Add OTEL tracing support for Wiremock + automatic OTEL for Aspire integration

examples-Aspire/AspireApp1.AppHost/AspireApp1.AppHost.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-    <Sdk Name="Aspire.AppHost.Sdk" Version="9.2.0" />
+    <Sdk Name="Aspire.AppHost.Sdk" Version="13.1.0" />
 
     <PropertyGroup>
         <OutputType>Exe</OutputType>
@@ -18,7 +18,7 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="Aspire.Hosting.AppHost" Version="9.2.0" />
+        <PackageReference Include="Aspire.Hosting.AppHost" Version="13.1.0" />
     </ItemGroup>
 
     <ItemGroup>

examples-Aspire/AspireApp1.AppHost/Program.cs

@@ -24,7 +24,8 @@
     .AsHttp2Service()
     .WithMappingsPath(mappingsPath)
     .WithWatchStaticMappings()
-    .WithApiMappingBuilder(WeatherForecastApiMock.BuildAsync);
+    .WithApiMappingBuilder(WeatherForecastApiMock.BuildAsync)
+    .WithOpenTelemetry(); // Enable OpenTelemetry tracing for Aspire dashboard
 
 //var apiServiceUsedForDocs = builder
 //    .AddWireMock("apiservice1", WireMockServerArguments.DefaultPort)

examples-Aspire/AspireApp1.AppHostOriginal/AspireApp1.AppHostOriginal.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-    <Sdk Name="Aspire.AppHost.Sdk" Version="9.2.0" />
+    <Sdk Name="Aspire.AppHost.Sdk" Version="13.1.0" />
 
     <PropertyGroup>
         <OutputType>Exe</OutputType>
@@ -15,7 +15,7 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="Aspire.Hosting.AppHost" Version="9.2.0" />
+        <PackageReference Include="Aspire.Hosting.AppHost" Version="13.1.0" />
     </ItemGroup>
 
 </Project>

examples-Aspire/AspireApp1.Tests/AspireApp1.Tests.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Aspire.Hosting.Testing" Version="8.0.0" />
+    <PackageReference Include="Aspire.Hosting.Testing" Version="13.1.0" />
     <PackageReference Include="coverlet.collector" Version="6.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageReference Include="xunit" Version="2.5.3" />

examples/WireMock.Net.Console.NET6.WithCertificate/WireMock.Net.Console.NET6.WithCertificate.csproj

@@ -7,7 +7,6 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\WireMock.Net\WireMock.Net.csproj" />
-    <PackageReference Include="Microsoft.Extensions.Configuration" Version="6.0.0" />
   </ItemGroup>
 
   <ItemGroup>

examples/WireMock.Net.OpenTelemetryDemo/Program.cs

@@ -0,0 +1,141 @@
+// Copyright © WireMock.Net
+// OpenTelemetry Tracing Demo for WireMock.Net
+// This demo uses the Console Exporter to visualize traces in the terminal.
+
+using OpenTelemetry;
+using OpenTelemetry.Trace;
+using WireMock.Server;
+using WireMock.Settings;
+using WireMock.RequestBuilders;
+using WireMock.ResponseBuilders;
+using WireMock.OpenTelemetry;
+
+Console.WriteLine("=== WireMock.Net OpenTelemetry Tracing Demo ===\n");
+
+// WireMock.Net creates Activity objects using System.Diagnostics.Activity (built into .NET).
+// These activities are automatically created when ActivityTracingEnabled is set to true.
+//
+// To export these traces, you have two options:
+//
+// Option 1: Configure your own TracerProvider (shown below)
+//   - Full control over exporters (Console, OTLP, Jaeger, etc.)
+//   - Add additional instrumentation (HttpClient, database, etc.)
+//   - Recommended for most applications
+//
+// Option 2: Use WireMock.Net.OpenTelemetry package
+//   - Reference the WireMock.Net.OpenTelemetry NuGet package
+//   - Use services.AddWireMockOpenTelemetry(openTelemetryOptions)
+//   - Adds WireMock + ASP.NET Core instrumentation and OTLP exporter
+//   - Good for quick setup with all-in-one configuration
+
+// Option 1: Custom TracerProvider with Console exporter for this demo
+using var tracerProvider = Sdk.CreateTracerProviderBuilder()
+    .AddWireMockInstrumentation(new OpenTelemetryOptions() { ExcludeAdminRequests = true })
+    .AddHttpClientInstrumentation()      // HTTP client traces (for our test requests)
+    .AddConsoleExporter()                // Export traces to console for demo purposes
+    .Build();
+
+Console.WriteLine("Console Exporter configured to visualize:");
+Console.WriteLine("  - WireMock.Net traces (wiremock.* tags)");
+Console.WriteLine("  - ASP.NET Core server traces");
+Console.WriteLine("  - HTTP client traces\n");
+
+// Start WireMock server with OpenTelemetry enabled (ActivityTracingOptions != null enables tracing)
+var server = WireMockServer.Start(new WireMockServerSettings
+{
+    StartAdminInterface = true,
+    ActivityTracingOptions = new ActivityTracingOptions
+    {
+        ExcludeAdminRequests = true
+    }
+});
+
+Console.WriteLine($"WireMock server started at: {string.Join(", ", server.Urls)}\n");
+
+// Configure some mock mappings
+server
+    .Given(Request.Create()
+        .WithPath("/api/hello")
+        .UsingGet())
+    .RespondWith(Response.Create()
+        .WithStatusCode(200)
+        .WithBody("Hello from WireMock!"));
+
+server
+    .Given(Request.Create()
+        .WithPath("/api/user/*")
+        .UsingGet())
+    .RespondWith(Response.Create()
+        .WithStatusCode(200)
+        .WithHeader("Content-Type", "application/json")
+        .WithBody(@"{""name"": ""John Doe"", ""email"": ""john@example.com""}"));
+
+server
+    .Given(Request.Create()
+        .WithPath("/api/error")
+        .UsingGet())
+    .RespondWith(Response.Create()
+        .WithStatusCode(500)
+        .WithBody("Internal Server Error"));
+
+Console.WriteLine("Mock mappings configured:");
+Console.WriteLine("  GET /api/hello     -> 200 OK");
+Console.WriteLine("  GET /api/user/*    -> 200 OK (JSON)");
+Console.WriteLine("  GET /api/error     -> 500 Error");
+Console.WriteLine();
+
+// Make some test requests to generate traces
+using var httpClient = server.CreateClient();
+
+Console.WriteLine("Making test requests to generate traces...\n");
+Console.WriteLine("─────────────────────────────────────────────────────────────────");
+
+// Request 1: Successful request
+Console.WriteLine("\n>>> Request 1: GET /api/hello");
+var response1 = await httpClient.GetAsync("/api/hello");
+Console.WriteLine($"<<< Response: {(int)response1.StatusCode} {response1.StatusCode}");
+Console.WriteLine($"    Body: {await response1.Content.ReadAsStringAsync()}");
+
+await Task.Delay(500); // Small delay to let trace export complete
+
+// Request 2: Another successful request with path parameter
+Console.WriteLine("\n>>> Request 2: GET /api/user/123");
+var response2 = await httpClient.GetAsync("/api/user/123");
+Console.WriteLine($"<<< Response: {(int)response2.StatusCode} {response2.StatusCode}");
+Console.WriteLine($"    Body: {await response2.Content.ReadAsStringAsync()}");
+
+await Task.Delay(500);
+
+// Request 3: Error response
+Console.WriteLine("\n>>> Request 3: GET /api/error");
+var response3 = await httpClient.GetAsync("/api/error");
+Console.WriteLine($"<<< Response: {(int)response3.StatusCode} {response3.StatusCode}");
+Console.WriteLine($"    Body: {await response3.Content.ReadAsStringAsync()}");
+
+await Task.Delay(500);
+
+// Request 4: No matching mapping (404)
+Console.WriteLine("\n>>> Request 4: GET /api/notfound");
+var response4 = await httpClient.GetAsync("/api/notfound");
+Console.WriteLine($"<<< Response: {(int)response4.StatusCode} {response4.StatusCode}");
+
+await Task.Delay(500);
+
+// Request 5: Admin API request (should be excluded from tracing)
+Console.WriteLine("\n>>> Request 5: GET /__admin/health");
+var response5 = await httpClient.GetAsync("/__admin/health");
+Console.WriteLine($"<<< Admin Health Status: {response5.StatusCode}");
+
+Console.WriteLine("\n─────────────────────────────────────────────────────────────────");
+Console.WriteLine("\nTraces above show OpenTelemetry activities from WireMock.Net!");
+Console.WriteLine("Look for 'Activity.TraceId', 'Activity.SpanId', and custom tags like:");
+Console.WriteLine("  - http.request.method");
+Console.WriteLine("  - url.path");
+Console.WriteLine("  - http.response.status_code");
+Console.WriteLine("  - wiremock.mapping.matched");
+Console.WriteLine("  - wiremock.mapping.guid");
+Console.WriteLine();
+
+// Cleanup
+server.Stop();
+Console.WriteLine("WireMock server stopped. Demo complete!");

examples/WireMock.Net.OpenTelemetryDemo/WireMock.Net.OpenTelemetryDemo.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\WireMock.Net.OpenTelemetry\WireMock.Net.OpenTelemetry.csproj" />
+    <ProjectReference Include="..\..\src\WireMock.Net\WireMock.Net.csproj" />
+  </ItemGroup>
+
+</Project>

src/WireMock.Net.Aspire/WireMock.Net.Aspire.csproj

@@ -45,7 +45,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Aspire.Hosting" Version="9.2.0" />
+        <PackageReference Include="Aspire.Hosting" Version="13.1.0" />
     </ItemGroup>
 
     <ItemGroup>

src/WireMock.Net.Aspire/WireMockServerArguments.cs

@@ -79,6 +79,22 @@
     /// </summary>
     public Dictionary<string, string[]> ProtoDefinitions { get; set; } = [];
 
+    /// <summary>
+    /// Gets or sets a value indicating whether OpenTelemetry tracing is enabled.
+    /// When enabled, WireMock.Net will emit distributed traces for request processing.
+    /// Default value is <c>false</c>.
+    /// </summary>
+    public bool OpenTelemetryEnabled { get; set; }
+
+    /// <summary>
+    /// Gets or sets the OTLP exporter endpoint URL.
+    /// When set, traces will be exported to this endpoint using the OTLP protocol.
+    /// Example: "http://localhost:4317" for gRPC or "http://localhost:4318" for HTTP.
+    /// If not set, the OTLP exporter will use the <c>OTEL_EXPORTER_OTLP_ENDPOINT</c> environment variable,
+    /// or fall back to the default endpoint (<c>http://localhost:4317</c> for gRPC).
+    /// </summary>
+    public string? OpenTelemetryOtlpExporterEndpoint { get; set; }
+
     /// <summary>
     /// Add an additional Urls on which WireMock should listen.
     /// </summary>
@@ -138,6 +154,20 @@
             Add(args, "--WatchStaticMappingsInSubdirectories", "true");
         }
 
+        if (OpenTelemetryEnabled)
+        {
+            // Enable activity tracing (creates System.Diagnostics.Activity objects)
+            Add(args, "--ActivityTracingEnabled", "true");
+
+            // Enable OpenTelemetry exporter
+            Add(args, "--OpenTelemetryEnabled", "true");
+
+            if (!string.IsNullOrEmpty(OpenTelemetryOtlpExporterEndpoint))
+            {
+                Add(args, "--OpenTelemetryOtlpExporterEndpoint", OpenTelemetryOtlpExporterEndpoint);
+            }
+        }
+
         if (AdditionalUrls.Count > 0)
         {
             Add(args, "--Urls", $"http://*:{HttpContainerPort} {string.Join(' ', AdditionalUrls)}");
@@ -153,7 +183,7 @@
         args[argument] = value;
     }
 
     private static void Add(IDictionary<string, string> args, string argument, Func<string> action)
     {
         args[argument] = action();
     }

src/WireMock.Net.Aspire/WireMockServerBuilderExtensions.cs

@@ -135,7 +135,7 @@
         });
 
         // Always add the lifecycle hook to support dynamic mappings and proto definitions
         resourceBuilder.ApplicationBuilder.Services.TryAddLifecycleHook<WireMockServerLifecycleHook>();
 
         return resourceBuilder;
     }
@@ -287,6 +287,40 @@
         return wiremock;
     }
 
+    /// <summary>
+    /// Configures OpenTelemetry distributed tracing for the WireMock.Net server.
+    /// This enables automatic trace export to the Aspire dashboard.
+    /// </summary>
+    /// <param name="wiremock">The <see cref="IResourceBuilder{WireMockServerResource}"/>.</param>
+    /// <returns>A reference to the <see cref="IResourceBuilder{WireMockServerResource}"/>.</returns>
+    /// <remarks>
+    /// When enabled, WireMock.Net will emit distributed traces for each request processed,
+    /// including information about:
+    /// <list type="bullet">
+    ///   <item>HTTP method, URL, and status code</item>
+    ///   <item>Mapping match results and scores</item>
+    ///   <item>Request processing duration</item>
+    /// </list>
+    /// The traces will automatically appear in the Aspire dashboard.
+    /// </remarks>
+    public static IResourceBuilder<WireMockServerResource> WithOpenTelemetry(this IResourceBuilder<WireMockServerResource> wiremock)
+    {
+        Guard.NotNull(wiremock);
+
+        // Enable OpenTelemetry in WireMock server arguments
+        wiremock.Resource.Arguments.OpenTelemetryEnabled = true;
+
+        // Use Aspire's standard WithOtlpExporter to configure OTEL environment variables for the container
+        // This sets OTEL_EXPORTER_OTLP_ENDPOINT which the OTLP exporter reads automatically
+        var containerBuilder = wiremock as IResourceBuilder<ContainerResource>;
+        if (containerBuilder != null)
+        {
+            containerBuilder.WithOtlpExporter();
+        }
+
+        return wiremock;
+    }
+
     private static Task<ExecuteCommandResult> OnRunOpenInspectorCommandAsync(IResourceBuilder<WireMockServerResource> builder)
     {
         WireMockInspector.Inspect(builder.Resource.GetEndpoint().Url);

src/WireMock.Net.Minimal/Owin/ActivityTracing/ActivityTracingOptions.cs

@@ -0,0 +1,38 @@
+// Copyright © WireMock.Net
+
+#if ACTIVITY_TRACING_SUPPORTED
+
+namespace WireMock.Owin.ActivityTracing;
+
+/// <summary>
+/// Options for controlling activity tracing in WireMock.Net middleware.
+/// These options control the creation of System.Diagnostics.Activity objects
+/// but do not require any OpenTelemetry exporter dependencies.
+/// </summary>
+public class ActivityTracingOptions
+{
+    /// <summary>
+    /// Gets or sets a value indicating whether to exclude admin interface requests from tracing.
+    /// Default is <c>true</c>.
+    /// </summary>
+    public bool ExcludeAdminRequests { get; set; } = true;
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to record request body in trace attributes.
+    /// Default is <c>false</c> due to potential PII concerns.
+    /// </summary>
+    public bool RecordRequestBody { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to record response body in trace attributes.
+    /// Default is <c>false</c> due to potential PII concerns.
+    /// </summary>
+    public bool RecordResponseBody { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to record mapping match details in trace attributes.
+    /// Default is <c>true</c>.
+    /// </summary>
+    public bool RecordMatchDetails { get; set; } = true;
+}
+#endif

src/WireMock.Net.Minimal/Owin/ActivityTracing/ActivityTracingValidator.cs

@@ -0,0 +1,34 @@
+// Copyright © WireMock.Net
+
+#if !ACTIVITY_TRACING_SUPPORTED
+using System;
+#endif
+using WireMock.Settings;
+
+namespace WireMock.Owin.ActivityTracing;
+
+/// <summary>
+/// Validator for Activity Tracing configuration.
+/// </summary>
+internal static class ActivityTracingValidator
+{
+    /// <summary>
+    /// Validates that Activity Tracing is supported on the current framework.
+    /// Throws an exception if ActivityTracingOptions is configured on an unsupported framework.
+    /// </summary>
+    /// <param name="settings">The WireMock server settings to validate.</param>
+    /// <exception cref="System.InvalidOperationException">
+    /// Thrown when ActivityTracingOptions is configured but the current framework does not support System.Diagnostics.Activity.
+    /// </exception>
+    public static void ValidateActivityApiPresence(WireMockServerSettings settings)
+    {
+#if !ACTIVITY_TRACING_SUPPORTED
+        if (settings.ActivityTracingOptions is not null)
+        {
+            throw new InvalidOperationException(
+                "Activity Tracing is not supported on this target framework. " +
+                "It requires .NET 5.0 or higher which includes System.Diagnostics.Activity support.");
+        }
+#endif
+    }
+}