HDFS-14388. RBF: Prevent loading metric system when disabled. Contributed by Inigo Goiri.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/FederationRPCPerformanceMonitor.java

@@ -154,48 +154,66 @@ public class FederationRPCPerformanceMonitor implements RouterRpcMonitor {
 
   @Override
   public void proxyOpFailureCommunicate() {
+    if (metrics != null) {
       metrics.incrProxyOpFailureCommunicate();
     }
+  }
 
   @Override
   public void proxyOpFailureClientOverloaded() {
+    if (metrics != null) {
       metrics.incrProxyOpFailureClientOverloaded();
     }
+  }
 
   @Override
   public void proxyOpNotImplemented() {
+    if (metrics != null) {
       metrics.incrProxyOpNotImplemented();
     }
+  }
 
   @Override
   public void proxyOpRetries() {
+    if (metrics != null) {
       metrics.incrProxyOpRetries();
     }
+  }
 
   @Override
   public void proxyOpNoNamenodes() {
+    if (metrics != null) {
       metrics.incrProxyOpNoNamenodes();
     }
+  }
 
   @Override
   public void routerFailureStateStore() {
+    if (metrics != null) {
       metrics.incrRouterFailureStateStore();
     }
+  }
 
   @Override
   public void routerFailureSafemode() {
+    if (metrics != null) {
       metrics.incrRouterFailureSafemode();
     }
+  }
 
   @Override
   public void routerFailureReadOnly() {
+    if (metrics != null) {
       metrics.incrRouterFailureReadOnly();
     }
+  }
 
   @Override
   public void routerFailureLocked() {
+    if (metrics != null) {
       metrics.incrRouterFailureLocked();
     }
+  }
 
 
   /**

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/NullStateStoreMetrics.java

@@ -0,0 +1,56 @@
+/**
+ * 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.hdfs.server.federation.metrics;
+
+/**
+ * Implementation of the State Store metrics which does not do anything.
+ * This is used when the metrics are disabled (e.g., tests).
+ */
+public class NullStateStoreMetrics extends StateStoreMetrics {
+  public void addRead(long latency) {}
+  public long getReadOps() {
+    return -1;
+  }
+  public double getReadAvg() {
+    return -1;
+  }
+  public void addWrite(long latency) {}
+  public long getWriteOps() {
+    return -1;
+  }
+  public double getWriteAvg() {
+    return -1;
+  }
+  public void addFailure(long latency) {  }
+  public long getFailureOps() {
+    return -1;
+  }
+  public double getFailureAvg() {
+    return -1;
+  }
+  public void addRemove(long latency) {}
+  public long getRemoveOps() {
+    return -1;
+  }
+  public double getRemoveAvg() {
+    return -1;
+  }
+  public void setCacheSize(String name, int size) {}
+  public void reset() {}
+  public void shutdown() {}
+}

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/StateStoreMetrics.java

@@ -39,7 +39,7 @@ import com.google.common.annotations.VisibleForTesting;
  */
 @Metrics(name = "StateStoreActivity", about = "Router metrics",
     context = "dfs")
-public final class StateStoreMetrics implements StateStoreMBean {
+public class StateStoreMetrics implements StateStoreMBean {
 
   private final MetricsRegistry registry = new MetricsRegistry("router");
 
@@ -54,6 +54,8 @@ public final class StateStoreMetrics implements StateStoreMBean {
 
   private Map<String, MutableGaugeInt> cacheSizes;
 
+  protected StateStoreMetrics() {}
+
   private StateStoreMetrics(Configuration conf) {
     registry.tag(SessionId, "RouterSession");
     registry.tag(ProcessName, "Router");

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcServer.java

@@ -304,12 +304,17 @@ public class RouterRpcServer extends AbstractService
     this.rpcAddress = new InetSocketAddress(
         confRpcAddress.getHostName(), listenAddress.getPort());
 
+    if (conf.getBoolean(RBFConfigKeys.DFS_ROUTER_METRICS_ENABLE,
+        RBFConfigKeys.DFS_ROUTER_METRICS_ENABLE_DEFAULT)) {
       // Create metrics monitor
       Class<? extends RouterRpcMonitor> rpcMonitorClass = this.conf.getClass(
           RBFConfigKeys.DFS_ROUTER_METRICS_CLASS,
           RBFConfigKeys.DFS_ROUTER_METRICS_CLASS_DEFAULT,
           RouterRpcMonitor.class);
       this.rpcMonitor = ReflectionUtils.newInstance(rpcMonitorClass, conf);
+    } else {
+      this.rpcMonitor = null;
+    }
 
     // Create the client
     this.rpcClient = new RouterRpcClient(this.conf, this.router,
@@ -326,7 +331,7 @@ public class RouterRpcServer extends AbstractService
     this.conf = configuration;
 
     if (this.rpcMonitor == null) {
-      LOG.error("Cannot instantiate Router RPC metrics class");
+      LOG.info("Do not start Router RPC metrics");
     } else {
       this.rpcMonitor.init(this.conf, this, this.router.getStateStore());
     }

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/store/StateStoreService.java

@@ -33,6 +33,7 @@ import javax.management.StandardMBean;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.server.federation.metrics.NullStateStoreMetrics;
 import org.apache.hadoop.hdfs.server.federation.metrics.StateStoreMBean;
 import org.apache.hadoop.hdfs.server.federation.metrics.StateStoreMetrics;
 import org.apache.hadoop.hdfs.server.federation.router.RBFConfigKeys;
@@ -172,6 +173,8 @@ public class StateStoreService extends CompositeService {
     this.cacheUpdater = new StateStoreCacheUpdateService(this);
     addService(this.cacheUpdater);
 
+    if (conf.getBoolean(RBFConfigKeys.DFS_ROUTER_METRICS_ENABLE,
+        RBFConfigKeys.DFS_ROUTER_METRICS_ENABLE_DEFAULT)) {
       // Create metrics for the State Store
       this.metrics = StateStoreMetrics.create(conf);
 
@@ -186,6 +189,10 @@ public class StateStoreService extends CompositeService {
       } catch (MetricsException e) {
         LOG.error("Failed to register State Store bean {}", e.getMessage());
       }
+    } else {
+      LOG.info("State Store metrics not enabled");
+      this.metrics = new NullStateStoreMetrics();
+    }
 
     super.serviceInit(this.conf);
   }