Teach OOP how to MEF (#9953)

I'm mainly putting this up so @DustinCampbell can tell me what I did
wrong :)

As part of cohosting we're going to need a lot more things to run in
OOP, so its probably best to move away from these hand-constructed
services that it has. This PR introduced MEF, in a reasonably
unsophisticated way, into the procedure so that services can at least
get some things from an `ExportProvider`. Once in that world, obviously
everything works as expected with attributes etc.

Along the way I also found that our telemetry reporting in OOP wasn't
doing anything, so fixed that and moved it to the MEF composition too.
Also improved the `launchSettings.json` file a little, and found it was
previously in the `.gitignore`. This seemed wrong to me, but maybe
@dotnet/razor-compiler will have something different to say about that?
I can always move the compiler one back in if necessary.

Part of #9519

.gitignore

@@ -12,7 +12,6 @@
 *.user
 *.userosscache
 *.sln.docstates
-launchSettings.json
 
 # Build results
 artifacts/

src/Compiler/perf/Microsoft.AspNetCore.Razor.Microbenchmarks.Generator/SampleApp/Properties/launchSettings.json

@@ -0,0 +1,12 @@
+{
+  "profiles": {
+    "SampleApp": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+      "applicationUrl": "https://localhost:53331;http://localhost:53332"
+    }
+  }
+}

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/Microsoft.CodeAnalysis.Remote.Razor.csproj

@@ -23,6 +23,10 @@
     <ProjectReference Include="..\Microsoft.CodeAnalysis.Razor.Workspaces\Microsoft.CodeAnalysis.Razor.Workspaces.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Compile Include="..\Microsoft.VisualStudio.Editor.Razor\Telemetry\TelemetryReporter.cs" Link="Telemetry\TelemetryReporter.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <!--
       Pinning packages to avoid misaligned reference CI failures.

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/RazorServiceFactoryBase.ExportProvider.cs

@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+using System.Reflection;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.Composition;
+using Microsoft.VisualStudio.Threading;
+
+namespace Microsoft.CodeAnalysis.Remote.Razor;
+
+internal abstract partial class RazorServiceFactoryBase<TService>
+{
+    internal static readonly ImmutableArray<Assembly> RemoteHostAssemblies = [typeof(RazorServiceFactoryBase<TService>).Assembly];
+
+#pragma warning disable VSTHRD012 // Provide JoinableTaskFactory where allowed
+    private static readonly AsyncLazy<ExportProvider> s_exportProviderLazy = new(GetExportProviderAsync);
+#pragma warning restore VSTHRD012 // Provide JoinableTaskFactory where allowed
+
+    // Inspired by https://github.com/dotnet/roslyn/blob/25aa74d725e801b8232dbb3e5abcda0fa72da8c5/src/Workspaces/Remote/ServiceHub/Host/RemoteWorkspaceManager.cs#L77
+    private static async Task<ExportProvider> GetExportProviderAsync()
+    {
+        var resolver = Resolver.DefaultInstance;
+        var discovery = new AttributedPartDiscovery(resolver, isNonPublicSupported: true); // MEFv2 only
+        var parts = await discovery.CreatePartsAsync(RemoteHostAssemblies).ConfigureAwait(false);
+        var catalog = ComposableCatalog.Create(resolver).AddParts(parts);
+
+        var configuration = CompositionConfiguration.Create(catalog).ThrowOnErrors();
+        var runtimeComposition = RuntimeComposition.CreateRuntimeComposition(configuration);
+        var exportProviderFactory = runtimeComposition.CreateExportProviderFactory();
+        return exportProviderFactory.CreateExportProvider();
+    }
+}

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/RazorServiceFactoryBase.cs

@@ -5,10 +5,10 @@
 using System.IO;
 using System.IO.Pipelines;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 using Microsoft.ServiceHub.Framework;
 using Microsoft.ServiceHub.Framework.Services;
+using Microsoft.VisualStudio.Composition;
 using Nerdbank.Streams;
 
 namespace Microsoft.CodeAnalysis.Remote.Razor;
@@ -19,10 +19,9 @@ namespace Microsoft.CodeAnalysis.Remote.Razor;
 /// <remarks>
 /// Implementors of <see cref="IServiceHubServiceFactory" /> (and thus this class) MUST provide a parameterless constructor or ServiceHub will fail to construct them.
 /// </remarks>
-internal abstract class RazorServiceFactoryBase<TService> : IServiceHubServiceFactory where TService : class
+internal abstract partial class RazorServiceFactoryBase<TService> : IServiceHubServiceFactory where TService : class
 {
     private readonly RazorServiceDescriptorsWrapper _razorServiceDescriptors;
-    private ITelemetryReporter? _telemetryReporter;
 
     /// <summary>
     /// </summary>
@@ -45,23 +44,23 @@ public Task<object> CreateAsync(
         // Dispose the AuthorizationServiceClient since we won't be using it
         authorizationServiceClient?.Dispose();
 
-        _telemetryReporter = (ITelemetryReporter)hostProvidedServices.GetService(typeof(ITelemetryReporter));
-
-        return Task.FromResult((object)Create(stream.UsePipe(), serviceBroker));
+        return CreateAsync(stream.UsePipe(), serviceBroker);
     }
 
-    internal TService Create(IDuplexPipe pipe, IServiceBroker serviceBroker)
+    private async Task<object> CreateAsync(IDuplexPipe pipe, IServiceBroker serviceBroker)
     {
         var descriptor = _razorServiceDescriptors.GetDescriptorForServiceFactory(typeof(TService));
         var serverConnection = descriptor.ConstructRpcConnection(pipe);
 
-        var service = CreateService(serviceBroker, _telemetryReporter ?? NoOpTelemetryReporter.Instance);
+        var exportProvider = await s_exportProviderLazy.GetValueAsync().ConfigureAwait(false);
+
+        var service = CreateService(serviceBroker, exportProvider);
 
         serverConnection.AddLocalRpcTarget(service);
         serverConnection.StartListening();
 
         return service;
     }
 
-    protected abstract TService CreateService(IServiceBroker serviceBroker, ITelemetryReporter telemetryReporter);
+    protected abstract TService CreateService(IServiceBroker serviceBroker, ExportProvider exportProvider);
 }

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/RemoteTagHelperDeltaProvider.cs

@@ -2,11 +2,13 @@
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
 using System.Collections.Immutable;
+using System.Composition;
 using Microsoft.AspNetCore.Razor.Serialization;
 using Microsoft.AspNetCore.Razor.Utilities;
 
 namespace Microsoft.CodeAnalysis.Remote.Razor;
 
+[Export(typeof(RemoteTagHelperDeltaProvider)), Shared]
 internal class RemoteTagHelperDeltaProvider
 {
     private readonly TagHelperResultCache _resultCache = new();

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/RemoteTagHelperProviderService.cs

@@ -4,14 +4,15 @@
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.AspNetCore.Razor.Serialization;
-using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor.Api;
 using Microsoft.ServiceHub.Framework;
+using Microsoft.VisualStudio.Composition;
 
 namespace Microsoft.CodeAnalysis.Remote.Razor;
 
@@ -20,11 +21,11 @@ internal sealed class RemoteTagHelperProviderService : RazorServiceBase, IRemote
     private readonly RemoteTagHelperResolver _tagHelperResolver;
     private readonly RemoteTagHelperDeltaProvider _tagHelperDeltaProvider;
 
-    internal RemoteTagHelperProviderService(IServiceBroker serviceBroker, ITelemetryReporter telemetryReporter)
+    internal RemoteTagHelperProviderService(IServiceBroker serviceBroker, ExportProvider exportProvider)
         : base(serviceBroker)
     {
-        _tagHelperResolver = new RemoteTagHelperResolver(telemetryReporter);
-        _tagHelperDeltaProvider = new RemoteTagHelperDeltaProvider();
+        _tagHelperResolver = exportProvider.GetExportedValue<RemoteTagHelperResolver>().AssumeNotNull();
+        _tagHelperDeltaProvider = exportProvider.GetExportedValue<RemoteTagHelperDeltaProvider>().AssumeNotNull();
     }
 
     public ValueTask<FetchTagHelpersResult> FetchTagHelpersAsync(

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/RemoteTagHelperProviderServiceFactory.cs

@@ -1,8 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.ServiceHub.Framework;
+using Microsoft.VisualStudio.Composition;
 
 namespace Microsoft.CodeAnalysis.Remote.Razor;
 
@@ -14,6 +14,6 @@ public RemoteTagHelperProviderServiceFactory()
     {
     }
 
-    protected override IRemoteTagHelperProviderService CreateService(IServiceBroker serviceBroker, ITelemetryReporter telemetryReporter)
-        => new RemoteTagHelperProviderService(serviceBroker, telemetryReporter);
+    protected override IRemoteTagHelperProviderService CreateService(IServiceBroker serviceBroker, ExportProvider exportProvider)
+        => new RemoteTagHelperProviderService(serviceBroker, exportProvider);
 }

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/RemoteTagHelperResolver.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Composition;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
@@ -13,6 +14,8 @@
 
 namespace Microsoft.CodeAnalysis.Remote.Razor;
 
+[Export(typeof(RemoteTagHelperResolver)), Shared]
+[method: ImportingConstructor]
 internal class RemoteTagHelperResolver(ITelemetryReporter telemetryReporter)
 {
     /// <summary>

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/Telemetry/OutOfProcessTelemetryReporter.cs

@@ -0,0 +1,17 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Composition;
+using Microsoft.AspNetCore.Razor.Telemetry;
+using Microsoft.VisualStudio.Telemetry;
+
+namespace Microsoft.CodeAnalysis.Remote.Razor.Telemetry;
+
+[Export(typeof(ITelemetryReporter)), Shared]
+internal class OutOfProcessTelemetryReporter : TelemetryReporter
+{
+    public OutOfProcessTelemetryReporter()
+        : base([TelemetryService.DefaultSession])
+    {
+    }
+}

src/Razor/src/Microsoft.VisualStudio.RazorExtension/Properties/launchSettings.json

@@ -0,0 +1,23 @@
+{
+  "profiles": {
+    "Razor": {
+      "commandName": "Project",
+      "environmentVariables": {
+        "CPS_DiagnosticRuntime": "1",
+        "CPS_MetricsCollection": "1",
+        "ServiceHubTraceLevel": "All",
+      },
+      "nativeDebugging": true
+    },
+    "Razor (with ServiceHub debugging)": {
+      "commandName": "Project",
+      "environmentVariables": {
+        "CPS_DiagnosticRuntime": "1",
+        "CPS_MetricsCollection": "1",
+        "ServiceHubTraceLevel": "All",
+        "SERVICEHUBDEBUGHOSTONSTARTUP": "ServiceHub.RoslynCodeAnalysisService.exe"
+      },
+      "nativeDebugging": true
+    }
+  }
+}