Can I hook to log4net Log, Debug, Info, and Error?

Question

I want to set different console colors depending on the severity of the logged message.

I would want something like

_log.Error("Expected exception",e);

to somehow do

Console.PushColor(ConsoleColor.DarkRed);
_log.Error("Expected exception",e);
Console.PopColor();

Is there an easy way to hook the console logger to do stuff like this?

I think Log4Net already has a coloredConsol appender, if I remember well... — Davide Piras
…and, if not, there is your answer: create your own appender that logs where and how you want. — Jay
It does have a console appender that deals with colour: ColoredConsoleAppender. — adrianbanks

csharptest.net csharptest.net · Accepted Answer · 2011-12-15T17:32:46

First yes, log4Net provides it's own color log adapter:

We use two appender configurations to enable output to both std:out and std:err

<log4net  xsi:noNamespaceSchemaLocation="http://csharptest.net/downloads/schema/log4net.xsd"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <root>
    <level value="ALL" />
    <appender-ref ref="console.out" />
    <appender-ref ref="console.error" />
  </root>

  <appender name="console.out" type="log4net.Appender.ColoredConsoleAppender">
    <target value="Console.Out" />
    <filter type="log4net.Filter.LevelRangeFilter">
      <levelMin value="DEBUG"/><!-- "DEBUG" OR "INFO" if you want to display these -->
      <levelMax value="INFO"/>
    </filter>
    <mapping>
      <level value="INFO"/>
      <foreColor value="White, HighIntensity"/>
    </mapping>
    <mapping>
      <level value="DEBUG"/>
      <foreColor value="White"/>
    </mapping>
  </appender>

  <appender name="console.error" type="log4net.Appender.ColoredConsoleAppender">
    <target value="Console.Error" />
    <filter type="log4net.Filter.LevelRangeFilter">
      <levelMin value="WARN"/>
      <levelMax value="FATAL"/>
    </filter>
    <mapping>
      <level value="FATAL"/>
      <foreColor value="Yellow, HighIntensity"/>
      <backColor value="Red"/>
    </mapping>
    <mapping>
      <level value="ERROR"/>
      <foreColor value="Red, HighIntensity"/>
    </mapping>
    <mapping>
      <level value="WARN"/>
      <foreColor value="Yellow, HighIntensity"/>
    </mapping>
  </appender>

</log4net>

If you still want to hand-code the output, use an ILog implementation. It basically gives you methods for each type of output. To bind your custom adapter you create the configuration section like this...

<appender name="name" type="NameSpace.ClassOfTypeILog, AssemblyName">
    ...
</appender>

Can I hook to log4net Log, Debug, Info, and Error?

1 Answers