Configure log4net logging framework for ASP.NET MVC

This post will provide a short overview of the steps needed to integrate the Apache log4net logging framework to an ASP.NET MVC Web application:

1. Include the log4net in your MVC project, you can use the NuGet package manager (Alternatively, you can also download and add the log4net.dll reference manually):

   PM> install-package Log4Net

2. Add the following tags to the MVC Web.config file:

   <configuration>
     <configSections>
       [...]
       <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
     </configSections>
     [...]
     <log4net>
       <appender name="RollingFile" type="log4net.Appender.RollingFileAppender">
         <file value="C:\Temp\log4net.log" />
         <appendToFile value="true" />
         <maximumFileSize value="500KB" />
         <maxSizeRollBackups value="2" />
         <layout type="log4net.Layout.PatternLayout">
           <conversionPattern value="%date %level %logger - %message%newline" />
         </layout>
       </appender>
       <root>
         <level value="All" />
         <appender-ref ref="RollingFile" />
       </root>
     </log4net>
   </configuration>

3. Add the following line to the AssemblyInfo.cs file:

   [assembly: log4net.Config.XmlConfigurator(ConfigFile = "Web.config", Watch = true)]

4. To test the log4net logging add the following lines of code to the HomeController.cs file:

   private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(HomeController));
   [...]
   public ActionResult Index()
   {
     log.Info("Action Index has been fired.");
     [...]
   }

5. To use relative path for the log file instead of the absolute path, change the following tag in the web.config: From:

   <file value="C:\Logs\log4net.log" />

   To (But first you should create a new folder under your MVC application and name it as "Logs"):

   <file value="Logs/log4net.log" />