Implement AWS Lambda detector

src/OpenTelemetry.Instrumentation.AWSLambda/.publicApi/PublicAPI.Unshipped.txt

@@ -0,0 +1,2 @@
+OpenTelemetry.Instrumentation.AWSLambda.AWSLambdaResourceBuilderExtensions
+static OpenTelemetry.Instrumentation.AWSLambda.AWSLambdaResourceBuilderExtensions.AddAWSLambdaDetector(this OpenTelemetry.Resources.ResourceBuilder! builder) -> OpenTelemetry.Resources.ResourceBuilder!

src/OpenTelemetry.Instrumentation.AWSLambda/AWSLambdaResourceBuilderExtensions.cs

@@ -0,0 +1,29 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+using OpenTelemetry.AWS;
+using OpenTelemetry.Instrumentation.AWSLambda.Implementation;
+using OpenTelemetry.Internal;
+using OpenTelemetry.Resources;
+using OpenTelemetry.Trace;
+
+namespace OpenTelemetry.Instrumentation.AWSLambda;
+
+/// <summary>
+/// Extension methods to simplify registering of AWS Lambda resource detectors.
+/// </summary>
+public static class AWSLambdaResourceBuilderExtensions
+{
+    /// <summary>
+    /// Enables AWS Lambda resource detector. Do not call this method while also calling <see cref="TracerProviderBuilderExtensions.AddAWSLambdaConfigurations(TracerProviderBuilder)" /> or <see cref="TracerProviderBuilderExtensions.AddAWSLambdaConfigurations(TracerProviderBuilder, System.Action{AWSLambdaInstrumentationOptions})" />.
+    /// </summary>
+    /// <param name="builder">The <see cref="ResourceBuilder"/> being configured.</param>
+    /// <returns>The instance of <see cref="ResourceBuilder"/> being configured.</returns>
+    public static ResourceBuilder AddAWSLambdaDetector(this ResourceBuilder builder)
+    {
+        Guard.ThrowIfNull(builder);
+
+        var semanticConventionBuilder = new AWSSemanticConventions();
+        return builder.AddDetector(new AWSLambdaResourceDetector(semanticConventionBuilder));
+    }
+}

src/OpenTelemetry.Instrumentation.AWSLambda/CHANGELOG.md

@@ -12,6 +12,8 @@ Released 2025-Nov-13
 * Update Amazon.Lambda.Core dependency from 2.2.0 to 2.8.0 which reworks the internal
   logic for determining the trace id created by AWS Lambda.
   ([#3410](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/3410))
+* Implement AWS Lambda detector.
+  ([#3411](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/3411))
 
 * Update .NET 10.0 NuGet package versions from `10.0.0-rc.2.25502.107` to `10.0.0`.
   ([#3403](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/3403))

src/OpenTelemetry.Instrumentation.AWSLambda/TracerProviderBuilderExtensions.cs

@@ -22,7 +22,7 @@ public static TracerProviderBuilder AddAWSLambdaConfigurations(this TracerProvid
         AddAWSLambdaConfigurations(builder, configure: null);
 
     /// <summary>
-    /// Add AWS Lambda configurations.
+    /// Add AWS Lambda configurations. Do not call this method if also calling <see cref="AWSLambdaResourceBuilderExtensions.AddAWSLambdaDetector" /> as it already adds the detector.
     /// </summary>
     /// <param name="builder"><see cref="TracerProviderBuilder"/> being configured.</param>
     /// <param name="configure">AWS lambda instrumentation options.</param>

test/OpenTelemetry.Instrumentation.AWSLambda.Tests/AWSLambdaResourceBuilderExtensionsTests.cs

@@ -0,0 +1,51 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+using OpenTelemetry.Resources;
+using Xunit;
+
+namespace OpenTelemetry.Instrumentation.AWSLambda.Tests;
+
+public class AWSLambdaResourceBuilderExtensionsTests : IDisposable
+{
+    // Expected Semantic Conventions
+    private const string AttributeCloudProvider = "cloud.provider";
+    private const string AttributeCloudRegion = "cloud.region";
+    private const string AttributeFaasName = "faas.name";
+    private const string AttributeFaasVersion = "faas.version";
+    private const string AttributeFaasInstance = "faas.instance";
+    private const string AttributeFaasMaxMemory = "faas.max_memory";
+
+    private readonly IDisposable environmentScope = EnvironmentVariableScope.Create(
+        ("AWS_REGION", "us-east-1"),
+        ("AWS_LAMBDA_FUNCTION_NAME", "testfunction"),
+        ("AWS_LAMBDA_FUNCTION_VERSION", "latest"),
+        ("AWS_LAMBDA_FUNCTION_MEMORY_SIZE", "128"),
+        ("AWS_LAMBDA_LOG_STREAM_NAME", "2025/07/21/[$LATEST]7b176c212e954e62adfb9b5451cb5374"));
+
+    public void Dispose() => this.environmentScope.Dispose();
+
+    [Fact]
+    public void AssertAttributes()
+    {
+        var resourceBuilder = ResourceBuilder.CreateDefault();
+        resourceBuilder.AddAWSLambdaDetector();
+
+        var resource = resourceBuilder.Build();
+
+        var resourceAttributes = resource.Attributes
+            .ToDictionary(x => x.Key, x => x.Value);
+
+        Assert.Equal("aws", resourceAttributes[AttributeCloudProvider]);
+        Assert.Equal("us-east-1", resourceAttributes[AttributeCloudRegion]);
+        Assert.Equal("testfunction", resourceAttributes[AttributeFaasName]);
+        Assert.Equal("latest", resourceAttributes[AttributeFaasVersion]);
+        Assert.Equal("2025/07/21/[$LATEST]7b176c212e954e62adfb9b5451cb5374",
+            resourceAttributes[AttributeFaasInstance]);
+        Assert.Equal(134217728L, resourceAttributes[AttributeFaasMaxMemory]);
+    }
+
+    [Fact]
+    public void AssertArgumentNullException() =>
+        Assert.Throws<ArgumentNullException>(() => AWSLambdaResourceBuilderExtensions.AddAWSLambdaDetector(null!));
+}