How do I enable ASP.NET detailed error tracking?

LeanSentry tracks every error across the server, IIS, and ASP.NET application stack.  However, in some configurations ASP.NET may not provide complete error information for request errors, which will cause LeanSentry to under-report ASP.NET errors, and in some cases to never show them.

To enable accurate ASP.NET error tracking, you will need to make 2 small changes to your application:

1. Enable every ASP.NET error to be logged (in all ASP.NET applications)

2. For ASP.NET MVC applications, update default HandleErrorAttribute to fix error logging (ASP.NET MVC applications only)

Make sure ASP.NET exception logging is on (all ASP.NET applications)

Open your environment settings, and check "Enable full ASP.NET error tracking":

This will cause LeanSentry to enable full ASP.NET error logging to the Event Log for all ASP.NET applications on the server, by making a small change to the default ASP.NET Health Monitoring configuration in the Framework's root web.config (for 32 bit and 64 bit frameworks of all currently-installed versions).

NOTE: Consider making this change during off-peak times, because it can cause your ASP.NET applications to restart the first time it's applied.

Alternatively, you can make the following change directly to your application's web.config: 

1. <system.web>
   
       <!-- Add this section -->
       <healthMonitoring>
           <rules>
               <!-- Make sure all errors are logged to the EventLogProvider ("Default" profile only allows 1 error per minute) -->
               <remove name="All Errors Default" />
               <add name="All Errors Default" eventName="All Errors" profile="Critical" provider="EventLogProvider" />
           </rules>
       </healthMonitoring>
   
   </system.web>
   

For ASP.NET MVC applications, update default HandleErrorAttribute to fix error logging 

1. Make the following change in your global.asax.cs:

public class MvcApplication : System.Web.HttpApplication
{
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        // Use the fixed HandleErrorAttributeWithHealthMonitoring
        filters.Add(new HandleErrorAttributeWithHealthMonitoring());
    }  
                
    // ...
}      

2. Add the HandleErrorAttributeWithHealthMonitoring class:

public class HandleErrorAttributeWithHealthMonitoring : HandleErrorAttribute
{
    public override void OnException(ExceptionContext context)
    {
        base.OnException(context);
            
        // Raise the error to health monitoring
        new MyRequestErrorWebEvent("An unhandled request exception has occurred", context.Exception).Raise();
    }
}   
                    
public class MyRequestErrorWebEvent : WebRequestErrorEvent 
{
    public const int CustomEventCode = 100801;

    public MyRequestErrorWebEvent(string msg, Exception e)
        : base(msg, null, CustomEventCode, e)
    {
    }
}
	

For more information, see http://weblogs.asp.net/awilinsk/archive/2008/12/11/handleerrorattribute-and-health-monitoring.aspx.

For WCF applications, enable unhandled exception logging

See this article for more information: https://leansentry.zendesk.com/entries/27297257-Enable-WCF-detailed-error-tracking.

If you have any questions about this, email us and we'll be glad to help.