Does the Log4net SMTPAppender send email Asynchronously?

Question

Does the Log4net SMTPAppender send email asynchronously? If it doesn't, how can I send logging emails asynchronously?

My log4net.config is:

<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
  </configSections>
  <log4net>
    <appender name="SMTPAppender" type="log4net.Appender.SMTPAppender">
      <authentication value="Basic" />
      <to value="[e-mail]" />
      <from value="[e-mail]" />
      <username value="[e-mail]" />
      <password value="yyy" />
      <subject value="xxx" />
      <smtpHost value="smtp.xx.com" />
      <lossy value="true" />
      <evaluator type="log4net.Core.LevelEvaluator">
        <threshold value="WARN" />
      </evaluator>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%newline%date [%thread] %-5level %logger %newline %message%newline%newline%newline" />
      </layout>
    </appender>
    <root>
      <level value="INFO"></level>
    </root>
    <logger name="MyLogger">
      <level value="INFO"></level>
      <appender-ref ref="SMTPAppender"></appender-ref>
    </logger>
  </log4net>
</configuration>

Answer 1

You could just call the logging method asynchronously like this:

Task.Factory.StartNew(() => log.Info("Message I want to email"));

I actually got this suggestion from the following SO article:

How do I create an asynchronous wrapper for log4net?

Answer 2

There is a simple workaround before the solid solution is released.

public class SmtpAsyncAppender : SmtpAppender
{
    protected override void SendEmail(string messageBody)
    {
        Task.Run(() => base.SendEmail(messageBody));
    }
}

It presumes that SmtpAppender.SendEmail is thread-safe and reenterable. It is for log4net v1.2.13.0 and there is no reason not to be in the future.

Answer 3

Log4net has not built in appender that is asynchronous. If you need that functionality you need to write your own appender. Downloading the log4net source code should get you started...