在 Windows 服务中执行任务循环的最佳方法 [英] Best way to do a task looping in Windows Service

问题描述

我有一种方法可以向我们的客户发送一些短信，如下所示:

I have a method that send some SMS to our customers that look like below:

public void ProccessSmsQueue()
{
   SmsDbContext context = new SmsDbContext();
   ISmsProvider provider = new ZenviaProvider();
   SmsManager manager = new SmsManager(context, provider);

   try
   {
      manager.ProcessQueue();
   }
   catch (Exception ex)
   {
      EventLog.WriteEntry(ex.Message, EventLogEntryType.Error);
   }
   finally
   {
      context.Dispose();
   }
}

protected override void OnStart(string[] args)
{
   Task.Factory.StartNew(DoWork).ContinueWith( ??? )
}

所以，我有一些问题:

1. 我不知道方法运行需要多长时间；

1. I don´t know how long it takes for the method run;

该方法可以抛出异常，我想写在EventLog上

The method can throw exceptions, that I want to write on EventLog

我想在循环中运行这个方法，每 10 分钟，但只能在最后一次执行完成之后.

I want to run this method in loop, every 10 min, but only after last execution finish.

我如何才能做到这一点?我想过使用ContinueWith()，但我仍然对如何构建整个逻辑有疑问.

How I can achieve this? I thought about using ContinueWith(), but I still have questions on how to build the entire logic.

推荐答案

你应该有一个接受 CancellationToken 的异步方法，这样它就知道什么时候停止，调用 ProccessSmsQueue在 try-catch 块中并使用 Task.Delay 异步等待直到下一次需要运行:

You should have an async method that accepts a CancellationToken so it knows when to stop, calls ProccessSmsQueue in a try-catch block and uses Task.Delay to asynchronously wait until the next time it needs to run:

public async Task DoWorkAsync(CancellationToken token)
{
    while (true)
    {
        try
        {
            ProccessSmsQueue();
        }
        catch (Exception e)
        {
            // Handle exception
        }
        await Task.Delay(TimeSpan.FromMinutes(10), token);
    }
}

您可以在应用程序启动时调用此方法，并且 Task.Wait 返回的任务存在之前，以便您知道它已完成并且没有异常:

You can call this method when your application starts and Task.Wait the returned task before existing so you know it completes and has no exceptions:

private Task _proccessSmsQueueTask;
private CancellationTokenSource _cancellationTokenSource;

protected override void OnStart(string[] args)
{
    _cancellationTokenSource = new CancellationTokenSource();
    _proccessSmsQueueTask = Task.Run(() => DoWorkAsync(_cancellationTokenSource.Token));
}

protected override void OnStop()
{
    _cancellationTokenSource.Cancel();
    try
    {
        _proccessSmsQueueTask.Wait();
    }
    catch (Exception e)
    {
        // handle exeption
    }
}

这篇关于在 Windows 服务中执行任务循环的最佳方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！