Call AddMetrics inside AddRouting (#50168)

Author: JamesNK

src/Http/Routing/src/DependencyInjection/RoutingServiceCollectionExtensions.cs

@@ -43,6 +43,9 @@ public static IServiceCollection AddRoutingCore(this IServiceCollection services
     {
         ArgumentNullException.ThrowIfNull(services);
 
+        // Required for IMeterFactory dependency.
+        services.AddMetrics();
+
         services.TryAddTransient<IInlineConstraintResolver, DefaultInlineConstraintResolver>();
         services.TryAddTransient<ObjectPoolProvider, DefaultObjectPoolProvider>();
         services.TryAddSingleton<ObjectPool<UriBuildingContext>>(s =>

src/Http/Routing/src/Microsoft.AspNetCore.Routing.csproj

@@ -46,6 +46,7 @@
     <Reference Include="Microsoft.AspNetCore.Http.Features" />
     <Reference Include="Microsoft.AspNetCore.Http.Abstractions" />
     <Reference Include="Microsoft.AspNetCore.Routing.Abstractions" />
+    <Reference Include="Microsoft.Extensions.Diagnostics" />
     <Reference Include="Microsoft.Extensions.Features" />
     <Reference Include="Microsoft.Extensions.ObjectPool" />
     <Reference Include="Microsoft.Extensions.Options" />

src/Http/Routing/test/UnitTests/EndpointRoutingMiddlewareTest.cs

@@ -10,6 +10,7 @@
 using Microsoft.AspNetCore.Routing.Matching;
 using Microsoft.AspNetCore.Routing.TestObjects;
 using Microsoft.AspNetCore.Testing;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Logging.Testing;
@@ -393,6 +394,36 @@ public async Task Endpoint_HasBodySizeFeature_SetUsingSizeLimitMetadata(bool isR
         Assert.Equal(expectedRequestSizeLimit, actualRequestSizeLimit);
     }
 
+    [Fact]
+    public async Task Create_WithoutHostBuilder_Success()
+    {
+        // Arrange
+        var httpContext = CreateHttpContext();
+
+        var services = new ServiceCollection();
+        services.AddLogging();
+        services.AddOptions();
+        services.AddSingleton<DiagnosticListener>(s => new DiagnosticListener("Test"));
+        services.AddRouting();
+
+        var applicationBuilder = new ApplicationBuilder(services.BuildServiceProvider());
+
+        applicationBuilder.UseRouting();
+        applicationBuilder.UseEndpoints(endpoints =>
+        {
+            endpoints.MapGet("/", (HttpContext c) => Task.CompletedTask);
+        });
+
+        var requestDelegate = applicationBuilder.Build();
+
+        // Act
+        await requestDelegate(httpContext);
+
+        // Assert
+        var endpointFeature = httpContext.Features.Get<IEndpointFeature>();
+        Assert.NotNull(endpointFeature);
+    }
+
     private class RequestSizeLimitMetadata(long? maxRequestBodySize) : IRequestSizeLimitMetadata
     {