.Net Core 3.0每天午夜運行BackgroundService

Question

我想每天午夜運行后台服務。 .NET 核心默認 BackgroundService 在task.delay上運行，我想每半夜（24 小時間隔）運行一次。

我的問題是 BackgroundService 在每個任務上運行。 task.Delay間隔而不是指定的特定時間。

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

這是我的解決方案。

 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

放置一個等待到午夜的初始Task.Delay ，做任何你需要做的事情，然后Task.Delay 24 小時怎么樣？

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

我使用 NCrontab 3.3.1

https://www.nuget.org/packages/ncrontab/

這樣，您就可以使用 cron； 否則，我會同意之前的評論之一，即創建一個控制台應用程序並將其作為 cron 或服務直接在您的服務器上運行。

下面是我如何實施 NCrontab 的示例。

public class YourServiceName : BackgroundService
{
    private CrontabSchedule _schedule;
    private DateTime _nextRun;
    // My CrontabHelper class simply returns a string representing a cron schedule. You can just use 0 0 0 * * * to run every day at midnight instead
    private string Schedule => CrontabHelper.Schedule(CrontabHelper.CronType.Day); 

    public YourServiceName()
    {
        _schedule = CrontabSchedule.Parse(Schedule, new CrontabSchedule.ParseOptions { IncludingSeconds = true });
        _nextRun = _schedule.GetNextOccurrence(DateTime.Now);
    }

    protected async override Task ExecuteAsync(CancellationToken stoppingToken)
    {
        do
        {
            var now = DateTime.Now;
            if (now > _nextRun)
            {
                // DO WORK HERE
            }

            await Task.Delay(5000, stoppingToken);
        }
        while (!stoppingToken.IsCancellationRequested);
    }
}

然后在你的 program.cs 中包含這個

builder.Services.AddHostedService<YourServiceName>();

希望這可以幫助！

Answer 4

您可以將 Quartz.NET 庫用於后台服務。