Queue

This library provides a flexible abstraction layer for working with queues.

It can be installed in whichever way you prefer, but we recommend Composer.

~$ composer require graze/queue

Documentation

Queue operations center around lists of Message objects. Whether you're sending one or multiple Messages, it's always an array. Workers work only on one Message object at a time, whether a list of one or multiple is received from the queue.

use Aws\Sqs\SqsClient;
use Graze\Queue\Adapter\SqsAdapter;
use Graze\Queue\Client;
use Graze\Queue\Message\MessageInterface;

$client = new Client(new SqsAdapter(new SqsClient([
    'region'  => 'us-east-1',
    'version' => '2012-11-05',
    'credentials' => [
        'key'    => 'ive_got_the_key',
        'secret' => 'ive_got_the_secret'
    ],
]), 'queue_name'));

// Producer
$client->send([
    $client->create('foo'),
]);

// Consumer
$client->receive(function (MessageInterface $msg) {
    var_dump($msg->getBody());
    var_dump($msg->getMetadata()->getAll());
});

Adapters

The Adapter object is used to fulfill the low level requests to the queue provider.

Currently supported queue providers are:

• Array
• AWS SQS (with the AWS SDK)

Handlers

The Handler object is used to execute worker callables with a list of received messages and handle Acknowledgement.

The current handlers are:

• Batch Acknowledgement to acknowledge batches
• Eager Acknowledgement to acknowledge immediately after work
• Null Acknowledgement for development

use Graze\Queue\Client;
use Graze\Queue\Adapter\ArrayAdapter;
use Graze\Queue\Handler\BatchAcknowledgementHandler;
use Graze\Queue\Message\MessageInterface;

// Create client with the Batch Acknowledgement Handler.
$client = new Client(new ArrayAdapter(), [
    'handler' => new BatchAcknowledgementHandler(),
]);

// Receive a maximum of 10 messages.
$client->receive(function (MessageInterface $message) {
    // Do some work.
}, 10);

Polling

Polling a queue is supported by passing null as the limit argument to the receive method. The second argument given to your worker is a Closure you should use to stop polling when you're finished working. Make sure you use a handler that acknowledges work effectively too!

Note that the individual Adapter objects may decide to stop polling at any time. A likely scenario where it may stop would be if the queue is of finite length and all possible messages have been received.

use Graze\Queue\Client;
use Graze\Queue\Adapter\ArrayAdapter;
use Graze\Queue\Handler\BatchAcknowledgementHandler;
use Graze\Queue\Message\MessageInterface;

// Create client with the Batch Acknowledgement Handler.
$client = new Client(new ArrayAdapter(), [
    'handler' => new BatchAcknowledgeHandler(100), // Acknowledge after 100 messages.
]);

// Poll until `$done()` is called.
$client->receive(function (MessageInterface $message, Closure $done) {
    // Do some work.

    // You should always define a break condition (i.e. timeout, expired session, etc).
    if ($breakCondition) $done();
}, null);

License

The content of this library is released under the MIT License by Nature Delivered Ltd.

You can find a copy of this license in LICENSE or at http://opensource.org/licenses/mit.