Draft of driver metrics

driver/pom.xml

@@ -29,6 +29,10 @@
       <groupId>io.netty</groupId>
       <artifactId>netty-handler</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.hdrhistogram</groupId>
+      <artifactId>HdrHistogram</artifactId>
+    </dependency>
 
     <!-- Test dependencies -->
     <dependency>
@@ -208,13 +212,18 @@
               <artifactSet>
                 <includes>
                   <include>io.netty:*</include>
+                  <include>org.HdrHistogram:*</include>
                 </includes>
               </artifactSet>
               <relocations>
                 <relocation>
                   <pattern>io.netty</pattern>
                   <shadedPattern>org.neo4j.driver.internal.shaded.io.netty</shadedPattern>
                 </relocation>
+                <relocation>
+                  <pattern>org.HdrHistogram</pattern>
+                  <shadedPattern>org.neo4j.driver.internal.shaded.org.HdrHistogram</shadedPattern>
+                </relocation>
               </relocations>
               <shadeTestJar>true</shadeTestJar>
             </configuration>

driver/src/main/java/org/neo4j/driver/internal/DriverFactory.java

@@ -38,6 +38,9 @@
 import org.neo4j.driver.internal.cluster.loadbalancing.LoadBalancingStrategy;
 import org.neo4j.driver.internal.cluster.loadbalancing.RoundRobinLoadBalancingStrategy;
 import org.neo4j.driver.internal.logging.NettyLogging;
+import org.neo4j.driver.internal.metrics.DriverMetricsListener;
+import org.neo4j.driver.internal.metrics.InternalAbstractDriverMetrics;
+import org.neo4j.driver.internal.metrics.InternalDriverMetrics;
 import org.neo4j.driver.internal.retry.ExponentialBackoffRetryLogic;
 import org.neo4j.driver.internal.retry.RetryLogic;
 import org.neo4j.driver.internal.retry.RetrySettings;
@@ -56,6 +59,8 @@
 import org.neo4j.driver.v1.exceptions.ServiceUnavailableException;
 
 import static java.lang.String.format;
+import static org.neo4j.driver.internal.metrics.InternalAbstractDriverMetrics.DEV_NULL_METRICS;
+import static org.neo4j.driver.internal.metrics.spi.DriverMetrics.isDriverMetricsEnabled;
 import static org.neo4j.driver.internal.security.SecurityPlan.insecure;
 
 public class DriverFactory
@@ -77,18 +82,19 @@ public final Driver newInstance( URI uri, AuthToken authToken, RoutingSettings r
         EventExecutorGroup eventExecutorGroup = bootstrap.config().group();
         RetryLogic retryLogic = createRetryLogic( retrySettings, eventExecutorGroup, config.logging() );
 
-        ConnectionPool connectionPool = createConnectionPool( authToken, securityPlan, bootstrap, config );
+        InternalAbstractDriverMetrics metrics = createDriverMetrics( config );
+        ConnectionPool connectionPool = createConnectionPool( authToken, securityPlan, bootstrap, metrics, config );
 
         InternalDriver driver = createDriver( uri, address, connectionPool, config, newRoutingSettings,
                 eventExecutorGroup, securityPlan, retryLogic );
 
+        driver.driverMetrics( metrics );
         verifyConnectivity( driver, connectionPool, config );
 
         return driver;
     }
 
-    protected ConnectionPool createConnectionPool( AuthToken authToken, SecurityPlan securityPlan,
-            Bootstrap bootstrap, Config config )
+    protected ConnectionPool createConnectionPool( AuthToken authToken, SecurityPlan securityPlan, Bootstrap bootstrap, DriverMetricsListener metrics, Config config )
     {
         Clock clock = createClock();
         ConnectionSettings settings = new ConnectionSettings( authToken, config.connectionTimeoutMillis() );
@@ -97,7 +103,19 @@ protected ConnectionPool createConnectionPool( AuthToken authToken, SecurityPlan
                 config.connectionAcquisitionTimeoutMillis(), config.maxConnectionLifetimeMillis(),
                 config.idleTimeBeforeConnectionTest()
         );
-        return new ConnectionPoolImpl( connector, bootstrap, poolSettings, config.logging(), clock );
+        return new ConnectionPoolImpl( connector, bootstrap, poolSettings, metrics, config.logging(), clock );
+    }
+
+    protected static InternalAbstractDriverMetrics createDriverMetrics( Config config )
+    {
+        if( isDriverMetricsEnabled() )
+        {
+            return new InternalDriverMetrics( config );
+        }
+        else
+        {
+            return DEV_NULL_METRICS;
+        }
     }
 
     protected ChannelConnector createConnector( ConnectionSettings settings, SecurityPlan securityPlan,

driver/src/main/java/org/neo4j/driver/internal/InternalDriver.java

@@ -21,6 +21,7 @@
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import org.neo4j.driver.internal.metrics.spi.DriverMetrics;
 import org.neo4j.driver.internal.security.SecurityPlan;
 import org.neo4j.driver.internal.util.Futures;
 import org.neo4j.driver.v1.AccessMode;
@@ -38,6 +39,7 @@ public class InternalDriver implements Driver
     private final Logger log;
 
     private AtomicBoolean closed = new AtomicBoolean( false );
+    private DriverMetrics driverMetrics;
 
     InternalDriver( SecurityPlan securityPlan, SessionFactory sessionFactory, Logging logging )
     {
@@ -144,6 +146,16 @@ private void assertOpen()
         }
     }
 
+    public DriverMetrics driverMetrics()
+    {
+        return this.driverMetrics;
+    }
+
+    void driverMetrics( DriverMetrics driverMetrics )
+    {
+        this.driverMetrics = driverMetrics;
+    }
+
     private static RuntimeException driverCloseException()
     {
         return new IllegalStateException( "This driver instance has already been closed" );

driver/src/main/java/org/neo4j/driver/internal/async/NettyConnection.java

@@ -34,6 +34,8 @@
 import org.neo4j.driver.internal.messaging.PullAllMessage;
 import org.neo4j.driver.internal.messaging.ResetMessage;
 import org.neo4j.driver.internal.messaging.RunMessage;
+import org.neo4j.driver.internal.metrics.DriverMetricsListener;
+import org.neo4j.driver.internal.metrics.ListenerEvent.ConnectionListenerEvent;
 import org.neo4j.driver.internal.spi.Connection;
 import org.neo4j.driver.internal.spi.ResponseHandler;
 import org.neo4j.driver.internal.util.Clock;
@@ -54,8 +56,10 @@ public class NettyConnection implements Connection
     private final Clock clock;
 
     private final AtomicReference<Status> status = new AtomicReference<>( Status.OPEN );
+    private final DriverMetricsListener metricsListener;
+    private final ConnectionListenerEvent inUseEvent;
 
-    public NettyConnection( Channel channel, ChannelPool channelPool, Clock clock )
+    public NettyConnection( Channel channel, ChannelPool channelPool, Clock clock, DriverMetricsListener driverMetricsListener )
     {
         this.channel = channel;
         this.messageDispatcher = ChannelAttributes.messageDispatcher( channel );
@@ -64,6 +68,9 @@ public NettyConnection( Channel channel, ChannelPool channelPool, Clock clock )
         this.channelPool = channelPool;
         this.releaseFuture = new CompletableFuture<>();
         this.clock = clock;
+        this.metricsListener = driverMetricsListener;
+        this.inUseEvent = driverMetricsListener.createConnectionListenerEvent();
+        driverMetricsListener.afterAcquiredOrCreated( this.serverAddress, this.inUseEvent );
     }
 
     @Override
@@ -124,6 +131,7 @@ public CompletionStage<Void> release()
     {
         if ( status.compareAndSet( Status.OPEN, Status.RELEASED ) )
         {
+            metricsListener.afterReleased( this.serverAddress, this.inUseEvent );
             ChannelReleasingResetResponseHandler handler = new ChannelReleasingResetResponseHandler( channel,
                     channelPool, messageDispatcher, clock, releaseFuture );
 
@@ -137,6 +145,7 @@ public void terminateAndRelease( String reason )
     {
         if ( status.compareAndSet( Status.OPEN, Status.TERMINATED ) )
         {
+            metricsListener.afterReleased( this.serverAddress, this.inUseEvent );
             setTerminationReason( channel, reason );
             channel.close();
             channelPool.release( channel );