protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
try
{
if (!await _reader.Ensure(stoppingToken))
{
_logger.LogError("Cannot ensure that Azure storage queue exists.");
return;
}
if (!await _writer.Verify(stoppingToken))
{
_logger.LogError("Cannot verify MongoDB database connection.");
return;
}
while (!stoppingToken.IsCancellationRequested)
{
var messages = _reader.GetChanges(stoppingToken);
await foreach (var message in messages.WithCancellation(stoppingToken))
{
var change = message.Change;
_logger.LogInformation("a1. Process Mutation with Entity ID: {entityId}; MutationId: {mutationId}", change.EntityId, change.MutationId);
if (await _writer.Append(change, stoppingToken))
{
_logger.LogInformation("a2. Successful processed Entity ID: {entityId}; MutationId: {mutationId}",
change.EntityId, change.MutationId);
await _reader.DeleteMessage(message, stoppingToken);
}
else
{
_logger.LogWarning("a2. Cannot process Entity ID: {entityId}; MutationId: {mutationId}", change.EntityId, change.MutationId);
}
}
_logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
await Task.Delay(100, stoppingToken);
}
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.Message);
throw;
}
}
void ReceiveMessages(CancellationToken outer, IEnumerable <string> queues)
{
using (var source = CancellationTokenSource.CreateLinkedTokenSource(_disposal.Token, outer))
{
var token = source.Token;
MessageEnvelope envelope;
foreach (var queue in queues)
{
while (_queueReader.TakeMessage(queue, token, out envelope))
{
try
{
var msg = envelope.MessageReference.Message;
var consumers = _consumerFactory.GetMessageConsumers(msg);
foreach (var consumer in consumers)
{
_observer.Notify(new ConsumeBegin(msg, consumer, envelope.QueueName));
consumer.Consume(msg);
_observer.Notify(new ConsumeEnd(msg, consumer, envelope.QueueName));
}
}
catch (Exception ex)
{
_observer.Notify(new FailedToConsumeMessage(ex, envelope.EnvelopeId, envelope.QueueName));
}
try
{
_queueReader.DeleteMessage(envelope);
}
catch (Exception ex)
{
// not a big deal. Message will be processed again.
_observer.Notify(new FailedToAckMessage(ex, envelope.EnvelopeId, envelope.QueueName));
}
}
}
}
}