Create per-server daemon telemetry sessions

src/LanguageServer/DaemonConnection/DaemonPipeName.cs

@@ -41,9 +41,10 @@ internal static class DaemonPipeName
     public const string PipeNameOverrideEnvironmentVariable = "ROSLYN_LANGUAGE_SERVER_DAEMON_PIPE_NAME";
 
     /// <summary>
-    /// Computes the pipe name for the current user, scoped by <paramref name="toolIdentifier"/>.
+    /// Computes the pipe name for the current user, scoped by <paramref name="toolIdentifier"/> and
+    /// <paramref name="telemetryLevel"/>.
     /// </summary>
-    public static string GetPipeName(string toolIdentifier)
+    public static string GetPipeName(string toolIdentifier, string? telemetryLevel)
     {
         // Prefix with username and elevation so different users / elevation levels don't share a daemon.
         var isAdmin = false;
@@ -54,22 +55,22 @@ public static string GetPipeName(string toolIdentifier)
             isAdmin = principal.IsInRole(WindowsBuiltInRole.Administrator);
         }
 
-        return GetPipeName(Environment.UserName, isAdmin, toolIdentifier);
+        return GetPipeName(Environment.UserName, isAdmin, toolIdentifier, telemetryLevel);
     }
 
     /// <summary>
     /// Computes the pipe name from the user identity and a tool identifier. The
     /// <paramref name="toolIdentifier"/> ensures only compatible clients connect to a compatible
     /// server; we use the full path to the server executable (in a versioned location).
     /// </summary>
-    public static string GetPipeName(string userName, bool isAdmin, string toolIdentifier)
+    public static string GetPipeName(string userName, bool isAdmin, string toolIdentifier, string? telemetryLevel)
     {
         // Windows paths are case-insensitive. Preserve casing on other platforms, where paths may be
         // case-sensitive and distinct executables must not share a daemon.
         if (OperatingSystem.IsWindows())
             toolIdentifier = toolIdentifier.ToLowerInvariant();
 
-        var pipeNameInput = $"{userName}.{isAdmin}.{toolIdentifier}";
+        var pipeNameInput = $"{userName}.{isAdmin}.{toolIdentifier}.{telemetryLevel}";
         var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(pipeNameInput));
         return Convert.ToBase64String(bytes)
             .Replace("/", "_")

src/LanguageServer/DaemonConnection/TelemetryLevelResolver.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.CodeAnalysis.LanguageServer.Daemon;
+
+internal static class TelemetryLevelResolver
+{
+    private const string CopilotTelemetryLevelEnvironmentVariable = "COPILOT_TELEMETRY_LEVEL";
+
+    public static string? Resolve(string? telemetryLevel)
+        => telemetryLevel ?? Environment.GetEnvironmentVariable(CopilotTelemetryLevelEnvironmentVariable);
+}

src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer.UnitTests/Daemon/DaemonPipeNameTests.cs

@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
@@ -14,40 +14,40 @@ public sealed class DaemonPipeNameTests
     [Fact]
     public void PipeName_IsDeterministic()
     {
-        var first = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier);
-        var second = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier);
+        var first = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
+        var second = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
         Assert.Equal(first, second);
     }
 
     [Fact]
     public void PipeName_DiffersByToolIdentifier()
     {
-        var v1 = DaemonPipeName.GetPipeName("user", isAdmin: false, "/tools/v1/server.dll");
-        var v2 = DaemonPipeName.GetPipeName("user", isAdmin: false, "/tools/v2/server.dll");
+        var v1 = DaemonPipeName.GetPipeName("user", isAdmin: false, "/tools/v1/server.dll", telemetryLevel: "all");
+        var v2 = DaemonPipeName.GetPipeName("user", isAdmin: false, "/tools/v2/server.dll", telemetryLevel: "all");
         Assert.NotEqual(v1, v2);
     }
 
     [Fact]
     public void PipeName_DiffersByUser()
     {
-        var user1 = DaemonPipeName.GetPipeName("user1", isAdmin: false, ToolIdentifier);
-        var user2 = DaemonPipeName.GetPipeName("user2", isAdmin: false, ToolIdentifier);
+        var user1 = DaemonPipeName.GetPipeName("user1", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
+        var user2 = DaemonPipeName.GetPipeName("user2", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
         Assert.NotEqual(user1, user2);
     }
 
     [Fact]
     public void PipeName_DiffersByElevation()
     {
-        var standard = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier);
-        var elevated = DaemonPipeName.GetPipeName("user", isAdmin: true, ToolIdentifier);
+        var standard = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
+        var elevated = DaemonPipeName.GetPipeName("user", isAdmin: true, ToolIdentifier, telemetryLevel: "all");
         Assert.NotEqual(standard, elevated);
     }
 
     [Fact]
     public void PipeName_NormalizesToolIdentifierCasingOnWindows()
     {
-        var mixedCase = DaemonPipeName.GetPipeName("user", isAdmin: false, "/Tools/V1/Server.dll");
-        var lowerCase = DaemonPipeName.GetPipeName("user", isAdmin: false, "/tools/v1/server.dll");
+        var mixedCase = DaemonPipeName.GetPipeName("user", isAdmin: false, "/Tools/V1/Server.dll", telemetryLevel: "all");
+        var lowerCase = DaemonPipeName.GetPipeName("user", isAdmin: false, "/tools/v1/server.dll", telemetryLevel: "all");
         if (OperatingSystem.IsWindows())
             Assert.Equal(mixedCase, lowerCase);
         else
@@ -57,7 +57,7 @@ public void PipeName_NormalizesToolIdentifierCasingOnWindows()
     [Fact]
     public void PipeName_IsFileSystemAndUrlSafe()
     {
-        var name = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier);
+        var name = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
         Assert.False(string.IsNullOrWhiteSpace(name));
         Assert.DoesNotContain('/', name);
         Assert.DoesNotContain('=', name);
@@ -66,7 +66,7 @@ public void PipeName_IsFileSystemAndUrlSafe()
     [Fact]
     public void MutexNames_HaveExpectedShapeAndDiffer()
     {
-        var pipeName = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier);
+        var pipeName = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
         var serverMutex = DaemonPipeName.GetServerMutexName(pipeName);
         var clientMutex = DaemonPipeName.GetClientMutexName(pipeName);
 
@@ -78,4 +78,13 @@ public void MutexNames_HaveExpectedShapeAndDiffer()
         Assert.Contains(pipeName, serverMutex);
         Assert.Contains(pipeName, clientMutex);
     }
+
+    [Fact]
+    public void PipeName_DiffersByTelemetryLevel()
+    {
+        var enabled = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "all");
+        var disabled = DaemonPipeName.GetPipeName("user", isAdmin: false, ToolIdentifier, telemetryLevel: "off");
+
+        Assert.NotEqual(enabled, disabled);
+    }
 }

src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer.UnitTests/Daemon/LanguageServerDaemonTests.cs

@@ -6,8 +6,12 @@
 using System.Runtime.CompilerServices;
 using System.Threading;
 using Microsoft.CodeAnalysis.Host;
+using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.CodeAnalysis.LanguageServer.HostWorkspace;
+using Microsoft.CodeAnalysis.LanguageServer.HostWorkspace.Razor;
+using Microsoft.CodeAnalysis.LanguageServer.Telemetry;
 using Microsoft.CodeAnalysis.Text;
+using Microsoft.VisualStudio.Telemetry;
 using Roslyn.LanguageServer.Protocol;
 using Roslyn.Test.Utilities;
 using Xunit.Abstractions;
@@ -74,6 +78,83 @@ public async Task Daemon_SecondConcurrentConnection_IsIsolatedFromDaemonAndFirst
         Assert.Equal(2, daemon.GetStartedServers().Length);
     }
 
+    [Fact]
+    public async Task Daemon_EachServerHasAnIsolatedTelemetrySession()
+    {
+        var configuration = DefaultServerConfiguration with { IsDaemon = true, TelemetryLevel = "error" };
+        await using var daemon = await CreateDaemonServerAsync(serverConfiguration: configuration);
+        var daemonClientDisconnected = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+        var daemonEvents = new RecordingEventSink(onLog: functionId =>
+        {
+            if (functionId == FunctionId.VSCode_LanguageServer_Daemon_Client_Disconnected)
+                daemonClientDisconnected.TrySetResult(true);
+        });
+        using var daemonEventRegistration = daemon.DaemonTelemetry.AddEventSink(daemonEvents);
+
+        var first = await daemon.CreateClientAsync();
+        await using var second = await daemon.CreateClientAsync();
+
+        var firstTelemetry = first.GetRequiredLspService<RoslynTelemetry>();
+        var secondTelemetry = second.GetRequiredLspService<RoslynTelemetry>();
+        var firstSession = Assert.IsType<TelemetrySession>(TelemetryReporterWrapper.GetSession(firstTelemetry));
+        var secondSession = Assert.IsType<TelemetrySession>(TelemetryReporterWrapper.GetSession(secondTelemetry));
+
+        // Each server has a distinct child session correlated to the shared daemon session.
+        Assert.NotNull(daemon.DaemonSessionId);
+        Assert.NotEqual(firstSession.SessionId, secondSession.SessionId);
+        Assert.Equal(
+            daemon.DaemonSessionId,
+            GetDaemonSessionId(firstSession));
+        Assert.Equal(
+            daemon.DaemonSessionId,
+            GetDaemonSessionId(secondSession));
+
+        var firstEvents = new RecordingEventSink();
+        var secondEvents = new RecordingEventSink();
+        var firstTelemetryFlushed = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+        var firstMetrics = new RecordingMetricSink(onFlush: () => firstTelemetryFlushed.TrySetResult(true));
+        var secondMetrics = new RecordingMetricSink();
+        using var firstEventRegistration = firstTelemetry.AddEventSink(firstEvents);
+        using var secondEventRegistration = secondTelemetry.AddEventSink(secondEvents);
+        using var firstMetricRegistration = firstTelemetry.AddMetricSink(firstMetrics);
+        using var secondMetricRegistration = secondTelemetry.AddMetricSink(secondMetrics);
+
+        var firstDocumentUri = LoadProjectWithDocument(
+            first.GetRequiredLspService<LanguageServerWorkspaceFactory>(),
+            "FirstTelemetryServer");
+        var hover = await first.ExecuteRequestAsync<HoverParams, Hover>(
+            Methods.TextDocumentHoverName,
+            new HoverParams
+            {
+                TextDocument = new TextDocumentIdentifier { DocumentUri = firstDocumentUri },
+                Position = new Position(0, 6),
+            },
+            CancellationToken.None);
+
+        // A request handled by the first server records metrics only in that server's sink.
+        Assert.NotNull(hover);
+        Assert.True(firstMetrics.MeasurementCount > 0);
+        Assert.Equal(0, secondMetrics.MeasurementCount);
+
+        var daemonEventsBeforeDisconnect = daemonEvents.Events.Length;
+        await first.DisposeAsync();
+        await Task.WhenAll(firstTelemetryFlushed.Task, daemonClientDisconnected.Task);
+
+        // Disconnecting the first server flushes it, preserves the second, and attributes lifecycle telemetry to the daemon.
+        Assert.Null(TelemetryReporterWrapper.GetSession(firstTelemetry));
+        Assert.Equal(0, secondMetrics.FlushCount);
+        Assert.Equal(daemonEventsBeforeDisconnect + 1, daemonEvents.Events.Length);
+        Assert.Equal(FunctionId.VSCode_LanguageServer_Daemon_Client_Disconnected, daemonEvents.Events[^1]);
+        Assert.DoesNotContain(FunctionId.VSCode_LanguageServer_Daemon_Client_Disconnected, firstEvents.Events);
+        Assert.DoesNotContain(FunctionId.VSCode_LanguageServer_Daemon_Client_Disconnected, secondEvents.Events);
+
+        static string GetDaemonSessionId(TelemetrySession telemetrySession)
+        {
+            Assert.True(telemetrySession.TryGetCommonPropertyValue(LanguageServerTelemetry.DaemonSessionIdPropertyName, out var daemonSessionId));
+            return Assert.IsType<string>(daemonSessionId);
+        }
+    }
+
     // Each connected client gets its own server with its own Host workspace. A project loaded into one server's
     // workspace must not be visible to the other server, and each server's registration service must track only
     // its own workspaces.

src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer.UnitTests/LanguageServerRequestTelemetryTests.cs

@@ -2,12 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.CodeAnalysis.Telemetry;
-using Microsoft.VisualStudio.Telemetry;
-using Microsoft.VisualStudio.Telemetry.Metrics.Events;
 using Roslyn.LanguageServer.Protocol;
 using Xunit;
 using Xunit.Abstractions;
@@ -21,16 +18,6 @@ namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests;
 public sealed class LanguageServerRequestTelemetryTests(ITestOutputHelper testOutputHelper)
     : AbstractLanguageServerHostTests(testOutputHelper)
 {
-    private sealed class RecordingPoster : VSMetricSink.IMetricPoster
-    {
-        public List<TelemetryEvent> PostedEvents { get; } = [];
-
-        public bool IsOptedIn => true;
-
-        public void Post(TelemetryEvent telemetryEvent, TelemetryMetricEvent metricEvent)
-            => PostedEvents.Add(telemetryEvent);
-    }
-
     [Fact]
     public async Task RealRequestsProduceAggregatedTelemetry()
     {