Add more than one task to my worker class (BackgroundService ASP.Net Core 3.1)

Question

User-158191824 posted

Using ASP.Net Core 3.1, I have a simple background task which is working successfully :

public class UserActivitiesCleaner : BackgroundService
{
    private readonly IWorker worker;

    public UserActivitiesCleaner(IWorker worker)
    {
        this.worker = worker;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        await worker.DoWork(stoppingToken);
    }
}

Here is my current worker:

  public class Worker : IWorker
    {            
        private readonly IServiceScopeFactory serviceProvider;
        public Worker(IServiceScopeFactory serviceProvider)
        {               
            this.serviceProvider = serviceProvider;
        }

        public async Task DoWork(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                using (var scope = serviceProvider.CreateScope())
                {
                    var _unitOfWork = scope.ServiceProvider.GetRequiredService<IUnitOfWork>();
                    while (!stoppingToken.IsCancellationRequested)
                    {                       
                        await _unitOfWork.userActivityRepository.DeleteByDapper();
                        await Task.Delay(1000 * 3600);                      
                    }                
                }
            }
        }
    }

The problem is : I need to know if I can have another task with different delay time in the same worker without creating a new worker : ( looking for simplicity) So I tried this :

public async Task DoWork(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            using (var scope = serviceProvider.CreateScope())
            {
                var _unitOfWork = scope.ServiceProvider.GetRequiredService<IUnitOfWork>();
                while (!stoppingToken.IsCancellationRequested)
                {                       
                    await _unitOfWork.userActivityRepository.DeleteByDapper();
                    await Task.Delay(1000 * 3600);                      
                }
                while (!stoppingToken.IsCancellationRequested)
                {                       
                    await _unitOfWork.userActivityRepository.DoSomethingElse();
                    await Task.Delay(TimeSpan.FromDays(1));                       
                }                   
            }
        }
    }

but the code never enters the second while-loop, in the time that the program is running . Any idea of having more than one task in a worker is appreciated..

Answer 1

User475983607 posted

Use a timer not a delay.

https://docs.microsoft.com/en-us/dotnet/api/system.timers.timer?view=net-5.0

Answer 2

User-158191824 posted

So after saying thanks, the code will be something like this, I couldn't manage `BackgroundService`  so changed to `IHostedService` . It is working but I need to know if it is true or not ? And I do not know if the code is async or not, cause I can't use await while I want to query on my database 

I want to use await in the following code without getting errors..

public class UserActivitiesManager : IHostedService, IDisposable
    {
        private readonly ILogger<UserActivitiesManager> _logger;
        private readonly IServiceScopeFactory serviceProvider;
        public UserActivitiesManager(ILogger<UserActivitiesManager> logger, IServiceScopeFactory serviceProvider)
        {
            _logger = logger;
            this.serviceProvider = serviceProvider;
        }
        private Timer _timer;       
        public Task StartAsync(CancellationToken cancellationToken)
        {
            _timer = new Timer(DoWork1Async, null, TimeSpan.Zero, TimeSpan.FromSeconds(5));
            _timer = new Timer(DoWork2, null, TimeSpan.Zero, TimeSpan.FromSeconds(10));
            return Task.CompletedTask;
        }

        private void DoWork1Async(object state)
        {
            using (var scope = serviceProvider.CreateScope())
            {
                var _unitOfWork = scope.ServiceProvider.GetRequiredService<IUnitOfWork>();
                _unitOfWork.userActivityRepository.ChangeByDapper();
                _logger.LogError($"{DateTime.Now.TimeOfDay} ---- I am task of DoWork1");

            };
        }
        private void DoWork2(object state)
        {
            using (var scope = serviceProvider.CreateScope())
            {
                var _unitOfWork = scope.ServiceProvider.GetRequiredService<IUnitOfWork>();
                _unitOfWork.userActivityRepository.DeleteByDapper();
                _logger.LogError($"{DateTime.Now.TimeOfDay} ---- I am task of DoWork2");
            };
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            return Task.CompletedTask;
        }
        public void Dispose()
        {
            _timer?.Dispose();           
        }
    }

Answer 3

User1312693872 posted

Hi,ehsan_kabiri_33

The BackgroundService class is new in ASP.NET Core 3.0 and is basically an abstract class that already implements the IHostedService Interface.

I want to use await in the following code without getting errors..

await can't be used in void, you should change your void to async:

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

You can also check the following links:

https://medium.com/@daniel.sagita/backgroundservice-for-a-long-running-work-3debe8f8d25b

https://girishgodage.in/blog/customize-hostedservices

Best Regards,

Jerry Cai.