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NetCore 2.1 Generic Host as a service

I'm trying to build a Windows Service using the latest Dotnet Core 2.1 runtime. I'm NOT hosting any aspnet, I do not want or need it to respond to http requests.

I've followed the code found here in the samples: https://github.com/aspnet/Docs/tree/master/aspnetcore/fundamentals/host/generic-host/samples/2.x/GenericHostSample

I've also read this article: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/host/generic-host?view=aspnetcore-2.1

The code works great when run inside of a console window using dotnet run. I need it to run as a windows service. I know there's the Microsoft.AspNetCore.Hosting.WindowsServices, but that's for the WebHost, not the generic host. We'd use host.RunAsService() to run as a service, but I don't see that existing anywhere.

How do I configure this to run as a service?

using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace MyNamespace

public class Program



public static async Task Main(string args)

try

var host = new HostBuilder()
.ConfigureHostConfiguration(configHost =>

configHost.SetBasePath(Directory.GetCurrentDirectory());
configHost.AddJsonFile("hostsettings.json", optional: true);
configHost.AddEnvironmentVariables(prefix: "ASPNETCORE_");
configHost.AddCommandLine(args);
)
.ConfigureAppConfiguration((hostContext, configApp) =>

configApp.AddJsonFile("appsettings.json", optional: true);
configApp.AddJsonFile(
$"appsettings.hostContext.HostingEnvironment.EnvironmentName.json",
optional: true);
configApp.AddEnvironmentVariables(prefix: "ASPNETCORE_");
configApp.AddCommandLine(args);
)
.ConfigureServices((hostContext, services) =>

services.AddLogging();
services.AddHostedService<TimedHostedService>();
)
.ConfigureLogging((hostContext, configLogging) =>

configLogging.AddConsole();
configLogging.AddDebug();

)

.Build();

await host.RunAsync();

catch (Exception ex)










#region snippet1
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();


#endregion



EDIT: I repeat, this is not to host an ASP.NET Core app. This is a generic hostbuilder, not a WebHostBuilder.

Not a dupe. That is for hosting asp.net core. WebHost.RunAsService. I'm not using a WebHost, I'm using a generic host.
– Darthg8r
Jun 14 at 1:16

Again, look at the host builder. It's not a WebHostBuilder for listening for http requests. It's a generic HostBuilder, designed for running background tasks ONLY, and it doesn't listen for http requests. Required reading: docs.microsoft.com/en-us/aspnet/core/fundamentals/host/…
– Darthg8r
Jun 14 at 6:40

3 Answers
3

As others have said you simply need to reuse the code that is there for the IWebHost interface here is an example.

IWebHost

public class GenericServiceHost : ServiceBase

private IHost _host;
private bool _stopRequestedByWindows;

public GenericServiceHost(IHost host)

_host = host ?? throw new ArgumentNullException(nameof(host));


protected sealed override void OnStart(string args)

OnStarting(args);

_host
.Services
.GetRequiredService<IApplicationLifetime>()
.ApplicationStopped
.Register(() =>

if (!_stopRequestedByWindows)

Stop();

);

_host.Start();

OnStarted();


protected sealed override void OnStop()

_stopRequestedByWindows = true;
OnStopping();
try

_host.StopAsync().GetAwaiter().GetResult();

finally

_host.Dispose();
OnStopped();



protected virtual void OnStarting(string args)

protected virtual void OnStarted()

protected virtual void OnStopping()

protected virtual void OnStopped()


public static class GenericHostWindowsServiceExtensions

public static void RunAsService(this IHost host)

var hostService = new GenericServiceHost(host);
ServiceBase.Run(hostService);




IHostedService if for [asp.net core] backendjob,
if u want to build a windows service on .net core, u should reference this package System.ServiceProcess.ServiceController, and use ServiceBase as base class.
(you can also start from a .net framework windows service and then change the .csproj file)

IHostedService

ServiceBase

.csproj

edit: please see this doc and this code https://github.com/aspnet/Hosting/blob/dev/src/Microsoft.AspNetCore.Hosting.WindowsServices/WebHostWindowsServiceExtensions.cs.
To create a windows service ServiceBase for manage your IHost

ServiceBase

IHost

you too have the problem understanding the difference between IWebHost and IHost. The link you provided is for IWebHost. This project is for IHost, it does not listen for http requests. I'm not going to use IWebHost because it makes no sense for the service to listen for http requests. Required reading: docs.microsoft.com/en-us/aspnet/core/fundamentals/host/…
– Darthg8r
Jun 14 at 6:56

yes, the link is for IWebHost , but it's almost the same as IHost, what I try to tell u is how to run it under windows service eg ServiceBase, It's not difficult to understand, What the RunAsService extensions method do is that it create a simple ServiceBase class named WebHostService to start/stop the IWebHost (IHost in your case)
– John
Jun 14 at 7:30

IWebHost

IHost

ServiceBase

RunAsService

WebHostService

I hope you found the solution for this problem.

In my case I used generic host (introduced in 2.1) for such purpose and then just wrap it up with systemd to run it as a service on Linux host.

I wrote a small article about it https://dejanstojanovic.net/aspnet/2018/june/clean-service-stop-on-linux-with-net-core-21/

I hope this helps

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