CommunityToolkit · aaronpowell · Sep 5, 2025 · Aug 7, 2025 · Aug 7, 2025 · Aug 7, 2025
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
@@ -42,6 +42,7 @@ jobs:
             Hosting.Ngrok.Tests,
             Hosting.NodeJS.Extensions.Tests,
             Hosting.Ollama.Tests,
+            Hosting.OpenTelemetryCollector.Tests,
             Hosting.PapercutSmtp.Tests,
             Hosting.PostgreSQL.Extensions.Tests,
             Hosting.PowerShell.Tests,

diff --git a/CODEOWNERS b/CODEOWNERS
@@ -125,3 +125,9 @@
 /tests/CommunityToolkit.Aspire.Hosting.SurrealDb.Tests/ @Odonno
 /src/CommunityToolkit.Aspire.SurrealDb/ @Odonno
 /tests/CommunityToolkit.Aspire.SurrealDb.Tests/ @Odonno
+
+# CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector
+
+/examples/opentelemetry-collector/ @martinjt
+/src/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector/ @martinjt
+/tests/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Tests/ @martinjt
diff --git a/CommunityToolkit.Aspire.slnx b/CommunityToolkit.Aspire.slnx
@@ -105,6 +105,11 @@
     <Project Path="examples/ollama/CommunityToolkit.Aspire.Hosting.Ollama.ServiceDefaults/CommunityToolkit.Aspire.Hosting.Ollama.ServiceDefaults.csproj" />
     <Project Path="examples/ollama/CommunityToolkit.Aspire.Hosting.Ollama.Web/CommunityToolkit.Aspire.Hosting.Ollama.Web.csproj" />
   </Folder>
+  <Folder Name="/examples/opentelemetry-collector/">
+    <Project Path="examples/opentelemetry-collector/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Api/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Api.csproj" />
+    <Project Path="examples/opentelemetry-collector/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.AppHost/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.AppHost.csproj" />
+    <Project Path="examples/opentelemetry-collector/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.ServiceDefaults/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.ServiceDefaults.csproj" />
+  </Folder>
   <Folder Name="/examples/papercut/">
     <Project Path="examples/papercut/CommunityToolkit.Aspire.Hosting.PapercutSmtp.AppHost/CommunityToolkit.Aspire.Hosting.PapercutSmtp.AppHost.csproj" />
     <Project Path="examples/papercut/CommunityToolkit.Aspire.Hosting.PapercutSmtp.SendMailApi/CommunityToolkit.Aspire.Hosting.PapercutSmtp.SendMailApi.csproj" />
@@ -172,6 +177,7 @@
     <Project Path="src/CommunityToolkit.Aspire.Hosting.Ngrok/CommunityToolkit.Aspire.Hosting.Ngrok.csproj" />
     <Project Path="src/CommunityToolkit.Aspire.Hosting.NodeJS.Extensions/CommunityToolkit.Aspire.Hosting.NodeJS.Extensions.csproj" />
     <Project Path="src/CommunityToolkit.Aspire.Hosting.Ollama/CommunityToolkit.Aspire.Hosting.Ollama.csproj" />
+    <Project Path="src/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.csproj" />
     <Project Path="src/CommunityToolkit.Aspire.Hosting.PapercutSmtp/CommunityToolkit.Aspire.Hosting.PapercutSmtp.csproj" />
     <Project Path="src/CommunityToolkit.Aspire.Hosting.PostgreSQL.Extensions/CommunityToolkit.Aspire.Hosting.PostgreSQL.Extensions.csproj" />
     <Project Path="src/CommunityToolkit.Aspire.Hosting.PowerShell/CommunityToolkit.Aspire.Hosting.PowerShell.csproj" />
@@ -221,6 +227,7 @@
     <Project Path="tests/CommunityToolkit.Aspire.Hosting.Ngrok.Tests/CommunityToolkit.Aspire.Hosting.Ngrok.Tests.csproj" />
     <Project Path="tests/CommunityToolkit.Aspire.Hosting.NodeJS.Extensions.Tests/CommunityToolkit.Aspire.Hosting.NodeJS.Extensions.Tests.csproj" />
     <Project Path="tests/CommunityToolkit.Aspire.Hosting.Ollama.Tests/CommunityToolkit.Aspire.Hosting.Ollama.Tests.csproj" />
+    <Project Path="tests/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Tests/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Tests.csproj" />
     <Project Path="tests/CommunityToolkit.Aspire.Hosting.PapercutSmtp.Tests/CommunityToolkit.Aspire.Hosting.PapercutSmtp.Tests.csproj" />
     <Project Path="tests/CommunityToolkit.Aspire.Hosting.PostgreSQL.Extensions.Tests/CommunityToolkit.Aspire.Hosting.PostgreSQL.Extensions.Tests.csproj" />
     <Project Path="tests/CommunityToolkit.Aspire.Hosting.PowerShell.Tests/CommunityToolkit.Aspire.Hosting.PowerShell.Tests.csproj" />

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.ServiceDefaults\CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.ServiceDefaults.csproj" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,6 @@
+@CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Api_HostAddress = http://localhost:5121
+
+GET {{CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Api_HostAddress}}/weatherforecast/
+Accept: application/json
+
+###
@@ -0,0 +1,31 @@
+var builder = WebApplication.CreateBuilder(args);
+
+builder.AddServiceDefaults();
+
+var app = builder.Build();
+
+var summaries = new[]
+{
+    "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
+};
+
+app.MapGet("/weatherforecast", () =>
+{
+    var forecast =  Enumerable.Range(1, 5).Select(index =>
+        new WeatherForecast
+        (
+            DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
+            Random.Shared.Next(-20, 55),
+            summaries[Random.Shared.Next(summaries.Length)]
+        ))
+        .ToArray();
+    return forecast;
+})
+.WithName("GetWeatherForecast");
+
+app.Run();
+
+record WeatherForecast(DateOnly Date, int TemperatureC, string? Summary)
+{
+    public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
+}
@@ -0,0 +1,23 @@
+{
+  "$schema": "https://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "http://localhost:5121",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "https": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "https://localhost:7262;http://localhost:5121",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}
@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*"
+}
@@ -0,0 +1,9 @@
+var builder = DistributedApplication.CreateBuilder(args);
+
+builder.AddProject<Projects.CommunityToolkit_Aspire_Hosting_OpenTelemetryCollector_Api>("api");
+
+builder.AddOpenTelemetryCollector("opentelemetry-collector")
+    .WithAppForwarding()
+    .WithConfig("./config.yaml");
+
+builder.Build().Run();
@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <Sdk Name="Aspire.AppHost.Sdk" Version="$(AspireAppHostSdkVersion)" />
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <UserSecretsId>f0af42ab-ea83-435c-9273-89269ca78d75</UserSecretsId>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Aspire.Hosting.AppHost"/>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Api\CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Api.csproj" />
+    <ProjectReference Include="..\..\..\src\CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector\CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.csproj" IsAspireProjectResource="false" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,29 @@
+{
+  "$schema": "https://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "https": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "applicationUrl": "https://localhost:17224;http://localhost:15263",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "DOTNET_ENVIRONMENT": "Development",
+        "ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL": "https://localhost:21066",
+        "ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL": "https://localhost:22110"
+      }
+    },
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "applicationUrl": "http://localhost:15263",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "DOTNET_ENVIRONMENT": "Development",
+        "ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL": "http://localhost:19260",
+        "ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL": "http://localhost:20086"
+      }
+    }
+  }
+}
@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning",
+      "Aspire.Hosting.Dcp": "Warning"
+    }
+  }
+}
@@ -0,0 +1,43 @@
+receivers:
+  otlp:
+    protocols:
+      grpc:
+        endpoint: 0.0.0.0:4317
+      http:
+        endpoint: 0.0.0.0:4318
+
+processors:
+  batch:
+  transform/add-collector-enabled:
+    error_mode: ignore
+    log_statements:
+      - set(resource.attributes["collector.enabled"], "true")
+    trace_statements:
+      - set(resource.attributes["collector.enabled"], "true")
+    metric_statements:
+      - set(resource.attributes["collector.enabled"], "true")
+
+exporters:
+  debug:
+    verbosity: detailed
+  otlp/aspire:
+    endpoint: ${env:ASPIRE_ENDPOINT}
+    headers:
+      x-otlp-api-key: ${env:ASPIRE_API_KEY}
+    tls:
+      insecure_skip_verify: true
+
+service:
+  pipelines:
+    traces:
+      receivers: [otlp]
+      processors: [batch, transform/add-collector-enabled]
+      exporters: [otlp/aspire]
+    metrics:
+      receivers: [otlp]
+      processors: [batch, transform/add-collector-enabled]
+      exporters: [otlp/aspire]
+    logs:
+      receivers: [otlp]
+      processors: [batch, transform/add-collector-enabled]
+      exporters: [debug,otlp/aspire]
@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsAspireSharedProject>true</IsAspireSharedProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+
+    <PackageReference Include="Microsoft.Extensions.Http.Resilience" />
+    <PackageReference Include="Microsoft.Extensions.ServiceDiscovery" />
+    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" />
+    <PackageReference Include="OpenTelemetry.Extensions.Hosting" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.Http" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.Runtime" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,126 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Diagnostics.HealthChecks;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+using Microsoft.Extensions.Logging;
+using OpenTelemetry;
+using OpenTelemetry.Metrics;
+using OpenTelemetry.Trace;
+
+namespace Microsoft.Extensions.Hosting;
+
+// Adds common .NET Aspire services: service discovery, resilience, health checks, and OpenTelemetry.
+// This project should be referenced by each service project in your solution.
+// To learn more about using this project, see https://aka.ms/dotnet/aspire/service-defaults
+public static class Extensions
+{
+    private const string HealthEndpointPath = "/health";
+    private const string AlivenessEndpointPath = "/alive";
+
+    public static TBuilder AddServiceDefaults<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
+    {
+        builder.ConfigureOpenTelemetry();
+
+        builder.AddDefaultHealthChecks();
+
+        builder.Services.AddServiceDiscovery();
+
+        builder.Services.ConfigureHttpClientDefaults(http =>
+        {
+            // Turn on resilience by default
+            http.AddStandardResilienceHandler();
+
+            // Turn on service discovery by default
+            http.AddServiceDiscovery();
+        });
+
+        // Uncomment the following to restrict the allowed schemes for service discovery.
+        // builder.Services.Configure<ServiceDiscoveryOptions>(options =>
+        // {
+        //     options.AllowedSchemes = ["https"];
+        // });
+
+        return builder;
+    }
+
+    public static TBuilder ConfigureOpenTelemetry<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
+    {
+        builder.Logging.AddOpenTelemetry(logging =>
+        {
+            logging.IncludeFormattedMessage = true;
+            logging.IncludeScopes = true;
+        });
+
+        builder.Services.AddOpenTelemetry()
+            .WithMetrics(metrics =>
+            {
+                metrics.AddAspNetCoreInstrumentation()
+                    .AddHttpClientInstrumentation()
+                    .AddRuntimeInstrumentation();
+            })
+            .WithTracing(tracing =>
+            {
+                tracing.AddSource(builder.Environment.ApplicationName)
+                    .AddAspNetCoreInstrumentation(tracing =>
+                        // Exclude health check requests from tracing
+                        tracing.Filter = context =>
+                            !context.Request.Path.StartsWithSegments(HealthEndpointPath)
+                            && !context.Request.Path.StartsWithSegments(AlivenessEndpointPath)
+                    )
+                    // Uncomment the following line to enable gRPC instrumentation (requires the OpenTelemetry.Instrumentation.GrpcNetClient package)
+                    //.AddGrpcClientInstrumentation()
+                    .AddHttpClientInstrumentation();
+            });
+
+        builder.AddOpenTelemetryExporters();
+
+        return builder;
+    }
+
+    private static TBuilder AddOpenTelemetryExporters<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
+    {
+        var useOtlpExporter = !string.IsNullOrWhiteSpace(builder.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
+
+        if (useOtlpExporter)
+        {
+            builder.Services.AddOpenTelemetry().UseOtlpExporter();
+        }
+
+        // Uncomment the following lines to enable the Azure Monitor exporter (requires the Azure.Monitor.OpenTelemetry.AspNetCore package)
+        //if (!string.IsNullOrEmpty(builder.Configuration["APPLICATIONINSIGHTS_CONNECTION_STRING"]))
+        //{
+        //    builder.Services.AddOpenTelemetry()
+        //       .UseAzureMonitor();
+        //}
+
+        return builder;
+    }
+
+    public static TBuilder AddDefaultHealthChecks<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
+    {
+        builder.Services.AddHealthChecks()
+            // Add a default liveness check to ensure app is responsive
+            .AddCheck("self", () => HealthCheckResult.Healthy(), ["live"]);
+
+        return builder;
+    }
+
+    public static WebApplication MapDefaultEndpoints(this WebApplication app)
+    {
+        // Adding health checks endpoints to applications in non-development environments has security implications.
+        // See https://aka.ms/dotnet/aspire/healthchecks for details before enabling these endpoints in non-development environments.
+        if (app.Environment.IsDevelopment())
+        {
+            // All health checks must pass for app to be considered ready to accept traffic after starting
+            app.MapHealthChecks(HealthEndpointPath);
+
+            // Only health checks tagged with the "live" tag must pass for app to be considered alive
+            app.MapHealthChecks(AlivenessEndpointPath, new HealthCheckOptions
+            {
+                Predicate = r => r.Tags.Contains("live")
+            });
+        }
+
+        return app;
+    }
+}