TelemetryLogger refactoring and testing

src/VisualStudio/Core/Def/Implementation/Watson/FaultReporter.cs

@@ -11,6 +11,7 @@
 using System.Threading;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.CodeAnalysis.Remote;
+using Microsoft.CodeAnalysis.Telemetry;
 using Microsoft.VisualStudio.LanguageServices.Telemetry;
 using Microsoft.VisualStudio.Telemetry;
 
@@ -104,7 +105,7 @@ public static void ReportFault(Exception exception, FaultSeverity severity, bool
                 }
 
                 var faultEvent = new FaultEvent(
-                    eventName: FunctionId.NonFatalWatson.GetEventName(),
+                    eventName: TelemetryLogger.GetEventName(FunctionId.NonFatalWatson),
                     description: GetDescription(exception),
                     severity,
                     exceptionObject: exception,

src/VisualStudio/Core/Def/Telemetry/TelemetryLogger.cs

@@ -0,0 +1,195 @@
+// 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.
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using Microsoft.CodeAnalysis.Internal.Log;
+using Microsoft.VisualStudio.Telemetry;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.Telemetry
+{
+    internal abstract class TelemetryLogger : ILogger
+    {
+        private sealed class Implementation : TelemetryLogger
+        {
+            private readonly TelemetrySession _session;
+
+            public Implementation(TelemetrySession session)
+                => _session = session;
+
+            public override bool IsEnabled(FunctionId functionId)
+                => _session.IsOptedIn;
+
+            protected override void PostEvent(TelemetryEvent telemetryEvent)
+                => _session.PostEvent(telemetryEvent);
+
+            protected override object Start(string eventName, LogType type)
+                => type switch
+                {
+                    LogType.Trace => _session.StartOperation(eventName),
+                    LogType.UserAction => _session.StartUserTask(eventName),
+                    _ => throw ExceptionUtilities.UnexpectedValue(type),
+                };
+
+            protected override TelemetryEvent GetEndEvent(object scope)
+                => scope switch
+                {
+                    TelemetryScope<OperationEvent> operation => operation.EndEvent,
+                    TelemetryScope<UserTaskEvent> userTask => userTask.EndEvent,
+                    _ => throw ExceptionUtilities.UnexpectedValue(scope)
+                };
+
+            protected override void End(object scope, TelemetryResult result)
+            {
+                if (scope is TelemetryScope<OperationEvent> operation)
+                    operation.End(result);
+                else if (scope is TelemetryScope<UserTaskEvent> userTask)
+                    userTask.End(result);
+                else
+                    throw ExceptionUtilities.UnexpectedValue(scope);
+            }
+        }
+
+        private readonly ConcurrentDictionary<int, object> _pendingScopes = new(concurrencyLevel: 2, capacity: 10);
+
+        private const string EventPrefix = "vs/ide/vbcs/";
+        private const string PropertyPrefix = "vs.ide.vbcs.";
+
+        // these don't have concurrency limit on purpose to reduce chance of lock contention. 
+        // if that becomes a problem - by showing up in our perf investigation, then we will consider adding concurrency limit.
+        private static readonly ConcurrentDictionary<FunctionId, string> s_eventMap = new();
+        private static readonly ConcurrentDictionary<(FunctionId id, string name), string> s_propertyMap = new();
+
+        internal static string GetEventName(FunctionId id)
+             => s_eventMap.GetOrAdd(id, id => EventPrefix + GetTelemetryName(id, separator: '/'));
+
+        internal static string GetPropertyName(FunctionId id, string name)
+            => s_propertyMap.GetOrAdd((id, name), key => PropertyPrefix + GetTelemetryName(id, separator: '.') + "." + key.name.ToLowerInvariant());
+
+        private static string GetTelemetryName(FunctionId id, char separator)
+            => Enum.GetName(typeof(FunctionId), id)!.Replace('_', separator).ToLowerInvariant();
+
+        public static TelemetryLogger Create(TelemetrySession session)
+            => new Implementation(session);
+
+        public abstract bool IsEnabled(FunctionId functionId);
+        protected abstract void PostEvent(TelemetryEvent telemetryEvent);
+        protected abstract object Start(string eventName, LogType type);
+        protected abstract void End(object scope, TelemetryResult result);
+        protected abstract TelemetryEvent GetEndEvent(object scope);
+
+        public void Log(FunctionId functionId, LogMessage logMessage)
+        {
+            if (IgnoreMessage(logMessage))
+            {
+                return;
+            }
+
+            var telemetryEvent = new TelemetryEvent(GetEventName(functionId));
+            SetProperties(telemetryEvent, functionId, logMessage);
+
+            try
+            {
+                PostEvent(telemetryEvent);
+            }
+            catch
+            {
+            }
+        }
+
+        public void LogBlockStart(FunctionId functionId, LogMessage logMessage, int blockId, CancellationToken cancellationToken)
+        {
+            if (IgnoreMessage(logMessage))
+            {
+                return;
+            }
+
+            var eventName = GetEventName(functionId);
+            var kind = GetKind(logMessage);
+
+            try
+            {
+                _pendingScopes[blockId] = Start(eventName, kind);
+            }
+            catch
+            {
+            }
+        }
+
+        public void LogBlockEnd(FunctionId functionId, LogMessage logMessage, int blockId, int delta, CancellationToken cancellationToken)
+        {
+            if (IgnoreMessage(logMessage))
+            {
+                return;
+            }
+
+            Contract.ThrowIfFalse(_pendingScopes.TryRemove(blockId, out var scope));
+
+            var endEvent = GetEndEvent(scope);
+            SetProperties(endEvent, functionId, logMessage);
+
+            var result = cancellationToken.IsCancellationRequested ? TelemetryResult.UserCancel : TelemetryResult.Success;
+
+            try
+            {
+                End(scope, result);
+            }
+            catch
+            {
+            }
+        }
+
+        private static bool IgnoreMessage(LogMessage logMessage)
+            => logMessage.LogLevel < LogLevel.Information;
+
+        private static LogType GetKind(LogMessage logMessage)
+            => logMessage is KeyValueLogMessage kvLogMessage
+                                ? kvLogMessage.Kind
+                                : logMessage.LogLevel switch
+                                {
+                                    >= LogLevel.Information => LogType.UserAction,
+                                    _ => LogType.Trace
+                                };
+
+        private static void SetProperties(TelemetryEvent telemetryEvent, FunctionId functionId, LogMessage logMessage)
+        {
+            if (logMessage is KeyValueLogMessage kvLogMessage)
+            {
+                AppendProperties(telemetryEvent, functionId, kvLogMessage);
+            }
+            else
+            {
+                var message = logMessage.GetMessage();
+                if (!string.IsNullOrWhiteSpace(message))
+                {
+                    var propertyName = GetPropertyName(functionId, "Message");
+                    telemetryEvent.Properties.Add(propertyName, message);
+                }
+            }
+        }
+
+        private static void AppendProperties(TelemetryEvent telemetryEvent, FunctionId functionId, KeyValueLogMessage logMessage)
+        {
+            foreach (var (name, value) in logMessage.Properties)
+            {
+                // call SetProperty. VS telemetry will take care of finding correct
+                // API based on given object type for us.
+                // 
+                // numeric data will show up in ES with measurement prefix.
+
+                telemetryEvent.Properties.Add(GetPropertyName(functionId, name), value switch
+                {
+                    PiiValue pii => new TelemetryPiiProperty(pii.Value),
+                    IEnumerable<object> items => new TelemetryComplexProperty(items.Select(item => (item is PiiValue pii) ? new TelemetryPiiProperty(pii.Value) : item)),
+                    _ => value
+                });
+            }
+        }
+    }
+}