.NET CORE中的后台任務調度

Question

我想根據每個請求創建動態cron作業（如果應用程序服務器關閉，后台任務也不會受到影響），並且cron作業可以重新安排或刪除。在.net core中實現它的最佳方法是什么。

Answer 1

創建一個新的.net核心控制台應用程序並使用以下模板

在您的Program.cs內部主要方法中（C＃級別為7）：

public static async Task Main(string[] args)
{  
    var builder = new HostBuilder()
        .ConfigureAppConfiguration((hostingContext, config) =>
        {
        // i needed the input argument for command line, you can use it or simply remove this block
            config.AddEnvironmentVariables();

            if (args != null)
            {
                config.AddCommandLine(args);
            }

            Shared.Configuration = config.Build();
        })
        .ConfigureServices((hostContext, services) =>
        {
            // dependency injection

            services.AddOptions();
           // here is the core, where you inject the
           services.AddSingleton<Daemon>();
           services.AddSingleton<IHostedService, MyService>();
        })
        .ConfigureLogging((hostingContext, logging) => {
           // console logging 
            logging.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
            logging.AddConsole();
        });

    await builder.RunConsoleAsync();
}

這是守護程序/服務代碼

public class MyService: IHostedService, IDisposable
   {
       private readonly ILogger _logger;
       private readonly Daemon _deamon;

       public MyService(ILogger<MyService> logger, Daemon daemon /* and probably the rest of dependencies*/)
       {
           _logger = logger;         
           _daemon = daemon;  
       }

       public async Task StartAsync(CancellationToken cancellationToken)
       {
           await _deamon.StartAsync(cancellationToken);
       }

       public async Task StopAsync(CancellationToken cancellationToken)
       {
           await _deamon.StopAsync(cancellationToken);
       }

       public void Dispose()
       {
           _deamon.Dispose();
       }
}

這是您想要做的核心，下面的代碼是一個模板，您必須提供正確的實現 ：

public class Daemon: IDisposable
   {
       private ILogger<Daemon> _logger;


       protected TaskRunnerBase(ILogger<Daemon> logger)
       {
          _logger = logger;
       }

       public async Task StartAsync(CancellationToken cancellationToken)
       {            
           while (!cancellationToken.IsCancellationRequested)
           {
                await MainAction.DoAsync(cancellationToken); // main job 
            }
       }

       public async Task StopAsync(CancellationToken cancellationToken)
       {
           await Task.WhenAny(MainAction, Task.Delay(-1, cancellationToken));
           cancellationToken.ThrowIfCancellationRequested();
       }

       public void Dispose()
       {
            MainAction.Dispose();
       }
}

1. 既然您使用的是.NET CORE，就可以在WINDOWS和LINUX上同時運行它
2. 我的.NET核心版本= 2.1