[Documentation] Startup Exceptions may prevent SSL from being enabled

[Tratcher]

SSL is enabled for kestrel via connection filters in Startup.Configure. app.UseKestrelHttps(...); If an exception happens before this line in Startup then hosting will catch it, start the server, and display an http error page on that port. If an exception happens after that line then the error page will be served over https instead.

I'm filing this to document the odd behavior, I don't think we'd be able to fix it.

[NickCraver]

If we were using this in production and Startup failed for any reason, I'd much rather the server fail to start completely (e.g. process crash) and go to the logs to figure out why rather than have it partially functional in unexpected and less-likely-to-notice ways.

Is it possible to completely bomb instead? I think most sysadmins would desire this behavior vs. a partial/unknown failure.

[Tratcher]

@NickCraver It used to be that way but we explicitly changed it back in beta8. aspnet/Hosting#77. The only way to opt out is if you call WebHostBuilder directly. If you want more control then you can start that discussion in Hosting.

[muratg]

@glennc will look into documenting this behavior somewhere.

[DamianEdwards]

Didn't we change the Hosting behavior back to the app explicitly requiring an opt-in to capturing startup errors?

[Tratcher]

No, it's still opt-out.

[DamianEdwards]

OK. Given that in RC2 apps have to use the WebHostBuilder API directly, this can always be turned off by an app if desired. Let's ensure it's documented.

[muratg]

@danroth27 Could you track documentation here?

[danroth27]

dotnet/AspNetCore.Docs#1095