Question

我想每天半夜运行一次后台服务。 .NET Core默认BackgroundService在task.delay上运行，我想每隔半夜（24小时间隔）运行一次。

我有BackgroundService的问题在每个task.Delay间隔而不是指定的特定时间运行。

public class Worker : BackgroundService
    {
        private readonly ILogger<Worker> _logger;
        private readonly IServiceScopeFactory _serviceScopeFactory;

        public Worker(ILogger<Worker> logger, IServiceScopeFactory serviceScopeFactory)
        {
            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
            _serviceScopeFactory = serviceScopeFactory ?? throw new ArgumentNullException(nameof(serviceScopeFactory));
        }
        protected override async Task ExecuteAsync(CancellationToken cancellationToken)
        {
            while (!cancellationToken.IsCancellationRequested)
            {
                // We ultimately resolve the actual services we use from the scope we create below.
                // This ensures that all services that were registered with services.AddScoped<T>()
                // will be disposed at the end of the service scope (the current iteration).
                using var scope = _serviceScopeFactory.CreateScope();

                var configuration = scope.ServiceProvider.GetRequiredService<IWorkFlowScheduleService>();
                configuration.DailySchedule(dateTime: DateTime.Now);

                _logger.LogInformation($"Sending message to ");

                await Task.Delay(TimeSpan.FromSeconds(10), cancellationToken);
            }
        }
    }

Answer 1

这是我的解决方法。

 protected override async Task ExecuteAsync(CancellationToken stoppingToken)
 {
     do
     {
         int hourSpan = 24 - DateTime.Now.Hour;
         int numberOfHours = hourSpan;

         if (hourSpan == 24)
         {
             //do something
             numberOfHours = 24;
         }

         await Task.Delay(TimeSpan.FromHours(numberOfHours), stoppingToken);
     }
     while (!stoppingToken.IsCancellationRequested);
 }

Answer 2

加入一个等待到午夜的初始 Task.Delay，做任何你需要做的事情，然后 Task.Delay 24 小时如何？

protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
    // calculate seconds till midnight
    var now = DateTime.Now;
    var hours = 23 - now.Hour;
    var minutes = 59 - now.Minute;
    var seconds = 59 - now.Second;
    var secondsTillMidnight = hours * 3600 + minutes * 60 + seconds;

    // wait till midnight
    await Task.Delay(TimeSpan.FromSeconds(secondsTillMidnight), stoppingToken);

    while (!stoppingToken.IsCancellationRequested)
    {
        // do stuff
        _logger.LogInformation($"Sending message to ");

        // wait 24 hours
        await Task.Delay(TimeSpan.FromHours(24), stoppingToken);
    }
}

Answer 3

您可以将Quartz.NET库用于后台服务。

每天午夜在.Net Core 3.0中运行BackgroundService

3 个答案: