How do I get a traceback of a HTTP500 from IIS running on Azure's "App Service" PaaS?

Question

I've inherited an ASP.NET project with instructions to run it on Azure's App Service. I set up a pipeline to compile it (with debug in the Configuration param & system.debug=true of the compilation step), created a release to deploy it, but it doesn't run (returns a HTTP500.0 with error code 0x00000000). But try as I might, I can't get a proper traceback out of IIS.

I have tried:

• Turning off CustomErrorMessages in Web.config ; this just shows IIS's "an error occurred and for security we're hiding the details" HTTP500 page.
• Viewing the live log feed in the "App Service Editor", then copy-pasting the html to view it (just gives generic error messages).
• Downloading the Application logs as per Microsoft's guide ; they're just generic HTTP500 pages with no trace.
• Enabling "Application Insights" APM and viewing failures, but 0 failures are reported.

I'm stumped. How do I get the App Service variant of IIS to show me a simple traceback?

Answer 1

The application stack trace is available in the logs, which can be viewed in "Advanced tools" menu of the App Service, or alternatively can be downloaded as a zip file as described in MSFT's instruction| . The relevant file that shows the stack trace inside this zipfile is eventlog.xml .