add dependency injection .net core console app
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
public class Program
{
    public static void Main(string[] args)
    {
        //setup our DI
        var serviceProvider = new ServiceCollection()
            .AddLogging()
            .AddSingleton<IFooService, FooService>()
            .AddSingleton<IBarService, BarService>()
            .BuildServiceProvider();
        //configure console logging
        serviceProvider
            .GetService<ILoggerFactory>()
            .AddConsole(LogLevel.Debug);
        var logger = serviceProvider.GetService<ILoggerFactory>()
            .CreateLogger<Program>();
        logger.LogDebug("Starting application");
        //do the actual work here
        var bar = serviceProvider.GetService<IBarService>();
        bar.DoSomeRealWork();
        logger.LogDebug("All done!");
    }
}