Add Razor language server telemetry to C# DevKit

Razor.sln

@@ -177,6 +177,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.Razor.
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.Razor.ProjectEngineHost.Test", "src\Razor\test\Microsoft.AspNetCore.Razor.ProjectEngineHost.Test\Microsoft.AspNetCore.Razor.ProjectEngineHost.Test.csproj", "{4126E0A6-1CA9-44B1-AD22-66EDB9FEE7AD}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.VisualStudio.DevKit.Razor", "src\Razor\src\Microsoft.VisualStudio.DevKit.Razor\Microsoft.VisualStudio.DevKit.Razor.csproj", "{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -737,6 +739,14 @@ Global
 		{4126E0A6-1CA9-44B1-AD22-66EDB9FEE7AD}.Release|Any CPU.Build.0 = Release|Any CPU
 		{4126E0A6-1CA9-44B1-AD22-66EDB9FEE7AD}.ReleaseNoVSIX|Any CPU.ActiveCfg = Release|Any CPU
 		{4126E0A6-1CA9-44B1-AD22-66EDB9FEE7AD}.ReleaseNoVSIX|Any CPU.Build.0 = Release|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.DebugNoVSIX|Any CPU.ActiveCfg = Debug|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.DebugNoVSIX|Any CPU.Build.0 = Debug|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.ReleaseNoVSIX|Any CPU.ActiveCfg = Release|Any CPU
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB}.ReleaseNoVSIX|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -818,6 +828,7 @@ Global
 		{53977089-1A87-4521-8368-0D50DFDA1279} = {3C0D6505-79B3-49D0-B4C3-176F0F1836ED}
 		{C0C2AD17-5F5B-4B11-956D-203D91C377FB} = {92463391-81BE-462B-AC3C-78C6C760741F}
 		{4126E0A6-1CA9-44B1-AD22-66EDB9FEE7AD} = {92463391-81BE-462B-AC3C-78C6C760741F}
+		{0F2D75D1-89AD-40A6-9F02-D45708AEA3EB} = {3C0D6505-79B3-49D0-B4C3-176F0F1836ED}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {0035341D-175A-4D05-95E6-F1C2785A1E26}

eng/AfterSigning.targets

@@ -41,4 +41,35 @@
     <!-- Build a .zip file from each platform's directory and write it to 'artifacts' -->
     <ZipDirectory SourceDirectory="%(LanguageServiceBinary.SourceDir)" DestinationFile="%(LanguageServiceBinary.ZipFile)" />
   </Target>
+
+  <Target Name="_ZipDevKitTelemetryBinaries" AfterTargets="_ZipLanguageServerBinaries" Condition="'$(ArcadeBuildFromSource)' != 'true'">
+    <!-- This target is defined in eng/targets/Packaging.targets and included in every project. -->
+    <MSBuild Projects="$(RepoRoot)src\Razor\src\Microsoft.VisualStudio.DevKit.Razor\Microsoft.VisualStudio.DevKit.Razor.csproj"
+        Targets="_GetPackageVersionInfo"
+        SkipNonexistentProjects="false">
+      <Output TaskParameter="TargetOutputs" ItemName="_ResolvedPackageVersionInfo" />
+    </MSBuild>
+
+    <!-- Build a .zip file from each platform's directory and write it to 'artifacts' -->
+    <PropertyGroup>
+      <RidsPublishDir>$(ArtifactsDir)DevKitTelemetry\$(Configuration)\</RidsPublishDir>
+      <ZipOutputDir>$(RidsPublishDir)</ZipOutputDir>
+      <_DotNetPath>$(DOTNET_HOST_PATH)</_DotNetPath>
+      <_DotNetPath Condition="'$(_DotNetPath)' == ''">dotnet</_DotNetPath>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <DevKitTelemetryBinaryDir Include="$([System.IO.Directory]::GetDirectories(&quot;$(RidsPublishDir)&quot;))" />
+      <DevKitTelemetryBinary Include="@(DevKitTelemetryBinaryDir)">
+        <SourceDir>%(DevKitTelemetryBinaryDir.Identity)</SourceDir>
+        <ZipFile>$(ZipOutputDir)DevKitTelemetry-%(DevKitTelemetryBinaryDir.Filename)-$(_PackageVersion).zip</ZipFile>
+      </DevKitTelemetryBinary>
+    </ItemGroup>
+
+    <MakeDir Directories="$(ZipOutputDir)" />
+    <Delete Files="%(DevKitTelemetryBinary.ZipFile)" />
+
+    <!-- Build a .zip file from each platform's directory and write it to 'artifacts' -->
+    <ZipDirectory SourceDirectory="%(DevKitTelemetryBinary.SourceDir)" DestinationFile="%(DevKitTelemetryBinary.ZipFile)" />
+  </Target>
 </Project>

eng/AfterSolutionBuild.targets

@@ -12,4 +12,16 @@
              Targets="PublishAllRids" />
   </Target>
 
+  <Target Name="_PublishDevKitTelemetryRids" AfterTargets="Pack" Condition="'$(DotNetBuildFromSource)' != 'true'">
+    <PropertyGroup>
+      <DevKitTelemetryProject>$(MSBuildThisFileDirectory)..\src\Razor\src\Microsoft.VisualStudio.DevKit.Razor\Microsoft.VisualStudio.DevKit.Razor.csproj</DevKitTelemetryProject>
+      <RazorSolutionPath>$(MSBuildThisFileDirectory)..\Razor.sln</RazorSolutionPath>
+    </PropertyGroup>
+
+    <MSBuild Projects="$(RazorSolutionPath)"
+             Targets="Restore" />
+    <MSBuild Projects="$(DevKitTelemetryProject)"
+             Targets="PublishAllRids" />
+  </Target>
+
 </Project>

eng/Publishing.props

@@ -8,8 +8,8 @@
 
   <ItemGroup>
     <!-- Prepare for _UpdatePublishItems target. -->
-    <_ItemsToPublish Include="$(ArtifactsPackagesDir)**\*.tgz" Condition="'$(OS)' == 'Windows_NT'" />
     <_ItemsToPublish Include="$(ArtifactsDir)LanguageServer\**\*.zip" />
+    <_ItemsToPublish Include="$(ArtifactsDir)DevKitTelemetry\**\*.zip" />
   </ItemGroup>
 
 <Target Name="_UpdatePublishItems">
@@ -28,7 +28,7 @@
       <!-- Packages can be built on all platforms, but are only published on Windows to avoid collisions from the other
            platforms. This does not affect the SB intermediate package. -->
       <ItemsToPushToBlobFeed Remove="$(ArtifactsDir)**\*.nupkg" Condition="'$(OS)' != 'Windows_NT' and '$(ArcadeBuildFromSource)' != 'true'" />
-      
+
       <ItemsToPushToBlobFeed Include="@(_ItemsToPublish)">
         <IsShipping>false</IsShipping>
         <ManifestArtifactData>ShipInstaller=dotnetcli;NonShipping=true</ManifestArtifactData>

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Exports/AssemblyLoadContextWrapper.cs

@@ -0,0 +1,176 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+#if !NET472
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Reflection;
+using System.Runtime.Loader;
+using Microsoft.Extensions.Internal;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Exports;
+
+internal sealed class AssemblyLoadContextWrapper
+{
+    private static readonly ConcurrentDictionary<AssemblyName, Assembly?> s_loadedSharedAssemblies = new(AssemblyNameComparer.Default);
+
+    private AssemblyLoadContext? _assemblyLoadContext;
+    private readonly ImmutableDictionary<string, Assembly> _loadedAssemblies;
+
+    private AssemblyLoadContextWrapper(AssemblyLoadContext assemblyLoadContext, ImmutableDictionary<string, Assembly> loadedFiles)
+    {
+        _assemblyLoadContext = assemblyLoadContext;
+        _loadedAssemblies = loadedFiles;
+    }
+
+    public static bool TryLoadExtension(string assemblyFilePath, string? sharedDependenciesPath, [NotNullWhen(true)] out Assembly? assembly)
+    {
+        var dir = Path.GetDirectoryName(assemblyFilePath);
+        var fileName = Path.GetFileName(assemblyFilePath);
+        var fileNameNoExt = Path.GetFileNameWithoutExtension(assemblyFilePath);
+
+        var loadContext = TryCreate(fileNameNoExt, dir!, sharedDependenciesPath);
+        if (loadContext != null)
+        {
+            assembly = loadContext.GetAssembly(fileName);
+            return true;
+        }
+
+        assembly = null;
+        return false;
+    }
+
+    public static AssemblyLoadContextWrapper? TryCreate(string name, string assembliesDirectoryPath, string? sharedDependenciesPath)
+    {
+        try
+        {
+            var loadContext = CreateLoadContext(name, sharedDependenciesPath);
+            var directory = new DirectoryInfo(assembliesDirectoryPath);
+            var builder = new Dictionary<string, Assembly>();
+            foreach (var file in directory.GetFiles("*.dll"))
+            {
+                // HACK: For some reason trying to load ProjectEngineHost here causes a second version of the
+                // expected dll to be loaded (one from rzls folder instead of the Razor telemetry folder). We'll
+                // skip loading it (and investigate later) since the one from the Razor telemetry folder is the
+                // one we want.
+                if (!file.Name.Contains("ProjectEngineHost"))
+                {
+                    builder.Add(file.Name, loadContext.LoadFromAssemblyPath(file.FullName));
+                }
+            }
+
+            return new AssemblyLoadContextWrapper(loadContext, builder.ToImmutableDictionary());
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private static AssemblyLoadContext CreateLoadContext(string name, string? sharedDependenciesPath)
+    {
+        var loadContext = new AssemblyLoadContext(name);
+
+        if (sharedDependenciesPath != null)    
+        {
+            loadContext.Resolving += (_, assemblyName) =>
+            {
+                if (assemblyName.Name is null)
+                {
+                    return null;
+                }
+
+                if (s_loadedSharedAssemblies.TryGetValue(assemblyName, out var loadedAssembly))
+                {
+                    return loadedAssembly;
+                }
+
+                var candidatePath = assemblyName.CultureName is not null
+                    ? Path.Combine(sharedDependenciesPath, assemblyName.CultureName, $"{assemblyName.Name}.dll")
+                    : Path.Combine(sharedDependenciesPath, $"{assemblyName.Name}.dll");
+
+                if (File.Exists(candidatePath))
+                {
+                    loadedAssembly = loadContext.LoadFromAssemblyPath(candidatePath);
+                }
+
+                s_loadedSharedAssemblies.TryAdd(assemblyName, loadedAssembly);
+
+                return s_loadedSharedAssemblies[assemblyName];
+            };
+        }
+
+        return loadContext;
+    }
+
+    public Assembly GetAssembly(string name) => _loadedAssemblies[name];
+
+    public MethodInfo? TryGetMethodInfo(string assemblyName, string className, string methodName)
+    {
+        try
+        {
+            return GetMethodInfo(assemblyName, className, methodName);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    public MethodInfo GetMethodInfo(string assemblyName, string className, string methodName)
+    {
+        var assembly = GetAssembly(assemblyName);
+        var completionHelperType = assembly.GetType(className);
+        if (completionHelperType == null)
+        {
+            throw new ArgumentException($"{assembly.FullName} assembly did not contain {className} class");
+        }
+        var createCompletionProviderMethodInto = completionHelperType?.GetMethod(methodName);
+        if (createCompletionProviderMethodInto == null)
+        {
+            throw new ArgumentException($"{className} from {assembly.FullName} assembly did not contain {methodName} method");
+        }
+        return createCompletionProviderMethodInto;
+    }
+
+    public void Dispose()
+    {
+        _assemblyLoadContext?.Unload();
+        _assemblyLoadContext = null;
+    }
+
+    private sealed class AssemblyNameComparer : IEqualityComparer<AssemblyName>
+    {
+        public static readonly AssemblyNameComparer Default = new();
+
+        public bool Equals(AssemblyName? x, AssemblyName? y)
+        {
+            if (ReferenceEquals(x, y))
+                return true;
+
+            if (x == null || y == null)
+                return false;
+
+            return string.Equals(x.Name, y.Name, StringComparison.OrdinalIgnoreCase)
+                && string.Equals(x.CultureName, y.CultureName, StringComparison.OrdinalIgnoreCase);
+        }
+
+        public int GetHashCode(AssemblyName obj)
+        {
+            var hashCodeCombiner = new HashCodeCombiner();
+            hashCodeCombiner.Add(new int[] {
+                StringComparer.OrdinalIgnoreCase.GetHashCode(obj.Name ?? string.Empty),
+                StringComparer.OrdinalIgnoreCase.GetHashCode(obj.CultureName ?? string.Empty)
+            });
+
+            return hashCodeCombiner.CombinedHash;
+        }
+    }
+}
+
+#endif

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Exports/CustomExportAssemblyLoader.cs

@@ -0,0 +1,96 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Reflection;
+using Microsoft.VisualStudio.Composition;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Exports;
+
+internal class CustomExportAssemblyLoader(string baseDirectory) : IAssemblyLoader
+{
+    /// <summary>
+    /// Cache assemblies that are already loaded by AssemblyName comparison
+    /// </summary>
+    private readonly Dictionary<AssemblyName, Assembly> _loadedAssemblies = new Dictionary<AssemblyName, Assembly>(AssemblyNameComparer.Instance);
+
+    /// <summary>
+    /// Base directory to search for <see cref="Assembly.LoadFrom(string)"/> if initial load fails
+    /// </summary>
+    private readonly string _baseDirectory = baseDirectory;
+
+    public Assembly LoadAssembly(AssemblyName assemblyName)
+    {
+        Assembly? value;
+        lock (_loadedAssemblies)
+        {
+            _loadedAssemblies.TryGetValue(assemblyName, out value);
+        }
+
+        if (value == null)
+        {
+            // Attempt to load the assembly normally, but fall back to Assembly.LoadFrom in the base
+            // directory if the assembly load fails
+            try
+            {
+                value = Assembly.Load(assemblyName);
+            }
+            catch (FileNotFoundException) when (assemblyName.Name is not null)
+            {
+                var filePath = Path.Combine(_baseDirectory, assemblyName.Name)
+                    + (assemblyName.Name.EndsWith(".dll", StringComparison.OrdinalIgnoreCase)
+                        ? ""
+                        : ".dll");
+
+                value = Assembly.LoadFrom(filePath);
+
+                if (value is null)
+                {
+                    throw;
+                }
+            }
+
+            lock (_loadedAssemblies)
+            {
+                _loadedAssemblies[assemblyName] = value;
+                return value;
+            }
+        }
+
+        return value;
+    }
+
+    public Assembly LoadAssembly(string assemblyFullName, string? codeBasePath)
+    {
+        var assemblyName = new AssemblyName(assemblyFullName);
+        return LoadAssembly(assemblyName);
+    }
+
+    private class AssemblyNameComparer : IEqualityComparer<AssemblyName>
+    {
+        public static AssemblyNameComparer Instance = new AssemblyNameComparer();
+
+        public bool Equals(AssemblyName? x, AssemblyName? y)
+        {
+            if (x == null && y == null)
+            {
+                return true;
+            }
+
+            if (x == null || y == null)
+            {
+                return false;
+            }
+
+            return x.Name == y.Name;
+        }
+
+        public int GetHashCode([DisallowNull] AssemblyName obj)
+        {
+            return obj.Name?.GetHashCode() ?? 0;
+        }
+    }
+}