Azure App Configuration

DataController.cs

using System.Collections.Generic;
using FeatureTogglerApp.Features;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Options;

namespace FeatureTogglerApp.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class DataController : ControllerBase
    {
        private readonly FeatureOptions _featureOptions;

        public DataController(IOptionsSnapshot<FeatureOptions> featureOptions)
        {
            _featureOptions = featureOptions.Value;
        }

        [HttpGet]
        public IEnumerable<string> Get()
        {
            var user = "janne"; // DEMO: Example user to look for feature flags

            // Use app level toggles first and then override with
            // possible (but not mandatory) user toggles
            var dataApiEnabled =
                _featureOptions.DataApiEnabled ||
                (_featureOptions.Users.ContainsKey(user) &&
                 _featureOptions.Users[user].DataApiEnabled);

            if (dataApiEnabled)
            {
                return new string[] { "cool", "api", "in", "use" };
            }
            else
            {
                return new string[] { /* None since api not in use. */ };
            }
        }
    }
}

FeatureOptions.cs

using System.Collections.Generic;

namespace FeatureTogglerApp.Features
{
    public class FeatureOptions : FeatureToggles
    {
        public string AppName { get; set; }
        public Dictionary<string, FeatureToggles> Users { get; set; }

        public FeatureOptions()
        {
            Users = new Dictionary<string, FeatureToggles>();
        }
    }

    public class FeatureToggles
    {
        public bool IndexPageCanvasEnabled { get; set; }
        public bool DataApiEnabled { get; set; }
    }
}

Program.cs

// ...
config.AddAzureAppConfiguration(options =>
{
    // Use with connection string:
    // options.Connect(connectionString)
    // or with managed identity:
    options.ConnectWithManagedIdentity(endpoint)
        .Use("FeatureToggler:*")
        .WatchAndReloadAll("FeatureToggler:UpdateKey", TimeSpan.FromSeconds(5));
});

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<FeatureOptions>(Configuration.GetSection("FeatureToggler"));
    // ...