Program.cs

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.
//
namespace Microsoft.Extensions.Configuration.AzureAppConfiguration.Examples.ConsoleApplication
{
    using Microsoft.Extensions.Configuration;
    using Microsoft.Extensions.Configuration.AzureAppConfiguration;
    using System;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;

    class Program
    {
        static IConfiguration Configuration { get; set; }
        static IConfigurationRefresher _refresher;

        static void Main(string[] args)
        {
            Configure();

            var cts = new CancellationTokenSource();

            _ = Run(cts.Token);

            // Finish on key press
            Console.ReadKey();
            cts.Cancel();
        }

        private static void Configure()
        {
            var builder = new ConfigurationBuilder();

            // Load a subset of the application's configuration from a json file and environment variables
            builder.AddJsonFile("appsettings.json")
                   .AddEnvironmentVariables();

            IConfiguration configuration = builder.Build();

            if (string.IsNullOrEmpty(configuration["connection_string"]))
            {
                Console.WriteLine("Connection string not found.");
                Console.WriteLine("Please set the 'connection_string' environment variable to a valid Azure App Configuration connection string and re-run this example.");
                return;
            }

            // Augment the configuration builder with Azure App Configuration
            // Pull the connection string from an environment variable
            builder.AddAzureAppConfiguration(options =>
            {
                options.Connect(configuration["connection_string"])
                       .Select("AppName")
                       .Select("Settings:BackgroundColor")
                       .ConfigureClientOptions(clientOptions => clientOptions.Retry.MaxRetries = 5)
                       .ConfigureRefresh(refresh =>
                       {
                           refresh.Register("AppName")
                                  .Register("Language", refreshAll: true)
                                  .SetCacheExpiration(TimeSpan.FromSeconds(10));
                       });

                // Get an instance of the refresher that can be used to refresh data
                _refresher = options.GetRefresher();
            });

            Configuration = builder.Build();
        }

        private static async Task Run(CancellationToken token)
        {
            string display = string.Empty;
            StringBuilder sb = new StringBuilder();

            while (!token.IsCancellationRequested)
            {
                // Trigger an async refresh for registered configuration settings without wait
                _ = _refresher.TryRefreshAsync();

                sb.AppendLine($"{Configuration["AppName"]} has been configured to run in {Configuration["Language"]}");
                sb.AppendLine();

                sb.AppendLine(string.Equals(Configuration["Language"], "spanish", StringComparison.OrdinalIgnoreCase) ? "Buenos Dias." : "Good morning");
                sb.AppendLine();

                sb.AppendLine("Press any key to exit...");
                await Task.Delay(1000);

                if (!sb.ToString().Equals(display))
                {
                    display = sb.ToString();

                    Console.Clear();
                    Console.Write(display);
                }

                sb.Clear();
            }
        }
    }
}