Add support for Resolver and DomainNameResolver to async Testkit backend

testkit-backend/src/main/java/neo4j/org/testkit/backend/TestkitState.java

@@ -19,12 +19,14 @@
 package neo4j.org.testkit.backend;
 
 import lombok.Getter;
+import neo4j.org.testkit.backend.messages.requests.TestkitCallbackResult;
+import neo4j.org.testkit.backend.messages.responses.TestkitCallback;
 import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
 
-import java.net.InetAddress;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -35,7 +37,6 @@
 import org.neo4j.driver.async.ResultCursor;
 import org.neo4j.driver.exceptions.Neo4jException;
 import org.neo4j.driver.internal.cluster.RoutingTableRegistry;
-import org.neo4j.driver.net.ServerAddress;
 
 @Getter
 public class TestkitState
@@ -52,15 +53,24 @@ public class TestkitState
     private int idGenerator = 0;
     private final Consumer<TestkitResponse> responseWriter;
     private final Supplier<Boolean> processor;
-    private final Map<String,Set<ServerAddress>> idToServerAddresses = new HashMap<>();
-    private final Map<String,InetAddress[]> idToResolvedAddresses = new HashMap<>();
+    private final Map<String,CompletableFuture<TestkitCallbackResult>> callbackIdToFuture = new HashMap<>();
 
     public TestkitState( Consumer<TestkitResponse> responseWriter, Supplier<Boolean> processor )
     {
         this.responseWriter = responseWriter;
         this.processor = processor;
     }
 
+    public CompletionStage<TestkitCallbackResult> dispatchTestkitCallback( TestkitCallback response )
+    {
+        CompletableFuture<TestkitCallbackResult> future = new CompletableFuture<>();
+        callbackIdToFuture.put( response.getCallbackId(), future );
+        responseWriter.accept( response );
+        // This is required for sync backend, but should be removed during migration to Netty implementation.
+        processor.get();
+        return future;
+    }
+
     public String newId()
     {
         return String.valueOf( idGenerator++ );

testkit-backend/src/main/java/neo4j/org/testkit/backend/channel/handler/TestkitRequestProcessorHandler.java

@@ -27,6 +27,7 @@
 import neo4j.org.testkit.backend.messages.responses.DriverError;
 import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
 
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
 
 import org.neo4j.driver.exceptions.Neo4jException;
@@ -49,20 +50,25 @@ public void channelRegistered( ChannelHandlerContext ctx ) throws Exception
     public void channelRead( ChannelHandlerContext ctx, Object msg )
     {
         TestkitRequest testkitRequest = (TestkitRequest) msg;
-        try
-        {
-            testkitRequest.processAsync( testkitState )
-                          .thenAccept( responseOpt -> responseOpt.ifPresent( ctx::writeAndFlush ) )
-                          .exceptionally( throwable ->
-                                          {
-                                              ctx.writeAndFlush( createErrorResponse( throwable ) );
-                                              return null;
-                                          } );
-        }
-        catch ( Throwable throwable )
-        {
-            ctx.writeAndFlush( createErrorResponse( throwable ) );
-        }
+        // Processing is done in a separate thread to avoid blocking EventLoop because some testing logic, like resolvers support, is blocking.
+        CompletableFuture.runAsync(
+                () ->
+                {
+                    try
+                    {
+                        testkitRequest.processAsync( testkitState )
+                                      .thenAccept( responseOpt -> responseOpt.ifPresent( ctx::writeAndFlush ) )
+                                      .exceptionally( throwable ->
+                                                      {
+                                                          ctx.writeAndFlush( createErrorResponse( throwable ) );
+                                                          return null;
+                                                      } );
+                    }
+                    catch ( Throwable throwable )
+                    {
+                        ctx.writeAndFlush( createErrorResponse( throwable ) );
+                    }
+                } );
     }
 
     private TestkitResponse createErrorResponse( Throwable throwable )

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/DomainNameResolutionCompleted.java

@@ -21,55 +21,26 @@
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
-import neo4j.org.testkit.backend.TestkitState;
-import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
 
-import java.net.InetAddress;
-import java.net.UnknownHostException;
 import java.util.List;
-import java.util.Optional;
-import java.util.concurrent.CompletionStage;
 
 @Setter
 @Getter
 @NoArgsConstructor
-public class DomainNameResolutionCompleted implements TestkitRequest
+public class DomainNameResolutionCompleted implements TestkitCallbackResult
 {
     private DomainNameResolutionCompletedBody data;
 
     @Override
-    public TestkitResponse process( TestkitState testkitState )
+    public String getCallbackId()
     {
-        testkitState.getIdToResolvedAddresses().put(
-                data.getRequestId(),
-                data.getAddresses()
-                    .stream()
-                    .map(
-                            addr ->
-                            {
-                                try
-                                {
-                                    return InetAddress.getByName( addr );
-                                }
-                                catch ( UnknownHostException e )
-                                {
-                                    throw new RuntimeException( e );
-                                }
-                            } )
-                    .toArray( InetAddress[]::new ) );
-        return null;
-    }
-
-    @Override
-    public CompletionStage<Optional<TestkitResponse>> processAsync( TestkitState testkitState )
-    {
-        throw new UnsupportedOperationException();
+        return data.getRequestId();
     }
 
     @Setter
     @Getter
     @NoArgsConstructor
-    private static class DomainNameResolutionCompletedBody
+    public static class DomainNameResolutionCompletedBody
     {
         private String requestId;
         private List<String> addresses;

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/NewDriver.java

@@ -30,15 +30,20 @@
 import neo4j.org.testkit.backend.messages.responses.ResolverResolutionRequired;
 import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
 
+import java.net.InetAddress;
 import java.net.URI;
+import java.net.UnknownHostException;
+import java.util.LinkedHashSet;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
 
 import org.neo4j.driver.AuthToken;
 import org.neo4j.driver.AuthTokens;
 import org.neo4j.driver.Config;
+import org.neo4j.driver.internal.BoltServerAddress;
 import org.neo4j.driver.internal.DefaultDomainNameResolver;
 import org.neo4j.driver.internal.DomainNameResolver;
 import org.neo4j.driver.internal.DriverFactory;
@@ -128,9 +133,20 @@ private ServerAddressResolver callbackResolver( TestkitState testkitState )
                     ResolverResolutionRequired.builder()
                                               .data( body )
                                               .build();
-            testkitState.getResponseWriter().accept( response );
-            testkitState.getProcessor().get();
-            return testkitState.getIdToServerAddresses().remove( callbackId );
+            CompletionStage<TestkitCallbackResult> c = testkitState.dispatchTestkitCallback( response );
+            ResolverResolutionCompleted resolutionCompleted;
+            try
+            {
+                resolutionCompleted = (ResolverResolutionCompleted) c.toCompletableFuture().get();
+            }
+            catch ( Exception e )
+            {
+                throw new RuntimeException( e );
+            }
+            return resolutionCompleted.getData().getAddresses()
+                                      .stream()
+                                      .map( BoltServerAddress::new )
+                                      .collect( Collectors.toCollection( LinkedHashSet::new ) );
         };
     }
 
@@ -144,13 +160,37 @@ private DomainNameResolver callbackDomainNameResolver( TestkitState testkitState
                                                                                  .id( callbackId )
                                                                                  .name( address )
                                                                                  .build();
-            DomainNameResolutionRequired response =
+            DomainNameResolutionRequired callback =
                     DomainNameResolutionRequired.builder()
                                                 .data( body )
                                                 .build();
-            testkitState.getResponseWriter().accept( response );
-            testkitState.getProcessor().get();
-            return testkitState.getIdToResolvedAddresses().remove( callbackId );
+
+            CompletionStage<TestkitCallbackResult> callbackStage = testkitState.dispatchTestkitCallback( callback );
+            DomainNameResolutionCompleted resolutionCompleted;
+            try
+            {
+                resolutionCompleted = (DomainNameResolutionCompleted) callbackStage.toCompletableFuture().get();
+            }
+            catch ( Exception e )
+            {
+                throw new RuntimeException( "Unexpected failure during Testkit callback", e );
+            }
+
+            return resolutionCompleted.getData().getAddresses()
+                                      .stream()
+                                      .map(
+                                              addr ->
+                                              {
+                                                  try
+                                                  {
+                                                      return InetAddress.getByName( addr );
+                                                  }
+                                                  catch ( UnknownHostException e )
+                                                  {
+                                                      throw new RuntimeException( e );
+                                                  }
+                                              } )
+                                      .toArray( InetAddress[]::new );
         };
     }
 

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/ResolverResolutionCompleted.java

@@ -21,36 +21,20 @@
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
-import neo4j.org.testkit.backend.TestkitState;
-import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
 
-import java.util.LinkedHashSet;
 import java.util.List;
-import java.util.Optional;
-import java.util.concurrent.CompletionStage;
-import java.util.stream.Collectors;
-
-import org.neo4j.driver.internal.BoltServerAddress;
 
 @Setter
 @Getter
 @NoArgsConstructor
-public class ResolverResolutionCompleted implements TestkitRequest
+public class ResolverResolutionCompleted implements TestkitCallbackResult
 {
     private ResolverResolutionCompletedBody data;
 
     @Override
-    public TestkitResponse process( TestkitState testkitState )
-    {
-        testkitState.getIdToServerAddresses().put( data.getRequestId(), data.getAddresses().stream().map( BoltServerAddress::new )
-                                                                            .collect( Collectors.toCollection( LinkedHashSet::new ) ) );
-        return null;
-    }
-
-    @Override
-    public CompletionStage<Optional<TestkitResponse>> processAsync( TestkitState testkitState )
+    public String getCallbackId()
     {
-        throw new UnsupportedOperationException();
+        return data.getRequestId();
     }
 
     @Setter

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/StartTest.java

@@ -41,13 +41,7 @@ public class StartTest implements TestkitRequest
 
     static
     {
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_fail_when_driver_closed_using_session_run$", "Does not throw error" );
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_read_successfully_on_empty_discovery_result_using_session_run$", "Resolver not implemented" );
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_request_rt_from_all_initial_routers_until_successful", "Resolver not implemented" );
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_revert_to_initial_router_if_known_router_throws_protocol_errors", "Resolver not implemented" );
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_successfully_acquire_rt_when_router_ip_changes$", "Resolver not implemented" );
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_use_resolver_during_rediscovery_when_existing_routers_fail$", "Resolver not implemented" );
-        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_reject_server_using_verify_connectivity_bolt_3x0", "Does not error as expected" );
+        ASYNC_SKIP_PATTERN_TO_REASON.put( "^.*.test_should_reject_server_using_verify_connectivity_bolt_3x0$", "Does not error as expected" );
     }
 
     private StartTestBody data;

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/TestkitCallbackResult.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) "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 neo4j.org.testkit.backend.messages.requests;
+
+import neo4j.org.testkit.backend.TestkitState;
+import neo4j.org.testkit.backend.messages.responses.TestkitCallback;
+import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
+
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+
+/**
+ * This request is sent by Testkit in response to previously sent {@link TestkitCallback}.
+ */
+public interface TestkitCallbackResult extends TestkitRequest
+{
+    String getCallbackId();
+
+    @Override
+    default TestkitResponse process( TestkitState testkitState )
+    {
+        testkitState.getCallbackIdToFuture().get( getCallbackId() ).complete( this );
+        return null;
+    }
+
+    @Override
+    default CompletionStage<Optional<TestkitResponse>> processAsync( TestkitState testkitState )
+    {
+        testkitState.getCallbackIdToFuture().get( getCallbackId() ).complete( this );
+        return CompletableFuture.completedFuture( Optional.empty() );
+    }
+}

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/responses/DomainNameResolutionRequired.java

@@ -25,7 +25,7 @@
 @Setter
 @Getter
 @Builder
-public class DomainNameResolutionRequired implements TestkitResponse
+public class DomainNameResolutionRequired implements TestkitCallback
 {
     private DomainNameResolutionRequiredBody data;
 
@@ -35,6 +35,12 @@ public String testkitName()
         return "DomainNameResolutionRequired";
     }
 
+    @Override
+    public String getCallbackId()
+    {
+        return data.getId();
+    }
+
     @Setter
     @Getter
     @Builder

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/responses/ResolverResolutionRequired.java

@@ -25,7 +25,7 @@
 @Setter
 @Getter
 @Builder
-public class ResolverResolutionRequired implements TestkitResponse
+public class ResolverResolutionRequired implements TestkitCallback
 {
     private ResolverResolutionRequiredBody data;
 
@@ -35,6 +35,12 @@ public String testkitName()
         return "ResolverResolutionRequired";
     }
 
+    @Override
+    public String getCallbackId()
+    {
+        return data.getId();
+    }
+
     @Setter
     @Getter
     @Builder