/// <summary>
/// StartConsumers - start consumers and connect them to a queue.
/// </summary>
/// <param name="consumerName">Consumer name</param>
/// <param name="retryQueueDetails">Retry queue details if a message needs to be requeued with a delay (a Dead letter exchange must be defined)</param>
/// <param name="queueName">Queue where the consumers will connect (optional - if not defined, the config value is used)</param>
/// <param name="totalConsumers">Total consumers to start (optional - if not defined, the config value is used)</param>
/// <param name="createQueue">Create queue to connect when starting consumers (optional - default is false)</param>
/// <exception cref="RabbitMQClientException"></exception>
public void StartConsumers(string consumerName, RetryQueueDetails retryQueueDetails, string queueName = null, byte?totalConsumers = null, bool createQueue = false)
{
var config = (IBrokerConfigConsumers)_config;
var totalConsumersToStart = totalConsumers ?? config.TotalInstances;
if (totalConsumersToStart <= 0)
{
throw new ArgumentException("Invalid total number of consumers to start");
}
var triedCreateQueue = false;
for (var i = 0; i < totalConsumersToStart; i++)
{
var routingKeyOrQueueName =
string.IsNullOrWhiteSpace(queueName) ? config.RoutingKeyOrQueueName : queueName;
var totalCreatedConsumers = _consumers.Count;
var connection = GetConnection(ServiceDescription + "_" + i, totalCreatedConsumers, MaxChannelsPerConnection);
var channel = connection.CreateModel();
if (createQueue && !triedCreateQueue)
{
try
{
RabbitMqUtilities.CreateQueueOrGetInfo(routingKeyOrQueueName, channel);
triedCreateQueue = true;
}
catch (Exception e)
{
throw new RabbitMqClientException($"Unable do create queue. Details: {e.Message}", e);
}
}
var consumer = new AsyncEventingBasicConsumerExtended(channel)
{
ConnectedToPort = connection.Endpoint.Port,
ConnectedToHost = connection.Endpoint.HostName,
ConnectionTime = DateTime.Now,
Id = i,
RetentionPeriodInRetryQueueMilliseconds = retryQueueDetails?.RetentionPeriodInRetryQueueMilliseconds ?? 0,
RetentionPeriodInRetryQueueMillisecondsMax = retryQueueDetails?.RetentionPeriodInRetryQueueMillisecondsMax ?? 0,
RetryQueue = retryQueueDetails?.RetryQueue
};
consumer.Received += Consumer_Received;
consumer.Shutdown += Consumer_Shutdown;
var tag = $"{consumerName}_{i}";
consumer.ConsumerTag = tag;
_consumers.Add(consumer);
channel.BasicConsume(routingKeyOrQueueName, false, tag, consumer);
}
}
private void RequeueMessageWithDelay(AsyncEventingBasicConsumerExtended consumer, BasicDeliverEventArgs deliveryArgs, string messageAdditionalInfo)
{
if (string.IsNullOrWhiteSpace(consumer.RetryQueue))
{
return;
}
var properties = consumer.Model.CreateBasicProperties();
RabbitMqUtilities.SetPropertiesSenderRequeueMessageWithDelay(properties, consumer.RetentionPeriodInRetryQueueMilliseconds, consumer.RetentionPeriodInRetryQueueMillisecondsMax);
var firstErrorTimeStamp = RabbitMqUtilities.GetFirstErrorTimeStampFromMessageArgs(deliveryArgs.BasicProperties);
SetFirstErrorTimeStampToProperties(firstErrorTimeStamp, properties);
SetMessageAdditionalInfoToProperties(messageAdditionalInfo, properties);
consumer.Model.BasicPublish(
"",
consumer.RetryQueue,
properties,
deliveryArgs.Body);
}
