Adding hosted service seems to crash Azure WebApp - azure

Question

So I have a webservice running in an Azure WebApp, that is the backend for a Blazor frontend. It has api controllers and SignalR.
For easier local development, I added a hosted service using .AddHostedService to have a small shell in the console for querying or triggering things without having to go through swagger or the frontend. This shell is a BackgroundService with practically this:
protected override Task ExecuteAsync(CancellationToken stoppingToken)
{
this.Looper = Task.Run(() => Loop(stoppingToken), stoppingToken);
return this.Looper;
}
private async void Loop(CancellationToken stoppingToken)
{
char chosenOption;
while (!stoppingToken.IsCancellationRequested && (chosenOption = GetChoice()) != 'Q')
{
await Commands[Commands.Keys.Single(key => key[0] == chosenOption)]();
}
}
private char GetChoice()
{
char chosenOption;
Console.WriteLine("Menu:");
do
{
foreach (var choice in Choices)
{
Console.WriteLine(choice);
}
chosenOption = char.ToUpper(Console.ReadKey().KeyChar);
Console.WriteLine();
} while (!IsValidChoice(chosenOption));
return chosenOption;
}
But for some reason, the Azure WebApp now crashes on startup.
Can an Azure WebApp just not handle a hosted service or shell? Because it works fine in the local self-hosted application.

Answer 1

So thanks to #mtkachenko I found the problem in the azure portal's diagnostic tools a few levels deep:
System.InvalidOperationException: Cannot read keys when either application does not have a console or when console input has been redirected
Turns out Console.ReadKey() interacts directly with the console, not just with the input stream. As there is no console connected to the Azure WebApp though (instead the streams are redirected), it crashes trying to interact with the non-existing console.
Console.Read or .ReadLine will work though, as the streams are there.