[ASP.NET Core] Set http.request.method as per spec

OpenTelemetry.sln

@@ -269,6 +269,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Shared", "Shared", "{A49299
 		src\Shared\PeriodicExportingMetricReaderHelper.cs = src\Shared\PeriodicExportingMetricReaderHelper.cs
 		src\Shared\PooledList.cs = src\Shared\PooledList.cs
 		src\Shared\ResourceSemanticConventions.cs = src\Shared\ResourceSemanticConventions.cs
+		src\Shared\RequestMethodHelper.cs = src\Shared\RequestMethodHelper.cs
 		src\Shared\SemanticConventions.cs = src\Shared\SemanticConventions.cs
 		src\Shared\SpanAttributeConstants.cs = src\Shared\SpanAttributeConstants.cs
 		src\Shared\SpanHelper.cs = src\Shared\SpanHelper.cs

src/OpenTelemetry.Instrumentation.AspNetCore/CHANGELOG.md

@@ -2,6 +2,22 @@
 
 ## Unreleased
 
+* Updated `http.request.method` to match specification guidelines.
+  * For activity, if the method does not belong to one of the [known
+    values](https://github.com/open-telemetry/semantic-conventions/blob/v1.22.0/docs/http/http-spans.md#:~:text=http.request.method%20has%20the%20following%20list%20of%20well%2Dknown%20values)
+    then the request method will be set on an additional tag
+    `http.request.method.original` and `http.request.method` will be set to
+    `_OTHER`.
+  * For metrics, if the original method does not belong to one of the [known
+    values](https://github.com/open-telemetry/semantic-conventions/blob/v1.22.0/docs/http/http-spans.md#:~:text=http.request.method%20has%20the%20following%20list%20of%20well%2Dknown%20values)
+    then `http.request.method` on `http.server.request.duration` metric will be
+    set to `_OTHER`
+
+  `http.request.method` is set on `http.server.request.duration` metric or
+  activity when `OTEL_SEMCONV_STABILITY_OPT_IN` environment variable is set to
+  `http` or `http/dup`.
+  ([#5001](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5001))
+
 ## 1.6.0-beta.2
 
 Released 2023-Oct-26

src/OpenTelemetry.Instrumentation.AspNetCore/Implementation/HttpInListener.cs

@@ -252,7 +252,16 @@ public void OnStartActivity(Activity activity, object payload)
                     activity.SetTag(SemanticConventions.AttributeUrlQuery, request.QueryString.Value);
                 }
 
-                activity.SetTag(SemanticConventions.AttributeHttpRequestMethod, request.Method);
+                if (RequestMethodHelper.TryResolveHttpMethod(request.Method, out var httpMethod))
+                {
+                    activity.SetTag(SemanticConventions.AttributeHttpRequestMethod, httpMethod);
+                }
+                else
+                {
+                    activity.SetTag(SemanticConventions.AttributeHttpRequestMethod, httpMethod);
+                    activity.SetTag(SemanticConventions.AttributeHttpRequestMethodOriginal, request.Method);
+                }
+
                 activity.SetTag(SemanticConventions.AttributeUrlScheme, request.Scheme);
                 activity.SetTag(SemanticConventions.AttributeUrlPath, path);
                 activity.SetTag(SemanticConventions.AttributeNetworkProtocolVersion, HttpTagHelper.GetFlavorTagValueFromProtocol(request.Protocol));

src/OpenTelemetry.Instrumentation.AspNetCore/Implementation/HttpInMetricsListener.cs

@@ -18,6 +18,8 @@
 using System.Diagnostics;
 using System.Diagnostics.Metrics;
 using Microsoft.AspNetCore.Http;
+using OpenTelemetry.Internal;
+
 #if NET6_0_OR_GREATER
 using Microsoft.AspNetCore.Routing;
 #endif
@@ -150,8 +152,9 @@ public void OnEventWritten_New(string name, object payload)
         tags.Add(new KeyValuePair<string, object>(SemanticConventions.AttributeNetworkProtocolName, NetworkProtocolName));
         tags.Add(new KeyValuePair<string, object>(SemanticConventions.AttributeNetworkProtocolVersion, HttpTagHelper.GetFlavorTagValueFromProtocol(context.Request.Protocol)));
         tags.Add(new KeyValuePair<string, object>(SemanticConventions.AttributeUrlScheme, context.Request.Scheme));
-        tags.Add(new KeyValuePair<string, object>(SemanticConventions.AttributeHttpRequestMethod, context.Request.Method));
         tags.Add(new KeyValuePair<string, object>(SemanticConventions.AttributeHttpResponseStatusCode, TelemetryHelper.GetBoxedStatusCode(context.Response.StatusCode)));
+        RequestMethodHelper.TryResolveHttpMethod(context.Request.Method, out var httpMethod);
+        tags.Add(new KeyValuePair<string, object>(SemanticConventions.AttributeHttpRequestMethod, httpMethod));
 
 #if NET6_0_OR_GREATER
         var route = (context.GetEndpoint() as RouteEndpoint)?.RoutePattern.RawText;

src/OpenTelemetry.Instrumentation.AspNetCore/MeterProviderBuilderExtensions.cs

@@ -42,8 +42,9 @@ public static MeterProviderBuilder AddAspNetCoreInstrumentation(
 #if NET8_0_OR_GREATER
         return builder.ConfigureMeters();
 #else
-        // Note: Warm-up the status code mapping.
+        // Note: Warm-up the status code and method mapping.
         _ = TelemetryHelper.BoxedStatusCodes;
+        _ = RequestMethodHelper.KnownMethods;
 
         builder.ConfigureServices(services =>
         {

src/OpenTelemetry.Instrumentation.AspNetCore/OpenTelemetry.Instrumentation.AspNetCore.csproj

@@ -14,6 +14,7 @@
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Instrumentation.GrpcNetClient\GrpcTagHelper.cs" Link="Includes\GrpcTagHelper.cs" />
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Instrumentation.GrpcNetClient\StatusCanonicalCode.cs" Link="Includes\StatusCanonicalCode.cs" />
     <Compile Include="$(RepoRoot)\src\Shared\Guard.cs" Link="Includes\Guard.cs" />
+    <Compile Include="$(RepoRoot)\src\Shared\RequestMethodHelper.cs" Link="Includes\RequestMethodHelper.cs" />
     <Compile Include="$(RepoRoot)\src\Shared\EnvironmentVariables\*.cs" Link="Includes\EnvironmentVariables\%(Filename).cs" Condition="'$(TargetFramework)' == 'netstandard2.0' OR '$(TargetFramework)' == 'netstandard2.1'" />
     <Compile Include="$(RepoRoot)\src\Shared\HttpSemanticConventionHelper.cs" Link="Includes\HttpSemanticConventionHelper.cs" />
     <Compile Include="$(RepoRoot)\src\Shared\Options\*.cs" Link="Includes\Options\%(Filename).cs" />

src/OpenTelemetry.Instrumentation.AspNetCore/TracerProviderBuilderExtensions.cs

@@ -63,8 +63,9 @@ public static TracerProviderBuilder AddAspNetCoreInstrumentation(
     {
         Guard.ThrowIfNull(builder);
 
-        // Note: Warm-up the status code mapping.
+        // Note: Warm-up the status code and method mapping.
         _ = TelemetryHelper.BoxedStatusCodes;
+        _ = RequestMethodHelper.KnownMethods;
 
         name ??= Options.DefaultName;
 

src/Shared/RequestMethodHelper.cs

@@ -0,0 +1,78 @@
+// <copyright file="RequestMethodHelper.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+#if NET8_0_OR_GREATER
+using System.Collections.Frozen;
+#endif
+
+namespace OpenTelemetry.Internal;
+
+internal static class RequestMethodHelper
+{
+#if NET8_0_OR_GREATER
+    internal static readonly FrozenDictionary<string, string> KnownMethods;
+#else
+    internal static readonly Dictionary<string, string> KnownMethods;
+#endif
+
+    static RequestMethodHelper()
+    {
+#if NET8_0_OR_GREATER
+        KnownMethods = FrozenDictionary.ToFrozenDictionary(
+            new[]
+            {
+                KeyValuePair.Create("GET", "GET"),
+                KeyValuePair.Create("PUT", "PUT"),
+                KeyValuePair.Create("POST", "POST"),
+                KeyValuePair.Create("DELETE", "DELETE"),
+                KeyValuePair.Create("HEAD", "HEAD"),
+                KeyValuePair.Create("OPTIONS", "OPTIONS"),
+                KeyValuePair.Create("TRACE", "TRACE"),
+                KeyValuePair.Create("PATCH", "PATCH"),
+                KeyValuePair.Create("CONNECT", "CONNECT"),
+            },
+            StringComparer.OrdinalIgnoreCase);
+#else
+        KnownMethods = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
+        {
+            { "GET", "GET" },
+            { "PUT", "PUT" },
+            { "POST", "POST" },
+            { "DELETE", "DELETE" },
+            { "HEAD", "HEAD" },
+            { "OPTIONS", "OPTIONS" },
+            { "TRACE", "TRACE" },
+            { "PATCH", "PATCH" },
+            { "CONNECT", "CONNECT" },
+        };
+#endif
+    }
+
+    public static bool TryResolveHttpMethod(string method, out string resolvedMethod)
+    {
+        if (KnownMethods.TryGetValue(method, out var result))
+        {
+            // KnownMethods ignores case. Use the value returned by the dictionary to have a consistent case.
+            resolvedMethod = result;
+            return true;
+        }
+
+        // Set to default "_OTHER" as per spec.
+        // https://github.com/open-telemetry/semantic-conventions/blob/v1.22.0/docs/http/http-spans.md#common-attributes
+        resolvedMethod = "_OTHER";
+        return false;
+    }
+}

src/Shared/SemanticConventions.cs

@@ -129,4 +129,5 @@ internal static class SemanticConventions
     public const string AttributeUrlScheme = "url.scheme"; // replaces: "http.scheme" (AttributeHttpScheme)
     public const string AttributeUrlQuery = "url.query";
     public const string AttributeUserAgentOriginal = "user_agent.original"; // replaces: "http.user_agent" (AttributeHttpUserAgent)
+    public const string AttributeHttpRequestMethodOriginal = "http.request.method_original";
 }

test/OpenTelemetry.Instrumentation.AspNetCore.Tests/BasicTests.cs

@@ -21,17 +21,21 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Moq;
 using OpenTelemetry.Context.Propagation;
 using OpenTelemetry.Instrumentation.AspNetCore.Implementation;
+using OpenTelemetry.Internal;
 using OpenTelemetry.Tests;
 using OpenTelemetry.Trace;
 using TestApp.AspNetCore;
 using TestApp.AspNetCore.Filters;
 using Xunit;
 
+using static OpenTelemetry.Internal.HttpSemanticConventionHelper;
+
 namespace OpenTelemetry.Instrumentation.AspNetCore.Tests;
 
 // See https://github.com/aspnet/Docs/tree/master/aspnetcore/test/integration-tests/samples/2.x/IntegrationTestsSample
@@ -647,6 +651,78 @@ void ConfigureTestServices(IServiceCollection services)
         Assert.Equal("api/Values/{id}", aspnetcoreframeworkactivity.DisplayName);
     }
 
+    [Theory]
+    [InlineData("CONNECT")]
+    [InlineData("DELETE")]
+    [InlineData("GET")]
+    [InlineData("PUT")]
+    [InlineData("HEAD")]
+    [InlineData("OPTIONS")]
+    [InlineData("PATCH")]
+    [InlineData("Get")]
+    [InlineData("POST")]
+    [InlineData("TRACE")]
+    [InlineData("CUSTOM")]
+    public async Task HttpRequestMethodIsSetAsPerSpec(string method)
+    {
+        var exportedItems = new List<Activity>();
+
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string> { [SemanticConventionOptInKeyName] = "http" })
+            .Build();
+
+        void ConfigureTestServices(IServiceCollection services)
+        {
+            this.tracerProvider = Sdk.CreateTracerProviderBuilder()
+                .ConfigureServices(services => services.AddSingleton<IConfiguration>(configuration))
+                .AddAspNetCoreInstrumentation()
+                .AddInMemoryExporter(exportedItems)
+                .Build();
+        }
+
+        // Arrange
+        using var client = this.factory
+            .WithWebHostBuilder(builder =>
+            {
+                builder.ConfigureTestServices(ConfigureTestServices);
+                builder.ConfigureLogging(loggingBuilder => loggingBuilder.ClearProviders());
+            })
+            .CreateClient();
+
+        var message = new HttpRequestMessage();
+
+        message.Method = new HttpMethod(method);
+
+        try
+        {
+            using var response = await client.SendAsync(message).ConfigureAwait(false);
+            response.EnsureSuccessStatusCode();
+        }
+        catch
+        {
+            // ignore error.
+        }
+
+        WaitForActivityExport(exportedItems, 1);
+
+        Assert.Single(exportedItems);
+
+        var activity = exportedItems[0];
+
+        Assert.Contains(activity.TagObjects, t => t.Key == SemanticConventions.AttributeHttpRequestMethod);
+
+        if (RequestMethodHelper.KnownMethods.TryGetValue(method, out var val))
+        {
+            Assert.Equal(val, activity.GetTagValue(SemanticConventions.AttributeHttpRequestMethod) as string);
+            Assert.DoesNotContain(activity.TagObjects, t => t.Key == SemanticConventions.AttributeHttpRequestMethodOriginal);
+        }
+        else
+        {
+            Assert.Equal("_OTHER", activity.GetTagValue(SemanticConventions.AttributeHttpRequestMethod) as string);
+            Assert.Equal(method, activity.GetTagValue(SemanticConventions.AttributeHttpRequestMethodOriginal) as string);
+        }
+    }
+
     [Fact]
     public async Task ActivitiesStartedInMiddlewareBySettingHostActivityToNullShouldNotBeUpdated()
     {

test/OpenTelemetry.Instrumentation.AspNetCore.Tests/MetricTests.cs

@@ -29,6 +29,7 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using OpenTelemetry.Internal;
 using OpenTelemetry.Metrics;
 using OpenTelemetry.Trace;
 using Xunit;
@@ -237,6 +238,89 @@ public async Task RequestMetricIsCaptured_New()
             expectedTagsCount: 6);
     }
 
+    [Theory]
+    [InlineData("CONNECT")]
+    [InlineData("DELETE")]
+    [InlineData("GET")]
+    [InlineData("GeT")]
+    [InlineData("PUT")]
+    [InlineData("HEAD")]
+    [InlineData("OPTIONS")]
+    [InlineData("PATCH")]
+    [InlineData("POST")]
+    [InlineData("TRACE")]
+    [InlineData("CUSTOM")]
+    public async Task HttpRequestMethodIsCapturedAsPerSpec(string method)
+    {
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string> { [SemanticConventionOptInKeyName] = "http" })
+            .Build();
+
+        var metricItems = new List<Metric>();
+
+        this.meterProvider = Sdk.CreateMeterProviderBuilder()
+            .ConfigureServices(services => services.AddSingleton<IConfiguration>(configuration))
+            .AddAspNetCoreInstrumentation()
+            .AddInMemoryExporter(metricItems)
+            .Build();
+
+        using var client = this.factory
+            .WithWebHostBuilder(builder =>
+            {
+                builder.ConfigureLogging(loggingBuilder => loggingBuilder.ClearProviders());
+            })
+            .CreateClient();
+
+        var message = new HttpRequestMessage();
+        message.Method = new HttpMethod(method);
+
+        try
+        {
+            using var response = await client.SendAsync(message).ConfigureAwait(false);
+        }
+        catch
+        {
+            // ignore error.
+        }
+
+        // We need to let End callback execute as it is executed AFTER response was returned.
+        // In unit tests environment there may be a lot of parallel unit tests executed, so
+        // giving some breezing room for the End callback to complete
+        await Task.Delay(TimeSpan.FromSeconds(1)).ConfigureAwait(false);
+
+        this.meterProvider.Dispose();
+
+        var requestMetrics = metricItems
+            .Where(item => item.Name == "http.server.request.duration")
+            .ToArray();
+
+        var metric = Assert.Single(requestMetrics);
+
+        Assert.Equal("s", metric.Unit);
+        var metricPoints = GetMetricPoints(metric);
+        Assert.Single(metricPoints);
+
+        var mp = metricPoints[0];
+
+        // Inspect Metric Attributes
+        var attributes = new Dictionary<string, object>();
+        foreach (var tag in mp.Tags)
+        {
+            attributes[tag.Key] = tag.Value;
+        }
+
+        if (RequestMethodHelper.KnownMethods.TryGetValue(method, out var val))
+        {
+            Assert.Contains(attributes, kvp => kvp.Key == SemanticConventions.AttributeHttpRequestMethod && kvp.Value.ToString() == method.ToUpper());
+        }
+        else
+        {
+            Assert.Contains(attributes, kvp => kvp.Key == SemanticConventions.AttributeHttpRequestMethod && kvp.Value.ToString() == "_OTHER");
+        }
+
+        Assert.DoesNotContain(attributes, t => t.Key == SemanticConventions.AttributeHttpRequestMethodOriginal);
+    }
+
 #if !NET8_0_OR_GREATER
     [Fact]
     public async Task RequestMetricIsCaptured_Old()