Logger.cs


namespace WinService
{
	using System;
	using System.Collections.Generic;
	using System.Linq;
	using System.Text;

	internal enum LogLevel : byte
	{
		All = 0,
		Trace = 1,
		Debug = 2,
		Info = 3,
		Warn = 4,
		Error = 5,
		Fatal = 6
	}

	internal static class Logger
	{
		private static Object consoleLockObj = new Object();
		private static Object fileLockObj = new Object();
		private static LogLevel CurrentLevel = LogLevel.Info;
		private static String logFile = null;

		static Logger()
		{
			String appLogLevel = System.Configuration.ConfigurationManager.AppSettings["SelfLogLevel"];
			CurrentLevel = (LogLevel)Enum.Parse(typeof(LogLevel), appLogLevel);
			logFile = System.Configuration.ConfigurationManager.AppSettings["SelfLogFile"];
			if (!String.IsNullOrEmpty(logFile))
			{
				logFile = Environment.ExpandEnvironmentVariables(logFile);
			}
		}


		private static Boolean CanLog(LogLevel level)
		{
			return level >= CurrentLevel;
		}
		private static ConsoleColor getColor(LogLevel level)
		{
			ConsoleColor ans = Console.ForegroundColor;
			switch (level)
			{
				case LogLevel.All:
					ans = ConsoleColor.White;
					break;
				case LogLevel.Trace:
					ans = ConsoleColor.Green;
					break;
				case LogLevel.Debug:
					ans = ConsoleColor.Yellow;
					break;
				case LogLevel.Info:
					ans = ConsoleColor.Gray;
					break;
				case LogLevel.Warn:
					ans = ConsoleColor.Cyan;
					break;
				case LogLevel.Error:
					ans = ConsoleColor.Red;
					break;
				case LogLevel.Fatal:
					ans = ConsoleColor.Magenta;

					break;
				default:
					break;
			}
			return ans;
		}

		internal static void WriteMessage(LogLevel level, String msg)
		{
			if (CanLog(level))
			{
				if (Environment.UserInteractive)
				{
					lock (consoleLockObj)
					{
						ConsoleColor currentColor = Console.ForegroundColor;
						Console.ForegroundColor = getColor(level);
						Console.WriteLine("{0} - {1}", DateTime.Now, msg);
						Console.ForegroundColor = currentColor;
					}
				}
				if (!String.IsNullOrEmpty(logFile))
				{
					lock (fileLockObj)
					{
						//TODO: Roll log (max size / daily)
						System.IO.File.AppendAllText(logFile, String.Format("{0} - {1}{2}", DateTime.Now, msg, Environment.NewLine), Encoding.UTF8);
					}
				}
			}
		}
		internal static void WriteMessage(String msg)
		{
			WriteMessage(LogLevel.Info, msg);
		}
		internal static void WriteMessage(LogLevel level, String format, params String[] args)
		{
			WriteMessage(level, String.Format(format, args));
		}
		internal static void WriteMessage(String format, params String[] args)
		{
			WriteMessage(String.Format(format, args));
		}

		internal static void WriteException(Exception e, String msg)
		{
			WriteMessage(LogLevel.Error, "{0} - {1} - {2}", msg, e.Message, e.StackTrace);
		}
	}
}