Default consumer type to the generic interface to shorten consumer co…

…nfiguration

Signed-off-by: Tomasz Maruszak <[email protected]>

docs/intro.md

@@ -236,7 +236,9 @@ public class SomeConsumer : IConsumer<SomeMessage>
 }
 ```
 
-The `SomeConsumer` needs to be registered in your DI container. The SMB runtime will ask the chosen DI to provide the desired number of consumer instances. Any collaborators of the consumer will be resolved according to your DI configuration.
+The `SomeConsumer` needs to be registered in the DI container. The SMB runtime will ask the DI to provide the consumer instance.
+
+> When `.WithConsumer<TConsumer>()` is not declared, then a default consumer of type `IConsumer<TMessage>` will be assumed (since v2.0.0).
 
 Alternatively, if you do not want to implement the `IConsumer<SomeMessage>`, then you can provide the method name (2) or a delegate that calls the consumer method (3):
 
@@ -546,7 +548,9 @@ mbb.Handle<SomeRequest, SomeResponse>(x => x
   )
 ```
 
-> The same micro-service can both send the request and also be the handler of those requests.
+The same micro-service can both send the request and also be the handler of those requests.
+
+> When `.WithHandler<THandler>()` is not declared, then a default handler of type `IRequestHandler<TRequest, TResponse>` will be assumed (since v2.0.0).
 
 ## Static accessor
 
@@ -598,6 +602,22 @@ services.AddMessageBusInterceptorsFromAssembly(Assembly.GetExecutingAssembly());
 services.AddMessageBusConfiguratorsFromAssembly(Assembly.GetExecutingAssembly());
 ```
 
+Consider the following example:
+
+```cs
+// Given a consumer that is found:
+public class SomeMessageConsumer : IConsumer<SomeMessage>
+{
+}
+
+// When auto-registration is used:
+services.AddMessageBusConsumersFromAssembly(Assembly.GetExecutingAssembly());
+
+// Then it will cause the following MSDI setup:
+services.TryAddTransient<SomeMessageConsumer>();
+services.TryAddTransient<IConsumer<SomeMessage>, SomeMessageConsumer>();
+```
+
 #### ASP.Net Core
 
 For ASP.NET services, it is recommended to use the [`AspNetCore`](https://www.nuget.org/packages/SlimMessageBus.Host.AspNetCore) plugin. To properly support request scopes for [MessageBus.Current](#static-accessor) static accessor, it has a dependency on the `IHttpContextAccessor` which [needs to be registered](https://docs.microsoft.com/en-us/aspnet/core/fundamentals/http-context?view=aspnetcore-6.0#use-httpcontext-from-custom-components) during application setup:

src/Host.Interceptor.Properties.xml

@@ -4,7 +4,7 @@
   <Import Project="Common.Properties.xml" />
 
   <PropertyGroup>
-    <Version>2.0.0-rc1</Version>
+    <Version>2.0.0-rc2</Version>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
   </PropertyGroup>
 </Project> 

src/Host.Transport.Properties.xml

@@ -4,7 +4,7 @@
 	<Import Project="Common.Properties.xml" />
 
 	<PropertyGroup>
-		<Version>2.0.0-rc1</Version>
+		<Version>2.0.0-rc2</Version>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
   </PropertyGroup>
 </Project>

src/SlimMessageBus.Host/Config/ConsumerSettings.cs

@@ -24,11 +24,6 @@ private void CalculateResponseType()
             .SingleOrDefault();
     }
 
-    public ConsumerSettings()
-    {
-        Invokers = new List<IMessageTypeConsumerInvokerSettings>();
-    }
-
     /// Type of consumer that is configured (subscriber or request handler).
     /// </summary>
     public ConsumerMode ConsumerMode { get; set; }
@@ -39,7 +34,7 @@ public ConsumerSettings()
     /// <summary>
     /// List of all declared consumers that handle any derived message type of the declared message type.
     /// </summary>
-    public IList<IMessageTypeConsumerInvokerSettings> Invokers { get; }
+    public ISet<IMessageTypeConsumerInvokerSettings> Invokers { get; } = new HashSet<IMessageTypeConsumerInvokerSettings>();
 
     public ConsumerSettings ParentSettings => this;
     /// <summary>

src/SlimMessageBus.Host/Config/Fluent/ConsumerBuilder.cs

@@ -5,6 +5,7 @@ public class ConsumerBuilder<T> : AbstractConsumerBuilder
     public ConsumerBuilder(MessageBusSettings settings, Type messageType = null)
         : base(settings, messageType ?? typeof(T))
     {
+        ConsumerSettings.ConsumerMode = ConsumerMode.Consumer;
     }
 
     public ConsumerBuilder<T> Path(string path)
@@ -35,7 +36,6 @@ public ConsumerBuilder<T> Path(string path, Action<ConsumerBuilder<T>> pathConfi
     public ConsumerBuilder<T> WithConsumer<TConsumer>()
         where TConsumer : class, IConsumer<T>
     {
-        ConsumerSettings.ConsumerMode = ConsumerMode.Consumer;
         ConsumerSettings.ConsumerType = typeof(TConsumer);
         ConsumerSettings.ConsumerMethod = (consumer, message) => ((IConsumer<T>)consumer).OnHandle((T)message);
 
@@ -98,7 +98,6 @@ public ConsumerBuilder<T> WithConsumer<TConsumer>(Func<TConsumer, T, Task> consu
     {
         if (consumerMethod == null) throw new ArgumentNullException(nameof(consumerMethod));
 
-        ConsumerSettings.ConsumerMode = ConsumerMode.Consumer;
         ConsumerSettings.ConsumerType = typeof(TConsumer);
         ConsumerSettings.ConsumerMethod = (consumer, message) => consumerMethod((TConsumer)consumer, (T)message);
 
@@ -135,7 +134,6 @@ public ConsumerBuilder<T> WithConsumer(Type consumerType, string consumerMethodN
 
         consumerMethodName ??= nameof(IConsumer<object>.OnHandle);
 
-        ConsumerSettings.ConsumerMode = ConsumerMode.Consumer;
         ConsumerSettings.ConsumerType = consumerType;
         SetupConsumerOnHandleMethod(ConsumerSettings, consumerMethodName);
 

src/SlimMessageBus.Host/Config/Fluent/HandlerBuilder.cs

@@ -7,6 +7,7 @@ public HandlerBuilder(MessageBusSettings settings, Type requestType = null, Type
     {
         if (settings == null) throw new ArgumentNullException(nameof(settings));
 
+        ConsumerSettings.ConsumerMode = ConsumerMode.RequestResponse;
         ConsumerSettings.ResponseType = responseType ?? typeof(TResponse);
     }
 
@@ -24,7 +25,7 @@ public HandlerBuilder(MessageBusSettings settings, Type requestType = null, Type
     /// <returns></returns>
     public HandlerBuilder<TRequest, TResponse> Path(string path)
     {
-        var consumerSettingsExist = Settings.Consumers.Any(x => x.Path == path && x.ConsumerMode == ConsumerMode.RequestResponse);
+        var consumerSettingsExist = Settings.Consumers.Any(x => x.Path == path && x.ConsumerMode == ConsumerMode.RequestResponse && x != ConsumerSettings);
         Assert.IsFalse(consumerSettingsExist,
             () => new ConfigurationMessageBusException($"Attempted to configure request handler for topic/queue '{path}' when one was already configured. You can only have one request handler for a given topic/queue, otherwise which response would you send back?"));
 
@@ -61,7 +62,6 @@ public HandlerBuilder<TRequest, TResponse> WithHandler<THandler>()
         Assert.IsNotNull(ConsumerSettings.ResponseType,
             () => new ConfigurationMessageBusException($"The {nameof(ConsumerSettings)}.{nameof(ConsumerSettings.ResponseType)} is not set"));
 
-        ConsumerSettings.ConsumerMode = ConsumerMode.RequestResponse;
         ConsumerSettings.ConsumerType = typeof(THandler);
         ConsumerSettings.ConsumerMethod = (consumer, message) => ((THandler)consumer).OnHandle((TRequest)message);
 
@@ -75,7 +75,6 @@ public HandlerBuilder<TRequest, TResponse> WithHandler(Type handlerType)
         Assert.IsNotNull(ConsumerSettings.ResponseType,
             () => new ConfigurationMessageBusException($"The {nameof(ConsumerSettings)}.{nameof(ConsumerSettings.ResponseType)} is not set"));
 
-        ConsumerSettings.ConsumerMode = ConsumerMode.RequestResponse;
         ConsumerSettings.ConsumerType = handlerType;
         SetupConsumerOnHandleMethod(ConsumerSettings);
 

src/SlimMessageBus.Host/Config/Fluent/MessageBusBuilder.cs

@@ -45,14 +45,14 @@ public MessageBusBuilder MergeFrom(MessageBusSettings settings)
     /// Configures (declares) the production (publishing for pub/sub or request sending in request/response) of a message 
     /// </summary>
     /// <typeparam name="T">Type of the message</typeparam>
-    /// <param name="producerBuilder"></param>
+    /// <param name="builder"></param>
     /// <returns></returns>
-    public MessageBusBuilder Produce<T>(Action<ProducerBuilder<T>> producerBuilder)
+    public MessageBusBuilder Produce<T>(Action<ProducerBuilder<T>> builder)
     {
-        if (producerBuilder == null) throw new ArgumentNullException(nameof(producerBuilder));
+        if (builder == null) throw new ArgumentNullException(nameof(builder));
 
         var item = new ProducerSettings();
-        producerBuilder(new ProducerBuilder<T>(item));
+        builder(new ProducerBuilder<T>(item));
         Settings.Producers.Add(item);
         return this;
     }
@@ -61,14 +61,14 @@ public MessageBusBuilder Produce<T>(Action<ProducerBuilder<T>> producerBuilder)
     /// Configures (declares) the production (publishing for pub/sub or request sending in request/response) of a message 
     /// </summary>
     /// <param name="messageType">Type of the message</param>
-    /// <param name="producerBuilder"></param>
+    /// <param name="builder"></param>
     /// <returns></returns>
-    public MessageBusBuilder Produce(Type messageType, Action<ProducerBuilder<object>> producerBuilder)
+    public MessageBusBuilder Produce(Type messageType, Action<ProducerBuilder<object>> builder)
     {
-        if (producerBuilder == null) throw new ArgumentNullException(nameof(producerBuilder));
+        if (builder == null) throw new ArgumentNullException(nameof(builder));
 
         var item = new ProducerSettings();
-        producerBuilder(new ProducerBuilder<object>(item, messageType));
+        builder(new ProducerBuilder<object>(item, messageType));
         Settings.Producers.Add(item);
         return this;
     }
@@ -77,27 +77,34 @@ public MessageBusBuilder Produce(Type messageType, Action<ProducerBuilder<object
     /// Configures (declares) the consumer of given message types in pub/sub or queue communication.
     /// </summary>
     /// <typeparam name="TMessage">Type of message</typeparam>
-    /// <param name="consumerBuilder"></param>
+    /// <param name="builder"></param>
     /// <returns></returns>
-    public MessageBusBuilder Consume<TMessage>(Action<ConsumerBuilder<TMessage>> consumerBuilder)
+    public MessageBusBuilder Consume<TMessage>(Action<ConsumerBuilder<TMessage>> builder)
     {
-        if (consumerBuilder == null) throw new ArgumentNullException(nameof(consumerBuilder));
-
-        consumerBuilder(new ConsumerBuilder<TMessage>(Settings));
+        if (builder == null) throw new ArgumentNullException(nameof(builder));
+
+        var b = new ConsumerBuilder<TMessage>(Settings);
+        builder(b);
+
+        if (b.ConsumerSettings.ConsumerType is null)
+        {
+            // Apply default consumer type of not set
+            b.WithConsumer<IConsumer<TMessage>>();
+        }
         return this;
     }
 
     /// <summary>
     /// Configures (declares) the consumer of given message types in pub/sub or queue communication.
     /// </summary>
     /// <param name="messageType">Type of message</param>
-    /// <param name="consumerBuilder"></param>
+    /// <param name="builder"></param>
     /// <returns></returns>
-    public MessageBusBuilder Consume(Type messageType, Action<ConsumerBuilder<object>> consumerBuilder)
+    public MessageBusBuilder Consume(Type messageType, Action<ConsumerBuilder<object>> builder)
     {
-        if (consumerBuilder == null) throw new ArgumentNullException(nameof(consumerBuilder));
+        if (builder == null) throw new ArgumentNullException(nameof(builder));
 
-        consumerBuilder(new ConsumerBuilder<object>(Settings, messageType));
+        builder(new ConsumerBuilder<object>(Settings, messageType));
         return this;
     }
 
@@ -106,13 +113,21 @@ public MessageBusBuilder Consume(Type messageType, Action<ConsumerBuilder<object
     /// </summary>
     /// <typeparam name="TRequest"></typeparam>
     /// <typeparam name="TResponse"></typeparam>
-    /// <param name="handlerBuilder"></param>
+    /// <param name="builder"></param>
     /// <returns></returns>
-    public MessageBusBuilder Handle<TRequest, TResponse>(Action<HandlerBuilder<TRequest, TResponse>> handlerBuilder)
+    public MessageBusBuilder Handle<TRequest, TResponse>(Action<HandlerBuilder<TRequest, TResponse>> builder)
     {
-        if (handlerBuilder == null) throw new ArgumentNullException(nameof(handlerBuilder));
-
-        handlerBuilder(new HandlerBuilder<TRequest, TResponse>(Settings));
+        if (builder == null) throw new ArgumentNullException(nameof(builder));
+
+        var b = new HandlerBuilder<TRequest, TResponse>(Settings);
+        builder(b);
+
+        if (b.ConsumerSettings.ConsumerType is null)
+        {
+            // Apply default handler type of not set
+            b.WithHandler<IRequestHandler<TRequest, TResponse>>();
+        }
+
         return this;
     }
 
@@ -121,15 +136,15 @@ public MessageBusBuilder Handle<TRequest, TResponse>(Action<HandlerBuilder<TRequ
     /// </summary>
     /// <typeparam name="TRequest"></typeparam>
     /// <typeparam name="TResponse"></typeparam>
-    /// <param name="handlerBuilder"></param>
+    /// <param name="builder"></param>
     /// <returns></returns>
-    public MessageBusBuilder Handle(Type requestType, Type responseType, Action<HandlerBuilder<object, object>> handlerBuilder)
+    public MessageBusBuilder Handle(Type requestType, Type responseType, Action<HandlerBuilder<object, object>> builder)
     {
         if (requestType == null) throw new ArgumentNullException(nameof(requestType));
         if (responseType == null) throw new ArgumentNullException(nameof(responseType));
-        if (handlerBuilder == null) throw new ArgumentNullException(nameof(handlerBuilder));
+        if (builder == null) throw new ArgumentNullException(nameof(builder));
 
-        handlerBuilder(new HandlerBuilder<object, object>(Settings, requestType, responseType));
+        builder(new HandlerBuilder<object, object>(Settings, requestType, responseType));
         return this;
     }
 

src/SlimMessageBus.Host/DependencyResolver/ServiceCollectionExtensions.cs

@@ -98,7 +98,7 @@ public static IServiceCollection AddSlimMessageBus(
 
     /// <summary>
     /// Scans the specified assemblies (using reflection) for types that implement either <see cref="IConsumer{TMessage}"/> or <see cref="IRequestHandler{TRequest, TResponse}"/>. 
-    /// The found types are registered in the DI as Transient service.
+    /// The found types are registered in the DI as Transient service (both the consumer type and its interface are registered).
     /// </summary>
     /// <param name="services"></param>
     /// <param name="filterPredicate">Filtering predicate that allows to further narrow down the </param>
@@ -107,9 +107,16 @@ public static IServiceCollection AddSlimMessageBus(
     public static IServiceCollection AddMessageBusConsumersFromAssembly(this IServiceCollection services, Func<Type, bool> filterPredicate, params Assembly[] assemblies)
     {
         var foundTypes = ReflectionDiscoveryScanner.From(assemblies).GetConsumerTypes(filterPredicate);
-        foreach (var foundType in foundTypes)
+        foreach (var (foundType, interfaceTypes) in foundTypes.GroupBy(x => x.ConsumerType, x => x.InterfaceType).ToDictionary(x => x.Key, x => x))
         {
-            services.AddTransient(foundType.ConsumerType);
+            // Register the consumer/handler type
+            services.TryAddTransient(foundType);
+
+            foreach (var interfaceType in interfaceTypes)
+            {
+                // Register the interface of the consumer / handler
+                services.TryAddTransient(interfaceType, foundType);
+            }
         }
 
         return services;

src/Tests/SlimMessageBus.Host.Outbox.DbContext.Test/OutboxTests.cs

@@ -1,6 +1,5 @@
 namespace SlimMessageBus.Host.Outbox.DbContext.Test;
 
-using System.Collections.Concurrent;
 using System.Reflection;
 
 using Confluent.Kafka;

src/Tests/SlimMessageBus.Host.Test/Config/ConsumerBuilderTest.cs

@@ -12,14 +12,16 @@ public ConsumerBuilderTest()
     }
 
     [Fact]
-    public void Given_MessageType_When_Configured_Then_MessageType_ProperlySet()
+    public void Given_MessageType_When_Configured_Then_MessageType_ProperlySet_And_ConsumerTypeNull()
     {
         // arrange
 
         // act
         var subject = new ConsumerBuilder<SomeMessage>(messageBusSettings);
 
         // assert
+        subject.ConsumerSettings.ConsumerMode.Should().Be(ConsumerMode.Consumer);
+        subject.ConsumerSettings.ConsumerType.Should().BeNull();
         subject.ConsumerSettings.MessageType.Should().Be(typeof(SomeMessage));
     }