Adds targeting middleware and targeting initializer

Microsoft.FeatureManagement.sln

@@ -27,6 +27,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.FeatureManagement
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "EvaluationDataToApplicationInsights", "examples\EvaluationDataToApplicationInsights\EvaluationDataToApplicationInsights.csproj", "{1502529E-47E9-4306-98C4-BF6CF7C7C275}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore", "src\Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore\Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore.csproj", "{C647611B-A8E5-4AD7-9DBA-60DDE276644B}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -73,6 +75,10 @@ Global
 		{1502529E-47E9-4306-98C4-BF6CF7C7C275}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1502529E-47E9-4306-98C4-BF6CF7C7C275}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1502529E-47E9-4306-98C4-BF6CF7C7C275}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C647611B-A8E5-4AD7-9DBA-60DDE276644B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C647611B-A8E5-4AD7-9DBA-60DDE276644B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C647611B-A8E5-4AD7-9DBA-60DDE276644B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C647611B-A8E5-4AD7-9DBA-60DDE276644B}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/Microsoft.FeatureManagement.AspNetCore/TargetingHttpContextMiddleware.cs

@@ -0,0 +1,63 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+using Microsoft.FeatureManagement.FeatureFilters;
+using System;
+using System.Threading.Tasks;
+
+namespace Microsoft.FeatureManagement
+{
+    /// <summary>
+    /// Used to add targeting information to HTTP context.
+    /// </summary>
+    public class TargetingHttpContextMiddleware
+    {
+        private readonly RequestDelegate _next;
+        private readonly ILogger _logger;
+
+        private const string TargetingIdKey = $"Microsoft.FeatureManagement.TargetingId";
+
+        /// <summary>
+        /// Creates an instance of the TargetingHttpContextMiddleware
+        /// </summary>
+        public TargetingHttpContextMiddleware(RequestDelegate next, ILoggerFactory loggerFactory) {
+            _next = next ?? throw new ArgumentNullException(nameof(next));
+            _logger = loggerFactory?.CreateLogger<TargetingHttpContextMiddleware>() ?? throw new ArgumentNullException(nameof(loggerFactory));
+        }
+
+        /// <summary>
+        /// Adds targeting information to the HTTP context.
+        /// </summary>
+        /// <param name="context">The <see cref="HttpContext"/> to add the targeting information to.</param>
+        /// <param name="targetingContextAccessor">The <see cref="ITargetingContextAccessor"/> to retrieve the targeting information from.</param>
+        /// <exception cref="ArgumentNullException">Thrown if the provided context or targetingContextAccessor is null.</exception>
+        public async Task InvokeAsync(HttpContext context, ITargetingContextAccessor targetingContextAccessor)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            if (targetingContextAccessor == null)
+            {
+                throw new ArgumentNullException(nameof(targetingContextAccessor));
+            }
+
+            TargetingContext targetingContext = await targetingContextAccessor.GetContextAsync().ConfigureAwait(false);
+
+            if (targetingContext != null)
+            {
+                context.Items[TargetingIdKey] = targetingContext.UserId;
+            }
+            else
+            {
+                _logger.LogDebug("The targeting context accessor returned a null TargetingContext");
+            }
+
+            await _next(context);
+        }
+    }
+}

src/Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore/Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore.csproj

@@ -0,0 +1,51 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <Import Project="..\..\build\NugetProperties.props" />
+
+  <!-- Official Version -->
+  <PropertyGroup>
+    <MajorVersion>4</MajorVersion>
+    <MinorVersion>0</MinorVersion>
+    <PatchVersion>0</PatchVersion>
+    <PreviewVersion>-preview</PreviewVersion>
+  </PropertyGroup>
+
+  <Import Project="..\..\build\Versioning.props" />
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\build\Microsoft.FeatureManagement.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <Description>Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore provides a solution for tagging Application Insights telemetry with Microsoft.FeatureManagement targeting information.</Description>
+    <Authors>Microsoft</Authors>
+    <Company>Microsoft</Company>
+    <PackageLicenseUrl>https://licenses.nuget.org/MIT</PackageLicenseUrl>
+    <PackageProjectUrl>https://github.com/Azure/AppConfiguration</PackageProjectUrl>
+    <PackageReleaseNotes>Release notes can be found at https://aka.ms/MicrosoftFeatureManagementReleaseNotes</PackageReleaseNotes>
+    <PackageTags>Microsoft FeatureManagement FeatureFlags ApplicationInsights</PackageTags>
+    <PackageIconUrl>https://aka.ms/AzureAppConfigurationPackageIcon</PackageIconUrl>
+    <Copyright>© Microsoft Corporation. All rights reserved.</Copyright>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.ApplicationInsights" Version="2.22.0" />
+    <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.22.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Microsoft.FeatureManagement\Microsoft.FeatureManagement.csproj" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\XMLComments\$(MSBuildProjectName).xml</DocumentationFile>
+  </PropertyGroup>
+
+  <Target Name="PrepublishScript" BeforeTargets="PrepareForPublish">
+    <Copy SourceFiles="$(DocumentationFile)" DestinationFolder="$(OutDir)\XMLComments" SkipUnchangedFiles="false" />
+  </Target>
+
+</Project>

src/Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore/TargetingTelemetryInitializer.cs

@@ -0,0 +1,63 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+
+using Microsoft.ApplicationInsights.AspNetCore.TelemetryInitializers;
+using Microsoft.ApplicationInsights.Channel;
+using Microsoft.ApplicationInsights.DataContracts;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.FeatureManagement.Telemetry.ApplicationInsights.AspNetCore
+{
+    /// <summary>
+    /// Used to add targeting information to outgoing Application Insights telemetry.
+    /// </summary>
+    public class TargetingTelemetryInitializer : TelemetryInitializerBase
+    {
+        private const string TargetingIdKey = $"Microsoft.FeatureManagement.TargetingId";
+
+        /// <summary>
+        /// Creates an instance of the TargetingTelemetryInitializer
+        /// </summary>
+        public TargetingTelemetryInitializer(IHttpContextAccessor httpContextAccessor) : base(httpContextAccessor)
+        {
+        }
+
+        /// <summary>
+        /// When telemetry is initialized, adds targeting information to all relevant telemetry.
+        /// </summary>
+        /// <param name="httpContext">The <see cref="HttpContext"/> to get the targeting information from.</param>
+        /// <param name="requestTelemetry">The <see cref="RequestTelemetry"/> relevant to the telemetry.</param>
+        /// <param name="telemetry">The <see cref="ITelemetry"/> to be initialized.</param>
+        /// <exception cref="ArgumentNullException">Thrown if the any param is null.</exception>
+        protected override void OnInitializeTelemetry(HttpContext httpContext, RequestTelemetry requestTelemetry, ITelemetry telemetry)
+        {
+            if (telemetry == null)
+            {
+                throw new ArgumentNullException("telemetry");
+            }
+
+            if (httpContext == null)
+            {
+                throw new ArgumentNullException("httpContext");
+            }
+
+            // Extract the targeting id from the http context
+            string targetingId = null;
+
+            if (httpContext.Items.TryGetValue(TargetingIdKey, out object value))
+            {
+                targetingId = value?.ToString();
+            }
+
+            if (!string.IsNullOrEmpty(targetingId))
+            {
+                // Telemetry.Properties is deprecated in favor of ISupportProperties
+                if (telemetry is ISupportProperties telemetryWithSupportProperties)
+                {
+                    telemetryWithSupportProperties.Properties["TargetingId"] = targetingId;
+                }
+            }
+        }
+    }
+}