Azure Portal: How to See Callstacks

Question

Apologies, this is not a short question:

Background

I have a B1 Azure Website, and for the life of me, cannot get exceptions with callstacks.

The WebAPI is hosted side-by-side with the website in the same solution, which I hear is unusual. Almost all configuration has been done through the solution, I believe. Most everything in the portal is probably default settings from a brand new site.

I will be the first to admit, I am a novice at Azure. I have previously hosted some exceedingly simple ASP websites (mostly pre-.NET) in the past. I have found the Azure Portal to be overwhelming, to say the least. Hence why I am here!

The main place I look for exceptions is in Application Insights, under Failures, Exceptions tab, however. While it usually (not always...) show that there were 500s, the vast majority of the time, it will show no callstack.

Situations

The few times it does catch a callstack, it's your normal bots poking at random directories... not the crippling exception I need to debug immediately. I recall hearing that Azure will use "AI to determine which callstacks to keep" or something market-y like that, but I can't find any settings regarding it. Even if that market-speak is true, why is it recording callstacks to daily bot attempts, but the rare application-crippling exception?

A month or so ago, I attempted to debug the live website via Visual Studio, but I get an error saying that Internet Explorer could not be found. Given that it's the year 2018 and Microsoft has moved onto Edge, I don't know why it wants Internet Explorer at all. I did find a response to this, saying to hack the registry and reinstall Internet Explorer, but that seemed overkill at the time.

Viewing Azure errors through Visual Studio's embedded Azure portal thing seems to show very similar data as the Azure portal does. No callstacks to be found.

Many years ago, a classic alert was set up for Http Server Errors, which still triggers to this day. It does not trigger on HttpExceptions from bots poking at the site, but it does for for important 500s, and that's good. What is interesting is that it is the most reliable way to hear about errors, besides user reports. Too bad they don't have callstacks...

Last night, we encountered an exception, presumably in the view, of a page. We got e-mails from the classic alert, as expected, but the Failures section does not show any failures at all. In the past, we'd see 500s, but no callstack. It would seem that last night's errors were not detected by anything but the classic alert and the user. I don't know if it is because last night's error was unique, or if we now mysteriously get even less information out of Azure.

Attempted Solutions

Over the years, I have followed a myriad of guides, ranging from flipping switches in the portal itself, to FTPing and looking at the raw logs (which apparently are not really about your application, as much as Microsoft hosting it). If I got a penny for every time I read a guide that said, "Simply click on the Exceptions tab to see your callstacks" I'd be rich :-P.

A month ago, I got so desperate I implemented Application_Error in the HttpApplication class for the application, and implemented ExceptionLogger for WebAPI, to manually log all exceptions to text files. Unfortunately, while this helped me fix one error, subsequent exceptions have not appeared there either. Just like Application Insights, mostly bots poking at non-existent directories show up in these logs.

A week ago, I got desperate enough that I wrote a janky "unit test" (ha!), that'd pull a copy of production data down and test it locally, which is absolutely bonkers.

I have spoken to other architect-level ASP.NET engineers that use Azure portal to varying frequencies, and they could not come up with any suggestions. We looked at the web.configs; there is one in the root and in the Views folder. We played with turning on customerrors, but obviously we can't have that running in production because it'd display the errors to the user. That being said, I wouldn't mind having real error messages appear to certain users. How would one accomplish that? If I were to guess, the issue is hidden in those web.configs, simply because they're ancient and so many hands have touched them.

Conclusion

I need a 100% bullet-proof way to get exceptions and their callstacks from ASP.NET hosted on Azure. Otherwise, it's nearly impossible to solve edge cases that appear unexpectedly in production. I don't recall this being a problem in my days before Azure.

I am certain an expert out there will have this solved in mere minutes, but, for now, I'm completely stumped. Thank you for your time!

Answer 1

A couple of things to try and check for:

1. Make sure that your Application Insights NuGet packages are up to date. I've had metrics quit working over the last couple of years, or new metrics show up on the AppInsights blade that I wasn't collecting. Upgrading to the latest NuGet packages did the trick.

2. Are you catching exceptions within your web app and then returning a HTTP 500 response explicitly? If so, you won't see a stack trace. Stack traces are captured after bubbling all the way up through your controller method unhandled.