Hello,

Configure prlogging.xml to add a JSON Appender and add this appender to the root logger.  This would enable output logs as JSON objects.

<appender name="JSONAppender" class="com.pega.pegarules.priv.util.DailySizeRollingFileAppenderPega"> 

       <param name="FileNamePattern" value="'PegaRULES-'yyyy-MMM-dd'.json.log'"/> 

                      <layout class="com.pega.pegarules.priv.LogLayoutJSON"> 

                           <param name="UserFields" value="src-vm:"",src-node:"",src-env:" ""/> 

                      </layout> 

</appender>

You can add user fields to add custom data to log events.

Thanks