HDDS-7394. OM RPC FairCallQueue decay decision metrics list caller username in the metric

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/server/http/PrometheusMetricsSink.java

@@ -24,9 +24,11 @@
 import java.util.Collections;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.List;
 import java.util.regex.Pattern;
 import org.apache.commons.configuration2.SubsetConfiguration;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.hadoop.hdds.utils.DecayRpcSchedulerUtil;
 import org.apache.hadoop.metrics2.AbstractMetric;
 import org.apache.hadoop.metrics2.MetricType;
 import org.apache.hadoop.metrics2.MetricsRecord;
@@ -61,11 +63,17 @@ public void putMetrics(MetricsRecord metricsRecord) {
       if (metrics.type() == MetricType.COUNTER
           || metrics.type() == MetricType.GAUGE) {
 
+        String metricName = DecayRpcSchedulerUtil
+            .splitMetricNameIfNeeded(metricsRecord.name(), metrics.name());
+        // If there is no username this should be null
+        String username = DecayRpcSchedulerUtil
+            .checkMetricNameForUsername(metricsRecord.name(), metrics.name());
+
         String key = prometheusName(
-            metricsRecord.name(), metrics.name());
+            metricsRecord.name(), metricName);
 
         String prometheusMetricKeyAsString =
-            getPrometheusMetricKeyAsString(metricsRecord, key);
+            getPrometheusMetricKeyAsString(metricsRecord, key, username);
 
         String metricKey = "# TYPE "
             + key
@@ -80,14 +88,20 @@ public void putMetrics(MetricsRecord metricsRecord) {
   }
 
   private String getPrometheusMetricKeyAsString(MetricsRecord metricsRecord,
-      String key) {
+      String key, String username) {
     StringBuilder prometheusMetricKey = new StringBuilder();
     prometheusMetricKey.append(key)
         .append("{");
     String sep = "";
 
+    // tagListWithUsernameIfNeeded() checks if username is null.
+    // If it's not then it returns a list with the existing
+    // metric tags and a username tag.
+    List<MetricsTag> metricTagList = DecayRpcSchedulerUtil
+        .tagListWithUsernameIfNeeded(metricsRecord, username);
+
     //add tags
-    for (MetricsTag tag : metricsRecord.tags()) {
+    for (MetricsTag tag : metricTagList) {
       String tagName = tag.name().toLowerCase();
 
       //ignore specific tag which includes sub-hierarchy

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/DecayRpcSchedulerUtil.java

@@ -0,0 +1,121 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.hdds.utils;
+
+import com.google.common.base.Strings;
+import org.apache.hadoop.metrics2.MetricsInfo;
+import org.apache.hadoop.metrics2.MetricsRecord;
+import org.apache.hadoop.metrics2.MetricsTag;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Helper functions for DecayRpcScheduler
+ * metrics for Prometheus.
+ */
+public final class DecayRpcSchedulerUtil {
+
+  private DecayRpcSchedulerUtil() {
+  }
+
+  private static final MetricsInfo USERNAME_INFO = new MetricsInfo() {
+    @Override
+    public String name() {
+      return "username";
+    }
+
+    @Override
+    public String description() {
+      return "caller username";
+    }
+  };
+
+  /**
+   * For Decay_Rpc_Scheduler, the metric name is in format
+   * "Caller(<callers_username>).Volume"
+   * or
+   * "Caller(<callers_username>).Priority"
+   * Split it and return the metric.
+   *
+   * If the recordName doesn't belong to Decay_Rpc_Scheduler,
+   * then return the metricName as it is without making
+   * any changes to it.
+   *
+   * @param recordName
+   * @param metricName "Caller(xyz).Volume" or "Caller(xyz).Priority"
+   * @return "Volume" or "Priority" or metricName(unchanged)
+   */
+  public static String splitMetricNameIfNeeded(String recordName,
+                                               String metricName) {
+    if (recordName.toLowerCase().contains("decayrpcscheduler") &&
+        metricName.toLowerCase().contains("caller(")) {
+      // names will contain ["Caller(xyz)", "Volume" / "Priority"]
+      String[] names = metricName.split("[.]");
+
+      // "Volume" or "Priority"
+      return names[1];
+    }
+    return metricName;
+  }
+
+  /**
+   * For Decay_Rpc_Scheduler, split the metric name
+   * and then get the part that is in the format "Caller(<callers_username>)"
+   * and split it to return the username.
+   * @param recordName
+   * @param metricName
+   * @return caller username or null if not present
+   */
+  public static String checkMetricNameForUsername(String recordName,
+                                                  String metricName) {
+    if (recordName.toLowerCase().contains("decayrpcscheduler") &&
+        metricName.toLowerCase().contains("caller(")) {
+      // names will contain ["Caller(xyz)", "Volume" / "Priority"]
+      String[] names = metricName.split("[.]");
+
+      // Caller(xyz)
+      String caller = names[0];
+
+      // subStrings will contain ["Caller", "xyz"]
+      String[] subStrings = caller.split("[()]");
+
+      String username = subStrings[1];
+
+      return username;
+    }
+    return null;
+  }
+
+  /**
+   * MetricRecord.tags() is an unmodifiable collection of tags.
+   * Store it in a list, to modify it and add a username tag.
+   * @param metricsRecord
+   * @return the new list with the metric tags and the username tag
+   */
+  public static List<MetricsTag> tagListWithUsernameIfNeeded(
+      MetricsRecord metricsRecord, String username) {
+    List<MetricsTag> list = new ArrayList<>(metricsRecord.tags());
+
+    if (!Strings.isNullOrEmpty(username)) {
+      MetricsTag tag = new MetricsTag(USERNAME_INFO, username);
+      list.add(tag);
+    }
+    return list;
+  }
+}

hadoop-hdds/framework/src/test/java/org/apache/hadoop/hdds/utils/TestDecayRpcSchedulerUtil.java

@@ -0,0 +1,75 @@
+/*
+ * 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.hdds.utils;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+/**
+ * Test class for DecayRpcSchedulerUtil.
+ */
+public class TestDecayRpcSchedulerUtil {
+
+  private static final String USERNAME = "testUser";
+  private static final String METRIC_NAME_VOLUME = "Volume";
+
+  private static final String RECORD_NAME =
+      "org.apache.hadoop.ipc.DecayRpcScheduler";
+  private static final String METRIC_NAME =
+      "Caller(" + USERNAME + ")." + METRIC_NAME_VOLUME;
+
+  private static final String RANDOM_RECORD_NAME = "JvmMetrics";
+  private static final String RANDOM_METRIC_NAME = "ThreadsNew";
+
+  @Test
+  public void testSplitMetricNameIfNeeded() {
+    // Split the metric name and return only the
+    // name of the metric type.
+    String splitName = DecayRpcSchedulerUtil
+        .splitMetricNameIfNeeded(RECORD_NAME, METRIC_NAME);
+
+    assertEquals(METRIC_NAME_VOLUME, splitName);
+
+    // This metric name should remain the same.
+    String unchangedName = DecayRpcSchedulerUtil
+        .splitMetricNameIfNeeded(RANDOM_RECORD_NAME, RANDOM_METRIC_NAME);
+
+    assertEquals(RANDOM_METRIC_NAME, unchangedName);
+  }
+
+  @Test
+  public void testCheckMetricNameForUsername() {
+    // Get the username from the metric name.
+    String decayRpcSchedulerUsername = DecayRpcSchedulerUtil
+        .checkMetricNameForUsername(RECORD_NAME, METRIC_NAME);
+
+    assertEquals(USERNAME, decayRpcSchedulerUsername);
+
+    // This metric doesn't contain a username in the metric name.
+    // DecayRpcSchedulerUtil.checkMetricNameForUsername()
+    // should return null.
+    String nullUsername = DecayRpcSchedulerUtil
+        .checkMetricNameForUsername(RANDOM_RECORD_NAME, RANDOM_METRIC_NAME);
+
+    assertNull(nullUsername);
+  }
+}