Question

Is there a way to constraint log4n appender to log messages based on host name? I want to enable logger only on production machines and disable logging n development machines.

I know that there is an easy way to log host name with property: %property{log4net:HostName}, then I could filter logged messages by this, but I want to use smtp appender and send logged messages via email and I would like to reduce number of sent emails.

Answer 1

I found solution using custom filter:

public class HostFilter : FilterSkeleton
{
    public string AllowedHostsNames { get; set; }
    private IList<string> HostNamesList
    {
        get
        {
            if (string.IsNullOrEmpty(AllowedHostsNames))
                return new List<string>();

            return AllowedHostsNames
                .Split(',')
                .Select(n => n.ToUpper().Trim())
                .ToList();
        }
    }

    public override FilterDecision Decide(LoggingEvent loggingEvent)
    {
        var names = HostNamesList;
        if (names.Contains(Environment.MachineName))
            return FilterDecision.Accept;

        return FilterDecision.Deny;
    }
}


<appender name="SomeAppender" type="log4net.Appender.SmtpAppender">
  <to value="" />
  <from value="" />
  <subject value="" />
  <smtpHost value="" />
  <authentication value="Basic" />
  <port value="25" />
  <username value="" />
  <password value="" />
  <bufferSize value="10" />
  <lossy value="false" />
  <layout type="log4net.Layout.PatternLayout">
     <conversionPattern value="%newline%date [%thread] %-5level %logger - %message%newline%newline%newline" />
  </layout>
  <filter type="Logging.HostFilter, AssemblyName">
    <allowedHostsNames value="host1, host2, host3" />
  </filter>
</appender>