How do you log errors (Exceptions) in your ASP.NET apps?

Question

I'm looking for the best way to log errors in an ASP.NET application. I want to be able to receive emails when errors occurs in my application, with detailed information about the Exception and the current Request.

In my company we used to have our own ErrorMailer, catching everything in the Global.asax Application_Error. It was "Ok" but not very flexible nor configurable.

We switched recently to NLog. It's much more configurable, we can define different targets for the errors, filter them, buffer them (not tried yet). It's a very good improvement.

But I discovered lately that there's a whole Namespace in the .Net framework for this purpose : System.Web.Management and it can be configured in the healthMonitoring section of web.config.

Have you ever worked with .Net health monitoring? What is your solution for error logging?

Answer 1

I use elmah. It has some really nice features and here is a CodeProject article on it. I think the StackOverflow team uses elmah also!

Answer 2

I've been using Log4net, configured to email details of fatal errors. It's also set up to log everything to a log file, which is invaluable when trying to debug problems. The other benefit is that if that standard functionality doesn't do what you want it to, it's fairly easy to write a custom appender which can process the logging information as required.

Having said that, I'm using this in tandem with a custom error handler which sends out a html email with a bit more information than is included in the standard log4net emails - page, session variables, cookies, http server variables, etc.

These are both wired up in the Application_OnError event, where the exception is logged as a fatal exception in log4net (which then causes it to be emailed to a specified email address), and also handled using the custom error handler.

First heard about Elmah from the Coding Horror blog entry, Crash Responsibly, and although it looks promising I'm yet to implement it any projects.

Answer 3

I've been using the Enterprise Library's Logging objects. It allows you to have different types of logging (flat file, e-mail, and/or database). It's pretty customizable and has a pretty good interface for updating your web.config for the configuration of the logging. Usually I call my logging from the On Error in the Global.asax.

Here's a link to the MSDN

Answer 4

I use log4net and where ever I expect an exception I log it to the appropriate level. I tend not to re-throw the exception because it doesn't really allow for as-nice user experience, there is less info you can provide at the current state.

I'll have Application_Error also configured to catch any exception which was not expected and the error is logged as a Fatal priority through log4net (well, 404's are detected and logged as Info as they aren't that high severity).