AddAzureWebAppDiagnostics() depends on AddConsole().

[Rick-Anderson]

Moved from dotnet/AspNetCore.Docs#16095 by @SidShetye

All extension methods referenced here are in C#, .net core 3.0 within Program.cs

It appears that removing logging.AddConsole(); breaks logging.AddAzureWebAppDiagnostics();. One would expect each logger to be independent but from our testing we found that AddAzureWebAppDiagnostics() depends on AddConsole().

Further more, going to the portal UI -> web app -> App Service logs -> Application Logging -> File System (enable) makes the AddAzureWebAppDiagnostics() redundant because linux AppService now automatically saves console logs to the webapp file system.

In addition, the documented folders are wrong on linux. There is no Application folder generated within LogFiles.

I suggest a documentation do-over on the Azure WebApp + Linux + .NET Core 3.x combination.

[davidfowl]

@SidShetye can you clarify? There should be no dependency, how does it break?

[javiercn]

@davidfowl is this external?

[SidShetye]

@davidfowl we noticed this with our ASP.NET app that we upgraded from net461 -> netcoreapp3.1. We also moved from Cloud Services -> App Service for Linux, so lots of moving parts.

What we found in that logging.AddConsole(); there is no app logging whatsoever. Nothing in /home/LogFiles or the portal streaming blade or az webapp log tail commands. Having AddAzureWebAppDiagnostics() or not having made no difference (still no logs).

Simply put logging.AddConsole(); back in got us application logging once again.

[yogigrantz]

I have a setup like this:
IHostBuilder host = Host.CreateDefaultBuilder(args);
host.ConfigureLogging(x =>
{
x.ClearProviders();
x.AddAzureWebAppDiagnostics();
});
No .AddConsole, yet I got my log in home/Logfiles . Just be sure to turn on the FileSystem

[JunTaoLuo]

3.0 is out of support now but I'm curious if this affects 3.1. I took a look at the code at https://github.com/dotnet/extensions/blob/release/3.1/src/Logging/Logging.AzureAppServices/src/AzureAppServicesLoggerFactoryExtensions.cs#L31 and it doesn't seem to me that AddAzureWebAppDiagnostics would depend on AddConsole. I suspect that there's an issue with how the app is configured. Could you share your startup?

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