Configure log4net for asp.net MVC3 project

Question

Ok, so I'm understood how to configure the log4Net in my application, But now

First I want to improve the configuration by differencing the level of the logs if the application it's a release or a debug, how can I do this?.

Second, If I had a folder in my project called LOG how can I set the configuration, to not used the physical folder of my application??

for example Instead of:

<file value="C:\physicalpath\LOG\Log.log" /> 

used

<file value="\LOG\Log.log" /> 

or

<file value="%some_variable%\LOG\Log.log" /> 

Answer 1

The documenation is straight forward:

file: the full or relative path to the log file.

So all you need to have is the full path like C:\physicalpath\LOG\Log.log or the ralative one, this needs to start with the dot char . like .\App_Data\Log4Net.Logs

you can also use the folder name in the file attribute, then you must use the datePattern attribute to specify the file name, for example:

<appender name="FileAppender" type="log4net.Appender.RollingFileAppender">
  <file value=".\\App_Data\\Log4Net.Logs\\backend"/>
  <datePattern value=".yyyy-MM-dd'.log'"/>
  <appendToFile value="true"/>
  <maximumFileSize value="256KB"/>
  <maxSizeRollBackups value="2"/>
  <rollingStyle value="Date"/>
  <staticLogFileName value="false"/>
  <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
  <layout type="log4net.Layout.PatternLayout">
     <conversionPattern value="%level %thread %logger - %message%newline"/>
  </layout>
</appender>

Also remember to add the

<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>

So you can avoid that log4net lock the file and you can't used it to append your messages.

If you're not used to log4net, don't forget to add the <root> node, this is the the one that let's log4net know what you want to use and not the <appender> nodes, for example, you can have 10 <appender> nodes and use only one, the <root> node is then only configured with the one you want to use...

---

here is a full configuration with 2 Mongo Appenders and 1 File Appender, the <root> specifies that only the file appender is in use:

  <log4net>
    <appender name="MongoAppender" type="log4net.Appender.MongoDBAppender, log4mongo-net">
      <!-- MongoDB 1 connection options -->
      <host value="staff.mongohq.com"/>
      <port value="10077"/>
      <databaseName value="myApp_2011"/>
      <collectionName value="logs_net"/>
      <userName value="myself"/>
      <password value="123456"/>
    </appender>
    <appender name="MongoAppenderAppHarbor" type="log4net.Appender.MongoDBAppender, log4mongo-net">
      <!-- MongoDB 2 connection options -->
      <host value="staff.mongohq.com"/>
      <port value="10048"/>
      <databaseName value="d1741d63-46b1-4a44-9c49-8c28cecae36b"/>
      <collectionName value="logs_net"/>
      <userName value="myself"/>
      <password value="123456"/>
    </appender>
    <appender name="FileAppender" type="log4net.Appender.RollingFileAppender">
      <!-- Local file options -->
      <file value=".\\App_Data\\Log4Net.Logs\\backend"/>
      <datePattern value=".yyyy-MM-dd'.log'"/>
      <appendToFile value="true"/>
      <maximumFileSize value="256KB"/>
      <maxSizeRollBackups value="2"/>
      <rollingStyle value="Date"/>
      <staticLogFileName value="false"/>
      <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%level %thread %logger - %message%newline"/>
      </layout>
    </appender>
    <root>
      <!--
         <level value="DEBUG" />
         <appender-ref ref="MongoAppender" />
         <appender-ref ref="MongoAppenderAppHarbor" />
      -->
      <appender-ref ref="FileAppender"/>
    </root>
  </log4net>