Keep messages from ACKing on get() using pecl-amqp - php

Question

I'm attempting to use pecl-amqp for a project of mine. I'm having difficulties though with the ACK process. I need to manually ACK each message I receive off a queue, but the messages appear to be auto-ACKing when the message is retrieved.
I've set my queue to AMQP_NOACK and am using AMQPQueue->get(AMQP_NOACK) but none of it seems to have any affect, the messages are still removed from the queue without me sending AMQPQueue->ack().
If anyone has any experience with the pecl-amqp I would appreciate the help.

Answer 1

I have been having the same problem but have managed to get the acknowledge mechanism to work using the consume method. Using rabbitmqctl to list the entries in the queue it appears to work OK, though I seems to be getting the messages off the queue in a different order to that in which they were sent - which kind of defeats the object of a queue. My code is as follows:
// Create the queue to be:
// AMQP_DURABLE - messages will withstand a broker restart (i.e. they are written to disk).
// AMQP_NOACK - when consumed messages will not be marked as delivered until an explicit ACK is received.
$q->declare($queueName, AMQP_DURABLE | AMQP_NOACK );
// Bind it on the exchange to routing key.
$q->bind($exchangeName, $routingKey);
// Set the options for our consumption of the messages:
// Get a minimum of 0 msg.
// Get a maximum of 1 msg.
// Don't ACK the message on consumption i.e. explicitly acknoledge later.
$options = array(
'min' => 0,
'max' => 1,
'ack' => false
);
// Get the messages
$results_array = $q->consume($options);
// show the message
print_r($results_array);
$delivery_tag = $results_array[0]['delivery_tag'];
echo 'delivery_tag: [' . $delivery_tag . "].\r\n";
// Acknowledge receipt of the message.
$q->ack($delivery_tag);

Answer 2

For reference, the AMQP extension did not support the AMQP_NOACK correctly. You can get it to do what you want, but it isnt pretty. I am working on fixing that now. FYI, AMQP_NOACK means that you will not have to come back to acknowledge the message later, i.e. as soon as the server sends the message to the client, the server marks the message as ack'ed. There has been some confusion around this, so I wanted to clarify.