HBASE-26891 Make MetricsConnection scope configurable

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncConnectionImpl.java

@@ -126,7 +126,8 @@ public AsyncConnectionImpl(Configuration conf, ConnectionRegistry registry, Stri
     this.connConf = new AsyncConnectionConfiguration(conf);
     this.registry = registry;
     if (conf.getBoolean(CLIENT_SIDE_METRICS_ENABLED_KEY, false)) {
-      this.metrics = Optional.of(new MetricsConnection(this.toString(), () -> null, () -> null));
+      String scope = MetricsConnection.getScope(conf, clusterId, this);
+      this.metrics = Optional.of(new MetricsConnection(scope, () -> null, () -> null));
     } else {
       this.metrics = Optional.empty();
     }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java

@@ -308,13 +308,6 @@ public class ConnectionImplementation implements ClusterConnection, Closeable {
     this.rpcCallerFactory = RpcRetryingCallerFactory.instantiate(conf, interceptor, this.stats);
     this.backoffPolicy = ClientBackoffPolicyFactory.create(conf);
     this.asyncProcess = new AsyncProcess(this, conf, rpcCallerFactory, rpcControllerFactory);
-    if (conf.getBoolean(CLIENT_SIDE_METRICS_ENABLED_KEY, false)) {
-      this.metrics =
-          new MetricsConnection(this.toString(), this::getBatchPool, this::getMetaLookupPool);
-    } else {
-      this.metrics = null;
-    }
-    this.metaCache = new MetaCache(this.metrics);
 
     boolean shouldListen =
         conf.getBoolean(HConstants.STATUS_PUBLISHED, HConstants.STATUS_PUBLISHED_DEFAULT);
@@ -333,6 +326,15 @@ public class ConnectionImplementation implements ClusterConnection, Closeable {
       }
       retrieveClusterId();
 
+      if (conf.getBoolean(CLIENT_SIDE_METRICS_ENABLED_KEY, false)) {
+        String scope = MetricsConnection.getScope(conf, clusterId, this);
+        this.metrics =
+          new MetricsConnection(scope, this::getBatchPool, this::getMetaLookupPool);
+      } else {
+        this.metrics = null;
+      }
+      this.metaCache = new MetaCache(this.metrics);
+
       this.rpcClient = RpcClientFactory.createClient(this.conf, this.clusterId, this.metrics);
 
       // Do we publish the status?

hbase-client/src/main/java/org/apache/hadoop/hbase/client/MetricsConnection.java

@@ -34,6 +34,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.MutateRequest;
@@ -58,6 +59,34 @@ public class MetricsConnection implements StatisticTrackable {
   /** Set this key to {@code true} to enable metrics collection of client requests. */
   public static final String CLIENT_SIDE_METRICS_ENABLED_KEY = "hbase.client.metrics.enable";
 
+  /**
+   * Set to specify a custom scope for the metrics published through {@link MetricsConnection}.
+   * The scope is added to JMX MBean objectName, and defaults to a combination of the Connection's
+   * clusterId and hashCode. For example, a default value for a connection to cluster "foo" might
+   * be "foo-7d9d0818", where "7d9d0818" is the hashCode of the underlying AsyncConnectionImpl.
+   * Users may set this key to give a more contextual name for this scope. For example, one might
+   * want to differentiate a read connection from a write connection by setting the scopes to
+   * "foo-read" and "foo-write" respectively.
+   *
+   * Scope is the only thing that lends any uniqueness to the metrics. Care should be taken to
+   * avoid using the same scope for multiple Connections, otherwise the metrics may aggregate in
+   * unforeseen ways.
+   */
+  public static final String METRICS_SCOPE_KEY = "hbase.client.metrics.scope";
+
+  /**
+   * Returns the scope for a MetricsConnection based on the configured {@link #METRICS_SCOPE_KEY}
+   * or by generating a default from the passed clusterId and connectionObj's hashCode.
+   * @param conf          configuration for the connection
+   * @param clusterId     clusterId for the connection
+   * @param connectionObj either a Connection or AsyncConnectionImpl, the instance
+   *                      creating this MetricsConnection.
+   */
+  static String getScope(Configuration conf, String clusterId, Object connectionObj) {
+    return conf.get(METRICS_SCOPE_KEY,
+      clusterId + "@" + Integer.toHexString(connectionObj.hashCode()));
+  }
+
   private static final String CNT_BASE = "rpcCount_";
   private static final String DRTN_BASE = "rpcCallDurationMs_";
   private static final String REQ_BASE = "rpcCallRequestSizeBytes_";
@@ -252,7 +281,7 @@ private static interface NewMetric<T> {
 
   private final MetricRegistry registry;
   private final JmxReporter reporter;
-  private final String scope;
+  protected final String scope;
 
   private final NewMetric<Timer> timerFactory = new NewMetric<Timer>() {
     @Override public Timer newMetric(Class<?> clazz, String name, String scope) {

hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestMetricsConnection.java

@@ -18,14 +18,18 @@
 package org.apache.hadoop.hbase.client;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
-
 import com.codahale.metrics.RatioGauge;
 import com.codahale.metrics.RatioGauge.Ratio;
 import java.io.IOException;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadPoolExecutor;
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.security.User;
 import org.apache.hadoop.hbase.testclassification.ClientTests;
 import org.apache.hadoop.hbase.testclassification.MetricsTests;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
@@ -35,9 +39,8 @@
 import org.junit.ClassRule;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
-
+import org.mockito.Mockito;
 import org.apache.hbase.thirdparty.com.google.protobuf.ByteString;
-
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.GetRequest;
@@ -67,6 +70,49 @@ public static void afterClass() {
     METRICS.shutdown();
   }
 
+  @Test
+  public void testMetricsConnectionScopeAsyncClient() throws IOException {
+    Configuration conf = new Configuration();
+    String clusterId = "foo";
+    String scope = "testScope";
+    conf.setBoolean(MetricsConnection.CLIENT_SIDE_METRICS_ENABLED_KEY, true);
+
+    AsyncConnectionImpl impl = new AsyncConnectionImpl(conf, null, "foo", User.getCurrent());
+    Optional<MetricsConnection> metrics = impl.getConnectionMetrics();
+    assertTrue("Metrics should be present", metrics.isPresent());
+    assertEquals(clusterId + "@" + Integer.toHexString(impl.hashCode()), metrics.get().scope);
+    conf.set(MetricsConnection.METRICS_SCOPE_KEY, scope);
+    impl = new AsyncConnectionImpl(conf, null, "foo", User.getCurrent());
+
+    metrics = impl.getConnectionMetrics();
+    assertTrue("Metrics should be present", metrics.isPresent());
+    assertEquals(scope, metrics.get().scope);
+  }
+
+  @Test
+  public void testMetricsConnectionScopeBlockingClient() throws IOException {
+    Configuration conf = new Configuration();
+    String clusterId = "foo";
+    String scope = "testScope";
+    conf.setBoolean(MetricsConnection.CLIENT_SIDE_METRICS_ENABLED_KEY, true);
+
+    ConnectionRegistry mockRegistry = Mockito.mock(ConnectionRegistry.class);
+    Mockito.when(mockRegistry.getClusterId())
+      .thenReturn(CompletableFuture.completedFuture(clusterId));
+
+    ConnectionImplementation impl = new ConnectionImplementation(conf, null,
+      User.getCurrent(), mockRegistry);
+    MetricsConnection metrics = impl.getConnectionMetrics();
+    assertNotNull("Metrics should be present", metrics);
+    assertEquals(clusterId + "@" + Integer.toHexString(impl.hashCode()), metrics.scope);
+    conf.set(MetricsConnection.METRICS_SCOPE_KEY, scope);
+    impl = new ConnectionImplementation(conf, null, User.getCurrent(), mockRegistry);
+
+    metrics = impl.getConnectionMetrics();
+    assertNotNull("Metrics should be present", metrics);
+    assertEquals(scope, metrics.scope);
+  }
+
   @Test
   public void testStaticMetrics() throws IOException {
     final byte[] foo = Bytes.toBytes("foo");