.net core 3.1 HostBuilder 没有 RunAsServiceAsync 方法（IHostBuilder 不包含 RunAsServiceAsync 的定义）

Question

我有 .net core 3.1 控制台应用程序，我想将它作为 Windows 服务运行，我的 program.cs 看起来像

public class Program
    {
        public static async Task Main(string[] args)
        {
            var isService = !(Debugger.IsAttached || args.Contains("--console"));

            var builder = CreateHostBuilder(args);

            if (isService)
            {
                await builder.RunAsServiceAsync();
            }
            else
            {
                await builder.RunConsoleAsync();
            }
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
            .UseWindowsService()
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHostedService<Worker1>();
                    services.AddHostedService<Worker2>();
                });
    }

.csproj 是

<Project Sdk="Microsoft.NET.Sdk.Worker">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <UserSecretsId>dotnet-MyWorkerService-16487890-DF99-45C2-8DC4-5475A21D6B75</UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="3.1.16" />
    <PackageReference Include="Microsoft.Extensions.Hosting.WindowsServices" Version="3.1.16" />
  </ItemGroup>
</Project>

但是对于 RunAsServiceAsync() 错误就像“IHostBuilder 不包含 RunAsServiceAsync 的定义”一样

谁能指出我在哪里/我错过了什么？

Answer 1

RunAsServiceAsync 似乎是IHostBuilder 上的第三方分机。

它似乎不是 .NET Core 原生的内置函数。

我在 GitHub here 上找到了一个旧实现，您可能可以自己实现

public static class ServiceBaseLifetimeHostExtensions
{
    public static IHostBuilder UseServiceBaseLifetime(this IHostBuilder hostBuilder)
    {
        return hostBuilder.ConfigureServices((hostContext, services) => services.AddSingleton<IHostLifetime, ServiceBaseLifetime>());
    }

    public static Task RunAsServiceAsync(this IHostBuilder hostBuilder, CancellationToken cancellationToken = default)
    {
        return hostBuilder.UseServiceBaseLifetime().Build().RunAsync(cancellationToken);
    }
}

public class ServiceBaseLifetime : ServiceBase, IHostLifetime
{
    private TaskCompletionSource<object> _delayStart = new TaskCompletionSource<object>();

    public ServiceBaseLifetime(IApplicationLifetime applicationLifetime)
    {
        ApplicationLifetime = applicationLifetime ?? throw new ArgumentNullException(nameof(applicationLifetime));
    }

    private IApplicationLifetime ApplicationLifetime { get; }

    public Task WaitForStartAsync(CancellationToken cancellationToken)
    {
        cancellationToken.Register(() => _delayStart.TrySetCanceled());
        ApplicationLifetime.ApplicationStopping.Register(Stop);

        new Thread(Run).Start(); // Otherwise this would block and prevent IHost.StartAsync from finishing.
        return _delayStart.Task;
    }

    private void Run()
    {
        try
        {
            Run(this); // This blocks until the service is stopped.
            _delayStart.TrySetException(new InvalidOperationException("Stopped without starting"));
        }
        catch (Exception ex)
        {
            _delayStart.TrySetException(ex);
        }
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        Stop();
        return Task.CompletedTask;
    }

    // Called by base.Run when the service is ready to start.
    protected override void OnStart(string[] args)
    {
        _delayStart.TrySetResult(null);
        base.OnStart(args);
    }

    // Called by base.Stop. This may be called multiple times by service Stop, ApplicationStopping, and StopAsync.
    // That's OK because StopApplication uses a CancellationTokenSource and prevents any recursion.
    protected override void OnStop()
    {
        ApplicationLifetime.StopApplication();
        base.OnStop();
    }
}

但现在在构建器上调用UseWindowsService 时，似乎已内置此基于服务的功能。

因此，在这种情况下，您需要相应地重构代码以获得所需的行为

public class Program {
    public static async Task Main(string[] args) {
        var isService = !(Debugger.IsAttached || args.Contains("--console"));

        var builder = CreateHostBuilder(args);

        if (isService) {
            await builder.RunAsServiceAsync();
        } else {
            await builder.RunConsoleAsync();
        }
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)            
            .ConfigureServices((hostContext, services) =>
            {
                services.AddHostedService<Worker1>();
                services.AddHostedService<Worker2>();
            });
}

public static class ServiceBaseLifetimeHostExtensions {
    public static Task RunAsServiceAsync(this IHostBuilder hostBuilder, CancellationToken cancellationToken = default) {
        return hostBuilder.UseWindowsService().Build().RunAsync(cancellationToken);
    }
}