configuration conf) {
     MetricsSystem ms = DefaultMetricsSystem.instance();
+    return forQueue(ms, queueName, parent, enableUserMetrics, conf);
+  }
+
+  /**
+   * Get the FS queue metric for the given queue. Create one and register it to
+   * metrics system if there isn't one for the queue.
+   *
+   * @param ms the metric system
+   * @param queueName queue name
+   * @param parent parent queue
+   * @param enableUserMetrics  if user metrics is needed
+   * @param conf configuration
+   * @return a FSQueueMetrics object
+   */
+  @VisibleForTesting
+  public synchronized
+  static FSQueueMetrics forQueue(MetricsSystem ms, String queueName,
+      Queue parent, boolean enableUserMetrics, Configuration conf) {
     QueueMetrics metrics = queueMetrics.get(queueName);
     if (metrics == null) {
       metrics = new FSQueueMetrics(ms, queueName, parent, enableUserMetrics, conf)
           .tag(QUEUE_INFO, queueName);
-      
+
       // Register with the MetricsSystems
       if (ms != null) {
         metrics = ms.register(
-                sourceName(queueName).toString(), 
+            sourceName(queueName).toString(),
-                "Metrics for queue: " + queueName, metrics);
+            "Metrics for queue: " + queueName, metrics);
       }
       queueMetrics.put(queueName, metrics);
     }
 
     return (FSQueueMetrics)metrics;
   }
-
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFSQueueMetrics.java

@@ -0,0 +1,69 @@
+/**
+ * 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.scheduler.fair;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.metrics2.MetricsSource;
+import org.apache.hadoop.metrics2.MetricsSystem;
+import org.apache.hadoop.metrics2.impl.MetricsCollectorImpl;
+import org.apache.hadoop.metrics2.impl.MetricsRecords;
+import org.apache.hadoop.metrics2.impl.MetricsSystemImpl;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.TestQueueMetrics;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The test class for {@link FSQueueMetrics}.
+ */
+public class TestFSQueueMetrics {
+  private static final Configuration CONF = new Configuration();
+
+  private MetricsSystem ms;
+
+  @Before public void setUp() {
+    ms = new MetricsSystemImpl();
+    QueueMetrics.clearQueueMetrics();
+  }
+
+  /**
+   * Test if the metric scheduling policy is set correctly.
+   */
+  @Test
+  public void testSchedulingPolicy() {
+    String queueName = "single";
+
+    FSQueueMetrics metrics = FSQueueMetrics.forQueue(ms, queueName, null, false,
+        CONF);
+    metrics.setSchedulingPolicy("drf");
+    checkSchedulingPolicy(queueName, "drf");
+
+    // test resetting the scheduling policy
+    metrics.setSchedulingPolicy("fair");
+    checkSchedulingPolicy(queueName, "fair");
+  }
+
+  private void checkSchedulingPolicy(String queueName, String policy) {
+    MetricsSource queueSource = TestQueueMetrics.queueSource(ms, queueName);
+    MetricsCollectorImpl collector = new MetricsCollectorImpl();
+    queueSource.getMetrics(collector, true);
+    MetricsRecords.assertTag(collector.getRecords().get(0), "SchedulingPolicy",
+        policy);
+  }
+}