#281 Access to underlying service collection in builder

.autover/changes/55b720e8-c5d2-41e0-abda-658b2f39f77e.json

@@ -0,0 +1,11 @@
+{
+  "Projects": [
+    {
+      "Name": "AWS.Messaging",
+      "Type": "Patch",
+      "ChangelogMessages": [
+        "Add builder overload to modify underlying service collection on build"
+      ]
+    }
+  ]
+}

src/AWS.Messaging/Configuration/IMessageBusBuilder.cs

@@ -101,6 +101,13 @@ public interface IMessageBusBuilder
     /// <returns></returns>
     IMessageBusBuilder AddAdditionalService(ServiceDescriptor serviceDescriptor);
 
+    /// <summary>
+    /// Add additional services to the <see cref="IMessageBusBuilder"/>. This method is used for AWS.Messaging plugins to add services for messaging.
+    /// </summary>
+    /// <param name="action">Configuration action to perform against the service collection.</param>
+    /// <returns></returns>
+    IMessageBusBuilder AddAdditionalService(Action<IMessageConfiguration, IServiceCollection> action);
+
     /// <summary>
     /// Enables the visibility of data messages in the logging framework, exception handling and other areas.
     /// If this is enabled, messages sent by this framework will be visible in plain text across the framework's components.

src/AWS.Messaging/Configuration/MessageBusBuilder.cs

@@ -29,7 +29,7 @@ public class MessageBusBuilder : IMessageBusBuilder
 {
     private static readonly ConcurrentDictionary<IServiceCollection, MessageConfiguration> _messageConfigurations = new();
     private readonly MessageConfiguration _messageConfiguration;
-    private readonly IList<ServiceDescriptor> _additionalServices = new List<ServiceDescriptor>();
+    private readonly IList<Action<IMessageConfiguration, IServiceCollection>> _additionalServices = new List<Action<IMessageConfiguration, IServiceCollection>>();
     private readonly IServiceCollection _serviceCollection;
 
     /// <summary>
@@ -301,7 +301,14 @@ MessageEnvelope envelopeFactory()
     /// <inheritdoc/>
     public IMessageBusBuilder AddAdditionalService(ServiceDescriptor serviceDescriptor)
     {
-        _additionalServices.Add(serviceDescriptor);
+        _additionalServices.Add((_, services) => services.TryAdd(serviceDescriptor));
+        return this;
+    }
+
+    /// <inheritdoc/>
+    public IMessageBusBuilder AddAdditionalService(Action<IMessageConfiguration, IServiceCollection> action)
+    {
+        _additionalServices.Add(action);
         return this;
     }
 
@@ -410,9 +417,9 @@ internal void Build()
             }
         }
 
-        foreach (var service in _additionalServices)
+        foreach (var action in _additionalServices)
         {
-            _serviceCollection.TryAdd(service);
+            action.Invoke(_messageConfiguration, _serviceCollection);
         }
     }