Sentinel/BackgroundService/BackgroundService.cs

using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using ProperDI.Azure.Endpoints.ResourceGroup.LogLooker;

public class RoleAssesorBackgroundService : IHostedService, IDisposable
{
    private readonly IActivityLogReader _activityLogReader;
    private readonly ILogger<RoleAssesorBackgroundService> _logger;
    private readonly IOptionsMonitor<RoleAssesorBackgroundServiceOptions> _options;
    private Timer? _timer;
    private int _runFrequencyInMinutes;

    public RoleAssesorBackgroundService(
        IActivityLogReader activityLogReader,
        ILogger<RoleAssesorBackgroundService> logger,
        IOptionsMonitor<RoleAssesorBackgroundServiceOptions> options)
    {
        _activityLogReader = activityLogReader;
        _logger = logger;
        _options = options;

        // This sets our initial run frequency
        _runFrequencyInMinutes = _options.CurrentValue.RunFrequencyInMinutes;

        // Subscribe to any changes in the config file
        _options.OnChange(UpdateTimerInterval);
    }

    private void UpdateTimerInterval(RoleAssesorBackgroundServiceOptions options)
    {
        var newFreq = options.RunFrequencyInMinutes;

        if (newFreq == _runFrequencyInMinutes)
            return;

        _runFrequencyInMinutes = newFreq;
        _logger.LogInformation("Run frequency updated to {RunFreq} minutes", _runFrequencyInMinutes);
        _timer?.Change(TimeSpan.Zero, TimeSpan.FromMinutes(_runFrequencyInMinutes));
    }

    public Task StartAsync(CancellationToken  cancellationToken)
    {
        _logger.LogInformation("Role Assessor background service is starting.");

        _timer = new Timer(async _ => await ProcessAsync(cancellationToken), null, TimeSpan.Zero, TimeSpan.FromMinutes(1));

        return Task.CompletedTask;
    }

    private async Task ProcessAsync(CancellationToken cancellationToken)
    {
        try
        {
            _logger.LogInformation("Role Assessor background service is running at: {time}", DateTimeOffset.Now);

            if (cancellationToken.IsCancellationRequested)
                return;

            await _activityLogReader.Scan(cancellationToken);    
        }
        catch (OperationCanceledException)
        {
            _logger.LogInformation("Operation was canceled");
        }
        catch (System.Exception ex)
        {
            _logger.LogError(ex, "An error occurred while reading the logs");
            throw;
        }
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Stopping the Role Assessor background service.");

        _timer?.Change(Timeout.Infinite, 0);

        return Task.CompletedTask;
    }

    public void Dispose()
    {
        _timer?.Dispose();
    }
}