Application Insights extension breaking Azure web app

Question

I had Application Insights running smoothly on an Azure Web App via the AI SDK, reporting to an AI instance hosted in Azure.

The only niggle was it didn't show detailed dependancy diagnostics, according to this page this was because I was using the SDK only, I needed to "Instrument your web app on the server", which looking at the docs can't be done if you already have an instance of AI running....helpful!

Reluctantly I deleted the AI instance, stripped the SDK from my code so I was starting fresh, and followed the steps, however as soon as I finished the process in the previous link my website broke and now responds to every single request (MVC5 and Web API) with an empty 404 request

The AI status page is showing green ticks for everything, and I can't discern anything from diagnostic log dump from KUDO or manage to remotely debug the site.

Deleting the AI extension under Web App -> Extensions in the Azure portal and then restarting the web app fixes the problem.

I've run out of ideas on how to fix this, is there anything else I can do to get to the bottom of the problem?

Answer 1

To fix this problem, delete the following 2 files from your web app's (or slot's) filesystem:

D:\home\siteextensions\Microsoft.ApplicationInsights.AzureWebSites\Instrumentation32\ProductionBreakpoints_x86.config
D:\home\siteextensions\Microsoft.ApplicationInsights.AzureWebSites\Instrumentation64\ProductionBreakpoints_x64.config

You can do this easily through Kudu.

Edit: Apparently this is/was an issue with the ProductionBreakpoints interacting with precompiled views. Microsoft has informed me a fix should be out within the next couple days. The version of Application Insights extension I have now that is still broken is 2.4.6 - I will post the "fixed" version when I can confirm it.

Edit 2: Confirmed this is fixed in 2.4.7 which is out now.