RDB-136 Flow tabel wordt niet meer opgeruimd Bij een exceptie in Flow

Refactoring om de actie van de Exceptionstrategie door te geven aan de cleanup stack
Megre bug geresolved

Tapeti.Flow/Default/FlowCleanupMiddleware.cs

@@ -9,7 +9,7 @@ namespace Tapeti.Flow.Default
 {
     public class FlowCleanupMiddleware : ICleanupMiddleware
     {
-        public async Task Handle(IMessageContext context, ConsumeResponse response)
+        public async Task Handle(IMessageContext context, HandlingResult handlingResult)
         {
             object flowContextObj;
             if (!context.Items.TryGetValue(ContextItems.FlowContext, out flowContextObj))
@@ -18,7 +18,8 @@ namespace Tapeti.Flow.Default
 
             if (flowContext.FlowStateLock != null)
             {
-                if (response == ConsumeResponse.Nack)
+                if (handlingResult.ConsumeResponse == ConsumeResponse.Nack 
+                    || handlingResult.MessageAction == MessageAction.ErrorLog)
                 {
                     await flowContext.FlowStateLock.DeleteFlowState();
                 }

Tapeti.Flow/Default/FlowStarter.cs

@@ -52,7 +52,34 @@ namespace Tapeti.Flow.Default
             };
 
             var flowHandler = config.DependencyResolver.Resolve<IFlowHandler>();
-            await flowHandler.Execute(context, yieldPoint);
+            HandlingResultBuilder handlingResult = new HandlingResultBuilder
+            {
+                ConsumeResponse = ConsumeResponse.Nack,
+            };
+            try
+            {
+                await flowHandler.Execute(context, yieldPoint);
+                handlingResult.ConsumeResponse = ConsumeResponse.Ack;
+            }
+            finally
+            {
+                await RunCleanup(context, handlingResult.ToHandlingResult());
+            }
+        }
+
+        private async Task RunCleanup(MessageContext context, HandlingResult handlingResult)
+        {
+            foreach (var handler in config.CleanupMiddleware)
+            {
+                try
+                {
+                    await handler.Handle(context, handlingResult);
+                }
+                catch (Exception eCleanup)
+                {
+                    logger.HandlerException(eCleanup);
+                }
+            }
         }
 
 

Tapeti/Config/ICleanupMiddleware.cs

@@ -8,6 +8,6 @@ namespace Tapeti.Config
 {
     public interface ICleanupMiddleware
     {
-        Task Handle(IMessageContext context, ConsumeResponse response);
+        Task Handle(IMessageContext context, HandlingResult handlingResult);
     }
 }

Tapeti/Config/IExceptionStrategyContext.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tapeti.Config
+{
+    public interface IExceptionStrategyContext
+    {
+        IMessageContext MessageContext { get; }
+
+        Exception Exception { get; }
+
+        HandlingResultBuilder HandlingResult { get; set; }
+    }
+}

Tapeti/Connection/TapetiConsumer.cs

@@ -44,7 +44,7 @@ namespace Tapeti.Connection
             {
                 ExceptionDispatchInfo exception = null;
                 MessageContext context = null;
-                ConsumeResponse response = ConsumeResponse.Nack;
+                HandlingResult handlingResult = null;
                 try
                 {
                     try
@@ -59,7 +59,11 @@ namespace Tapeti.Connection
 
                         await DispatchMesage(context, body);
 
-                        response = ConsumeResponse.Ack;
+                        handlingResult = new HandlingResult
+                        {
+                            ConsumeResponse = ConsumeResponse.Ack,
+                            MessageAction = MessageAction.None
+                        };
                     }
                     catch (Exception eDispatch)
                     {
@@ -67,7 +71,11 @@ namespace Tapeti.Connection
                         logger.HandlerException(eDispatch);
                         try
                         {
-                            response = exceptionStrategy.HandleException(null, exception.SourceException);
+                            var exceptionStrategyContext = new ExceptionStrategyContext(context, exception.SourceException);
+
+                            exceptionStrategy.HandleException(exceptionStrategyContext);
+
+                            handlingResult = exceptionStrategyContext.HandlingResult.ToHandlingResult();
                         }
                         catch (Exception eStrategy)
                         {
@@ -76,7 +84,15 @@ namespace Tapeti.Connection
                     }
                     try
                     {
-                        await RunCleanup(context, response);
+                        if (handlingResult == null)
+                        {
+                            handlingResult = new HandlingResult
+                            {
+                                ConsumeResponse = ConsumeResponse.Nack,
+                                MessageAction = MessageAction.None
+                            };
+                        }
+                        await RunCleanup(context, handlingResult);
                     }
                     catch (Exception eCleanup)
                     {
@@ -87,7 +103,15 @@ namespace Tapeti.Connection
                 {
                     try
                     {
-                        await worker.Respond(deliveryTag, response);
+                        if (handlingResult == null)
+                        {
+                            handlingResult = new HandlingResult
+                            {
+                                ConsumeResponse = ConsumeResponse.Nack,
+                                MessageAction = MessageAction.None
+                            };
+                        }
+                        await worker.Respond(deliveryTag, handlingResult.ConsumeResponse);
                     }
                     catch (Exception eRespond)
                     {
@@ -108,13 +132,13 @@ namespace Tapeti.Connection
             });
         }
 
-        private async Task RunCleanup(MessageContext context, ConsumeResponse response)
+        private async Task RunCleanup(MessageContext context, HandlingResult handlingResult)
         {
             foreach(var handler in cleanupMiddleware)
             {
                 try
                 {
-                    await handler.Handle(context, response);
+                    await handler.Handle(context, handlingResult);
                 }
                 catch (Exception eCleanup)
                 {

Tapeti/Default/ExceptionStrategyContext.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Tapeti.Config;
+
+namespace Tapeti.Default
+{
+    public class ExceptionStrategyContext : IExceptionStrategyContext
+    {
+        internal ExceptionStrategyContext(IMessageContext messageContext, Exception exception)
+        {
+            MessageContext = messageContext;
+            Exception = exception;
+        }
+
+        public IMessageContext MessageContext { get; }
+
+        public Exception Exception { get; }
+
+        private HandlingResultBuilder handlingResult;
+        public HandlingResultBuilder HandlingResult
+        {
+            get
+            {
+                if (handlingResult == null)
+                {
+                    handlingResult = new HandlingResultBuilder();
+                }
+                return handlingResult;
+            }
+
+            set
+            {
+                handlingResult = value;
+            }
+        }
+    }
+}

Tapeti/Default/NackExceptionStrategy.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Tapeti.Config;
+
+namespace Tapeti.Default
+{
+    public class NackExceptionStrategy : IExceptionStrategy
+    {
+        public void HandleException(IExceptionStrategyContext context)
+        {
+            context.HandlingResult.ConsumeResponse = ConsumeResponse.Nack;
+        }
+    }
+}

Tapeti/Default/RequeueExceptionStrategy.cs

@@ -5,10 +5,9 @@ namespace Tapeti.Default
 {
     public class RequeueExceptionStrategy : IExceptionStrategy
     {
-        public ConsumeResponse HandleException(IMessageContext context, Exception exception)
+        public void HandleException(IExceptionStrategyContext context)
         {
-            // TODO log exception
+            context.HandlingResult.ConsumeResponse = ConsumeResponse.Requeue;
-            return ConsumeResponse.Requeue;
         }
     }
 }

Tapeti/HandlingResult.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tapeti
+{
+    public class HandlingResult
+    {
+        public HandlingResult()
+        {
+            ConsumeResponse = ConsumeResponse.Nack;
+            MessageAction = MessageAction.None;
+        }
+
+        /// <summary>
+        /// Determines which response will be given to the message bus from where the message originates.
+        /// </summary>
+        public ConsumeResponse ConsumeResponse { get; internal set; }
+
+        /// <summary>
+        /// Registers which action the Exception strategy has taken or will take to handle the error condition
+        /// on the message. This is important to know for cleanup handlers registered by middleware.
+        /// </summary>
+        public MessageAction MessageAction { get; internal set; }
+
+    }
+
+    public class HandlingResultBuilder
+    {
+        private static readonly HandlingResult Default = new HandlingResult();
+
+        private HandlingResult data = Default;
+
+        public ConsumeResponse ConsumeResponse {
+            get
+            {
+                return data.ConsumeResponse;
+            }
+            set
+            {
+                GetWritableData().ConsumeResponse = value;
+            }
+        }
+
+        public MessageAction MessageAction
+        {
+            get
+            {
+                return data.MessageAction;
+            }
+            set
+            {
+                GetWritableData().MessageAction = value;
+            }
+        }
+
+        public HandlingResult ToHandlingResult()
+        {
+            if (data == Default)
+            {
+                return new HandlingResult();
+            }
+            var result = GetWritableData();
+            data = Default;
+            return result;
+        }
+
+        private HandlingResult GetWritableData()
+        {
+            if (data == Default)
+            {
+                data = new HandlingResult();
+            }
+            return data;
+        }
+    }
+}

Tapeti/IExceptionStrategy.cs

@@ -8,9 +8,9 @@ namespace Tapeti
         /// <summary>
         /// Called when an exception occurs while handling a message.
         /// </summary>
-        /// <param name="context">The message context if available. May be null!</param>
+        /// <param name="context">The exception strategy context containing the necessary data including the message context and the thrown exception.
-        /// <param name="exception">The exception instance</param>
+        /// Also the response to the message can be set.
-        /// <returns>The ConsumeResponse to determine whether to requeue, dead-letter (nack) or simply ack the message.</returns>
+        /// If there is any other handling of the message than the expected default than HandlingResult.MessageFutureAction must be set accordingly. </param>
-        ConsumeResponse HandleException(IMessageContext context, Exception exception);
+        void HandleException(IExceptionStrategyContext context);
     }
 }

Tapeti/MessageFutureAction.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tapeti
+{
+    public enum MessageAction
+    {
+        None = 1,
+        ErrorLog = 2,
+        Retry = 3,
+    }
+}

Tapeti/Tapeti.csproj

@@ -53,6 +53,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Config\IExceptionStrategyContext.cs" />
     <Compile Include="Config\ICleanupMiddleware.cs" />
     <Compile Include="Config\IPublishContext.cs" />
     <Compile Include="Config\IMessageFilterMiddleware.cs" />
@@ -64,6 +65,9 @@
     <Compile Include="Connection\TapetiWorker.cs" />
     <Compile Include="Default\ConsoleLogger.cs" />
     <Compile Include="Default\DevNullLogger.cs" />
+    <Compile Include="Default\ExceptionStrategyContext.cs" />
+    <Compile Include="Default\NackExceptionStrategy.cs" />
+    <Compile Include="HandlingResult.cs" />
     <Compile Include="Default\JsonMessageSerializer.cs" />
     <Compile Include="Default\MessageContext.cs" />
     <Compile Include="Default\PublishResultBinding.cs" />
@@ -84,6 +88,7 @@
     <Compile Include="Config\IConfig.cs" />
     <Compile Include="MessageController.cs" />
     <Compile Include="Config\IBindingMiddleware.cs" />
+    <Compile Include="MessageFutureAction.cs" />
     <Compile Include="TapetiAppSettingsConnectionParams.cs" />
     <Compile Include="TapetiConnectionParams.cs" />
     <Compile Include="TapetiConfig.cs" />

Tapeti/TapetiConfig.cs

@@ -143,7 +143,7 @@ namespace Tapeti
             container.RegisterDefault<IMessageSerializer, JsonMessageSerializer>();
             container.RegisterDefault<IExchangeStrategy, NamespaceMatchExchangeStrategy>();
             container.RegisterDefault<IRoutingKeyStrategy, TypeNameRoutingKeyStrategy>();
-            container.RegisterDefault<IExceptionStrategy, RequeueExceptionStrategy>();
+            container.RegisterDefault<IExceptionStrategy, NackExceptionStrategy>();
         }