Log registered IApiDescriptionProvider implementations on load

src/Mvc/Mvc.ApiExplorer/src/ApiDescriptionGroupCollectionProvider.cs

@@ -3,16 +3,18 @@
 
 using System.Linq;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
+using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Mvc.ApiExplorer;
 
 /// <inheritdoc />
-public class ApiDescriptionGroupCollectionProvider : IApiDescriptionGroupCollectionProvider
+public partial class ApiDescriptionGroupCollectionProvider : IApiDescriptionGroupCollectionProvider
 {
     private readonly IActionDescriptorCollectionProvider _actionDescriptorCollectionProvider;
     private readonly IApiDescriptionProvider[] _apiDescriptionProviders;
 
     private ApiDescriptionGroupCollection? _apiDescriptionGroups;
+    private readonly ILogger? _logger;
 
     /// <summary>
     /// Creates a new instance of <see cref="ApiDescriptionGroupCollectionProvider"/>.
@@ -28,7 +30,15 @@ public ApiDescriptionGroupCollectionProvider(
         IEnumerable<IApiDescriptionProvider> apiDescriptionProviders)
     {
         _actionDescriptorCollectionProvider = actionDescriptorCollectionProvider;
-        _apiDescriptionProviders = apiDescriptionProviders.OrderBy(item => item.Order).ToArray();
+        _apiDescriptionProviders = [.. apiDescriptionProviders.OrderBy(item => item.Order)];
+    }
+
+    internal ApiDescriptionGroupCollectionProvider(
+        IActionDescriptorCollectionProvider actionDescriptorCollectionProvider,
+        IEnumerable<IApiDescriptionProvider> apiDescriptionProviders,
+        ILoggerFactory loggerFactory) : this(actionDescriptorCollectionProvider, apiDescriptionProviders)
+    {
+        _logger = loggerFactory.CreateLogger<ApiDescriptionGroupCollectionProvider>();
     }
 
     /// <inheritdoc />
@@ -52,6 +62,10 @@ private ApiDescriptionGroupCollection GetCollection(ActionDescriptorCollection a
 
         foreach (var provider in _apiDescriptionProviders)
         {
+            if (_logger is not null)
+            {
+                Log.ApiDescriptionProviderExecuting(_logger, provider.GetType().Name, provider.GetType().Assembly.GetName().Name, provider.GetType().Assembly.GetName().Version?.ToString());
+            }
             provider.OnProvidersExecuting(context);
         }
 
@@ -67,4 +81,10 @@ private ApiDescriptionGroupCollection GetCollection(ActionDescriptorCollection a
 
         return new ApiDescriptionGroupCollection(groups, actionDescriptors.Version);
     }
+
+    private static partial class Log
+    {
+        [LoggerMessage(2, LogLevel.Debug, "Executing API description provider '{ProviderName}' from assembly {ProviderAssembly} v{AssemblyVersion}.", EventName = "ApiDescriptionProviderExecuting")]
+        public static partial void ApiDescriptionProviderExecuting(ILogger logger, string providerName, string? providerAssembly, string? assemblyVersion);
+    }
 }

src/Mvc/Mvc.ApiExplorer/src/DependencyInjection/EndpointMethodInfoApiExplorerServiceCollectionExtensions.cs

@@ -5,6 +5,7 @@
 using Microsoft.AspNetCore.Mvc.ApiExplorer;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Logging;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -21,7 +22,10 @@ public static IServiceCollection AddEndpointsApiExplorer(this IServiceCollection
     {
         // Try to add default services in case MVC services aren't added.
         services.TryAddSingleton<IActionDescriptorCollectionProvider, DefaultActionDescriptorCollectionProvider>();
-        services.TryAddSingleton<IApiDescriptionGroupCollectionProvider, ApiDescriptionGroupCollectionProvider>();
+        services.TryAddSingleton<IApiDescriptionGroupCollectionProvider>(sp => new ApiDescriptionGroupCollectionProvider(
+            sp.GetRequiredService<IActionDescriptorCollectionProvider>(),
+            sp.GetServices<IApiDescriptionProvider>(),
+            sp.GetRequiredService<ILoggerFactory>()));
 
         services.TryAddEnumerable(
             ServiceDescriptor.Transient<IApiDescriptionProvider, EndpointMetadataApiDescriptionProvider>());

src/Mvc/Mvc.ApiExplorer/src/DependencyInjection/MvcApiExplorerMvcCoreBuilderExtensions.cs

@@ -3,7 +3,9 @@
 
 using System.Diagnostics.CodeAnalysis;
 using Microsoft.AspNetCore.Mvc.ApiExplorer;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Logging;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -30,7 +32,10 @@ public static IMvcCoreBuilder AddApiExplorer(this IMvcCoreBuilder builder)
     [RequiresUnreferencedCode("MVC does not currently support trimming or native AOT.", Url = "https://aka.ms/aspnet/trimming")]
     internal static void AddApiExplorerServices(IServiceCollection services)
     {
-        services.TryAddSingleton<IApiDescriptionGroupCollectionProvider, ApiDescriptionGroupCollectionProvider>();
+        services.TryAddSingleton<IApiDescriptionGroupCollectionProvider>(sp => new ApiDescriptionGroupCollectionProvider(
+            sp.GetRequiredService<IActionDescriptorCollectionProvider>(),
+            sp.GetServices<IApiDescriptionProvider>(),
+            sp.GetRequiredService<ILoggerFactory>()));
         services.TryAddEnumerable(
             ServiceDescriptor.Transient<IApiDescriptionProvider, DefaultApiDescriptionProvider>());
     }

src/Mvc/test/Mvc.FunctionalTests/ApiExplorerTest.cs

@@ -1552,6 +1552,19 @@ public async Task ApiAction_ForActionWithVoidResponseType(string path, Type type
             });
     }
 
+    [Fact]
+    public async Task ApiExplorer_LogsInvokedDescriptionProvidersOnStartup()
+    {
+        // Arrange & Act
+        var response = await Client.GetAsync("http://localhost/ApiExplorerHttpMethod/All");
+
+        // Assert
+        Assert.Contains(TestSink.Writes, w => w.EventId.Name?.Equals("ApiDescriptionProviderExecuting", StringComparison.Ordinal) == true);
+        Assert.Contains(TestSink.Writes, w => w.LoggerName.Equals("Microsoft.AspNetCore.Mvc.ApiExplorer.ApiDescriptionGroupCollectionProvider", StringComparison.Ordinal));
+        Assert.Contains(TestSink.Writes, w => w.Message.Equals("Executing API description provider 'DefaultApiDescriptionProvider' from assembly Microsoft.AspNetCore.Mvc.ApiExplorer v9.0.0.0.", StringComparison.Ordinal));
+        Assert.Contains(TestSink.Writes, w => w.Message.Equals("Executing API description provider 'JsonPatchOperationsArrayProvider' from assembly Microsoft.AspNetCore.Mvc.NewtonsoftJson v42.42.42.42.", StringComparison.Ordinal));
+    }
+
     private IEnumerable<string> GetSortedMediaTypes(ApiExplorerResponseType apiResponseType)
     {
         return apiResponseType.ResponseFormats