Log registered IApiDescriptionProvider implementations on load

Author: captainsafia

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 +30,27 @@ public ApiDescriptionGroupCollectionProvider(
         IEnumerable<IApiDescriptionProvider> apiDescriptionProviders)
     {
         _actionDescriptorCollectionProvider = actionDescriptorCollectionProvider;
-        _apiDescriptionProviders = apiDescriptionProviders.OrderBy(item => item.Order).ToArray();
+        _apiDescriptionProviders = [.. apiDescriptionProviders.OrderBy(item => item.Order)];
+    }
+
+    /// <summary>
+    /// Creates a new instance of <see cref="ApiDescriptionGroupCollectionProvider"/>.
+    /// </summary>
+    /// <param name="actionDescriptorCollectionProvider">
+    /// The <see cref="IActionDescriptorCollectionProvider"/>.
+    /// </param>
+    /// <param name="apiDescriptionProviders">
+    /// The <see cref="IEnumerable{IApiDescriptionProvider}"/>.
+    /// </param>
+    /// <param name="loggerFactory">The <see cref="ILoggerFactory"/> to construct a logger.</param>
+    public ApiDescriptionGroupCollectionProvider(
+        IActionDescriptorCollectionProvider actionDescriptorCollectionProvider,
+        IEnumerable<IApiDescriptionProvider> apiDescriptionProviders,
+        ILoggerFactory loggerFactory)
+    {
+        _actionDescriptorCollectionProvider = actionDescriptorCollectionProvider;
+        _apiDescriptionProviders = [.. apiDescriptionProviders.OrderBy(item => item.Order)];
+        _logger = loggerFactory.CreateLogger<ApiDescriptionGroupCollectionProvider>();
     }
 
     /// <inheritdoc />
@@ -52,6 +74,10 @@ 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.OnProvidersExecuting(context);
         }
 
@@ -67,4 +93,10 @@ 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}.", EventName = "ApiDescriptionProviderExecuting")]
+        public static partial void ApiDescriptionProviderExecuting(ILogger logger, string providerName, string? providerAssembly);
+    }
 }

src/Mvc/Mvc.ApiExplorer/src/PublicAPI.Unshipped.txt

@@ -1 +1,2 @@
 #nullable enable
+Microsoft.AspNetCore.Mvc.ApiExplorer.ApiDescriptionGroupCollectionProvider.ApiDescriptionGroupCollectionProvider(Microsoft.AspNetCore.Mvc.Infrastructure.IActionDescriptorCollectionProvider! actionDescriptorCollectionProvider, System.Collections.Generic.IEnumerable<Microsoft.AspNetCore.Mvc.ApiExplorer.IApiDescriptionProvider!>! apiDescriptionProviders, Microsoft.Extensions.Logging.ILoggerFactory! loggerFactory) -> void

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.", StringComparison.Ordinal));
+        Assert.Contains(TestSink.Writes, w => w.Message.Equals("Executing API description provider 'JsonPatchOperationsArrayProvider' from assembly Microsoft.AspNetCore.Mvc.NewtonsoftJson.", StringComparison.Ordinal));
+    }
+
     private IEnumerable<string> GetSortedMediaTypes(ApiExplorerResponseType apiResponseType)
     {
         return apiResponseType.ResponseFormats