NLog Truncate syntax

Question

I'm changing NLog.config file for UiPath. I want to increase truncate value to 20000 and I've tried following syntax but it's not working.

<variable name="truncated_message" value="${replace:replaceWith=...TRUNCATED:regex=true:inner=${message}:searchFor=^[\s\S]{20000}}"/>
<target type="File" name="WorkflowLogFiles" fileName="${WorkflowLoggingDirectory}/${shortdate}_Execution.log" layout="${time} ${level} ${truncated_message}" keepFileOpen="true" openFileCacheTimeout="5" concurrentWrites="true" encoding="utf-8" writeBom="true" />

I've also tried following regex but they do not work for me

(^(?:\S+\s+\n?){0, 20000}) 
(?\=.\{20000\}).+

Can anyone please tell me what am I doing wrong and how to do set the truncate value to 20000?

Answer 1

This works for me:

<nlog>
   <variable name="truncated_message_new" value="${message:truncate=20000}" />
   <variable name="truncated_message_old" value="${trim-whitespace:inner=${message:padding=-20000:fixedLength=true}}" />

   <targets>
      <target type="File" name="WorkflowLogFiles" fileName="C:\temp\nlog/${shortdate}_Execution.log" layout="${time} ${level} ${truncated_message_old}" keepFileOpen="true" openFileCacheTimeout="5" concurrentWrites="true" encoding="utf-8" writeBom="true" />
   </targets>

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

It only saves 20000 characters:

var test = string.Empty.PadLeft(40000, '*');
NLog.LogManager.GetLogger("test").Info("Doing hard work! {Action}", test);