HBASE-14719 Add metrics for master WAL count (numMasterWALs). Metric numMasterWALs appears as follows in metrics dump

{
    "name" : "Hadoop:service=HBase,name=Master,sub=Procedure",
    "modelerType" : "Master,sub=Procedure",
    "tag.Context" : "master",
    "tag.Hostname" : "vrishal-mbp",
    "numMasterWALs" : 1
},

Signed-off-by: Elliott Clark <eclark@apache.org>

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterProcSource.java

@@ -0,0 +1,53 @@
+/**
+ * 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.hbase.master;
+
+import org.apache.hadoop.hbase.metrics.BaseSource;
+
+/**
+ * Interface that classes that expose metrics about the master will implement.
+ */
+public interface MetricsMasterProcSource extends BaseSource {
+
+  /**
+   * The name of the metrics
+   */
+  String METRICS_NAME = "Procedure";
+
+  /**
+   * The context metrics will be under.
+   */
+  String METRICS_CONTEXT = "master";
+
+  /**
+   * The name of the metrics context that metrics will be under in jmx
+   */
+  String METRICS_JMX_CONTEXT = "Master,sub=" + METRICS_NAME;
+
+  /**
+   * Description
+   */
+  String METRICS_DESCRIPTION = "Metrics about HBase master procedure";
+
+  // Strings used for exporting to metrics system.
+  String NUM_MASTER_WALS_NAME = "numMasterWALs";
+
+  String NUM_MASTER_WALS_DESC = "Number of master WAL files";
+
+}

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterProcSourceFactory.java

@@ -0,0 +1,28 @@
+/**
+ * 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.hbase.master;
+
+/**
+ * Interface of a factory to create MetricsMasterSource when given a MetricsMasterWrapper
+ */
+public interface MetricsMasterProcSourceFactory {
+
+  MetricsMasterProcSource create(MetricsMasterWrapper masterWrapper);
+
+}

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterSource.java

@@ -58,7 +58,6 @@ public interface MetricsMasterSource extends BaseSource {
   String CLUSTER_ID_NAME = "clusterId";
   String IS_ACTIVE_MASTER_NAME = "isActiveMaster";
 
-
   String CLUSTER_REQUESTS_NAME = "clusterRequests";
   String MASTER_ACTIVE_TIME_DESC = "Master Active Time";
   String MASTER_START_TIME_DESC = "Master Start Time";

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterWrapper.java

@@ -107,4 +107,9 @@ public interface MetricsMasterWrapper {
    */
   int getNumDeadRegionServers();
 
+  /**
+   * Get the number of master WAL files.
+   */
+  long getNumWALFiles();
+
 }

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterProcSourceFactoryImpl.java

@@ -0,0 +1,38 @@
+/**
+ * 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.hbase.master;
+
+import org.apache.hadoop.hbase.classification.InterfaceAudience;
+
+/**
+ * Factory to create MetricsMasterProcSource when given a MetricsMasterWrapper
+ */
+@InterfaceAudience.Private
+public class MetricsMasterProcSourceFactoryImpl implements MetricsMasterProcSourceFactory {
+
+  private MetricsMasterProcSource masterProcSource;
+
+  @Override
+  public synchronized MetricsMasterProcSource create(MetricsMasterWrapper masterWrapper) {
+    if (masterProcSource == null) {
+      masterProcSource = new MetricsMasterProcSourceImpl(masterWrapper);
+    }
+    return masterProcSource;
+  }
+}

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterProcSourceImpl.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.hbase.master;
+
+import org.apache.hadoop.hbase.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.metrics.BaseSourceImpl;
+import org.apache.hadoop.metrics2.MetricsCollector;
+import org.apache.hadoop.metrics2.MetricsRecordBuilder;
+import org.apache.hadoop.metrics2.lib.Interns;
+
+/**
+ * Hadoop2 implementation of MetricsMasterSource.
+ *
+ * Implements BaseSource through BaseSourceImpl, following the pattern
+ */
+@InterfaceAudience.Private
+public class MetricsMasterProcSourceImpl
+    extends BaseSourceImpl implements MetricsMasterProcSource {
+
+  private final MetricsMasterWrapper masterWrapper;
+
+  public MetricsMasterProcSourceImpl(MetricsMasterWrapper masterWrapper) {
+    this(METRICS_NAME,
+        METRICS_DESCRIPTION,
+        METRICS_CONTEXT,
+        METRICS_JMX_CONTEXT,
+        masterWrapper);
+  }
+
+  public MetricsMasterProcSourceImpl(String metricsName,
+                                     String metricsDescription,
+                                     String metricsContext,
+                                     String metricsJmxContext,
+                                     MetricsMasterWrapper masterWrapper) {
+    super(metricsName, metricsDescription, metricsContext, metricsJmxContext);
+    this.masterWrapper = masterWrapper;
+
+  }
+
+  @Override
+  public void init() {
+    super.init();
+  }
+
+  @Override
+  public void getMetrics(MetricsCollector metricsCollector, boolean all) {
+    MetricsRecordBuilder metricsRecordBuilder = metricsCollector.addRecord(metricsName);
+
+    // masterWrapper can be null because this function is called inside of init.
+    if (masterWrapper != null) {
+      metricsRecordBuilder
+          .addGauge(Interns.info(NUM_MASTER_WALS_NAME, NUM_MASTER_WALS_DESC),
+              masterWrapper.getNumWALFiles());
+    }
+
+    metricsRegistry.snapshot(metricsRecordBuilder, all);
+  }
+
+}

hbase-hadoop2-compat/src/main/resources/META-INF/services/org.apache.hadoop.hbase.master.MetricsMasterProcSourceFactory

@@ -0,0 +1,18 @@
+# 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.
+#
+org.apache.hadoop.hbase.master.MetricsMasterProcSourceFactoryImpl

hbase-hadoop2-compat/src/test/java/org/apache/hadoop/hbase/master/TestMetricsMasterProcSourceImpl.java

@@ -0,0 +1,46 @@
+/**
+ * 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.hbase.master;
+
+import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
+import org.apache.hadoop.hbase.testclassification.MetricsTests;
+import org.apache.hadoop.hbase.testclassification.SmallTests;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+/**
+ *  Test for MetricsMasterProcSourceImpl
+ */
+@Category({MetricsTests.class, SmallTests.class})
+public class TestMetricsMasterProcSourceImpl {
+
+  @Test
+  public void testGetInstance() throws Exception {
+    MetricsMasterProcSourceFactory metricsMasterProcSourceFactory = CompatibilitySingletonFactory
+        .getInstance(MetricsMasterProcSourceFactory.class);
+    MetricsMasterProcSource masterProcSource = metricsMasterProcSourceFactory.create(null);
+    assertTrue(masterProcSource instanceof MetricsMasterProcSourceImpl);
+    assertSame(metricsMasterProcSourceFactory,
+            CompatibilitySingletonFactory.getInstance(MetricsMasterProcSourceFactory.class));
+  }
+
+}

hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/ProcedureWALFile.java

@@ -121,7 +121,7 @@ public class ProcedureWALFile implements Comparable<ProcedureWALFile> {
   }
 
   public long getSize() {
-    return logStatus.getLen();
+    return logStatus != null ? logStatus.getLen() : 0;
   }
 
   public void removeFile() throws IOException {

hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java

@@ -2186,6 +2186,10 @@ public class HMaster extends HRegionServer implements MasterServices, Server {
     return masterActiveTime;
   }
 
+  public int getNumWALFiles() {
+    return procedureStore != null ? procedureStore.getActiveLogs().size() : 0;
+  }
+
   public int getRegionServerInfoPort(final ServerName sn) {
     RegionServerInfo info = this.regionServerTracker.getRegionServerInfo(sn);
     if (info == null || info.getInfoPort() == 0) {

hbase-server/src/main/java/org/apache/hadoop/hbase/master/MetricsMaster.java

@@ -23,9 +23,6 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.classification.InterfaceStability;
 import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
-import org.apache.hadoop.hbase.master.MetricsMasterSource;
-import org.apache.hadoop.hbase.master.MetricsMasterSourceFactory;
-import org.apache.hadoop.hbase.master.MetricsMasterWrapper;
 
 /**
  * This class is for maintaining the various master statistics
@@ -39,9 +36,12 @@ import org.apache.hadoop.hbase.master.MetricsMasterWrapper;
 public class MetricsMaster {
   private static final Log LOG = LogFactory.getLog(MetricsMaster.class);
   private MetricsMasterSource masterSource;
+  private MetricsMasterProcSource masterProcSource;
 
   public MetricsMaster(MetricsMasterWrapper masterWrapper) {
     masterSource = CompatibilitySingletonFactory.getInstance(MetricsMasterSourceFactory.class).create(masterWrapper);
+    masterProcSource =
+            CompatibilitySingletonFactory.getInstance(MetricsMasterProcSourceFactory.class).create(masterWrapper);
   }
 
   // for unit-test usage
@@ -49,6 +49,10 @@ public class MetricsMaster {
     return masterSource;
   }
 
+  public MetricsMasterProcSource getMetricsProcSource() {
+    return masterProcSource;
+  }
+
   /**
    * @param inc How much to add to requests.
    */

hbase-server/src/main/java/org/apache/hadoop/hbase/master/MetricsMasterWrapperImpl.java

@@ -118,4 +118,10 @@ public class MetricsMasterWrapperImpl implements MetricsMasterWrapper {
   public boolean getIsActiveMaster() {
     return master.isActiveMaster();
   }
+
+  @Override
+  public long getNumWALFiles() {
+    return master.getNumWALFiles();
+  }
+
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestMasterMetrics.java

@@ -129,4 +129,10 @@ public class TestMasterMetrics {
     metricsHelper.assertTag("clusterId", master.getClusterId(), masterSource);
     metricsHelper.assertTag("zookeeperQuorum", master.getZooKeeper().getQuorum(), masterSource);
   }
+
+  @Test
+  public void testDefaultMasterProcMetrics() throws Exception {
+    MetricsMasterProcSource masterSource = master.getMasterMetrics().getMetricsProcSource();
+    metricsHelper.assertGauge("numMasterWALs", master.getNumWALFiles(), masterSource);
+  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestMasterMetricsWrapper.java

@@ -73,5 +73,6 @@ public class TestMasterMetricsWrapper {
     }
     assertEquals(4, info.getNumRegionServers());
     assertEquals(1, info.getNumDeadRegionServers());
+    assertEquals(1, info.getNumWALFiles());
   }
 }