public ScheduledNotificationsJob(
SchedulesCache schedulesCache,
IApplicationRepositoryFactory repoFactory,
NotificationsQueue notificationsQueue,
ILogger <ScheduledNotificationsJob> logger,
ApplicationBehaviorHelper helper)
{
_schedulesCache = schedulesCache;
_repoFactory = repoFactory;
_notificationsQueue = notificationsQueue;
_logger = logger;
_helper = helper;
}
private int PollingBatchSize => _options.PendingNotificationExpiryInSeconds * 2; // Assuming 2 SMS per second
protected override async Task ExecuteAsync(CancellationToken cancellation)
{
_logger.LogInformation(GetType().Name + " Started.");
while (!cancellation.IsCancellationRequested)
{
// Grab a hold of a concrete list of adopted tenantIds at the current moment
var tenantIds = _instanceInfo.AdoptedTenantIds;
if (tenantIds.Any())
{
// Match every tenantID to the Task of polling
// Wait until all adopted tenants have returned
await Task.WhenAll(tenantIds.Select(async tenantId =>
{
try // To make sure the background service keeps running
{
// Begin serializable transaction
using var trx = TransactionFactory.Serializable(TransactionScopeOption.RequiresNew);
// Retrieve NEW or stale PENDING SMS messages, after marking them as fresh PENDING
var repo = _repoFactory.GetRepository(tenantId);
IEnumerable <MessageForSave> smsesReady = await repo.Notifications_Messages__Poll(
_options.PendingNotificationExpiryInSeconds, PollingBatchSize, cancellation);
// Queue the SMS messages for dispatching
foreach (SmsToSend sms in smsesReady.Select(e => NotificationsQueue.FromEntity(e, tenantId)))
{
_queue.QueueBackgroundWorkItem(sms);
}
trx.Complete();
// Log a warning, since in theory this job should rarely find anything, if it finds stuff too often it means something is wrong
if (smsesReady.Any())
{
_logger.LogWarning($"{nameof(SmsPollingJob)} found {smsesReady.Count()} SMSes in database for tenant {tenantId}.");
}
}
catch (TaskCanceledException) { }
catch (OperationCanceledException) { }
catch (Exception ex)
{
_logger.LogError(ex, $"Error in {GetType().Name}.");
}
}));
}
// Go to sleep until the next round
await Task.Delay(_options.NotificationCheckFrequencyInSeconds * 1000, cancellation);
}
}