How to restart manually a BackgroundService in ASP.net core

Question

I create the BackgroundService:

public class CustomService : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken cancellationToken)
    {
        //...
    }
}

and I added to the project:

public class Startup
{
    //...

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddHostedService<CustomService>();

        //...
    }

    //...
}

How can I find the CustomService from another class?
How to start it again?

Answer 1

Create an interface just for the call to StartAsync:

public interface ICustomServiceStarter
{
    Task StartAsync(CancellationToken token = default);
}

public class CustomService : BackgroundService, ICustomServiceStarter
{
    //...
    Task ICustomServiceStarter.StartAsync(CancellationToken token = default) => base.StartAsync(token);
    //...
}

Register the interface as a singleton:

public class Startup
{
    //...
    public void ConfigureServices(IServiceCollection services)
    {
        //...
        services.AddSingleton<ICustomServiceStarter, CustomService>();
    }
    //...
}

and inject ICustomServiceStarter when needed:

public class MyServiceControllerr : Controller
{
    ICustomServiceStarter _starter;

    public MyServiceController(ICustomServiceStarter starter)
    {
        _starter = starter;
    }

    [HttpPost]
    public async Task<IActionResult> Start()
    {
        await _starter.StartAsync();

        return Ok();
    }
}