looks like log4net Seq logging requires 2 (!) XmlConfigurator.ConfigureAndWatch calls

Question

i observe a strange behavior when using Seq.Client.log4Net (3.1.0) on .NET 6 :

logging to the Seq Server seems to work only if I call XmlConfigurator.ConfigureAndWatch before and after calling the log method. It seems that only the Seq appender is affected (Console and File Logging are executed without the second call of XmlConfigurator.ConfigureAndWatch!

Logging to Seq Server works fine:

 ILog log = LogManager.GetLogger(GetType());
 XmlConfigurator.ConfigureAndWatch( new FileInfo(@"\log4net.config"));
 log.Info("Entering application.");
 log.Warn("Exiting application.");
 XmlConfigurator.ConfigureAndWatch(new FileInfo(@"log4net.config")); //why is this required??

No Seq Logging:

 ILog log = LogManager.GetLogger(GetType());
 XmlConfigurator.ConfigureAndWatch( new FileInfo(@"\log4net.config"));
 log.Info("Entering application.");
 log.Warn("Exiting application.");

log4net.config is:

    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">      
 ..    
    </appender>
    
    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
 ..
    </appender>
    
    <appender name="SeqAppender" type="Seq.Client.Log4Net.SeqAppender, Seq.Client.Log4Net">
      <bufferSize value="100" />      
      <serverUrl value="https://xxx:yy" />
      <apiKey value="" />
      <parameter>
        <parameterName value="Runtime" />
        <layout type="log4net.Layout.PatternLayout">
          <conversionPattern value=".NET Framework" />
        </layout>
      </parameter>
      <parameter>
      <parameterName value="Config" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="ExternalConfig" />
      </layout>
      </parameter>     
    </appender>
   
    <root>
      <level value="DEBUG" />
      <appender-ref ref="ConsoleAppender" />
      <appender-ref ref="RollingLogFileAppender" />
      <appender-ref ref="SeqAppender" />
    </root>
  </log4net>

according to the documentation one call to ConfigureAndWatch is enough, so I am very confused what is going on here. hanks for any ideas!

Answer 1

You need to call LogManager.Shutdown() before exiting the application to ensure all events are flushed to Seq.