Dear All,
I have 2 micro services. One of the Microservice (Application A) has an Api endpoint that recieve messages from a partner Payment service. So my design is that once I recieve message from a payment partner. I would initiate a Queuing and pass message to
that my second Micro services Application B. would be the Consumer would get the message and process it for some other background functions.
I decided to go with this design because I want 100 % gauranttee.
I am using RabbitMQ queuing system. In this system you would have to create a Producer and a consumer.
Based on my design Application A is gong to be the Producer and Application B is going to be the Consumer.
My question goes thus: Is it right for me to create the Queueing producer code from within my endpoint. Endpoint in Application A. Or is the Queueing system suppose to be a background service. I would paste what my Controller end point looks like for Application
A.
public class Controller : ApiController
{
[HttpPost]
public JsonResponse Recieve(Request model){
//I process the request sent from payment partners and save to db.
//Below I now go and create a Queue which I would call
QueueProducer queue= new QueueProducer(model);
queue.ProcessQueue();//This message is going to process the queue.
}
}
.........Main Code snippet from QueueProducer below. That is what sends the Producer message to the Queue.
....
public void ProcessQueue()
{
using (var connection = CreateConnection())
using (var channel = connection.CreateModel())
{
bool isopen = connection.IsOpen;
channel.ConfirmSelect();
Console.WriteLine("Rabbit Queue connection is open "+isopen);
logger.Log(LogLevel.Information, "Rabbit Queue connection is open " + isopen);
QueueName = channel.QueueDeclare().QueueName;
logger.Log(LogLevel.Information, "Rabbit Queue Name " + QueueName);
Console.WriteLine("Rabbit Queue Name " + QueueName);
//channel.QueueDeclare(queue: QueueName);
/*channel.QueueDeclare(queue: QueueName,
durable: false,
exclusive: true,
autoDelete: true,
arguments: null);*/
var outstandingConfirms = new ConcurrentDictionary<ulong, string>();
outstandingConfirms.TryAdd(channel.NextPublishSeqNo, settlementRequest.ToString());
void cleanOutstandingConfirms(ulong sequenceNumber, bool multiple)
{
logger.Log(LogLevel.Information,"This callback is called when maessages are delivered and confirmed for clean up");
logger.Log(LogLevel.Information, "QueueProducer \n Cleans out outstanding confirmations in the queue based on delivery");
if (multiple)
{
var confirmed = outstandingConfirms.Where(k => k.Key <= sequenceNumber);
foreach (var entry in confirmed)
outstandingConfirms.TryRemove(entry.Key, out _);
}
else
outstandingConfirms.TryRemove(sequenceNumber, out _);
}
channel.BasicAcks += (sender, ea) => cleanOutstandingConfirms(ea.DeliveryTag, ea.Multiple);
channel.BasicNacks += (sender, ea) =>
{
outstandingConfirms.TryGetValue(ea.DeliveryTag, out string body);
Console.WriteLine($"Message with body {body} has been nack-ed. Sequence number: {ea.DeliveryTag}, multiple: {ea.Multiple}");
cleanOutstandingConfirms(ea.DeliveryTag, ea.Multiple);
};
//Convert the message to bytes
var bytes = ByteUtility.ObjectToByteArray(settlementRequest);
var body1 = bytes;
var timer = new Stopwatch();
timer.Start();
channel.BasicPublish(exchange: "", routingKey: QueueName, basicProperties: null, body: body1);
channel.WaitForConfirmsOrDie(new TimeSpan(0, 0, 5));
timer.Stop();
if (!WaitUntil(60, () => outstandingConfirms.IsEmpty))
{
logger.Log(LogLevel.Information, "QueueProducer \n All messages could not be confirmed in 60 seconds");
throw new Exception("All messages could not be confirmed in 60 seconds");
}
//{MESSAGE_COUNT:N0}
logger.Log(LogLevel.Information, $"QueueProducer \n Published messages and handled confirm asynchronously {timer.ElapsedMilliseconds:N0} ms");
//Console.WriteLine($"Published {MESSAGE_COUNT:N0} messages individually in {timer.ElapsedMilliseconds:N0} ms");
}
}I asked this question becos while I was readding RabbitMQ documentation. I read that this block of code
channel.ConfirmSelect();
is meant to be called once, it meant for initiating a Publisher confirmation for guarantteed delivery.
So with the approach that I am taking. My producer code is called to action every time a request hits my end point. So that means that I would always be making subsequest connection to the Rabbitmq server and calling the channel.ConfirmSelect(); method.
I dont have any other design flow in my head. So am just confused here. is there a better way to implement this.
