Program.cs

using System;
using System.IO;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace DI_Configuration_Logging_ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            using ServiceProvider serviceProvider = RegisterServices(args);
            IConfiguration configuration = serviceProvider.GetService<IConfiguration>();

            ILogger logger = serviceProvider.GetService<ILogger<Program>>();
            logger.LogInformation("Github api url is: {githubApiUrl}", configuration["github:apiUrl"]);
        }

        private static ServiceProvider RegisterServices(string[] args)
        {
            IConfiguration configuration = SetupConfiguration(args);
            var serviceCollection = new ServiceCollection();

            serviceCollection.AddLogging(cfg => cfg.AddConsole());
            serviceCollection.AddSingleton(configuration);

            return serviceCollection.BuildServiceProvider();
        }

        private static IConfiguration SetupConfiguration(string[] args)
        {
            return new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddEnvironmentVariables()
                .AddCommandLine(args)
                .Build();
        }
    }
}