Multi-databases support for routing driver

driver/src/main/java/org/neo4j/driver/exceptions/RoutingException.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed 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.neo4j.driver.exceptions;
+
+/**
+ * A routing error indicate a fatal problem to obtain routing tables such as the routing table for a specified database does not exist.
+ * This exception should not be retried.
+ * @since 2.0
+ */
+public class RoutingException extends ClientException
+{
+    public RoutingException( String message )
+    {
+        super( message );
+    }
+
+    public RoutingException( String code, String message )
+    {
+        super( code, message );
+    }
+}

driver/src/main/java/org/neo4j/driver/exceptions/SecurityException.java

@@ -24,7 +24,7 @@
  * Restart of server/driver/cluster might be required to recover from this error.
  * @since 1.1
  */
-public class SecurityException extends Neo4jException
+public class SecurityException extends ClientException
 {
     public SecurityException( String code, String message )
     {

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

@@ -21,7 +21,7 @@
 import java.util.concurrent.CompletionStage;
 
 import org.neo4j.driver.AccessMode;
-import org.neo4j.driver.internal.async.connection.DecoratedConnection;
+import org.neo4j.driver.internal.async.connection.DirectConnection;
 import org.neo4j.driver.internal.spi.Connection;
 import org.neo4j.driver.internal.spi.ConnectionPool;
 import org.neo4j.driver.internal.spi.ConnectionProvider;
@@ -47,13 +47,14 @@ public class DirectConnectionProvider implements ConnectionProvider
     @Override
     public CompletionStage<Connection> acquireConnection( String databaseName, AccessMode mode )
     {
-        return connectionPool.acquire( address ).thenApply( connection -> new DecoratedConnection( connection, databaseName, mode ) );
+        return connectionPool.acquire( address ).thenApply( connection -> new DirectConnection( connection, databaseName, mode ) );
     }
 
     @Override
     public CompletionStage<Void> verifyConnectivity()
     {
-        // we verify the connection by establishing the connection to the default database
+        // We verify the connection by establishing a connection with the remote server specified by the address.
+        // Database name will be ignored as no query is run in this connection and the connection is released immediately.
         return acquireConnection( ABSENT_DB_NAME, READ ).thenCompose( Connection::release );
     }
 

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

@@ -0,0 +1,311 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed 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.neo4j.driver.internal.async;
+
+import io.netty.channel.Channel;
+import io.netty.channel.pool.ChannelPool;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.neo4j.driver.internal.BoltServerAddress;
+import org.neo4j.driver.internal.async.connection.ChannelAttributes;
+import org.neo4j.driver.internal.async.inbound.InboundMessageDispatcher;
+import org.neo4j.driver.internal.handlers.ChannelReleasingResetResponseHandler;
+import org.neo4j.driver.internal.handlers.ResetResponseHandler;
+import org.neo4j.driver.internal.messaging.BoltProtocol;
+import org.neo4j.driver.internal.messaging.Message;
+import org.neo4j.driver.internal.messaging.request.ResetMessage;
+import org.neo4j.driver.internal.metrics.ListenerEvent;
+import org.neo4j.driver.internal.metrics.MetricsListener;
+import org.neo4j.driver.internal.spi.Connection;
+import org.neo4j.driver.internal.spi.ResponseHandler;
+import org.neo4j.driver.internal.util.Clock;
+import org.neo4j.driver.internal.util.ServerVersion;
+
+import static java.util.Collections.emptyMap;
+import static org.neo4j.driver.internal.async.connection.ChannelAttributes.setTerminationReason;
+
+/**
+ * This connection represents a simple network connection to a remote server.
+ * It wraps a channel obtained from a connection pool.
+ * The life cycle of this connection start from the moment the channel is borrowed out of the pool
+ * and end at the time the connection is released back to the pool.
+ */
+public class NetworkConnection implements Connection
+{
+    private final Channel channel;
+    private final InboundMessageDispatcher messageDispatcher;
+    private final BoltServerAddress serverAddress;
+    private final ServerVersion serverVersion;
+    private final BoltProtocol protocol;
+    private final ChannelPool channelPool;
+    private final CompletableFuture<Void> releaseFuture;
+    private final Clock clock;
+
+    private final AtomicReference<Status> status = new AtomicReference<>( Status.OPEN );
+    private final MetricsListener metricsListener;
+    private final ListenerEvent inUseEvent;
+
+    public NetworkConnection( Channel channel, ChannelPool channelPool, Clock clock, MetricsListener metricsListener )
+    {
+        this.channel = channel;
+        this.messageDispatcher = ChannelAttributes.messageDispatcher( channel );
+        this.serverAddress = ChannelAttributes.serverAddress( channel );
+        this.serverVersion = ChannelAttributes.serverVersion( channel );
+        this.protocol = BoltProtocol.forChannel( channel );
+        this.channelPool = channelPool;
+        this.releaseFuture = new CompletableFuture<>();
+        this.clock = clock;
+        this.metricsListener = metricsListener;
+        this.inUseEvent = metricsListener.createListenerEvent();
+        metricsListener.afterConnectionCreated( this.serverAddress, this.inUseEvent );
+    }
+
+    @Override
+    public boolean isOpen()
+    {
+        return status.get() == Status.OPEN;
+    }
+
+    @Override
+    public void enableAutoRead()
+    {
+        if ( isOpen() )
+        {
+            setAutoRead( true );
+        }
+    }
+
+    @Override
+    public void disableAutoRead()
+    {
+        if ( isOpen() )
+        {
+            setAutoRead( false );
+        }
+    }
+
+    @Override
+    public void flush()
+    {
+        if ( verifyOpen( null, null ) )
+        {
+            flushInEventLoop();
+        }
+    }
+
+    @Override
+    public void write( Message message, ResponseHandler handler )
+    {
+        if ( verifyOpen( handler, null ) )
+        {
+            writeMessageInEventLoop( message, handler, false );
+        }
+    }
+
+    @Override
+    public void write( Message message1, ResponseHandler handler1, Message message2, ResponseHandler handler2 )
+    {
+        if ( verifyOpen( handler1, handler2 ) )
+        {
+            writeMessagesInEventLoop( message1, handler1, message2, handler2, false );
+        }
+    }
+
+    @Override
+    public void writeAndFlush( Message message, ResponseHandler handler )
+    {
+        if ( verifyOpen( handler, null ) )
+        {
+            writeMessageInEventLoop( message, handler, true );
+        }
+    }
+
+    @Override
+    public void writeAndFlush( Message message1, ResponseHandler handler1, Message message2, ResponseHandler handler2 )
+    {
+        if ( verifyOpen( handler1, handler2 ) )
+        {
+            writeMessagesInEventLoop( message1, handler1, message2, handler2, true );
+        }
+    }
+
+    @Override
+    public CompletionStage<Void> reset()
+    {
+        CompletableFuture<Void> result = new CompletableFuture<>();
+        ResetResponseHandler handler = new ResetResponseHandler( messageDispatcher, result );
+        writeResetMessageIfNeeded( handler, true );
+        return result;
+    }
+
+    @Override
+    public CompletionStage<Void> release()
+    {
+        if ( status.compareAndSet( Status.OPEN, Status.RELEASED ) )
+        {
+            ChannelReleasingResetResponseHandler handler = new ChannelReleasingResetResponseHandler( channel,
+                    channelPool, messageDispatcher, clock, releaseFuture );
+
+            writeResetMessageIfNeeded( handler, false );
+            metricsListener.afterConnectionReleased( this.serverAddress, this.inUseEvent );
+        }
+        return releaseFuture;
+    }
+
+    @Override
+    public void terminateAndRelease( String reason )
+    {
+        if ( status.compareAndSet( Status.OPEN, Status.TERMINATED ) )
+        {
+            setTerminationReason( channel, reason );
+            channel.close();
+            channelPool.release( channel );
+            releaseFuture.complete( null );
+            metricsListener.afterConnectionReleased( this.serverAddress, this.inUseEvent );
+        }
+    }
+
+    @Override
+    public BoltServerAddress serverAddress()
+    {
+        return serverAddress;
+    }
+
+    @Override
+    public ServerVersion serverVersion()
+    {
+        return serverVersion;
+    }
+
+    @Override
+    public BoltProtocol protocol()
+    {
+        return protocol;
+    }
+
+    private void writeResetMessageIfNeeded( ResponseHandler resetHandler, boolean isSessionReset )
+    {
+        channel.eventLoop().execute( () ->
+        {
+            if ( isSessionReset && !isOpen() )
+            {
+                resetHandler.onSuccess( emptyMap() );
+            }
+            else
+            {
+                // auto-read could've been disabled, re-enable it to automatically receive response for RESET
+                setAutoRead( true );
+
+                messageDispatcher.enqueue( resetHandler );
+                channel.writeAndFlush( ResetMessage.RESET, channel.voidPromise() );
+            }
+        } );
+    }
+
+    private void flushInEventLoop()
+    {
+        channel.eventLoop().execute( channel::flush );
+    }
+
+    private void writeMessageInEventLoop( Message message, ResponseHandler handler, boolean flush )
+    {
+        channel.eventLoop().execute( () ->
+        {
+            messageDispatcher.enqueue( handler );
+
+            if ( flush )
+            {
+                channel.writeAndFlush( message, channel.voidPromise() );
+            }
+            else
+            {
+                channel.write( message, channel.voidPromise() );
+            }
+        } );
+    }
+
+    private void writeMessagesInEventLoop( Message message1, ResponseHandler handler1, Message message2, ResponseHandler handler2, boolean flush )
+    {
+        channel.eventLoop().execute( () ->
+        {
+            messageDispatcher.enqueue( handler1 );
+            messageDispatcher.enqueue( handler2 );
+
+            channel.write( message1, channel.voidPromise() );
+
+            if ( flush )
+            {
+                channel.writeAndFlush( message2, channel.voidPromise() );
+            }
+            else
+            {
+                channel.write( message2, channel.voidPromise() );
+            }
+        } );
+    }
+
+    private void setAutoRead( boolean value )
+    {
+        channel.config().setAutoRead( value );
+    }
+
+    private boolean verifyOpen( ResponseHandler handler1, ResponseHandler handler2 )
+    {
+        Status connectionStatus = this.status.get();
+        switch ( connectionStatus )
+        {
+        case OPEN:
+            return true;
+        case RELEASED:
+            Exception error = new IllegalStateException( "Connection has been released to the pool and can't be used" );
+            if ( handler1 != null )
+            {
+                handler1.onFailure( error );
+            }
+            if ( handler2 != null )
+            {
+                handler2.onFailure( error );
+            }
+            return false;
+        case TERMINATED:
+            Exception terminatedError = new IllegalStateException( "Connection has been terminated and can't be used" );
+            if ( handler1 != null )
+            {
+                handler1.onFailure( terminatedError );
+            }
+            if ( handler2 != null )
+            {
+                handler2.onFailure( terminatedError );
+            }
+            return false;
+        default:
+            throw new IllegalStateException( "Unknown status: " + connectionStatus );
+        }
+    }
+
+    private enum Status
+    {
+        OPEN,
+        RELEASED,
+        TERMINATED
+    }
+}