public Task StartSubscriptionAsync(ISubscription subscription, CancellationToken cancellationToken)
{
return(Task.Run(async() =>
{
_logger.LogInformation($"Start Subscription ...[{subscription.Identifier}]");
//Cancellation Actions
cancellationToken.Register(() =>
{
_logger.LogInformation(
$"Cancellation Token Requested for Subscription : [{subscription.Identifier}]");
});
if (subscription.IsRunning)
{
_logger.LogWarning($"The Subscription [{subscription.Identifier}] is in Running mode - cannot run again");
return;
}
//subscription.IsRunning = true;
while (!cancellationToken.IsCancellationRequested)
{
try
{
using (var connection = _queueClient.Factory.CreateConnection())
using (var channel = connection.CreateModel())
{
// Declare the exchange, the queue and bind them together.
channel.ExchangeDeclare(subscription.Exchange, "topic", true);
QueueDeclareOk queueDeclare = null;
if (!_queueClient.Options.DisableDeadLettering)
{
var deadLetterExchange =
subscription.Exchange + _queueClient.Options.DeadLetterPostFix;
var deadLetterQueue = subscription.Queue + _queueClient.Options.DeadLetterPostFix;
// Create the queue and set the bindings to the dead letter exchange
IDictionary <String, Object> args = new Dictionary <String, Object>();
args.Add("x-dead-letter-exchange", deadLetterExchange);
args.Add("x-dead-letter-routing-key", deadLetterQueue);
queueDeclare = channel.QueueDeclare(subscription.Queue, true, false, false, args);
// create the dead letter queue and bind it ignoring routing keys. Catch all.
channel.QueueDeclare(deadLetterQueue, true, false, false, null);
channel.QueueBind(deadLetterQueue, deadLetterExchange, deadLetterQueue);
}
else
{
queueDeclare = channel.QueueDeclare(subscription.Queue, true, false, false, null);
}
using (var passiveChannel = connection.CreateModel())
{
try
{
passiveChannel.ExchangeDeclarePassive(subscription.Exchange);
passiveChannel.QueueDeclarePassive(subscription.Queue);
passiveChannel.Close();
}
catch (Exception ex)
{
_logger.LogError(ex, "Exchange or Queue dose not exist");
passiveChannel.Close();
connection.Close();
break;
}
}
//Bind to Queue
channel.QueueBind(subscription.Queue, subscription.Exchange, subscription.EventType);
var consumer = new AsyncEventingBasicConsumer(channel);
_logger.LogInformation($"Start Listening ...[{subscription.Identifier}]");
consumer.Received += async(model, ea) =>
{
var body = ea.Body;
var rawMessage = Encoding.UTF8.GetString(body);
_logger.LogInformation($"Message Received : [{rawMessage}]");
Message messageObj = null;
messageObj = ParseMessage(rawMessage);
using (var scope = _serviceProvider.CreateScope())
{
var processor =
(IMessageProcessor)scope.ServiceProvider.GetRequiredService(
subscription
.ProcessorType);
IMessageControlService messageControlSrv =
scope.ServiceProvider.GetService <IMessageControlService>();
try
{
// Let the MessageController know know we got a message.
messageControlSrv?.SendMessageControl(MessageState.Received, messageObj, subscription);
var result = await processor.ProcessAsync(messageObj);
switch (result.Status)
{
case ResultStatus.Success:
channel.BasicAck(ea.DeliveryTag, false);
// Let the MessageController know we have a failure.
messageControlSrv?.SendMessageControl(MessageState.Success, messageObj, subscription, result.Response);
break;
case ResultStatus.Retry:
_logger.LogWarning(
$"SubscriptionID: {subscription.Identifier} - Returned Retry from Processor for MessageID: {messageObj.MessageID}");
channel.BasicNack(ea.DeliveryTag, false, false);
messageControlSrv?.SendMessageControl(MessageState.Retry, messageObj, subscription, result.Response);
break;
case ResultStatus.Failure:
_logger.LogWarning(
$"SubscriptionID: {subscription.Identifier} - Returned Failure from Processor for MessageID: {messageObj.MessageID}");
channel.BasicNack(ea.DeliveryTag, false, false);
messageControlSrv?.SendMessageControl(MessageState.Failure, messageObj, subscription, result.Response);
break;
}
}
catch (Exception ex)
{
_logger.LogError(ex,
$"SubscriptionId: [{subscription.Identifier}] - Error reported from messageTarget for MessageID: [{messageObj?.MessageID}]");
channel.BasicNack(ea.DeliveryTag, false, false);
messageControlSrv?.SendMessageControl(MessageState.Failure, messageObj, subscription, ex);
}
}
};
channel.BasicConsume(queue: queueDeclare.QueueName,
autoAck: false,
consumer: consumer);
subscription.IsRunning = true;
await Task.WhenAny(Task.Delay(Timeout.Infinite, cancellationToken));
}
}
catch (EndOfStreamException ex)
{
_logger.LogError(ex,
$"SubscriptionID: {subscription.Identifier} - An EndOfStreamException occurred with the rabbit queue process. We will not recover, and remove the subscriptions.");
break;
}
catch (RabbitMQ.Client.Exceptions.BrokerUnreachableException ex)
{
_logger.LogError(ex,
$"SubscriptionID: {subscription.Identifier} - An IOException occurred with the rabbit queue process. We will attempt to recover in {_queueClient.Options.SystemRecoveryInterval} seconds.");
await Task.Delay(_queueClient.Options.SystemRecoveryInterval * 1000, cancellationToken);
}
catch (IOException ex)
{
_logger.LogError(ex,
$"SubscriptionID: {subscription.Identifier} - An IOException occurred with the rabbit queue process. We will attempt to recover in {_queueClient.Options.SystemRecoveryInterval} seconds.");
await Task.Delay(_queueClient.Options.SystemRecoveryInterval * 1000, cancellationToken);
}
}
_logger.LogInformation($"Stop Subscription [{subscription.Identifier}]...");
}));
}
public Publisher(ILogger <Publisher> logger, IQueueClient queueClient, IMessageControlService messageControlService)
{
_logger = logger;
_queueClient = queueClient;
_messageControlService = messageControlService;
}
