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
// Then Wait until all adopted tenants have returned
await Task.WhenAll(tenantIds.Select(async tenantId =>
{
try // To make sure the background service keeps running
{
var repo = _repoFactory.GetRepository(tenantId);
// Begin serializable transaction
using var trx = TransactionFactory.Serializable(TransactionScopeOption.RequiresNew);
// Retrieve NEW or stale PENDING emails, after marking them as fresh PENDING
IEnumerable <EmailForSave> emailEntities = await repo.Notifications_Emails__Poll(_options.PendingNotificationExpiryInSeconds, PollingBatchSize, cancellation);
var emails = await NotificationsQueue.FromEntities(tenantId, emailEntities, _blobService, cancellation);
// IEnumerable<EmailToSend> emails = emailEntities.Select(e => NotificationsQueue.FromEntity(e, tenantId));
// Queue the emails for dispatching
_queue.QueueBackgroundWorkItem(emails);
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 (emails.Any())
{
_logger.LogWarning($"{nameof(EmailPollingJob)} found {emailEntities.Count()} emails in database for tenant {tenantId}.");
}
}
catch (TaskCanceledException) { }
catch (OperationCanceledException) { }
catch (Exception ex)
{
_logger.LogError(ex, $"Error in {GetType().Name}, tenantId {tenantId}.");
}
}));
}
// Go to sleep until the next round
await Task.Delay(_options.NotificationCheckFrequencyInSeconds * 1000, cancellation);
}
}
