How To configure Apache log4net for ASP.Net

Apache log4net is a tool that helps programmer to log outputs to a variety of output targets. Its basically a port of log4j framework and can be used with all types of .Net applications. In this post, we will see how to configure and start using the logging framework in an ASP.Net web application.

You can download the framework from Apache site. Once downloaded, you need to add the reference of Log4net.dll to the project.

Configuring the logging framework to work with your web application can be done by 3 simple steps:

Step 1: Update web.config file
In the web.config file, you will need to add a new section under configSections tag. Notice that you will already have some section in sectionGroup tag. Do not place the new tag in them as this will lead to build errors. You need to add the following:

<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" requirePermission="false" />

Step 2: Configure log4net
Next we need to provide some configurations to log4net. In our example, we are going to store all the logs in a file. You may refer the documentation for other Appenders available. Below is my log4net configuration:

<log4net>
    <appender name="FileAppender" type="log4net.Appender.FileAppender">
      <file value="D:\\Data\\logs\\log.txt" />
      <appendToFile value="true" />      
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date [%thread] %-5level %logger - %message %newline" />
      </layout>
    </appender>
    <root>
      <level value="ALL" />
      <appender-ref ref="FileAppender" />
    </root>
  </log4net>

There are different ways of presenting this configuration to our framework. You can store the configuration in a separate xml file or use web.config to store it. In this example, I am storing it in web.config. just after ending the configSections tag, I have my log4net configurations. Now, we are ready to start using the logging framework.

Step 3: Start using log4net
To start using log4net, our web application should read the configurations. To do so, need to inform log4net to configure the logging environment. This is done with the help of the statement given below:

log4net.Config.XmlConfigurator.Configure();

I would recommend you add this to Application_Start method in Global.asax so that the logging environment is ready at the start of the applications. Inorder to log any infomation you need to get an instance of the Logger. This is done with the help of GetLogger method as shown below:

private static readonly ILog log = LogManager.GetLogger(typeof(MyclassName));

And finally, you just need to call log.Info, Debug etc methods to log you messages.