Swarrot

Swarrot is PHP library to consume messages from a broker.

Installation

The recommended way to install Swarrot is through Composer. Require the swarrot/swarrot package into your composer.json file:

{
    "require": {
        "swarrot/swarrot": "@stable"
    }
}

Protip: you should browse the swarrot/swarrot page to choose a stable version to use, avoid the @stable meta constraint.

Usage

Basic usage

First, you need to create a message provider to retrieve message from you're broker. For example, with A PeclPackageMessageProvider (retrieve message from an AMQP broker with the pecl amqp package:

use Swarrot\Broker\PeclPackageMessageProvider;

// Create connection
$connection = new \AMQPConnection();
$connection->connect();
$channel = new \AMQPChannel($connection);
// Get the queue to consume
$queue = new \AMQPQueue($channel);
$queue->setName('global');

$messageProvider = new PeclPackageMessageProvider($queue);

Once it's done you need to create a Processor to process messages retrieved from the broker. This processor must implement Swarrot\Processor\ProcessorInterface. For example:

use Swarrot\Processor\ProcessorInterface;
use Swarrot\Broker\Message;

class Processor implements ProcessorInterface {
    public function process(Message $message, array $options) {
        echo sprintf("Consume message #%d\n", $message->getId());
    }
}

You now have a Swarrot\Broker\MessageProviderInterface to retrieve messages and a Processor to process them. So, ask the Swarrot\Consumerto do it's job :

use Swarrot\Message;

$consumer = new Consumer($messageProvider, $processor);
$consumer->consume();

Decorate your processor

Using the built in processors or by creating your own, you can extend the behavior of your processor. Let's imagine you want to catch exception during execution to avoid the consumer to stop in production environment, you can use the ExceptionCatcherProcessor like this:

use Swarrot\Processor\ExceptionCatcherProcessor;
use Swarrot\Processor\ProcessorInterface;
use Swarrot\Broker\Message;

class Processor implements ProcessorInterface {
    public function process(Message $message, array $options) {
        echo sprintf("Consume message #%d\n", $message->getId());
    }
}

$processor = new ExceptionCatcherProcessor(new Processor());

Take a look at this processor's code. It just decorate your own processor with a try/catch block.

Using a stack

Heavily inspired by stackphp/builder you can use Swarrot\Processor\Stack\Builder to stack your processors. Because it can be annoying to chain all you're processors, you can use the Builder like this:

use Swarrot\Processor\ProcessorInterface;
use Swarrot\Broker\Message;

class Processor implements ProcessorInterface {
    public function process(Message $message, array $options) {
        echo sprintf("Consume message #%d\n", $message->getId());
    }
}

$stack = (new \Swarrot\Processor\Stack\Builder())
    ->push('Swarrot\Processor\ExceptionCatcherProcessor')
    ->push('Swarrot\Processor\MaxMessagesProcessor', new Logger())
;

$processor = $stack->resolve(new Processor());

Processors

Official processors

• AckProcessor
• ExceptionCatcherProcessor
• InstantRetryProcessor
• MaxExecutionTimeProcessor (thanks to Remy Lemeunier)
• MaxMessagesProcessor (thanks to Remy Lemeunier)
• RetryProcessor
• SignalHandlerProcessor

Create your own processor

To create your own processor and be able to use it with the StackProcessor, you just need to implement ProcessorInterface and to take another ProcessorInterface as first argument in constructor.

Inspiration

• stackphp/builder

License

Swarrot is released under the MIT License. See the bundled LICENSE file for details.