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?

CodePudding user response：

• Turn on Application Logging and Detailed error messages for the Web App in
  Azure Portal =>Your Web App =>App Service Logs, turn on the settings, make sure level is set to Error

• The above settings will enable Application logging and start writing to log files into D:\home\LogFiles\Application.
• To view Application Log, below App Service logs click Log stream.
• Wait for some time to warm up and then refresh the page of the Web App.
• Make sure you are viewing the Application logs and not the Web Server logs.
• By navigating to Log stream and selecting Application Logs you could see a detailed error message
• In web.config, add customErrors mode

<configuration>
   <system.web>
      <customErrors mode="Off"/>
   </system.web>
</configuration>

This will add the markup to the deployed web.config file and gives you detailed errors.

• Restart the App and access the URL.

CodePudding user response：

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.