ASP.NET Core (Blazor) Loading customer specific configuration on startup by using Url or Virtual Path - asp.net-core

Question

Our application (Server-side Blazor in .NET Core 3.1) runs within IIS on a Windows Server. We have multiple sites in IIS running the same application but with different URL's for different customers.
At startup in (ConfigureServices) we want to load customer configuration for the application from a config file. That way we can have multiple instances of the application running with different configs. Loading this information from the database is not an option because the config contains the details to connect to the database.
In ASP.NET Framework we would have access to the virtual path or (sub)domain name in the Global and then load the configuration based on that information.
We need the same access in our ASP.Net Core applications or another work around.
Is there any to achieve the same result?

Answer 1

A better way to distinguish sites is by URL. The domain name and port bound to each site in IIS will not be repeated.
You can refer to these code to get URL in startup.cs.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env,IHostApplicationLifetime lifetime,IServiceProvider serviceProvider)
{
...other code...
lifetime.ApplicationStarted.Register(
() => logAddresses(app.ServerFeatures));
}
static void logAddresses(IFeatureCollection features)
{
var addressFeature = features.Get<IServerAddressesFeature>();
if (addressFeature != null)
{
foreach(var address in addressFeature.Addresses)
{
Console.Out.WriteLine(address);
}
}
}

Answer 2

I was able to grab the Application Pool ID from the Environment and then load the config section as the application config:
var appPool = Environment.GetEnvironmentVariable( "APP_POOL_ID", EnvironmentVariableTarget.Process )
van sectionname = SomeMagicToParseAppPool( appPool );
var config = Configuration.GetSection( sectionName );
if ( config == null ) throw new ApplicationException($" Cannot find config section for {host}");
services.Configure<ApplicationSettings>( config );
This allows me to load a different config for a different site. The only downside is that each application requires their own Application Pool. But that was already a requirement due to a .NET Core ASP.NET app having to run unmanaged in the Application Pool.