Adding custom parameters to the log

Sometimes it is difficult to troubleshoot errors in Sitecore’s standard log file due to the lack of some key pieces of information… namely: context user, context item id and the raw requested url. However, since Sitecore uses Log4Net, we can easily inject this information into our log entries. Alex Shyba has a great post that details exactly how to get this information into your logs… IF you are logging to a SQL database that is.

In my case, I wanted to just add this information into the existing (default) LogFileAppender. To do this, I extended Sitecore’s “SitecoreLogFileAppender” class as follows:

public class SitecoreLogFileAppenderEx : log4net.Appender.SitecoreLogFileAppender
{
    protected override void Append(LoggingEvent loggingEvent)
    {
        var properties = loggingEvent.Properties;

        properties["scuser"] = string.Empty;
        properties["scitemid"] = string.Empty;
        properties["rawurl"] = string.Empty;

        // Only log ERRORS or higher level events
        if (Sitecore.Context.Site != null && loggingEvent.Level >= Level.ERROR)
        {
            if (Sitecore.Context.User != null)
                try { properties["scuser"] = Sitecore.Context.User.Name; }
                catch { }
            if (Sitecore.Context.Item != null)
                try { properties["scitemid"] = Sitecore.Context.Item.ID.ToString(); }
                catch { }

            try { properties["rawurl"] = Sitecore.Web.WebUtil.GetServerUrl() + Sitecore.Web.WebUtil.GetRawUrl(); }
            catch { }
        }
        base.Append(loggingEvent);
    }
}

Then i modified the web.config log4net configuration to use my appender and added the custom properties to the PatternLayout as follows.:

		<appender name="LogFileAppender" type="log4net.Appender.SitecoreLogFileAppenderEx, Sitecore.Drexel.Logging">
			<file value="$(dataFolder)/logs/log.{date}.txt"/>
			<appendToFile value="true"/>
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%4t %d{ABSOLUTE} %-5p %c [%P{scuser} %P{scitemid} %P{rawurl}] %m%n"/>
			</layout>
		</appender>

It is important to note that when specifying the parameters in the PatternLayout, you must use a capital “P”.