Where will log4net create this log file?

When I set the file value to logs\log-file.txt, where exactly will it create this folder? In the /bin directory?

My web.config looks like this:

<log4net>
    <appender name="FileAppender" type="log4net.Appender.FileAppender">
      <file value="logs\log-file.txt" />
      <appendToFile value="true" />
      <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
      </layout>
    </appender>
</log4net>

Is this the correct way to log:

ILog logger = LogManager.GetLogger(typeof(CCController));
logger.Error("Some Page", ex);  // where ex is the exception instance

If you want your log file to be place at a specified location which will be decided at run time may be your project output directory then you can configure your .config file entry in that way

<file type="log4net.Util.PatternString" value="%property{LogFileName}.txt" />

and then in the code before calling log4net configure, set the new path like below

 log4net.GlobalContext.Properties["LogFileName"] = @"E:\\file1"; //log file path
 log4net.Config.XmlConfigurator.Configure();

How simple is it? :)


it will create the file in the root directory of your project/solution.

You can specify a location of choice in the web.config of your app as follows:

   <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="c:/ServiceLogs/Olympus.Core.log" />
      <appendToFile value="true" />
      <rollingStyle value="Date" />
      <datePattern value=".yyyyMMdd.log" />
      <maximumFileSize value="5MB" />
      <staticLogFileName value="true" />
      <lockingModel type="log4net.Appender.RollingFileAppender+MinimalLock" />
      <maxSizeRollBackups value="-1" />
      <countDirection value="1" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date %-5level [%thread] %logger - %message%newline%exception" />
      </layout>
    </appender>

the file tag specifies the location.


The file value can either be an absolute path like "c:\logs\log.txt" or a relative path which I believe is relative to the bin directory.

As far as implementing it, I usually place the following at the top of any class I plan to log in:

private static readonly ILog Log = LogManager.GetLogger( 
MethodBase.GetCurrentMethod().DeclaringType);

Finally, you can use it like so:

Log.Debug("This is a DEBUG level message.");

Log4net is saving into your project folder. Something like: \SolutionFolder\ProjectFolder\bin\SolutionConfiguration\logs\log-file.txt.

Where:

  • SolutionFolder is where you save your solution
  • ProjectFolder is the folder where your project lives into the solution and
  • SolutionConfiguration is the folder that contais all the binaries of your project (the default is Debug or Release)

Hope this helps!


FileAppender appender = repository.GetAppenders().OfType<FileAppender>().FirstOrDefault();
if (appender != null)
    logger.DebugFormat("log file located at : {0}", appender.File);
else
    logger.Error("Could not locate fileAppender");