当工作程序是事件驱动时，BackgroundService.ExecuteAsync 应该返回什么? [英] What should BackgroundService.ExecuteAsync return when the worker is event-driven?

问题描述

工作服务是在 .NET Core 3.x 中编写 Windows 服务的新方法.worker 类扩展 Microsoft.Extensions.Hosting.BackgroundService 并实现 ExecuteAsync.该方法的文档说:

A Worker Service is the new way to write a Windows service in .NET Core 3.x. The worker class extends Microsoft.Extensions.Hosting.BackgroundService and implements ExecuteAsync. The documentation for that method says:

该方法在 IHostedService 启动时调用.该实现应返回一个任务，该任务表示正在执行的长时间运行操作的生命周期.

This method is called when the IHostedService starts. The implementation should return a task that represents the lifetime of the long running operation(s) being performed.

当服务正在做的工作不是通常意义上的长时间运行的操作，而是事件驱动的时候，这个方法应该返回什么?例如，我正在编写一个设置 FileSystemWatcher.我如何将其封装在 Task 中?没有 Task.Never()，所以我应该根据很长的 Task.Delay() 返回一些东西以防止服务关闭吗?

What should this method return when the work being done by the service is not a long-running operation in the usual sense, but event-driven? For example, I'm writing a service that sets up a FileSystemWatcher. How would I encapsulate that in a Task? There's no Task.Never(), so should I just return something based on a very long Task.Delay() to prevent the service from shutting down?

private async Task DoStuffAsync(CancellationToken cancel)
{
  // register events
  while(!cancel.IsCancellationRequested)
  {
    await Task.Delay(TimeSpan.FromDays(1000000), cancel);
  }
  // unregister events
}

推荐答案

您也可以使用实际的无限延迟:

You could also use an actual infinite delay:

await Task.Delay(Timeout.Infinite, cancellationToken);

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