Reading settings from Azure Configuration instead of appsettings.json in .NET 7 Web API

I have a .NET 7 Web API project where I want to read application settings from Azure Configuration instead of relying on the traditional appsettings.json file.

The reason I want to do this is that I am using Azure Key Vault to securely store sensitive configuration values such as database connection strings, API keys, and other secrets. By leveraging Azure App Configuration, I can directly reference secrets stored in Azure Key Vault using the @Microsoft.KeyVault(SecretUri={SecretURL}) syntax.

But currently it is loading from appsettings.json only, Please suggest what changes I have to made to read settings from Azure App Configuration. It should load settings from appsettings.json only when running on localhost.

public static class ConfigurationExtensions
    {
        public static IConfigurationBuilder AddAppConfiguration(this IConfigurationBuilder configurationBuilder, IWebHostEnvironment hostingEnvironment)
        {
            configurationBuilder
                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true);

            // For Localhost, we're using appsettings.json file, it will not be overridden when running on Localhost
            if (!hostingEnvironment.IsEnvironment("Localhost"))
            {
                configurationBuilder.AddJsonFile($"appsettings.{hostingEnvironment.EnvironmentName}.json", optional: true, reloadOnChange: true);
                
            }
            configurationBuilder.AddEnvironmentVariables();
            return configurationBuilder;
        }
    }

This is my Program.cs

var builder = WebApplication.CreateBuilder(args);
{
    // Environment configuration
    var configuration = builder.Configuration;
    var env = builder.Environment;

    configuration.AddAppConfiguration(env);

    builder.Services.AddMediatR(cfg => cfg.RegisterServicesFromAssemblyContaining<Program>());
    builder.Services.AddHttpClient();

    builder.Services.AddApplication();
    builder.Services.AddInfrastructure(builder.Configuration);

    builder.Services.AddHelpers();

    builder.Services.AddControllers()
       // Configures the JSON serialization options for controllers.
       .AddJsonOptions(options =>
        {
            options.JsonSerializerOptions.PropertyNamingPolicy = null;
        });

    builder.Services.Configure<ApiBehaviorOptions>(options =>
    {
        options.SuppressModelStateInvalidFilter = true;
    });

}

var app = builder.Build();
{
    app.UseHttpsRedirection();

    // Authentication & Authorization
    app.UseAuthentication();
    app.UseAuthorization();
    app.MapControllers();

    app.UseRouting();
    app.UseSwaggerWithVersioning();
}

if (app.Environment.IsDevelopment())
{
    //DEV configurations
}

app.Run();

If you want to load settings from Azure App Configuration service, you can get the connection string from Azure Portal. Just go to your App Configuration service in Azure Portal and click on "Access keys". On the right hand side you will see the connection string which would be something like Endpoint=https://appconfigurationstore.azconfig.io;Id=/Bd4;Secret=Dv9LqAonMWSKnOdOkJdY1gQpV1mkmDydWzVoYeOqvZk=.

Once you have it, you can use the following code:

public static class ConfigurationExtensions
{
    public static IConfigurationBuilder AddAppConfiguration(this IConfigurationBuilder configurationBuilder, IWebHostEnvironment hostingEnvironment)
    {
        configurationBuilder.AddAzureAppConfiguration(options => 
        {
            options.Connect("your-connection-string-from-portal")
        });
        return configurationBuilder;
    }
}

If you do not want to use connection string, you can also make use of Managed identity (if your code is running in Azure). You can either use System Assigned or User Assigned Managed Identity. Please note that the Identity you are using to connect must be assigned appropriate App Configuration RBAC role (e.g. App Configuration Data Reader). In this case, you will use the App Configuration service's endpoint (https://appconfigurationstore.azconfig.io) only.

Your code in that case would be:

options.Connect(new Uri("your-app-configuration-service-endpoint"), new ManagedIdentityCredential("client-id-of-the-identity"));