Add manual+automatic instrumentation tests + fix SetUser bug

Datadog.Trace.sln

@@ -557,6 +557,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Samples.Amazon.Lambda.Runti
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Samples.Remoting", "tracer\test\test-applications\integrations\Samples.Remoting\Samples.Remoting.csproj", "{23EA38E3-0BF1-40DF-A52D-C34EA2FB3F26}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Samples.ManualInstrumentation", "tracer\test\test-applications\integrations\Samples.ManualInstrumentation\Samples.ManualInstrumentation.csproj", "{F24EB026-65FB-4247-ABF8-942B11ADAB64}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -1329,6 +1331,10 @@ Global
 		{23EA38E3-0BF1-40DF-A52D-C34EA2FB3F26}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{23EA38E3-0BF1-40DF-A52D-C34EA2FB3F26}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{23EA38E3-0BF1-40DF-A52D-C34EA2FB3F26}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F24EB026-65FB-4247-ABF8-942B11ADAB64}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F24EB026-65FB-4247-ABF8-942B11ADAB64}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F24EB026-65FB-4247-ABF8-942B11ADAB64}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F24EB026-65FB-4247-ABF8-942B11ADAB64}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -1545,6 +1551,7 @@ Global
 		{4E9535E2-C918-4C39-9F1B-F182C185DE64} = {8CEC2042-F11C-49F5-A674-2355793B600A}
 		{18A6904A-5AFD-4816-AC3F-9F5E433720B5} = {BAF8F246-3645-42AD-B1D0-0F7EAFBAB34A}
 		{23EA38E3-0BF1-40DF-A52D-C34EA2FB3F26} = {BAF8F246-3645-42AD-B1D0-0F7EAFBAB34A}
+		{F24EB026-65FB-4247-ABF8-942B11ADAB64} = {BAF8F246-3645-42AD-B1D0-0F7EAFBAB34A}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {160A1D00-1F5B-40F8-A155-621B4459D78F}

tracer/src/Datadog.Trace/AspNetCoreAvailabilityChecker.cs

@@ -0,0 +1,41 @@
+// <copyright file="AspNetCoreAvailabilityChecker.cs" company="Datadog">
+// Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
+// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
+// </copyright>
+
+#if !NETFRAMEWORK
+
+using System;
+
+namespace Datadog.Trace;
+
+internal static class AspNetCoreAvailabilityChecker
+{
+    private static readonly Lazy<bool> IsAvailable = new(CheckForRequiredTypes);
+
+    private static bool CheckForRequiredTypes()
+    {
+        try
+        {
+            // Try to load the HttpContext type
+            // Assumes that this is only called when we would expect the type to
+            // already be loaded, for example inside an ASP.NET Core request.
+            // As this is only checked _once_, it assumes the customer doesn't call
+            // this API both _before_ ASP.NET Core types are loaded _and_ afterwards.
+            var httpContextType = Type.GetType("Microsoft.AspNetCore.Http.HttpContext, Microsoft.AspNetCore.Http.Abstractions", throwOnError: false);
+            return httpContextType is not null;
+        }
+        catch
+        {
+            // Problem loading the type, so assume we're not in aspnetcore
+            return false;
+        }
+    }
+
+    /// <summary>
+    /// Should be called when ASP.NET Core is expected to be loaded,
+    /// and checks if ASP.NET Core types are available
+    /// </summary>
+    public static bool IsAspNetCoreAvailable() => IsAvailable.Value;
+}
+#endif

tracer/src/Datadog.Trace/SpanExtensions.Core.cs

@@ -4,17 +4,9 @@
 // </copyright>
 #if !NETFRAMEWORK
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Runtime.CompilerServices;
 using Datadog.Trace.AppSec;
 using Datadog.Trace.AppSec.Coordinator;
-using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Mvc.Abstractions;
-using Microsoft.AspNetCore.Routing;
-using Microsoft.AspNetCore.Routing.Template;
 
 namespace Datadog.Trace
 {
@@ -27,9 +19,19 @@ private static void RunBlockingCheck(Span span, string userId)
         {
             var security = Security.Instance;
 
-            if (security.Enabled && CoreHttpContextStore.Instance.Get() is { } httpContext)
+            if (security.Enabled && AspNetCoreAvailabilityChecker.IsAspNetCoreAvailable())
             {
-                security.CheckUser(httpContext, span, userId);
+                RunBlockingCheckUnsafe(security, span, userId);
+            }
+
+            // Don't inline this, so we don't load the aspnetcore types if they're not available
+            [MethodImpl(MethodImplOptions.NoInlining)]
+            static void RunBlockingCheckUnsafe(Security security, Span span, string userId)
+            {
+                if (CoreHttpContextStore.Instance.Get() is { } httpContext)
+                {
+                    security.CheckUser(httpContext, span, userId);
+                }
             }
         }
     }

tracer/test/Datadog.Trace.ClrProfiler.IntegrationTests/ManualInstrumentationTests.cs

@@ -0,0 +1,60 @@
+// <copyright file="ManualInstrumentationTests.cs" company="Datadog">
+// Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
+// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
+// </copyright>
+
+using System.Threading.Tasks;
+using Datadog.Trace.TestHelpers;
+using FluentAssertions;
+using FluentAssertions.Execution;
+using VerifyXunit;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Datadog.Trace.ClrProfiler.IntegrationTests;
+
+[UsesVerify]
+public class ManualInstrumentationTests : TestHelper
+{
+    public ManualInstrumentationTests(ITestOutputHelper output)
+        : base("ManualInstrumentation", output)
+    {
+    }
+
+    [SkippableFact]
+    [Trait("RunOnWindows", "True")]
+    public async Task ManualAndAutomatic()
+    {
+        const int expectedSpans = 36;
+        using var telemetry = this.ConfigureTelemetry();
+        using var agent = EnvironmentHelper.GetMockAgent();
+        using var assert = new AssertionScope();
+        using var process = RunSampleAndWaitForExit(agent);
+
+        var spans = agent.WaitForSpans(expectedSpans);
+        spans.Should().HaveCount(expectedSpans);
+
+        var settings = VerifyHelper.GetSpanVerifierSettings();
+
+        await VerifyHelper.VerifySpans(spans, settings);
+    }
+
+    [SkippableFact]
+    [Trait("RunOnWindows", "True")]
+    public async Task ManualOnly()
+    {
+        EnvironmentHelper.SetAutomaticInstrumentation(false);
+        const int expectedSpans = 29;
+        using var telemetry = this.ConfigureTelemetry();
+        using var agent = EnvironmentHelper.GetMockAgent();
+        using var assert = new AssertionScope();
+        using var process = RunSampleAndWaitForExit(agent);
+
+        var spans = agent.WaitForSpans(expectedSpans);
+        spans.Should().HaveCount(expectedSpans);
+
+        var settings = VerifyHelper.GetSpanVerifierSettings();
+
+        await VerifyHelper.VerifySpans(spans, settings);
+    }
+}