Monday, February 12, 2018

Get rid of annoying Application Insights Telemetry output items in ASP.Net Core web projects

I was working on this web ASP.Net Core 2.0 project that was spewing a lot of "Application Insights Telemetry (unconfigured): ..." messages in the Debug Output window. At first I thought I should just remove the Microsoft Application Insights NuGet package, but it didn't work. By default, it will still use insights even if you don't have it referenced anywhere in your code.

The solution is to do have installed Microsoft Application Insights NuGet package, but then set
Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration.Active.DisableTelemetry = true;
somewhere in Startup.cs (the constructor is fine).

Apparently, in the preview versions of Visual Studio 2017 there is an option under Options → Projects and Solutions → Web Projects → Disable local Application Insights for Core web projects, too.

Update: A comment suggested you need to Disable the automatic loading of hosting startup assemblies which can be done in two ways:
  1. setting ASPNETCORE_preventHostingStartup to True or 1 in the project properties → Debug → Environment variables
  2. Doing something like
        .UseSetting(WebHostDefaults.PreventHostingStartupKey, "true")
    - available from .NET Core 2.0

Either of these works, and although I agree with Andrei that the underlying issue for the unwanted telemetry is the automatic loading of hosting assemblies, I feel like the first option, the one that actually contains the word Telemetry in it is better for reasons of readability. But it's good there are three options to choose from.