Getting connection string for DBContext when deploying to Azure

EDIT: This question has been significantly restructured, now I’ve figured out a bit more of the problem and this should clarify things.

I am following this tutorial: https://learn.microsoft.com/en-us/azure/app-service/tutorial-dotnetcore-sqldb-app

I’ve deployed my own multiproject app, which works, but I can’t get the connection string working properly. For some reason, it only works if I hardcode the connection string into the OnConfiguring method of my DBContext class. Otherwise, it throws an error.

Like so:

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
        .UseSqlServer(
                "Nasty hard coded azure connection string",
                providerOptions => { providerOptions.EnableRetryOnFailure(); });
    } 

However, obviously, i want to get the connection string from a configuration file or environment variable.

Prior to deploying, I had the following. An extension method for IServiceColleciton which sets up the connection string:

public static void ConfigureSqlContext(this IServiceCollection services,
    IConfiguration configuration) =>
    services.AddDbContext<PeakedDbContext>(opts =>
 opts.UseSqlServer(configuration.GetConnectionString("defaultConnection")));

then this method is called in program.cs. A pretty normal setup.

And I also set up an IDesignTimeDBContextFactory like so:

 public class RepositoryContextFactory : IDesignTimeDbContextFactory<PeakedDbContext>
    {
        public PeakedDbContext CreateDbContext(string[] args)
        {
            var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json")
            .Build();
            var builder = new DbContextOptionsBuilder<PeakedDbContext>()
            .UseSqlServer(configuration.GetConnectionString("defaultConnection"));
            return new PeakedDbContext(builder.Options);
        }
    }

Both my appsettings.json AND the Azure App Service configuration have the same name "defaultConnection".

As far as I can tell this is the approach recommended here: https://learn.microsoft.com/en-us/ef/core/cli/dbcontext-creation?tabs=dotnet-core-cli

I have also tried adding an empty constructor for my DBContext. (Not sure how this affects things as I have other DIs on my DBContext constructor. My DBContext consructors are getting a bit out of hand:

    public PeakedDbContext()
    {
    }

    public PeakedDbContext(DbContextOptions options) : base(options)
    {
    }

    public PeakedDbContext(DbContextOptions options, ICurrentUserService currentUserService) : base(options)
    {
        _currentUserService = currentUserService;
    }

According the the second link, above, I shouldn’t need OnConfiguring method in my DBContext… and even if I do, what is the correct way to pass access to configuration.GetConnectionString, instead of hardcoding the connection string? Should I just add yet another DBContext constructor with the config injected? However, it ONLY works if I have the onconfiguring method. Neither the contextfactory nor the extension method setup are being used by azure app service.

Shouldn’t it use the designtime factory or the hostconfiguration extension method I’ve set up above? What is the right way to use _configuration.GetConnectionString("defaultConnection") so that it works both locally and on Azure Deployment?

Update:
Still no luck. I tried adding the database connection string as an environment variable on azure like so:

and then updating all my reference to getconnection string – in program.cs, IDesignFactory and OnConfiguring – like so:

Environment.GetEnvironmentVariable("PeakedDbConn")

This continues to work locally. But When deploying to Azure it claims the connection string in null… so it’s not seeing this variable. Nor can I find any code that will access the defaultConnection from the image. Which is strange, because it accesses the SECRET variable just fine.