void EnsureConsumerInitialized()
{
// if the consumer is null at this point, we see if we can initialize it...
if (_consumer == null)
{
lock (_consumerInitializationLock)
{
// if there is a consumer instance at this point, someone else went and initialized it...
if (_consumer == null)
{
try
{
_consumer = InitializeConsumer();
}
catch (OperationInterruptedException objectInterruptedException) when(objectInterruptedException.Message.Contains("code=404, text=\"NOT_FOUND - no queue"))
{
_log.Warn("Queue not found - attempting to recreate queue and restore subscriptions.");
ReconnectQueue();
_consumer = InitializeConsumer();
}
catch (Exception exception)
{
_log.Warn("Could not initialize consumer: {0} - waiting 2 seconds", exception);
Thread.Sleep(2000);
}
}
}
}
}
void ClearConsumer()
{
var currentConsumer = _consumer;
_consumer = null;
if (currentConsumer == null)
{
return;
}
try
{
currentConsumer.Model.Dispose();
}
catch { }
}
/// <summary>
/// Creates the consumer.
/// </summary>
CustomQueueingConsumer InitializeConsumer()
{
IConnection connection = null;
IModel model = null;
try
{
// receive must be done with separate model
connection = _connectionManager.GetConnection();
model = connection.CreateModel();
model.BasicQos(0, _maxMessagesToPrefetch, false);
var consumer = new CustomQueueingConsumer(model);
model.BasicConsume(Address, false, consumer);
_log.Info("Successfully initialized consumer for {queueName}", Address);
return(consumer);
}
catch (OperationInterruptedException objectInterruptedException) when(objectInterruptedException.Message.Contains("code=404, text=\"NOT_FOUND - no queue"))
{
_log.Warn("Queue not found - attempting to recreate queue and restore subscriptions.");
ReconnectQueue();
return(null);
}
catch (Exception)
{
try
{
model?.Dispose();
}
catch { }
try
{
connection?.Dispose();
}
catch { }
throw;
}
}
/// <summary>
/// Creates the consumer.
/// </summary>
CustomQueueingConsumer InitializeConsumer()
{
IConnection connection = null;
IModel model = null;
try
{
// receive must be done with separate model
connection = _connectionManager.GetConnection();
model = connection.CreateModel();
model.BasicQos(0, _maxMessagesToPrefetch, false);
var consumer = new CustomQueueingConsumer(model);
model.BasicConsume(Address, false, consumer);
_log.Info("Successfully initialized consumer for {0}", Address);
return(consumer);
}
catch (Exception)
{
try
{
model?.Dispose();
}
catch { }
try
{
connection?.Dispose();
}
catch { }
throw;
}
}
void EnsureConsumerInitialized()
{
// if the consumer is null at this point, we see if we can initialize it...
if (_consumer == null)
{
lock (_consumerInitializationLock)
{
// if there is a consumer instance at this point, someone else went and initialized it...
if (_consumer == null)
{
try
{
_consumer = InitializeConsumer();
}
catch (Exception exception)
{
_log.Warn("Could not initialize consumer: {0} - waiting 2 seconds", exception);
Thread.Sleep(2000);
}
}
}
}
}
/// <inheritdoc />
public async Task <TransportMessage> Receive(ITransactionContext context, CancellationToken cancellationToken)
{
if (Address == null)
{
throw new InvalidOperationException("This RabbitMQ transport does not have an input queue - therefore, it is not possible to reveive anything");
}
try
{
EnsureConsumerInitialized();
var consumer = _consumer;
// initialization must have failed
if (consumer == null)
{
return(null);
}
var model = consumer.Model;
if (!model.IsOpen)
{
// something is wrong - we would not be able to ACK messages - force re-initialization to happen
_consumer = null;
// try to get rid of the consumer we have here
try
{
model.Dispose();
}
catch { }
}
BasicDeliverEventArgs result;
if (!consumer.Queue.Dequeue(TwoSeconds, out result))
{
return(null);
}
var deliveryTag = result.DeliveryTag;
context.OnCommitted(async() =>
{
model.BasicAck(deliveryTag, false);
});
context.OnAborted(() =>
{
// we might not be able to do this, but it doesn't matter that much if it succeeds
try
{
model.BasicNack(deliveryTag, false, true);
}
catch { }
});
return(CreateTransportMessage(result.BasicProperties, result.Body));
}
catch (EndOfStreamException exception)
{
ClearConsumer();
throw new RebusApplicationException(exception,
"Queue throw EndOfStreamException(meaning it was canceled by rabbitmq)");
}
catch (Exception exception)
{
ClearConsumer();
Thread.Sleep(1000);
throw new RebusApplicationException(exception,
$"unexpected exception thrown while trying to dequeue a message from rabbitmq, queue address: {Address}");
}
}