Corrected the logging behavior when a channel is marked inactive due to a graceful connection pool shutdown. (#826)

Author: dotStart

driver/src/main/java/org/neo4j/driver/internal/async/inbound/ChannelErrorHandler.java

@@ -67,14 +67,20 @@ public void channelInactive( ChannelHandlerContext ctx )
     {
         log.debug( "Channel is inactive" );
 
+        String terminationReason = terminationReason( ctx.channel() );
+        Throwable error = ErrorUtil.newConnectionTerminatedError( terminationReason );
+
         if ( !failed )
         {
             // channel became inactive not because of a fatal exception that came from exceptionCaught
             // it is most likely inactive because actual network connection broke or was explicitly closed by the driver
 
-            String terminationReason = terminationReason( ctx.channel() );
-            ServiceUnavailableException error = ErrorUtil.newConnectionTerminatedError( terminationReason );
-            fail( ctx, error );
+            messageDispatcher.handleChannelInactive( error );
+            ctx.channel().close();
+        }
+        else
+        {
+            fail( error );
         }
     }
 
@@ -89,16 +95,14 @@ public void exceptionCaught( ChannelHandlerContext ctx, Throwable error )
         {
             failed = true;
             log.warn( "Fatal error occurred in the pipeline", error );
-            fail( ctx, error );
+            fail( error );
         }
     }
 
-    private void fail( ChannelHandlerContext ctx, Throwable error )
+    private void fail( Throwable error )
     {
         Throwable cause = transformError( error );
         messageDispatcher.handleChannelError( cause );
-        log.debug( "Closing channel because of a failure '%s'", error );
-        ctx.close();
     }
 
     private static Throwable transformError( Throwable error )

driver/src/main/java/org/neo4j/driver/internal/async/inbound/InboundMessageDispatcher.java

@@ -25,6 +25,7 @@
 import java.util.Map;
 import java.util.Queue;
 
+import org.neo4j.driver.exceptions.ServiceUnavailableException;
 import org.neo4j.driver.internal.handlers.ResetResponseHandler;
 import org.neo4j.driver.internal.logging.ChannelActivityLogger;
 import org.neo4j.driver.internal.messaging.ResponseMessageHandler;
@@ -45,6 +46,7 @@ public class InboundMessageDispatcher implements ResponseMessageHandler
     private final Queue<ResponseHandler> handlers = new LinkedList<>();
     private final Logger log;
 
+    private volatile boolean gracefullyClosed;
     private Throwable currentError;
     private boolean fatalErrorOccurred;
 
@@ -142,6 +144,20 @@ public void handleIgnoredMessage()
         handler.onFailure( error );
     }
 
+    public void handleChannelInactive( Throwable cause )
+    {
+        // report issue if the connection has not been terminated as a result of a graceful shutdown request from its
+        // parent pool
+        if ( !gracefullyClosed )
+        {
+            handleChannelError( cause );
+        }
+        else
+        {
+            channel.close();
+        }
+    }
+
     public void handleChannelError( Throwable error )
     {
         if ( currentError != null )
@@ -160,6 +176,9 @@ public void handleChannelError( Throwable error )
             ResponseHandler handler = removeHandler();
             handler.onFailure( currentError );
         }
+
+        log.debug( "Closing channel because of a failure '%s'", error );
+        channel.close();
     }
 
     public void clearCurrentError()
@@ -177,6 +196,11 @@ public boolean fatalErrorOccurred()
         return fatalErrorOccurred;
     }
 
+    public void prepareToCloseChannel( )
+    {
+        this.gracefullyClosed = true;
+    }
+
     /**
      * <b>Visible for testing</b>
      */

driver/src/main/java/org/neo4j/driver/internal/messaging/v3/BoltProtocolV3.java

@@ -33,6 +33,7 @@
 import org.neo4j.driver.internal.BookmarkHolder;
 import org.neo4j.driver.internal.DatabaseName;
 import org.neo4j.driver.internal.async.UnmanagedTransaction;
+import org.neo4j.driver.internal.async.inbound.InboundMessageDispatcher;
 import org.neo4j.driver.internal.cluster.RoutingContext;
 import org.neo4j.driver.internal.cursor.AsyncResultCursorOnlyFactory;
 import org.neo4j.driver.internal.cursor.ResultCursorFactory;
@@ -101,9 +102,13 @@ public void initializeChannel( String userAgent, AuthToken authToken, RoutingCon
     @Override
     public void prepareToCloseChannel( Channel channel )
     {
+        InboundMessageDispatcher messageDispatcher = messageDispatcher( channel );
+
         GoodbyeMessage message = GoodbyeMessage.GOODBYE;
-        messageDispatcher( channel ).enqueue( NoOpResponseHandler.INSTANCE );
+        messageDispatcher.enqueue( NoOpResponseHandler.INSTANCE );
         channel.writeAndFlush( message, channel.voidPromise() );
+
+        messageDispatcher.prepareToCloseChannel( );
     }
 
     @Override