public RabbitMQBatchConsumerWorker(ILogger logger, RabbitMQConnection connection, string queueName, IModel model,
IBatchProcessingWorker <T> batchProcessingWorker, IMessageRejectionHandler messageRejectionHandler,
ISerializer serializer)
{
_logger = logger;
_model = model;
_model.BasicQos(0, batchProcessingWorker.GetBatchSize(), false);
_queueName = queueName;
_batchProcessingWorker = batchProcessingWorker;
_messageRejectionHandler = messageRejectionHandler;
_serializer = serializer;
CheckAliveFrequency = new TimeSpan(0, 0, 10);
}
public async Task DoConsumeAsync(CancellationToken cancellationToken)
{
//Iterate while thread hasn't been canceled
while (!cancellationToken.IsCancellationRequested)
{
var currentBatchCounter = _batchProcessingWorker.GetBatchSize();
var currentBatch = new List <T>();
BasicGetResult result;
ulong lastDeliveryTag = 0;
do
{
result = _model.BasicGet(_queueName, false);
if (result != null)
{
lastDeliveryTag = result.DeliveryTag;
currentBatchCounter--;
var messageBody = GetBody(result);
try
{
var messageObject = _serializer.Deserialize <T>(messageBody);
currentBatch.Add(messageObject);
}
catch (Exception exception)
{
var deserializationException = new DeserializationException("Unable to deserialize data.", exception)
{
SerializedDataString = messageBody,
SerializedDataBinary = result.Body,
QueueName = _queueName
};
await _messageRejectionHandler.OnRejectionAsync(deserializationException).ConfigureAwait(false);
//Remove message from queue after RejectionHandler dealt with it
_model.BasicNack(result.DeliveryTag, false, false);
}
}
} while (currentBatchCounter > 0 && result != null);
if (currentBatch.Count > 0)
{
var batchFeedbackSender = new RabbitMQBatchFeedbackSender(_model, lastDeliveryTag);
try
{
await _batchProcessingWorker.OnBatchAsync(currentBatch, batchFeedbackSender,
cancellationToken).ConfigureAwait(false);
if (!batchFeedbackSender.HasAcknoledged)
{
//Acknoledge message
batchFeedbackSender.Ack();
}
}
catch (Exception e)
{
//If something went wrong with message processing and message hasn't been acknoledged yet
if (!batchFeedbackSender.HasAcknoledged)
{
//Negatively Acknoledge message, asking for requeue
batchFeedbackSender.Nack(true);
}
//Rethrow caught Exception
throw;
}
}
}
//Loop ended, dispose ConsumerWorker
Dispose();
}
