Log telemetry for tag helper discovery

Author: davidwengier

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/DefaultProjectWorkspaceStateGenerator.cs

@@ -9,7 +9,9 @@
 using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Workspaces;
@@ -19,31 +21,20 @@ namespace Microsoft.CodeAnalysis.Razor;
 [Shared]
 [Export(typeof(ProjectWorkspaceStateGenerator))]
 [Export(typeof(IProjectSnapshotChangeTrigger))]
-internal class DefaultProjectWorkspaceStateGenerator : ProjectWorkspaceStateGenerator, IDisposable
+[method: ImportingConstructor]
+internal class DefaultProjectWorkspaceStateGenerator(ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher, ITelemetryReporter telemetryReporter) : ProjectWorkspaceStateGenerator, IDisposable
 {
     // Internal for testing
-    internal readonly Dictionary<ProjectKey, UpdateItem> Updates;
+    internal readonly Dictionary<ProjectKey, UpdateItem> Updates = new();
+
+    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher ?? throw new ArgumentNullException(nameof(projectSnapshotManagerDispatcher));
+    private readonly ITelemetryReporter _telemetryReporter = telemetryReporter ?? throw new ArgumentNullException(nameof(telemetryReporter));
+    private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(initialCount: 1);
 
-    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher;
-    private readonly SemaphoreSlim _semaphore;
     private ProjectSnapshotManagerBase _projectManager;
     private ITagHelperResolver _tagHelperResolver;
     private bool _disposed;
 
-    [ImportingConstructor]
-    public DefaultProjectWorkspaceStateGenerator(ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher)
-    {
-        if (projectSnapshotManagerDispatcher is null)
-        {
-            throw new ArgumentNullException(nameof(projectSnapshotManagerDispatcher));
-        }
-
-        _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher;
-
-        _semaphore = new SemaphoreSlim(initialCount: 1);
-        Updates = new Dictionary<ProjectKey, UpdateItem>();
-    }
-
     // Used in unit tests to ensure we can control when background work starts.
     public ManualResetEventSlim BlockBackgroundWorkStart { get; set; }
 
@@ -134,6 +125,12 @@ private async Task UpdateWorkspaceStateAsync(Project workspaceProject, IProjectS
             return;
         }
 
+        // Specifically not using BeginBlock because we want to capture cases where tag helper discovery never finishes.
+        var telemetryId = Guid.NewGuid();
+        _telemetryReporter.ReportEvent("taghelperresolve/begin", Severity.Normal,
+            new Property("id", telemetryId),
+            new Property("tagHelperCount", projectSnapshot.ProjectWorkspaceState?.TagHelpers.Length ?? 0));
+
         try
         {
             // Only allow a single TagHelper resolver request to process at a time in order to reduce Visual Studio memory pressure. Typically a TagHelper resolution result can be upwards of 10mb+.
@@ -173,17 +170,35 @@ private async Task UpdateWorkspaceStateAsync(Project workspaceProject, IProjectS
                         csharpLanguageVersion = csharpParseOptions.LanguageVersion;
                     }
 
+                    using var _ = StopwatchPool.GetPooledObject(out var watch);
+
+                    watch.Restart();
                     var tagHelpers = await _tagHelperResolver.GetTagHelpersAsync(workspaceProject, projectSnapshot, cancellationToken).ConfigureAwait(false);
+                    watch.Stop();
+
+                    _telemetryReporter.ReportEvent("taghelperresolve/end", Severity.Normal,
+                        new Property("id", telemetryId),
+                        new Property("ellapsedms", watch.ElapsedMilliseconds),
+                        new Property("result", "success"),
+                        new Property("tagHelperCount", tagHelpers.Length));
+
                     workspaceState = new ProjectWorkspaceState(tagHelpers, csharpLanguageVersion);
                 }
             }
             catch (OperationCanceledException)
             {
                 // Abort work if we get a task cancelled exception
+                _telemetryReporter.ReportEvent("taghelperresolve/end", Severity.Normal,
+                    new Property("id", telemetryId),
+                    new Property("result", "cancel"));
                 return;
             }
             catch (Exception ex)
             {
+                _telemetryReporter.ReportEvent("taghelperresolve/end", Severity.Normal,
+                    new Property("id", telemetryId),
+                    new Property("result", "error"));
+
                 await _projectSnapshotManagerDispatcher.RunOnDispatcherThreadAsync(
                    () => _projectManager.ReportError(ex, projectSnapshot),
                    // Don't allow errors to be cancelled

src/Razor/test/Microsoft.VisualStudio.Editor.Razor.Test/DefaultProjectWorkspaceStateGeneratorTest.cs

@@ -11,6 +11,7 @@
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Xunit;
@@ -58,7 +59,7 @@ public DefaultProjectWorkspaceStateGeneratorTest(ITestOutputHelper testOutput)
     public void Dispose_MakesUpdateNoop()
     {
         // Arrange
-        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher))
+        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher, NoOpTelemetryReporter.Instance))
         {
             stateGenerator.BlockBackgroundWorkStart = new ManualResetEventSlim(initialState: false);
 
@@ -75,7 +76,7 @@ public void Dispose_MakesUpdateNoop()
     public void Update_StartsUpdateTask()
     {
         // Arrange
-        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher))
+        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher, NoOpTelemetryReporter.Instance))
         {
             stateGenerator.BlockBackgroundWorkStart = new ManualResetEventSlim(initialState: false);
 
@@ -92,7 +93,7 @@ public void Update_StartsUpdateTask()
     public void Update_SoftCancelsIncompleteTaskForSameProject()
     {
         // Arrange
-        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher))
+        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher, NoOpTelemetryReporter.Instance))
         {
             stateGenerator.BlockBackgroundWorkStart = new ManualResetEventSlim(initialState: false);
             stateGenerator.Update(_workspaceProject, _projectSnapshot, DisposalToken);
@@ -110,7 +111,7 @@ public void Update_SoftCancelsIncompleteTaskForSameProject()
     public async Task Update_NullWorkspaceProject_ClearsProjectWorkspaceState()
     {
         // Arrange
-        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher))
+        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher, NoOpTelemetryReporter.Instance))
         {
             stateGenerator.NotifyBackgroundWorkCompleted = new ManualResetEventSlim(initialState: false);
             var projectManager = new TestProjectSnapshotManager(_workspace, Dispatcher);
@@ -134,7 +135,7 @@ public async Task Update_NullWorkspaceProject_ClearsProjectWorkspaceState()
     public async Task Update_ResolvesTagHelpersAndUpdatesWorkspaceState()
     {
         // Arrange
-        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher))
+        using (var stateGenerator = new DefaultProjectWorkspaceStateGenerator(Dispatcher, NoOpTelemetryReporter.Instance))
         {
             stateGenerator.NotifyBackgroundWorkCompleted = new ManualResetEventSlim(initialState: false);
             var projectManager = new TestProjectSnapshotManager(_workspace, Dispatcher);