Create queues with some x-max-priority values fails

[ezequielgarcia88]

If if create a queue with x-max-priority at 255 it fails with the following error:

Error: Channel closed by server: 406 (PRECONDITION-FAILED) with message "PRECONDITION_FAILED - invalid arg 'x-max-priority' for queue 'tasks' in vhost '/': {value_negative,-1}"

This is my example code:

require('amqplib').connect('amqp://guest:guest@localhost:5672').then(function(conn) {
    return conn.createChannel().then(function(ch) {
        return ch.assertExchange('tasks-ex', 'fanout').then(function() {
            return ch.assertQueue('tasks', {
                arguments : {
                    'x-max-priority' : 255
                }
            }).then(function (qok) {
                return ch.bindQueue(qok.queue, 'tasks-ex', '').then(function () {
                    return qok.queue;
                });
            }).then(function (queue) {
                return ch.consume(queue, function (msg) {
                    if (msg !== null) {
                        console.log(' [x] Received "%s"', msg.content.toString());
                        ch.ack(msg);
                    }
                },{
                    noAck : false
                });
            });
        });
    });
}).then(null, console.warn);

Do you know why this happens?

[michaelklishin]

The message says what the problem is: you already have a queue named tasks and it has different attributes (headers, in this case). Delete it and declare it again with the headers you want.

[ezequielgarcia88]

Hi, thanks for the quick answer. I don't have the queue created in RabbitMQ, and also the example code works by only changing the x-max-priority to 256.

This is the error I get if the queue was already created with different attributes:

Error: Channel closed by server: 406 (PRECONDITION-FAILED) with message "PRECONDITION_FAILED - inequivalent arg 'x-max-priority' for queue 'tasks' in vhost '/': received '258' but current is '256'"

[michaelklishin]

@ezequielgarcia88

inequivalent arg 'x-max-priority' for queue 'tasks' in vhost '/': received '258' but current is '256'"

suggests that you do have that queue in vhost /. In an unrelated note, 256 priorities is excessive and will introduce a lot of unnecessary overhead. 5-10 should be sufficient for most use cases.

[squaremo]

In the first example, the error was invalid arg 'x-max-priority' for queue 'tasks' in vhost '/': {value_negative,-1}, which suggests to me some weird encoding is going on. Maybe RabbitMQ expects an unsigned encoding, but the client library uses a signed encoding (because how is it supposed to know, for arbitrary arguments).

[squaremo]

Iiiiinteresting: rabbitmq/rabbitmq-server@a640f74

[taoyanli0808]

Here's a tour.

[Laksh47]

replace the 'x-max-priority' with 'maxPriority'
reference: http://www.squaremobius.net/amqp.node/channel_api.html#channel_assertQueue

[tholisam-sasikala]

data queue should be created with arg x-max-length-bytes" = int64(1000000000)
Max length should be set in the call to queue declare using the params argument, not externally with rabbitmqctl...