Add routing metrics

src/Http/Routing/perf/Microbenchmarks/EndpointRoutingShortCircuitBenchmark.cs

@@ -7,6 +7,7 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing.Matching;
 using Microsoft.AspNetCore.Routing.ShortCircuit;
+using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 using Microsoft.Extensions.Primitives;
@@ -21,6 +22,7 @@ public class EndpointRoutingShortCircuitBenchmark
     [GlobalSetup]
     public void Setup()
     {
+        var routingMetrics = new RoutingMetrics(new TestMeterFactory());
         var normalEndpoint = new Endpoint(context => Task.CompletedTask, new EndpointMetadataCollection(), "normal");
 
         _normalEndpointMiddleware = new EndpointRoutingMiddleware(
@@ -30,6 +32,7 @@ public void Setup()
             new BenchmarkEndpointDataSource(),
             new DiagnosticListener("benchmark"),
             Options.Create(new RouteOptions()),
+            routingMetrics,
             context => Task.CompletedTask);
 
         var shortCircuitEndpoint = new Endpoint(context => Task.CompletedTask, new EndpointMetadataCollection(new ShortCircuitMetadata(200)), "shortcircuit");
@@ -41,8 +44,8 @@ public void Setup()
             new BenchmarkEndpointDataSource(),
             new DiagnosticListener("benchmark"),
             Options.Create(new RouteOptions()),
+            routingMetrics,
             context => Task.CompletedTask);
-
     }
 
     [Benchmark]

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

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
@@ -31,6 +31,7 @@
     <Compile Include="..\..\test\UnitTests\Matching\TreeRouterMatcherBuilder.cs">
       <Link>Matching\TreeRouterMatcherBuilder.cs</Link>
     </Compile>
+    <Compile Include="$(SharedSourceRoot)Metrics\TestMeterFactory.cs" LinkBase="shared" />
     <Compile Include="..\..\test\UnitTests\TestObjects\TestServiceProvider.cs" Link="Matching\TestServiceProvider.cs" />
   </ItemGroup>
 
@@ -39,6 +40,7 @@
     <Reference Include="Microsoft.AspNetCore.Http" />
     <Reference Include="Microsoft.AspNetCore.Routing" />
     <Reference Include="Microsoft.Extensions.DependencyInjection" />
+    <Reference Include="Microsoft.Extensions.Diagnostics" />
     <Reference Include="Microsoft.Extensions.Logging" />
 
     <Compile Include="$(SharedSourceRoot)BenchmarkRunner\*.cs" />

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

@@ -108,6 +108,7 @@ public static IServiceCollection AddRoutingCore(this IServiceCollection services
         //
         services.TryAddSingleton<TemplateBinderFactory, DefaultTemplateBinderFactory>();
         services.TryAddSingleton<RoutePatternTransformer, DefaultRoutePatternTransformer>();
+        services.TryAddSingleton<RoutingMetrics>();
 
         // Set RouteHandlerOptions.ThrowOnBadRequest in development
         services.TryAddEnumerable(ServiceDescriptor.Transient<IConfigureOptions<RouteHandlerOptions>, ConfigureRouteHandlerOptions>());

src/Http/Routing/src/EndpointRoutingMiddleware.cs

@@ -7,6 +7,7 @@
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Cors.Infrastructure;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Metadata;
 using Microsoft.AspNetCore.Routing.Matching;
 using Microsoft.AspNetCore.Routing.ShortCircuit;
 using Microsoft.Extensions.Logging;
@@ -22,6 +23,7 @@ internal sealed partial class EndpointRoutingMiddleware
     private readonly ILogger _logger;
     private readonly EndpointDataSource _endpointDataSource;
     private readonly DiagnosticListener _diagnosticListener;
+    private readonly RoutingMetrics _metrics;
     private readonly RequestDelegate _next;
     private readonly RouteOptions _routeOptions;
     private Task<Matcher>? _initializationTask;
@@ -33,13 +35,15 @@ public EndpointRoutingMiddleware(
         EndpointDataSource rootCompositeEndpointDataSource,
         DiagnosticListener diagnosticListener,
         IOptions<RouteOptions> routeOptions,
+        RoutingMetrics metrics,
         RequestDelegate next)
     {
         ArgumentNullException.ThrowIfNull(endpointRouteBuilder);
 
         _matcherFactory = matcherFactory ?? throw new ArgumentNullException(nameof(matcherFactory));
         _logger = logger ?? throw new ArgumentNullException(nameof(logger));
         _diagnosticListener = diagnosticListener ?? throw new ArgumentNullException(nameof(diagnosticListener));
+        _metrics = metrics;
         _next = next ?? throw new ArgumentNullException(nameof(next));
         _routeOptions = routeOptions.Value;
 
@@ -98,6 +102,7 @@ private Task SetRoutingAndContinue(HttpContext httpContext)
         if (endpoint == null)
         {
             Log.MatchFailure(_logger);
+            _metrics.MatchFailure();
         }
         else
         {
@@ -107,12 +112,21 @@ private Task SetRoutingAndContinue(HttpContext httpContext)
                 Write(_diagnosticListener, httpContext);
             }
 
-            Log.MatchSuccess(_logger, endpoint);
-
-            if (_logger.IsEnabled(LogLevel.Debug)
-                && endpoint.Metadata.GetMetadata<FallbackMetadata>() is not null)
+            if (_logger.IsEnabled(LogLevel.Debug) || _metrics.MatchSuccessCounterEnabled)
             {
-                Log.FallbackMatch(_logger, endpoint);
+                var isFallback = endpoint.Metadata.GetMetadata<FallbackMetadata>() is not null;
+
+                Log.MatchSuccess(_logger, endpoint);
+
+                if (isFallback)
+                {
+                    Log.FallbackMatch(_logger, endpoint);
+                }
+
+                // It shouldn't be possible for a route to be matched via the route matcher and not have a route.
+                // Just in case, add a special (missing) value as the route tag to metrics.
+                var route = endpoint.Metadata.GetMetadata<IRouteDiagnosticsMetadata>()?.Route ?? "(missing)";
+                _metrics.MatchSuccess(route, isFallback);
             }
 
             var shortCircuitMetadata = endpoint.Metadata.GetMetadata<ShortCircuitMetadata>();
@@ -290,7 +304,7 @@ public static void MatchSkipped(ILogger logger, Endpoint endpoint)
         [LoggerMessage(6, LogLevel.Information, "The endpoint '{EndpointName}' is being short circuited without running additional middleware or producing a response.", EventName = "ShortCircuitedEndpoint")]
         public static partial void ShortCircuitedEndpoint(ILogger logger, Endpoint endpointName);
 
-        [LoggerMessage(7, LogLevel.Debug, "Matched endpoint '{EndpointName}' is a fallback endpoint.", EventName = "FallbackMatch", SkipEnabledCheck = true)]
+        [LoggerMessage(7, LogLevel.Debug, "Matched endpoint '{EndpointName}' is a fallback endpoint.", EventName = "FallbackMatch")]
         public static partial void FallbackMatch(ILogger logger, Endpoint endpointName);
     }
 }

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

@@ -42,6 +42,7 @@
     <Reference Include="Microsoft.AspNetCore.Authorization" />
     <Reference Include="Microsoft.AspNetCore.Http.Extensions" />
     <Reference Include="Microsoft.AspNetCore.Routing.Abstractions" />
+    <Reference Include="Microsoft.Extensions.Diagnostics.Abstractions" />
     <Reference Include="Microsoft.Extensions.ObjectPool" />
     <Reference Include="Microsoft.Extensions.Options" />
   </ItemGroup>

src/Http/Routing/src/RoutingMetrics.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics.Metrics;
+using Microsoft.Extensions.Diagnostics.Metrics;
+
+namespace Microsoft.AspNetCore.Routing;
+
+internal sealed class RoutingMetrics
+{
+    public const string MeterName = "Microsoft.AspNetCore.Routing";
+
+    private readonly Meter _meter;
+    private readonly Counter<long> _matchSuccessCounter;
+    private readonly Counter<long> _matchFailureCounter;
+
+    public RoutingMetrics(IMeterFactory meterFactory)
+    {
+        _meter = meterFactory.Create(MeterName);
+
+        _matchSuccessCounter = _meter.CreateCounter<long>(
+           "routing-match-success",
+            description: "Number of requests that successfully matched to an endpoint.");
+
+        _matchFailureCounter = _meter.CreateCounter<long>(
+           "routing-match-failure",
+            description: "Number of requests that failed to match to an endpoint. An unmatched request may be handled by later middleware, such as the static files or authentication middleware.");
+    }
+
+    public bool MatchSuccessCounterEnabled => _matchSuccessCounter.Enabled;
+
+    public void MatchSuccess(string route, bool isFallback)
+    {
+        _matchSuccessCounter.Add(1,
+            new KeyValuePair<string, object?>("route", route),
+            new KeyValuePair<string, object?>("fallback", isFallback));
+    }
+
+    public void MatchFailure()
+    {
+        _matchFailureCounter.Add(1);
+    }
+}

src/Http/Routing/test/UnitTests/Builder/EndpointRoutingApplicationBuilderExtensionsTest.cs

@@ -9,6 +9,7 @@
 using Microsoft.AspNetCore.Routing.Patterns;
 using Microsoft.AspNetCore.Routing.TestObjects;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.Metrics;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Options;
 using Moq;
@@ -354,6 +355,7 @@ private IServiceProvider CreateServices(MatcherFactory matcherFactory)
             services.AddSingleton<MatcherFactory>(matcherFactory);
         }
 
+        services.AddMetrics();
         services.AddLogging();
         services.AddOptions();
         services.AddRouting();

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

@@ -7,6 +7,7 @@
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Routing.Matching;
 using Microsoft.AspNetCore.Routing.TestObjects;
+using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Logging.Testing;
@@ -90,7 +91,6 @@ public async Task Invoke_BackCompatGetRouteValue_ValueUsedFromEndpointFeature()
     {
         // Arrange
         var httpContext = CreateHttpContext();
-
         var middleware = CreateMiddleware();
 
         // Act
@@ -282,6 +282,7 @@ private EndpointRoutingMiddleware CreateMiddleware(
         logger ??= new Logger<EndpointRoutingMiddleware>(NullLoggerFactory.Instance);
         matcherFactory ??= new TestMatcherFactory(true);
         listener ??= new DiagnosticListener("Microsoft.AspNetCore");
+        var metrics = new RoutingMetrics(new TestMeterFactory());
 
         var middleware = new EndpointRoutingMiddleware(
             matcherFactory,
@@ -290,6 +291,7 @@ private EndpointRoutingMiddleware CreateMiddleware(
             new DefaultEndpointDataSource(),
             listener,
             Options.Create(new RouteOptions()),
+            metrics,
             next);
 
         return middleware;

src/Http/Routing/test/UnitTests/Microsoft.AspNetCore.Routing.Tests.csproj

@@ -12,9 +12,12 @@
     <Reference Include="Microsoft.AspNetCore.Routing" />
     <Reference Include="Microsoft.AspNetCore.Http.Results" />
     <Reference Include="Microsoft.Extensions.DependencyInjection" />
+    <Reference Include="Microsoft.Extensions.Diagnostics" />
     <Reference Include="Microsoft.Extensions.Hosting.Abstractions" />
     <Reference Include="Microsoft.Extensions.Logging" />
     <Reference Include="Microsoft.Extensions.WebEncoders" />
+
+    <Compile Include="$(SharedSourceRoot)Metrics\TestMeterFactory.cs" LinkBase="shared" />
   </ItemGroup>
 
 </Project>