Optionally register OpenTelemetry (#2472)

* Optionally register OpenTelemetry

* Set env var for integration tests

* fix dispose pattern

Author: Mpdreamz

docs-builder.sln.DotSettings

@@ -4,4 +4,5 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=frontmatter/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=linenos/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=literalinclude/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Otlp/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=_0060_0060inli/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

src/Elastic.Documentation.ServiceDefaults/Extensions.cs

@@ -37,6 +37,11 @@ public static TBuilder AddServiceDefaults<TBuilder>(this TBuilder builder) where
 
 	public static TBuilder AddOpenTelemetryDefaults<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
 	{
+
+		var useOtlpExporter = !string.IsNullOrWhiteSpace(builder.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
+		if (!useOtlpExporter)
+			return builder;
+
 		_ = builder.Logging.AddOpenTelemetry(logging =>
 		{
 			logging.IncludeFormattedMessage = true;
@@ -86,14 +91,6 @@ private static TBuilder AddOpenTelemetryExporters<TBuilder>(this TBuilder builde
 
 			_ = 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;
 	}
 

src/api/Elastic.Documentation.Api.Infrastructure/MappingsExtensions.cs

@@ -14,14 +14,16 @@ namespace Elastic.Documentation.Api.Infrastructure;
 
 public static class MappingsExtension
 {
-	public static void MapElasticDocsApiEndpoints(this IEndpointRouteBuilder group)
+	public static void MapElasticDocsApiEndpoints(this IEndpointRouteBuilder group, bool mapOtlpEndpoints = true)
 	{
+
 		_ = group.MapGet("/", () => Results.Empty);
 		_ = group.MapPost("/", () => Results.Empty);
 		MapAskAiEndpoint(group);
 		MapNavigationSearch(group);
 		MapFullSearch(group);
-		MapOtlpProxyEndpoint(group);
+		if (mapOtlpEndpoints)
+			MapOtlpProxyEndpoint(group);
 	}
 
 	private static void MapAskAiEndpoint(IEndpointRouteBuilder group)

src/api/Elastic.Documentation.Api.Infrastructure/OpenTelemetry/OpenTelemetryExtensions.cs

@@ -71,10 +71,13 @@ public static TracerProviderBuilder AddDocsApiTracing(this TracerProviderBuilder
 	/// </summary>
 	/// <param name="builder">The web application builder</param>
 	/// <returns>The builder for chaining</returns>
-	public static TBuilder AddDocsApiOpenTelemetry<TBuilder>(
-		this TBuilder builder)
+	public static TBuilder AddDocsApiOpenTelemetry<TBuilder>(this TBuilder builder)
 		where TBuilder : IHostApplicationBuilder
 	{
+		var useOtlpExporter = !string.IsNullOrWhiteSpace(builder.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
+		if (!useOtlpExporter)
+			return builder;
+
 		var options = new ElasticOpenTelemetryOptions
 		{
 			// In AOT mode, assembly scanning is not supported, so we skip it

src/api/Elastic.Documentation.Api.Lambda/Program.cs

@@ -49,7 +49,9 @@
 		_ = app.UseDeveloperExceptionPage();
 
 	var v1 = app.MapGroup("/docs/_api/v1");
-	v1.MapElasticDocsApiEndpoints();
+
+	var mapOtlpEndpoints = !string.IsNullOrWhiteSpace(builder.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
+	v1.MapElasticDocsApiEndpoints(mapOtlpEndpoints);
 	Console.WriteLine("API endpoints mapped");
 
 	Console.WriteLine("Application startup completed successfully");

src/tooling/docs-builder/Http/DocumentationWebHost.cs

@@ -142,7 +142,8 @@ private void SetUpRoutes()
 
 		var apiV1 = _webApplication.MapGroup("/docs/_api/v1");
 #if DEBUG
-		apiV1.MapElasticDocsApiEndpoints();
+		var mapOtlpEndpoints = !string.IsNullOrWhiteSpace(_webApplication.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
+		apiV1.MapElasticDocsApiEndpoints(mapOtlpEndpoints);
 #endif
 
 		_ = _webApplication.MapGet("{**slug}", (string slug, ReloadableGeneratorState holder, Cancel ctx) =>

src/tooling/docs-builder/Http/StaticWebHost.cs

@@ -85,7 +85,8 @@ private void SetUpRoutes()
 
 		var apiV1 = WebApplication.MapGroup("/docs/_api/v1");
 #if DEBUG
-		apiV1.MapElasticDocsApiEndpoints();
+		var mapOtlpEndpoints = !string.IsNullOrWhiteSpace(WebApplication.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
+		apiV1.MapElasticDocsApiEndpoints(mapOtlpEndpoints);
 #endif
 
 	}

tests-integration/Elastic.Documentation.Api.IntegrationTests/EuidEnrichmentIntegrationTests.cs

@@ -17,8 +17,23 @@ namespace Elastic.Documentation.Api.IntegrationTests;
 /// Integration tests for euid cookie enrichment in OpenTelemetry traces and logging.
 /// Uses WebApplicationFactory to test the real API configuration with mocked AskAi services.
 /// </summary>
-public class EuidEnrichmentIntegrationTests
+public class EuidEnrichmentIntegrationTests : IAsyncLifetime
 {
+	private const string OtlpEndpoint = "http://localhost:4318";
+
+	public ValueTask InitializeAsync()
+	{
+		Environment.SetEnvironmentVariable("OTEL_EXPORTER_OTLP_ENDPOINT", OtlpEndpoint);
+		return ValueTask.CompletedTask;
+	}
+
+	public ValueTask DisposeAsync()
+	{
+		GC.SuppressFinalize(this);
+		Environment.SetEnvironmentVariable("OTEL_EXPORTER_OTLP_ENDPOINT", null);
+		return ValueTask.CompletedTask;
+	}
+
 	/// <summary>
 	/// Test that verifies euid cookie is added to both HTTP span and custom AskAi span,
 	/// and appears in log entries - using the real API configuration.

tests-integration/Elastic.Documentation.Api.IntegrationTests/OtlpProxyIntegrationTests.cs

@@ -13,8 +13,23 @@
 
 namespace Elastic.Documentation.Api.IntegrationTests;
 
-public class OtlpProxyIntegrationTests
+public class OtlpProxyIntegrationTests : IAsyncLifetime
 {
+	private const string OtlpEndpoint = "http://localhost:4318";
+
+	public ValueTask InitializeAsync()
+	{
+		Environment.SetEnvironmentVariable("OTEL_EXPORTER_OTLP_ENDPOINT", OtlpEndpoint);
+		return ValueTask.CompletedTask;
+	}
+
+	public ValueTask DisposeAsync()
+	{
+		GC.SuppressFinalize(this);
+		Environment.SetEnvironmentVariable("OTEL_EXPORTER_OTLP_ENDPOINT", null);
+		return ValueTask.CompletedTask;
+	}
+
 	[Fact]
 	public async Task OtlpProxyTracesEndpointForwardsToCorrectUrl()
 	{
@@ -71,7 +86,7 @@ public async Task OtlpProxyTracesEndpointForwardsToCorrectUrl()
 		response.StatusCode.Should().Be(HttpStatusCode.NoContent);
 		capturedRequest.Should().NotBeNull();
 		capturedRequest!.RequestUri.Should().NotBeNull();
-		capturedRequest.RequestUri!.ToString().Should().Be("http://localhost:4318/v1/traces");
+		capturedRequest.RequestUri!.ToString().Should().Be($"{OtlpEndpoint}/v1/traces");
 		capturedRequest.Method.Should().Be(HttpMethod.Post);
 		capturedRequest.Content.Should().NotBeNull();
 		capturedRequest.Content!.Headers.ContentType!.MediaType.Should().Be("application/json");
@@ -131,7 +146,7 @@ public async Task OtlpProxyLogsEndpointForwardsToCorrectUrl()
 		// Assert - verify the enum ToStringFast() generates "logs" (lowercase)
 		response.StatusCode.Should().Be(HttpStatusCode.NoContent);
 		capturedRequest.Should().NotBeNull();
-		capturedRequest!.RequestUri!.ToString().Should().Be("http://localhost:4318/v1/logs");
+		capturedRequest!.RequestUri!.ToString().Should().Be($"{OtlpEndpoint}/v1/logs");
 
 		// Cleanup mock response
 		mockResponse.Dispose();
@@ -184,7 +199,7 @@ public async Task OtlpProxyMetricsEndpointForwardsToCorrectUrl()
 		// Assert - verify the enum ToStringFast() generates "metrics" (lowercase)
 		response.StatusCode.Should().Be(HttpStatusCode.NoContent);
 		capturedRequest.Should().NotBeNull();
-		capturedRequest!.RequestUri!.ToString().Should().Be("http://localhost:4318/v1/metrics");
+		capturedRequest!.RequestUri!.ToString().Should().Be($"{OtlpEndpoint}/v1/metrics");
 
 		// Cleanup mock response
 		mockResponse.Dispose();