Custom logging handler for NLOG

Just a quick one - below is a custom Nlog helper which offers a centralized location for logging in a windows service. Its compatible to use with elmahs add proc. It allows you to easily log to multiple NLog settings using a flagged enum.

Class code (Must add the nlog dll as a reference)

 using System;
    using System.Collections.Generic;
    using System.Configuration;
    using System.Linq;
    using System.Security.Principal;
    using System.Text;
    using NLog;
    using PixelTrackingQueueService.Exceptions;
  
    public class LogHelper
    {
        public static LogHelper CurrentHelper = new LogHelper();

        [Flags]
        public enum LogType
        {
            Error = 0x01,
            CriticalError = 0x02,
            Warning = 0x04,
            Info = 0x08,
            Debug = 0x10,
            Trace = 0x20
        }

      
        public void Log(string message, LogType logType, Exception ex = null, Type currentType = null)
        {
            Logger logger = (currentType == null)
                                ? LogManager.GetCurrentClassLogger()
                                : LogManager.GetLogger(currentType.FullName);

            Action<string> log = null;
            Action<string, Exception> exLog = null;

            foreach (LogType flag in Enum.GetValues(typeof(LogType)))
            {

                LogType logLevel = (flag & logType);
                LogLevel level = LogLevel.Off;
                switch (logLevel)
                {
                    case LogType.Warning:
                        level = LogLevel.Warn;
                        break;
                    case LogType.CriticalError:
                        level = LogLevel.Fatal;
                        break;
                    case LogType.Error:
                        level = LogLevel.Error;
                        break;
                    case LogType.Info:
                        level = LogLevel.Info;
                        break;
                    case LogType.Trace:
                        level = LogLevel.Trace;
                        break;
                    case LogType.Debug:
                        level = LogLevel.Debug;
                        break;
                    default:
                        continue;
                }

                DoLog(logger, message, level, ex, currentType);
            }
        }


        private static void DoLog(Logger logger, string message, LogLevel level, Exception ex = null, Type type = null)
        {
            LogEventInfo info = new LogEventInfo(level,
                                                ((type == null) ? typeof(LogManager).FullName : type.FullName),
                                                null,
                                                message,null, ex);

            info.Properties["ApplicationName"] = ConfigurationManager.AppSettings["ApplicationName"];
            info.Properties["Host"] = System.Environment.MachineName;
            info.Properties["Type"] = (ex == null) ? level.ToString() : ex.GetType().FullName;
            info.Properties["CurrentUser"] = WindowsIdentity.GetCurrent().Name;
            info.Properties["Source"] = ex == null ? level.ToString() : ex.Source;

            string error = ex == null ? message : ex.ToString();
            string stackTrace = ex == null ? level.ToString() : ex.StackTrace;

            info.Properties["Error"] =
                string.Format(
                    @"<error host=""{0}"" type=""{1}"" message=""{2}"" source=""{3}"" detail=""{4}"" ><serverVariables>
                        <item name=""SERVICE_NAME""><value string=""{5}""/></item>              
                        <item name=""LOGON_USER""><value string=""{6}""/></item>
                        </serverVariables></error>",
                    System.Environment.MachineName,
                    info.Properties["Type"],
                    System.Security.SecurityElement.Escape(message),
                     info.Properties["Source"],
                    System.Security.SecurityElement.Escape(error),
                    "ServiceName",
                    info.Properties["CurrentUser"]);

            

            logger.Log(info);

        }
   
        private Logger GetLoggerFromType(Type currentType)
        {
             return  (currentType == null)
                                ? LogManager.GetCurrentClassLogger()
                                : LogManager.GetLogger(currentType.FullName);
        }
      
    }

 Nlog Config (with elmah proc) 

Add this file to your solution, calling it Nlog.config. This is the file Nlog will look for:

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >

  <!--
  See http://nlog-project.org/wiki/Configuration_file
  for information on customizing logging rules and outputs.
   -->
  <targets>
    <!-- add your targets here -->
   
    <!--
    <target xsi:type="File" name="f" fileName="${basedir}/logs/${shortdate}.log"
            layout="${longdate} ${uppercase:${level}} ${message}" />
    -->
    <target name="elmah" xsi:type="Database" keepConnection="true" useTransactions="true"
        dbProvider="sqlserver" connectionString="Data Source=im-dev01\;Initial Catalog=Elmah;Integrated Security=False;User ID=Elmah;Password=1234;">
      <commandText>
        DECLARE @ID UNIQUEIDENTIFIER = NEWID(), @time DATETIME = GETUTCDATE()
        SELECT @time
        EXEC ELMAH_LogError @ID ,'${event-context:item=ApplicationName}', '${event-context:item=Host}',
        '${event-context:item=Type}', '${event-context:item=Source}', '${message}','${event-context:item=CurrentUser}','${event-context:Error}', 1, @time
      </commandText>     
    </target>
    <target xsi:type="Mail" name="mailman" smtpServer="Mail.MailService.local" from="serviceerror@somewhere.com"
            html="true" to="someone@somewhere.com"
            subject="Service Error"
            cc="someoneelse@somewhere.com"
            body="&lt;h1&gt;Date and Time&lt;/h1&gt;${longdate}    &lt;h1&gt;Message&lt;/h1&gt;${message} &lt;h1&gt;Exception Details&lt;/h1&gt;
                  &lt;h2&gt;Error Details&lt;/h2&gt; ${exception:format=ToString} &lt;h2&gt;Stack Trace Details&lt;/h2&gt; ${exception:format=StackTrace}" />
    <target name="TraceLog" xsi:type="File" fileName="Logs/Traces.log" createDirs="true"/>
    <target name="ErrorLog" xsi:type="File" fileName="Logs/Errors.log" createDirs="true" layout="${message}\r\n${exception:format=ToString}"/>
    <target name="WarningLog" xsi:type="File" fileName="Logs/Warnings.log" createDirs="true"/>
    <target name="InfoLog" xsi:type="File" fileName="Logs/Info.log" createDirs="true"/>
  </targets>

  <rules>
    <logger name="*" level="Fatal" writeTo="mailman" />   
    <logger name="*" level="Error" writeTo="elmah" />
    <logger name="*" level="Info" writeTo="elmah" />
    <logger name="*" level="Trace" writeTo="elmah" />
    <logger name="*" level="Warn" writeTo="elmah" />
    <logger name="*" level="Debug" writeTo="elmah" />
  </rules> 
</nlog>

Example on using the code:

LogHelper.CurrentHelper.Log("Error has occured", LogHelper.LogType.Debug | LogHelper.LogType.CriticalError, exceptionObject, this.GetType());       

will log to both elmah and send a mail at the same time.