Logging in multiple files using Nlog

Question

I am using NLog for logging purpose.

My code is as follows:

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

  <!-- make sure to set 'Copy To Output Directory' option for this file -->
  <!-- go to http://nlog-project.org/wiki/Configuration_file for more information -->

  <targets>
    <target
      name="logfile"
      xsi:type="File"
      layout="${message}"
      fileName="${basedir}../Data/debugLog1.txt"
      archiveAboveSize ="5000000"
      maxArchiveFiles="2"/>
  </targets>

  <rules>
    <logger name="*" minlevel="Trace" writeTo="logfile" />
  </rules>
</nlog>

I am logging data in debugLog1.txt. Now from another location in project I also want to log data but this data is of another type so I want to make a debugLog2.txt and log data to it. How can I modify my above code to do this

Answer 1

I think you need to define another logger.

<logger name="SpecialLogger" minlevel="Trace" writeTo="logfile2" />

And then into this another location in project log to it:

var logger = LogManager.GetLogger("SpecialLogger");

Answer 2

If you want a separate file to log information from another part of your program you can add a logger and another target.

For example if you have a program that is completing two different tasks and you want to log those tasks separately you could do the following

<targets>
  <target
    name="task1File"
    xsi:type="File"
    layout="${message}"
    fileName="${basedir}../Data/debugLog1.txt"
    archiveAboveSize ="5000000"
    maxArchiveFiles="2"/>
  <target
    name="task2File"
    xsi:type="File"
    layout="${message}"
    fileName="${basedir}../Data/debugLog2.txt"
    archiveAboveSize ="5000000"
    maxArchiveFiles="2"/>
</targets>

<rules>
  <logger name="task1Logger" minlevel="Trace" writeTo="task1File" />
  <logger name="task2Logger" minlevel="Trace" writeTo="task2File" />
</rules>

Then in your program access them with:

var task1Logger = NLog.LogManager.GetLogger("task1Logger")
var task2Logger = NLog.LogManager.GetLogger("task2Logger")

Answer 3

Please note that you could use layout renderers in the filename (even custom layout renderers) and so this will also make multiple files:

 <target
      name="logfile"
      xsi:type="File"
      layout="${message}"
      fileName="${basedir}../Data/${level}.txt" 
      ...
   />

In this example it's a log file for each loglevel (fatal, error, warn, info, debug, trace)