Getting Started

Create Service

A service is defined by implementing a class derived from Service. The method StartAsync will be called when the service is started, and can be considered as the entry point to the service. Optionally, StopAsync can be overridden to implement clean up activities, like disposing services.

public class TimeService : Service
{
  private readonly IWorldClock _clock;
  private Timer _timer;

  public TimeService(IWorldClock clock)
  {
    _clock = clock;
  }

  public override async Task StartAsync(CancellationToken ct = default(CancellationToken))
  {
    _timer = new Timer(time =>
    {
      Log.Information("It is {timeOfDay}, and all is well", _clock.GetTime());
    }, null, TimeSpan.Zero, TimeSpan.FromSeconds(10));
  }
}

Create Bootstrap

The IServiceBootstrap is responsible for configuring the applicatoin logger and wire-up the dependency injection container. It is not primed to any specific frameworks, as the interface only contains hooks. For convinience, there are implementations that wire up different populare libraries.

The OpinionatedServiceBootstrap configures a Serilog logger and creates an Autofac container to register services in.

public class TimeBootstrap : OpinionatedServiceBootstrap<TimeService>
{
  public override ServiceMetadata CreateMetadata()
  {
    return new ServiceMetadata
    {
      Type = typeof(TimeService),
      Name = nameof(TimeService),
      Description = "Tells the time"
    };
  }

  protected override void RegisterDependencies(ContainerBuilder builder)
  {
    builder
      .RegisterType<WorldClock>()
      .AsImplementedInterfaces();
    builder
      .RegisterType<TimeService>()
      .AsSelf();
  }
}

Run the service

The service can be run in a few different ways. The most straight forward option is to use the ConsoleRuner

public class Program
{
    public static void Main(string[] args)
    {
        MainAsync(args).GetAwaiter().GetResult();
    }

    public static async Task MainAsync(string[] args)
    {
        await ConsoleRunner.StartAsync(new TimeBootstrap());
    }
}

The console runner is a great option for running services on .NET Core in Docker containers. On a Windows system, the TopshelfRunner can be used to run the service as an actual Windows Service

TopshelfRunner.Start(new TimeBootstrap());

There are more sophisticated ways to run a service, that allows hybrid services that runs an ASP.NET Core API as well as a traditional service. This is achieved by using the ServiceHost and related classes.