Fixed #6: Use 'mandatory' on replies

Tapeti.Flow/Default/FlowProvider.cs

@@ -80,7 +80,7 @@ namespace Tapeti.Flow.Default
 
             await context.Store();
 
-            await publisher.Publish(message, properties);
+            await publisher.Publish(message, properties, true);
         }
 
 
@@ -105,9 +105,9 @@ namespace Tapeti.Flow.Default
 
             // TODO disallow if replyto is not specified?
             if (reply.ReplyTo != null)
-                await publisher.PublishDirect(message, reply.ReplyTo, properties);
+                await publisher.PublishDirect(message, reply.ReplyTo, properties, true);
             else
-                await publisher.Publish(message, properties);
+                await publisher.Publish(message, properties, true);
 
             await context.Delete();
         }

Tapeti.Serilog/TapetiSeriLogger.cs

@@ -1,6 +1,8 @@
 using System;
 using ISeriLogger = Serilog.ILogger;
 
+// ReSharper disable UnusedMember.Global
+
 namespace Tapeti.Serilog
 {
     public class TapetiSeriLogger: ILogger

Tapeti/Config/IConfig.cs

@@ -7,6 +7,8 @@ namespace Tapeti.Config
 {
     public interface IConfig
     {
+        bool UsePublisherConfirms { get; }
+
         IDependencyResolver DependencyResolver { get; }
         IReadOnlyList<IMessageMiddleware> MessageMiddleware { get; }
         IReadOnlyList<ICleanupMiddleware> CleanupMiddleware { get; }

Tapeti/Connection/TapetiPublisher.cs

@@ -17,19 +17,19 @@ namespace Tapeti.Connection
 
         public Task Publish(object message)
         {
-            return workerFactory().Publish(message, null);
+            return workerFactory().Publish(message, null, false);
         }
 
 
-        public Task Publish(object message, IBasicProperties properties)
+        public Task Publish(object message, IBasicProperties properties, bool mandatory)
         {
-            return workerFactory().Publish(message, properties);
+            return workerFactory().Publish(message, properties, mandatory);
         }
 
 
-        public Task PublishDirect(object message, string queueName, IBasicProperties properties)
+        public Task PublishDirect(object message, string queueName, IBasicProperties properties, bool mandatory)
         {
-            return workerFactory().PublishDirect(message, queueName, properties);
+            return workerFactory().PublishDirect(message, queueName, properties, mandatory);
         }
     }
 }

Tapeti/Connection/TapetiWorker.cs

@@ -1,10 +1,12 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 using RabbitMQ.Client;
 using RabbitMQ.Client.Exceptions;
 using RabbitMQ.Client.Framing;
 using Tapeti.Config;
+using Tapeti.Exceptions;
 using Tapeti.Helpers;
 using Tapeti.Tasks;
 
@@ -13,6 +15,7 @@ namespace Tapeti.Connection
     public class TapetiWorker
     {
         private const int ReconnectDelay = 5000;
+        private const int MandatoryReturnTimeout = 30000;
         private const int PublishMaxConnectAttempts = 3;
 
         private readonly IConfig config;
@@ -24,8 +27,11 @@ namespace Tapeti.Connection
         private readonly IRoutingKeyStrategy routingKeyStrategy;
         private readonly IExchangeStrategy exchangeStrategy;
         private readonly Lazy<SingleThreadTaskQueue> taskQueue = new Lazy<SingleThreadTaskQueue>();
+
+        // These fields are for use in the taskQueue only!
         private RabbitMQ.Client.IConnection connection;
         private IModel channelInstance;
+        private TaskCompletionSource<int> publishResultTaskSource;
 
 
         public TapetiWorker(IConfig config)
@@ -39,15 +45,15 @@ namespace Tapeti.Connection
         }
 
 
-        public Task Publish(object message, IBasicProperties properties)
+        public Task Publish(object message, IBasicProperties properties, bool mandatory)
         {
-            return Publish(message, properties, exchangeStrategy.GetExchange(message.GetType()), routingKeyStrategy.GetRoutingKey(message.GetType()));
+            return Publish(message, properties, exchangeStrategy.GetExchange(message.GetType()), routingKeyStrategy.GetRoutingKey(message.GetType()), mandatory);
         }
 
 
-        public Task PublishDirect(object message, string queueName, IBasicProperties properties)
+        public Task PublishDirect(object message, string queueName, IBasicProperties properties, bool mandatory)
         {
-            return Publish(message, properties, "", queueName);
+            return Publish(message, properties, "", queueName, mandatory);
         }
 
 
@@ -147,7 +153,7 @@ namespace Tapeti.Connection
         }
 
 
-        private Task Publish(object message, IBasicProperties properties, string exchange, string routingKey)
+        private Task Publish(object message, IBasicProperties properties, string exchange, string routingKey, bool mandatory)
         {
             var context = new PublishContext
             {
@@ -172,8 +178,39 @@ namespace Tapeti.Connection
                 () => taskQueue.Value.Add(async () =>
                 {
                     var body = messageSerializer.Serialize(context.Message, context.Properties);
-                    (await GetChannel(PublishMaxConnectAttempts)).BasicPublish(context.Exchange, context.RoutingKey, false,
+                    Task<int> publishResultTask = null;
-                        context.Properties, body);
+
+                    if (config.UsePublisherConfirms)
+                    {
+                        publishResultTaskSource = new TaskCompletionSource<int>();
+                        publishResultTask = publishResultTaskSource.Task;
+                    }
+                    else
+                        mandatory = false;
+
+                    (await GetChannel(PublishMaxConnectAttempts)).BasicPublish(context.Exchange, context.RoutingKey, mandatory, context.Properties, body);
+
+                    if (publishResultTask != null)
+                    {
+                        var timerCancellationSource = new CancellationTokenSource();
+
+                        if (await Task.WhenAny(publishResultTask, Task.Delay(MandatoryReturnTimeout, timerCancellationSource.Token)) == publishResultTask)
+                        {
+                            timerCancellationSource.Cancel();
+
+                            var replyCode = publishResultTask.Result;
+
+                            // There is no RabbitMQ.Client.Framing.Constants value for this "No route" reply code
+                            // at the time of writing...
+                            if (replyCode == 312)
+                                throw new NoRouteException($"Mandatory message with class {context.Message?.GetType().FullName ?? "null"} does not have a route");
+
+                            if (replyCode > 0)
+                                throw new NoRouteException($"Mandatory message with class {context.Message?.GetType().FullName ?? "null"} could not be delivery, reply code {replyCode}");
+                        }
+                        else
+                            throw new TimeoutException($"Timeout while waiting for basic.return for message with class {context.Message?.GetType().FullName ?? "null"} and Id {context.Properties.MessageId}");
+                    }
                 }).Unwrap());
             // ReSharper restore ImplicitlyCapturedClosure
         }
@@ -207,13 +244,25 @@ namespace Tapeti.Connection
 
                     connection = connectionFactory.CreateConnection();
                     channelInstance = connection.CreateModel();
+                    channelInstance.ConfirmSelect();
 
                     if (ConnectionParams.PrefetchCount > 0)
                         channelInstance.BasicQos(0, ConnectionParams.PrefetchCount, false);
 
                     ((IRecoverable)connection).Recovery += (sender, e) => ConnectionEventListener?.Reconnected();
 
-                    channelInstance.ModelShutdown += (sender, e) => ConnectionEventListener?.Disconnected();
+                    channelInstance.ModelShutdown += (sender, eventArgs) => ConnectionEventListener?.Disconnected();
+                    channelInstance.BasicReturn += (sender, eventArgs) =>
+                    {
+                        publishResultTaskSource?.SetResult(eventArgs.ReplyCode);
+                        publishResultTaskSource = null;
+                    };
+
+                    channelInstance.BasicAcks += (sender, eventArgs) =>
+                    {
+                        publishResultTaskSource?.SetResult(0);
+                        publishResultTaskSource = null;
+                    };
 
                     ConnectionEventListener?.Connected();
                     logger.ConnectSuccess(ConnectionParams);

Tapeti/Default/ConsoleLogger.cs

@@ -16,7 +16,7 @@ namespace Tapeti.Default
 
         public void ConnectSuccess(TapetiConnectionParams connectionParams)
         {
-            Console.WriteLine($"[Tapeti] Connected");
+            Console.WriteLine("[Tapeti] Connected");
         }
 
         public void HandlerException(Exception e)

Tapeti/Default/PublishResultBinding.cs

@@ -69,9 +69,9 @@ namespace Tapeti.Default
                 properties.CorrelationId = messageContext.Properties.CorrelationId;
 
             if (messageContext.Properties.IsReplyToPresent())
-                return publisher.PublishDirect(message, messageContext.Properties.ReplyTo, properties);
+                return publisher.PublishDirect(message, messageContext.Properties.ReplyTo, properties, true);
 
-            return publisher.Publish(message, properties);
+            return publisher.Publish(message, properties, false);
         }
     }
 }

Tapeti/Exceptions/NoRouteException.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Tapeti.Exceptions
+{
+    public class NoRouteException : Exception
+    {
+        public NoRouteException(string message) : base(message) { }
+    }
+}

Tapeti/IPublisher.cs

@@ -13,7 +13,7 @@ namespace Tapeti
 
     public interface IInternalPublisher : IPublisher
     {
-        Task Publish(object message, IBasicProperties properties);
+        Task Publish(object message, IBasicProperties properties, bool mandatory);
-        Task PublishDirect(object message, string queueName, IBasicProperties properties);
+        Task PublishDirect(object message, string queueName, IBasicProperties properties, bool mandatory);
     }
 }

Tapeti/TapetiConfig.cs

@@ -8,6 +8,7 @@ using Tapeti.Config;
 using Tapeti.Default;
 using Tapeti.Helpers;
 
+// ReSharper disable UnusedMember.Global
 
 namespace Tapeti
 {
@@ -31,6 +32,8 @@ namespace Tapeti
 
         private readonly IDependencyResolver dependencyResolver;
 
+        private bool usePublisherConfirms = true;
+
 
         public TapetiConfig(IDependencyResolver dependencyResolver)
         {
@@ -90,7 +93,16 @@ namespace Tapeti
                 queues.AddRange(dynamicBindings.Select(bl => new Queue(new QueueInfo { Dynamic = true, Name = GetDynamicQueueName(prefixGroup.Key) }, bl)));
             }
 
-            var config = new Config(dependencyResolver, messageMiddleware, cleanupMiddleware, publishMiddleware, queues);
+            var config = new Config(queues)
+            {
+                DependencyResolver = dependencyResolver, 
+                MessageMiddleware = messageMiddleware, 
+                CleanupMiddleware = cleanupMiddleware, 
+                PublishMiddleware = publishMiddleware,
+
+                UsePublisherConfirms = usePublisherConfirms
+            };
+
             (dependencyResolver as IDependencyContainer)?.RegisterDefaultSingleton<IConfig>(config);
 
             return config;
@@ -154,11 +166,34 @@ namespace Tapeti
             return this;
         }
 
+        
+        /// <summary>
+        /// WARNING: disabling publisher confirms means there is no guarantee that a Publish succeeds,
+        /// and disables Tapeti.Flow from verifying if a request/response can be routed. This may
+        /// result in never-ending flows. Only disable if you can accept those consequences.
+        /// </summary>
+        public TapetiConfig DisablePublisherConfirms()
+        {
+            usePublisherConfirms = false;
+            return this;
+        }
+
+
+        /// <summary>
+        /// WARNING: disabling publisher confirms means there is no guarantee that a Publish succeeds,
+        /// and disables Tapeti.Flow from verifying if a request/response can be routed. This may
+        /// result in never-ending flows. Only disable if you accept those consequences.
+        /// </summary>
+        public TapetiConfig SetPublisherConfirms(bool enabled)
+        {
+            usePublisherConfirms = enabled;
+            return this;
+        }
+
 
         public void RegisterDefaults()
         {
-            var container = dependencyResolver as IDependencyContainer;
+            if (!(dependencyResolver is IDependencyContainer container))
-            if (container == null)
                 return;
 
             if (ConsoleHelper.IsAvailable())
@@ -399,21 +434,19 @@ namespace Tapeti
 
         protected class Config : IConfig
         {
-            public IDependencyResolver DependencyResolver { get; }
+            public bool UsePublisherConfirms { get; set; }
-            public IReadOnlyList<IMessageMiddleware> MessageMiddleware { get; }
+
-            public IReadOnlyList<ICleanupMiddleware> CleanupMiddleware { get; }
+            public IDependencyResolver DependencyResolver { get; set; }
-            public IReadOnlyList<IPublishMiddleware> PublishMiddleware { get; }
+            public IReadOnlyList<IMessageMiddleware> MessageMiddleware { get; set; }
+            public IReadOnlyList<ICleanupMiddleware> CleanupMiddleware { get; set; }
+            public IReadOnlyList<IPublishMiddleware> PublishMiddleware { get; set; }
             public IEnumerable<IQueue> Queues { get; }
 
             private readonly Dictionary<MethodInfo, IBinding> bindingMethodLookup;
 
 
-            public Config(IDependencyResolver dependencyResolver, IReadOnlyList<IMessageMiddleware> messageMiddleware, IReadOnlyList<ICleanupMiddleware> cleanupMiddleware, IReadOnlyList<IPublishMiddleware> publishMiddleware, IEnumerable<IQueue> queues)
+            public Config(IEnumerable<IQueue> queues)
             {
-                DependencyResolver = dependencyResolver;
-                MessageMiddleware = messageMiddleware;
-                CleanupMiddleware = cleanupMiddleware;
-                PublishMiddleware = publishMiddleware;
                 Queues = queues.ToList();
 
                 bindingMethodLookup = Queues.SelectMany(q => q.Bindings).ToDictionary(b => b.Method, b => b);

Test/MyLogger.cs

@@ -1,25 +0,0 @@
-using System;
-using Tapeti;
-
-namespace Test
-{
-    public class MyLogger : ILogger
-    {
-        public void Connect(TapetiConnectionParams connectionParams)
-        {
-        }
-
-        public void ConnectFailed(TapetiConnectionParams connectionParams, Exception exception)
-        {
-        }
-
-        public void ConnectSuccess(TapetiConnectionParams connectionParams)
-        {
-        }
-
-        public void HandlerException(Exception e)
-        {
-            Console.WriteLine("Mylogger: " + e.Message);
-        }
-    }
-}

Test/Program.cs

@@ -5,7 +5,6 @@ using Tapeti.DataAnnotations;
 using Tapeti.Flow;
 using Tapeti.SimpleInjector;
 using System.Threading;
-using Tapeti.Flow.SQL;
 
 namespace Test
 {
@@ -14,58 +13,60 @@ namespace Test
         private static void Main()
         {
             // TODO logging
-
+            try
-            var container = new Container();
-            container.Register<MarcoEmitter>();
-            container.Register<Visualizer>();
-            container.Register<ILogger, Tapeti.Default.ConsoleLogger>();
-
-            var config = new TapetiConfig(new SimpleInjectorDependencyResolver(container))
-                //.WithFlowSqlRepository("Server=localhost;Database=TapetiTest;Integrated Security=true")
-                .WithFlow()
-                .WithDataAnnotations()
-                .RegisterAllControllers()
-                .Build();
-
-            using (var connection = new TapetiConnection(config)
             {
-                Params = new TapetiAppSettingsConnectionParams()
+                var container = new Container();
-            })
+                container.Register<MarcoEmitter>();
+                container.Register<Visualizer>();
+                container.Register<ILogger, Tapeti.Default.ConsoleLogger>();
+
+                var config = new TapetiConfig(new SimpleInjectorDependencyResolver(container))
+                    //.WithFlowSqlRepository("Server=localhost;Database=TapetiTest;Integrated Security=true")
+                    .WithFlow()
+                    .WithDataAnnotations()
+                    .RegisterAllControllers()
+                    //.DisablePublisherConfirms() -> you probably never want to do this if you're using Flow or want requeues when a publish fails
+                    .Build();
+
+                using (var connection = new TapetiConnection(config)
+                {
+                    Params = new TapetiAppSettingsConnectionParams()
+                })
+                {
+                    var flowStore = container.GetInstance<IFlowStore>();
+                    var flowStore2 = container.GetInstance<IFlowStore>();
+
+                    Console.WriteLine("IFlowHandler is singleton = " + (flowStore == flowStore2));
+
+                    connection.Connected += (sender, e) => { Console.WriteLine("Event Connected"); };
+                    connection.Disconnected += (sender, e) => { Console.WriteLine("Event Disconnected"); };
+                    connection.Reconnected += (sender, e) => { Console.WriteLine("Event Reconnected"); };
+
+                    Console.WriteLine("Subscribing...");
+                    var subscriber = connection.Subscribe(false).Result;
+
+                    Console.WriteLine("Consuming...");
+                    subscriber.Resume().Wait();
+
+                    Console.WriteLine("Done!");
+
+                    connection.GetPublisher().Publish(new FlowEndController.PingMessage());
+
+                    //container.GetInstance<IFlowStarter>().Start<MarcoController, bool>(c => c.StartFlow, true).Wait();
+                    container.GetInstance<IFlowStarter>().Start<MarcoController>(c => c.TestParallelRequest).Wait();
+
+                    Thread.Sleep(1000);
+
+                    var emitter = container.GetInstance<MarcoEmitter>();
+                    emitter.Run().Wait();
+
+
+                }
+            }
+            catch (Exception e)
             {
-                var flowStore = container.GetInstance<IFlowStore>();
+                Console.WriteLine(e.ToString());
-                var flowStore2 = container.GetInstance<IFlowStore>();
+                Console.ReadKey();
-
-                Console.WriteLine("IFlowHandler is singleton = " + (flowStore == flowStore2));
-
-                connection.Connected += (sender, e) => {
-                    Console.WriteLine("Event Connected");
-                };
-                connection.Disconnected += (sender, e) => {
-                    Console.WriteLine("Event Disconnected");
-                };
-                connection.Reconnected += (sender, e) => {
-                    Console.WriteLine("Event Reconnected");
-                };
-
-                Console.WriteLine("Subscribing...");
-                var subscriber = connection.Subscribe(false).Result;
-
-                Console.WriteLine("Consuming...");
-                subscriber.Resume().Wait();
-
-                Console.WriteLine("Done!");
-
-                connection.GetPublisher().Publish(new FlowEndController.PingMessage());
-
-                //container.GetInstance<IFlowStarter>().Start<MarcoController, bool>(c => c.StartFlow, true);
-                container.GetInstance<IFlowStarter>().Start<MarcoController>(c => c.TestParallelRequest);
-
-                Thread.Sleep(1000);
-
-                var emitter = container.GetInstance<MarcoEmitter>();
-                emitter.Run().Wait();
-
-
             }
         }
     }