Kestrel Client Decorator

EC_KestrelClient.php

<?php
/**
 * A thin kestrel client that wraps Memcached (libmemcached extension)
 *
 * @author    Bill Shupp <[email protected]>
 * @copyright 2010-2011 Empower Campaigns
 */
class EC_KestrelClient
{
    /**
     * The Memcached instance
     *
     * @var Memcached
     */
    protected $_memcached = null;

    /**
     * The Kestrel server IP
     *
     * @var string
     */
    protected $_host = '127.0.0.1';

    /**
     * The Kestrel server port
     *
     * @var string
     */
    protected $_port = 22133;

    /**
     * Optional options, not currently used
     *
     * @var array
     */
    protected $_options = array();

    /**
     * Sets the host, port, and options to be used
     *
     * @param string $host    The host to use, defaults to 127.0.0.1
     * @param int    $port    The port to use, defaults to 22133
     * @param array  $options Memcached options, not currently used
     *
     * @return void
     */
    public function __construct(
        $host = '127.0.0.1', $port = 22133, array $options = array()
    )
    {
        $this->_host = $host;
        $this->_port = $port;
        $this->setOptions($options);
    }


    /**
     * Sets job data on the queue, json_encoding the value to avoid problematic
     * serialization.
     *
     * @param string $queue The queue name
     * @param mixed $data   The data to store
     *
     * @return bool
     */
    public function set($queue, $data)
    {
        // Local json serialization, as kestrel doesn't send serialization flags
        return $this->getMemcached()->set($queue, json_encode($data));
    }

    /**
     * Reliably read an item off of the queue.  Meant to be run in a loop, and
     * call closeReliableRead() when done to make sure the final job is not left
     * on the queue.
     *
     * @param mixed $queue   The queue name to read from
     * @param int   $timeout The timeout to wait for a job to appear
     *
     * @return array|false
     * @see closeReliableRead()
     */
    public function reliableRead($queue, $timeout = 1000)
    {
        $queue = $queue . '/close/open/t=' . $timeout;
        $result = $this->getMemcached()->get($queue);
        if ($result === false) {
            return $result;
        }
        // Local json serialization, as kestrel doesn't send serialization flags
        return json_decode($result, true);
    }

    /**
     * Closes any existing open read
     *
     * @param string $queue The queue name
     *
     * @return false
     */
    public function closeReliableRead($queue)
    {
        $queue = $queue . '/close';
        return $this->getMemcached()->get($queue);
    }

    /**
     * Aborts an existing reliable read
     *
     * @param string $queue The queue name
     *
     * @return false
     */
    public function abortReliableRead($queue)
    {
        $queue = $queue . '/abort';
        return $this->getMemcached()->get($queue);
    }

    /**
     * Set an option to be used with the Memcached client.  Not used.
     *
     * @param string $name  The option name
     * @param value  $value The option value
     *
     * @return void
     */
    public function setOption($name, $value)
    {
        $this->_options[$name] = $value;
    }

    /**
     * Sets multiple options
     *
     * @param array $options Array of key/values to set
     *
     * @return void
     */
    public function setOptions(array $options)
    {
        foreach ($options as $name => $value) {
            $this->setOption($name, $value);
        }
    }

    /**
     * Gets a current option's value
     *
     * @param string $name The option name
     *
     * @return mixed
     */
    public function getOption($name)
    {
        if (isset($this->_options[$name])) {
            return $this->_options[$name];
        }
        return null;
    }

    /**
     * Gets all current options
     *
     * @return array
     */
    public function getOptions()
    {
        return $this->_options;
    }

    /**
     * Gets a singleton instance of the Memcached client
     *
     * @return Memcached
     */
    public function getMemcached()
    {
        if ($this->_memcached === null) {
            $this->_initMemcached();
        }
        return $this->_memcached;
    }

    /**
     * Initialized the Memcached client instance
     *
     * @return void
     */
    protected function _initMemcached()
    {
        $this->_memcached = $this->_getMemcachedInstance();
        foreach ($this->_options as $option => $value) {
            $this->_memcached->setOption($option, $value);
        }
        $this->_memcached->addServer($this->_host, $this->_port);
        $this->_memcached->setOption(Memcached::OPT_COMPRESSION, false);
    }

    // @codeCoverageIgnoreStart
    /**
     * Returns a new instance of Memcached.  Abstracted for testing.
     *
     * @return Memcached
     */
    protected function _getMemcachedInstance()
    {
        return new Memcached();
    }
    // @codeCoverageIgnoreEnd
}