NLog: How to send log message to console from two different targets without duplications?

Question

I have three targets - Engine, Tasks and Error. Please, find belog their NLog configuration:

<targets>
  <target name="EngineLog" xsi:type="File" fileName="C:\Log\EngineLog.txt" layout="${layout}"/>
  <target name="ErrorLog" xsi:type="File" fileName="C:\Log\ErrorLog.txt" layout="${layout}"/>
  <target name="TasksLog" xsi:type="File" fileName="C:\Log\TasksLog.txt" layout="${layout}"/>
  <target name="ConsoleLog" xsi:type="ColoredConsole" layout="${consoleLayout}"/>
</targets>
<rules>
  <logger name="*" minLevel="Error" writeTo="ErrorLog"/>

  <logger name="N1.*" minLevel="Warn" writeTo="EngineLog" final="true"/>
  <logger name="N2.*" minLevel="Info" writeTo="EngineLog" final="true" />
  <logger name="N3.*" minLevel="Info" writeTo="EngineLog" final="true" />
  <logger name="N4.*" minLevel="Info" writeTo="EngineLog" final="true" />
  <logger name="N5.*" minLevel="Info" writeTo="EngineLog" final="true" />

  <logger name="N6" minLevel="Info" writeTo="EngineLog" />
  <logger name="*" minlevel="Info" writeTo="TasksLog" />
</rules>

Of course, the real namespace names are not N1...N6, what matters is that I have:

5 namespaces which are logged to the Engine log exclusively (N1-N5)
All the errors (both Engine and Tasks) are logged to the same Error log in addition to the respective dedicated target.
One namespace is logged both to Engine and Tasks (N6)
The rest is considered Tasks

Now I would like additionally to log everything going to either ErrorLog or TasksLog to the console.

My first try was to wrap the ErrorLog and TasksLog with a SplitGroup grouping each target with the console target, like this:

<target name="ErrorLog" xsi:type="SplitGroup">
  <target xsi:type="File" fileName="C:\Log\ErrorLog.txt" layout="${layout}"/>
  <target xsi:type="ColoredConsole" layout="${consoleLayout}"/>
</target>
<target name="TasksLog" xsi:type="SplitGroup">
  <target xsi:type="File" fileName="C:\Log\TasksLog.txt" layout="${layout}"/>
  <target xsi:type="ColoredConsole" layout="${consoleLayout}"/>
</target>

But this is a wrong approach, because every error gets logged twice on the console - first on behalf of the ErrorLog and then on behalf of the TasksLog.

How can I log errors to the console without duplications while allowing them to go to both the ErrorLog target and the TasksLog/EngineLog targets?

EDIT

The desired effect can be achieved if I could specify to log messages, but not if they are Error or Fatal (because these have already been logged).

mark mark · Accepted Answer · 2013-06-24T15:44:04

OK, I think I have found the solution:

<target name="ErrorLog" xsi:type="SplitGroup">
  <target xsi:type="File" fileName="C:\Log\ErrorLog.txt" layout="${layout}"/>
  <target name="ConsoleLog" xsi:type="ColoredConsole" layout="${consoleLayout}"/>
</target>

And add the following rule at the end:

<logger name="*" levels="Warn, Info, Debug, Trace" writeTo="ConsoleLog" />

NLog: How to send log message to console from two different targets without duplications?

1 Answers