Merge pull request #650 from Excel-DNA/Logging

Logging configuration from environment and registry

Author: govert

Source/ExcelDna.Integration/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.Integration/LogDisplayTraceListener.cs

@@ -17,9 +17,11 @@ public LogDisplayTraceListener()
         {
         }
 
-        public LogDisplayTraceListener(string name)
+        public LogDisplayTraceListener(string name, TraceEventType? filterLevel)
             : base(name)
         {
+            if (filterLevel.HasValue)
+                Filter = new DiagnosticsFilter(filterLevel.Value);
         }
 
         public override void TraceEvent(TraceEventCache eventCache, string source, TraceEventType eventType, int id, string message)

Source/ExcelDna.Integration/Logging.cs

@@ -87,10 +87,12 @@ 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.
-                IntegrationTraceSource = new TraceSource(TraceSourceName, SourceLevels.Warning);
+                IntegrationTraceSource = new TraceSource(TraceSourceName, settings.SourceLevel);
 
                 bool logDisplayTraceListenerIsConfigured = false;
                 TraceListener logDisplayTraceListenerToRemove = null; // The one we want to remove if configured as "Off"
@@ -109,6 +111,10 @@ public static void Initialize()
                         }
                         logDisplayTraceListenerIsConfigured = true;
                     }
+                    else if (tl.Name == "Default" && settings.DebuggerLevel.HasValue)
+                    {
+                        tl.Filter = new DiagnosticsFilter(settings.DebuggerLevel.Value);
+                    }
                 }
 
                 try
@@ -134,7 +140,17 @@ public static void Initialize()
                     else
                     {
                         // No explicit configuration for this default listener, so we add it
-                        IntegrationTraceSource.Listeners.Add(new LogDisplayTraceListener("LogDisplay"));
+                        IntegrationTraceSource.Listeners.Add(new LogDisplayTraceListener("LogDisplay", settings.LogDisplayLevel));
+                    }
+
+                    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);
+                        IntegrationTraceSource.Listeners.Add(textWriterTraceListener);
                     }
 
                     AppDomain currentDomain = AppDomain.CurrentDomain;

Source/ExcelDna.Integration/LoggingSettings.cs

@@ -0,0 +1,38 @@
+using Microsoft.Win32;
+using System;
+using System.Diagnostics;
+
+namespace ExcelDna.Logging
+{
+    internal class LoggingSettings
+    {
+        public SourceLevels SourceLevel { get; }
+        public TraceEventType? LogDisplayLevel { 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("LOGDISPLAY_LEVEL", "LogDisplayLevel"), out TraceEventType logDisplayLevelResult))
+                LogDisplayLevel = logDisplayLevelResult;
+
+            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_DIAGNOSTICS_{environmentName}") ??
+                (Registry.GetValue(@"HKEY_CURRENT_USER\Software\ExcelDna\Diagnostics", registryName, null) as string ??
+                Registry.GetValue(@"HKEY_LOCAL_MACHINE\Software\ExcelDna\Diagnostics", registryName, null) as string);
+        }
+    }
+}