Concept: Services

Conceptual classes for handling lifetime events of hosting agnostic services

• Targets .NET Standard 2.0, runs on .NET Core
• Clear separation between service, bootstrapper and host
• No-dependency base libraries for custom implementations, add on libraries with opinionated defaults
• Host hybrid service with ASP.NET Core

📘 Full documentation at dotnet-concepts-services.readthedocs.io.

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());
    }
}