MatthieuGD MatthieuGD - 3 months ago 23
ASP.NET (C#) Question

How to Get Error Details of an ASP.NET 5 app deployed on Azure Websites?

I have an ASP.NET 5 solution with a website and several project libraries. I'm using MVC 6 and Entity Framework 7. Locally the app is working fine and until today it was working also on Azure deployed as an Azure Website.

But today after the latest deployment on Azure I got an error 500 like this on the startup (still working fine locally):

enter image description here

I tried to get more details by :


  • using middleware diagnostics

  • adding the customError / httpError settings in the web.config file

  • downloading the DetailedError page generated



It seems that the error/exception is happening during the Startup/Configure step but I'm still getting the generic error page without details. Even the version generated on the server (DetailedErrors folder) I got this:

enter image description here

I enabled the Failed Request Tracing but still no useful information:

enter image description here

Even if I strip down the code in the Startup/Configure and add a try/catch as suggested I got the same error without d├ętails. It seems to be a configuration/compilation issue but hard to debug without any information.

Answer

In RC1 (as of beta8, perhaps), one should apparently use:

app.UseDeveloperExceptionPage();

.. which apparently only works if app.Properties["host.AppMode"] is "development".

But this didn't work for me. The error message I was getting was specifically "An error occurred while starting the application", I have found that none of the given configurations will resolve this because the error is occurring before the configurations execute.

Somehow, the publish target folder must have gotten corrupted during publish because I found that deleting the entire deployment directory and re-publishing resolved the problem.

Otherwise, here is the reference: http://docs.asp.net/en/latest/fundamentals/diagnostics.html