Setting x-message-ttl Exception

[ZedZipDev]

I have an existing Queue with messages and want to change the Queues TTL.

Do it:

var args = new Dictionary<string, object>();
args.Add("x-message-ttl", 20000);
model.QueueDeclare("DoBeDo", false, false, false, args);

But receive:

The AMQP operation was interrupted: AMQP close-reason, initiated by Peer, code=406, text='PRECONDITION_FAILED - 
inequivalent arg 'x-message-ttl' for queue 'DoBeDo' in vhost '/': 
received the value '20000' of type 'signedint' but current is none', classId=50, methodId=10

What is wrong? Is it possible to change the TTL for the existing Queue with messages?

[michaelklishin]

I will convert this issue to a GitHub discussion. Currently GitHub will automatically close and lock the issue even though your question will be transferred and responded to elsewhere. This is to let you know that we do not intend to ignore this but this is how the current GitHub conversion mechanism makes it seem for the users :(

[michaelklishin]

You cannot modify properties of a previously declared queue: they are immutable and checked for equivalence. Either delete the queue and re-declare it, or delete it, redeclare and use a policy instead.

[sungam3r]

the channel closed and I cannot use it anymore

It is intended behavior due to AMQP spec.

[ZedZipDev]

"What is it?"
It is :

var args = new Dictionary<string, object>();
args.Add("x-message-ttl", 30000);
try
{
channel.QueueDeclare(QueName, true, false, false, args);

[sungam3r]

The exception is generated when the queue is declared/redeclared.

for existing queue

How to know if queue exists or not ?

[ZedZipDev]

I run the dashboard and see all queues including this queue

[ZedZipDev]

@sungam3r but channel closed too in this case and I cannot work with it. That is the problem.

[ZedZipDev]

How to check if queue already exists?
When I try in my c# app to change TTL for the queue I catch an exception and channel is closed.
How to check if queue already exists to prevent this situation? i.e. if queue do not exist I create it with TTL and other parameters else I do not try to create it.

[sungam3r]

https://www.rabbitmq.com/api-guide.html#passive-declaration

[ZedZipDev]

I use this approach.
There is my function:

 public static bool RMQQueueExists(IModel channel, string QueName)
        {
            bool b = false;
            try
            {
                var xxOk = channel.QueueDeclarePassive(QueName);
                b = true;
            }
            catch (Exception x)
            {
                Console.WriteLine("Queue {0} does not exist", x.Message); 
              // and channel.IsClosed  here!
            }
            return b;
        }

In case of queue does not exist (exception) the channel closed and cannot be used anymore.

Please correct me what is wrong?