using System;

using System.Threading;

using System.IO;

using System.Threading.Tasks;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.Logging;

public class Program

{

    public static async Task Main(string[] args)

        {

            var host = new HostBuilder()

                .ConfigureHostConfiguration(configHost =>

                {

                    configHost.SetBasePath(Directory.GetCurrentDirectory());

                    configHost.AddJsonFile("https://raw.githubusercontent.com/aspnet/AspNetCore.Docs/master/aspnetcore/fundamentals/host/generic-host/samples/2.x/GenericHostSample/hostsettings.json", optional: true);

                    configHost.AddEnvironmentVariables(prefix: "PREFIX_");

                    configHost.AddCommandLine(args);

                })

                .ConfigureAppConfiguration((hostContext, configApp) =>

                {

                    configApp.AddJsonFile("https://raw.githubusercontent.com/aspnet/AspNetCore.Docs/master/aspnetcore/fundamentals/host/generic-host/samples/2.x/GenericHostSample/appsettings.json", optional: true);

                    configApp.AddEnvironmentVariables(prefix: "PREFIX_");

                    configApp.AddCommandLine(args);

                })

                .ConfigureServices((hostContext, services) =>

                {

                    //services.AddHostedService<LifetimeEventsHostedService>();

                    services.AddHostedService<TimedHostedService>();

                })

                .ConfigureLogging((hostContext, configLogging) =>

                {

                    configLogging.AddConsole();

                    configLogging.AddDebug();

                })

                .UseConsoleLifetime()

                .Build();

​

            await host.RunAsync();

        }

}

​

internal class TimedHostedService : IHostedService, IDisposable

    {

        private readonly ILogger _logger;

        private Timer _timer;

​

        public TimedHostedService(ILogger<TimedHostedService> logger)

        {

            _logger = logger;

        }

​

        public Task StartAsync(CancellationToken cancellationToken)

        {

            _logger.LogInformation("Timed Background Service is starting.");

​

            _timer = new Timer(DoWork, null, TimeSpan.Zero, 

                TimeSpan.FromSeconds(5));

​

            return Task.CompletedTask;

        }

​

        private void DoWork(object state)

        {

            _logger.LogInformation("Timed Background Service is working.");

        }

​

        public Task StopAsync(CancellationToken cancellationToken)

        {

            _logger.LogInformation("Timed Background Service is stopping.");

​

            _timer?.Change(Timeout.Infinite, 0);

​

            return Task.CompletedTask;

        }

​

        public void Dispose()

        {

            _timer?.Dispose();

        }

    }