Is it possible to create a patch config file for log level?

Question

I've created this patch file for a Sitecore 9 instance, but looking at showconfig.aspx it has had no effect. The config file name begins with a 'z' to try to ensure it's processed last.

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <log4net>
      <root>
        <priority value="ERROR" />
      </root>
      <logger name="Sitecore.Diagnostics.WebDAV" additivity="false">
        <level value="ERROR"/>
      </logger>
      <logger name="Sitecore.Diagnostics.Publishing" additivity="false">
        <level value="ERROR"/>
      </logger>
    </log4net>
  </sitecore>
</configuration>

Is it possible to patch in log4net config settings? If so, is my config file formatted incorrectly?

Answer 1

You forgot to use patch:attribute syntax. Valid patch file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <log4net>
      <root>
        <priority>
            <patch:attribute name="value">ERROR</patch:attribute>
        </priority>
      </root>
      <logger name="Sitecore.Diagnostics.WebDAV" additivity="false">
        <level>
            <patch:attribute name="value">ERROR</patch:attribute>
        </level>
      </logger>
      <logger name="Sitecore.Diagnostics.Publishing" additivity="false">
        <level>
            <patch:attribute name="value">ERROR</patch:attribute>
        </level>
      </logger>
    </log4net>
  </sitecore>
</configuration>