DRAB/Drab.Logic/Utils/DbFetcher.cs

using Microsoft.Extensions.Hosting;

namespace Drab.Logic.Utils;

public class DbFetcher : BackgroundService
{
    private readonly IDrabSettings _drabSettings;
    private readonly IServiceScopeFactory _serviceScopeFactory;
    private readonly IOrderProcessor _orderProcessor;
    private readonly ILogger<DbFetcher> _logger;

    public DbFetcher(IDrabSettings drabSettings, IServiceScopeFactory serviceScopeFactory, IOrderProcessor orderProcessor, ILogger<DbFetcher> logger)
    {
        _drabSettings = drabSettings;
        _serviceScopeFactory = serviceScopeFactory;
        _orderProcessor = orderProcessor;
        _logger = logger;
    }

    protected override Task ExecuteAsync(CancellationToken stoppingToken)
    {
        Start();
        return Task.CompletedTask;
    }

    private async Task Start()
    {
        await Task.Delay(TimeSpan.FromSeconds(2));
        while (true)
        {
            _logger.LogInformation("Fetch database for new orders");
            try
            {
                using var scope = _serviceScopeFactory.CreateScope();
                using var orderStore = scope.ServiceProvider.GetService<IOrdersStore>();
                var result = await orderStore.FetchOrders();

                if (result.IsNotOk)
                    _logger.LogWarning($"Fetch orders result failed: {result.Error}");

                result.Value.ToList()
                    .ForEach(x => _orderProcessor.ProcessOrder(x));
            }
            catch (Exception e)
            {
                _logger.LogError(e, "Error on fetching new orders data:");
            }
            finally
            {
                await Task.Delay(TimeSpan.FromSeconds(_drabSettings.DbPollingFrequencyInSeconds));
            }
        }
    }
}