Added logging configuration to support .NET 6+

Supports environment variable / registry based overrides

Author: govert

Source/ExcelDna.IntelliSense.Host/App.config

@@ -6,12 +6,9 @@
       <source name="ExcelDna.IntelliSense" switchValue="All">
         <listeners>
           <!--<remove name="Default" />-->
-          <!--<add name="LogDisplay" type="ExcelDna.Logging.LogDisplayTraceListener,ExcelDna.Integration">
-            <filter type="System.Diagnostics.EventTypeFilter" initializeData="All"/>
-          </add>-->
-          <!-- <add name="File" type="System.Diagnostics.TextWriterTraceListener" initializeData="ExcelDna.IntelliSense.log" >
-            <filter type="System.Diagnostics.EventTypeFilter" initializeData="All"/>
-          </add> -->
+          <add name="File" type="System.Diagnostics.TextWriterTraceListener" initializeData="ExcelDna.IntelliSense.log" >
+            <filter type="System.Diagnostics.EventTypeFilter" initializeData="Information"/>
+          </add>
         </listeners>
       </source>
     </sources>

Source/ExcelDna.IntelliSense/DiagnosticsFilter.cs

@@ -0,0 +1,19 @@
+using System.Diagnostics;
+
+namespace ExcelDna.Logging
+{
+    internal class DiagnosticsFilter : TraceFilter
+    {
+        private TraceEventType filterLevel;
+
+        public DiagnosticsFilter(TraceEventType filterLevel)
+        {
+            this.filterLevel = filterLevel;
+        }
+
+        public override bool ShouldTrace(TraceEventCache cache, string source, TraceEventType eventType, int id, string formatOrMessage, object[] args, object data1, object[] data)
+        {
+            return eventType <= filterLevel;
+        }
+    }
+}

Source/ExcelDna.IntelliSense/IntelliSenseServer.cs

@@ -30,7 +30,7 @@ namespace ExcelDna.IntelliSense
     // REMEMBER: COM events are not necessarily safe macro contexts.
     public static class IntelliSenseServer
     {
-        const string ServerVersion = "1.7.3";  // TODO: Define and manage this somewhere else
+        const string ServerVersion = "1.8.0";  // TODO: Define and manage this somewhere else
 
         // NOTE: Do not change these constants in custom versions. 
         //       They are part of the co-operative safety mechanism allowing different add-ins providing IntelliSense to work together safely.

Source/ExcelDna.IntelliSense/Logging.cs

@@ -5,6 +5,7 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Security;
+using ExcelDna.Logging;
 
 namespace ExcelDna.IntelliSense
 {
@@ -77,10 +78,22 @@ public static void Initialize()
         {
             if (!s_LoggingInitialized)
             {
+                LoggingSettings settings = new LoggingSettings();
+
                 bool loggingEnabled = false;
                 // DOCUMENT: By default the TraceSource is configured to source only Warning, Error and Fatal.
                 //           the configuration can override this.
-                IntelliSenseTraceSource = new TraceSource(TraceSourceName, SourceLevels.Warning);
+                IntelliSenseTraceSource = new TraceSource(TraceSourceName, settings.SourceLevel);
+
+                Debug.Print("{0} TraceSource created. Listeners:", TraceSourceName);
+                foreach (TraceListener tl in IntelliSenseTraceSource.Listeners)
+                {
+                    Debug.Print("    {0} - {1}", tl.Name, tl.TraceOutputOptions);
+                    if (tl.Name == "Default" && settings.DebuggerLevel.HasValue)
+                    {
+                        tl.Filter = new DiagnosticsFilter(settings.DebuggerLevel.Value);
+                    }
+                }
 
                 try
                 {
@@ -100,8 +113,19 @@ public static void Initialize()
                     Close();
                     loggingEnabled = false;
                 }
+
                 if (loggingEnabled)
                 {
+                    if (!string.IsNullOrWhiteSpace(settings.FileName))
+                    {
+                        Trace.AutoFlush = true;
+
+                        TextWriterTraceListener textWriterTraceListener = new TextWriterTraceListener(settings.FileName, "FileWriter");
+                        if (settings.FileLevel.HasValue)
+                            textWriterTraceListener.Filter = new DiagnosticsFilter(settings.FileLevel.Value);
+                        IntelliSenseTraceSource.Listeners.Add(textWriterTraceListener);
+                    }
+
                     AppDomain currentDomain = AppDomain.CurrentDomain;
                     //currentDomain.UnhandledException += UnhandledExceptionHandler;
                     currentDomain.DomainUnload += AppDomainUnloadEvent;
@@ -147,8 +171,14 @@ static void AppDomainUnloadEvent(object sender, EventArgs e)
 
         static void Close()
         {
+            AppDomain currentDomain = AppDomain.CurrentDomain;
+            currentDomain.DomainUnload -= AppDomainUnloadEvent;
+            currentDomain.ProcessExit -= ProcessExitEvent;
+
             if (IntelliSenseTraceSource != null)
                 IntelliSenseTraceSource.Close();
+
+            s_LoggingInitialized = false;
         }
 
     }
@@ -249,4 +279,5 @@ public void Error(Exception ex, string message, params object[] args)
         static internal Logger Display { get; } = new Logger(IntelliSenseTraceEventId.Display);
         static internal Logger Monitor { get; } = new Logger(IntelliSenseTraceEventId.Monitor);
     }
+
 }

Source/ExcelDna.IntelliSense/LoggingSettings.cs

@@ -0,0 +1,34 @@
+using Microsoft.Win32;
+using System;
+using System.Diagnostics;
+
+namespace ExcelDna.Logging
+{
+    internal class LoggingSettings
+    {
+        public SourceLevels SourceLevel { get; }
+        public TraceEventType? DebuggerLevel { get; }
+        public TraceEventType? FileLevel { get; }
+        public string FileName { get; }
+
+        public LoggingSettings()
+        {
+            SourceLevel = Enum.TryParse(GetCustomSetting("SOURCE_LEVEL", "SourceLevel"), out SourceLevels sourceLevelResult) ? sourceLevelResult : SourceLevels.Warning;
+
+            if (Enum.TryParse(GetCustomSetting("DEBUGGER_LEVEL", "DebuggerLevel"), out TraceEventType debuggerLevelResult))
+                DebuggerLevel = debuggerLevelResult;
+
+            if (Enum.TryParse(GetCustomSetting("FILE_LEVEL", "FileLevel"), out TraceEventType fileLevelResult))
+                FileLevel = fileLevelResult;
+
+            FileName = GetCustomSetting("FILE_NAME", "FileName");
+        }
+
+        private static string GetCustomSetting(string environmentName, string registryName)
+        {
+            return Environment.GetEnvironmentVariable($"EXCELDNA_INTELLISENSE_DIAGNOSTICS_{environmentName}") ??
+                (Registry.GetValue(@"HKEY_CURRENT_USER\Software\ExcelDna\IntelliSense\Diagnostics", registryName, null) as string ??
+                Registry.GetValue(@"HKEY_LOCAL_MACHINE\Software\ExcelDna\IntelliSense\Diagnostics", registryName, null) as string);
+        }
+    }
+}