PHP implements message queue class instance sharing

<?php

namespace Common\Business;

/**

 * beanstalk: A minimalistic PHP beanstalk client.

 *

 * Copyright (c) 2009-2015 David Persson

 *

 * Distributed under the terms of the MIT License.

 * Redistributions of files must retain the above copyright notice.

 */

use RuntimeException;

/**

 * An interface to the beanstalk queue service. Implements the beanstalk

 * protocol spec 1.9. Where appropriate the documentation from the protocol

 * has been added to the docblocks in this class.

 *

 * @link https://github.com/kr/beanstalkd/blob/master/doc/protocol.txt

 */

class BeanStalk {

  /**

   * Minimum priority value which can be assigned to a job. The minimum

   * priority value is also the _highest priority_ a job can have.

   *

   * @var integer

   */

  const MIN_PRIORITY = 0;

  /**

   * Maximum priority value which can be assigned to a job. The maximum

   * priority value is also the _lowest priority_ a job can have.

   *

   * @var integer

   */

  const MAX_PRIORITY = 4294967295;

  /**

   * Holds a boolean indicating whether a connection to the server is

   * currently established or not.

   *

   * @var boolean

   */

  public $connected = false;

  /**

   * Holds configuration values.

   *

   * @var array

   */

  protected $_config = [];

  /**

   * The current connection resource handle (if any).

   *

   * @var resource

   */

  protected $_connection;

  /**

   * Constructor.

   *

   * @param array $config An array of configuration values:

   *    - `'persistent'` Whether to make the connection persistent or

   *             not, defaults to `true` as the FAQ recommends

   *             persistent connections.

   *    - `'host'`    The beanstalk server hostname or IP address to

   *             connect to, defaults to `127.0.0.1`.

   *    - `'port'`    The port of the server to connect to, defaults

   *             to `11300`.

   *    - `'timeout'`   Timeout in seconds when establishing the

   *             connection, defaults to `1`.

   *    - `'logger'`   An instance of a PSR-3 compatible logger.

   *

   * @link https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-3-logger-interface.md

   * @return void

   */

  public function __construct(array $config = []) {

    $defaults = [

      'persistent' => true,

      'host' => '127.0.0.1',

      'port' => 11300,

      'timeout' => 1,

      'logger' => null

    ];

    $this->_config = $config + $defaults;

  }

  /**

   * Destructor, disconnects from the server.

   *

   * @return void

   */

  public function __destruct() {

    $this->disconnect();

  }

  /**

   * Initiates a socket connection to the beanstalk server. The resulting

   * stream will not have any timeout set on it. Which means it can wait

   * an unlimited amount of time until a packet becomes available. This

   * is required for doing blocking reads.

   *

   * @see \Beanstalk\Client::$_connection

   * @see \Beanstalk\Client::reserve()

   * @return boolean `true` if the connection was established, `false` otherwise.

   */

  public function connect() {

    if (isset($this->_connection)) {

      $this->disconnect();

    }

    $errNum = '';

    $errStr = '';

    $function = $this->_config['persistent'] ? 'pfsockopen' : 'fsockopen';

    $params = [$this->_config['host'], $this->_config['port'], &$errNum, &$errStr];

    if ($this->_config['timeout']) {

      $params[] = $this->_config['timeout'];

    }

    $this->_connection = @call_user_func_array($function, $params);

    if (!empty($errNum) || !empty($errStr)) {

      $this->_error("{$errNum}: {$errStr}");

    }

    $this->connected = is_resource($this->_connection);

    if ($this->connected) {

      stream_set_timeout($this->_connection, -1);

    }

    return $this->connected;

  }

  /**

   * Closes the connection to the beanstalk server by first signaling

   * that we want to quit then actually closing the socket connection.

   *

   * @return boolean `true` if diconnecting was successful.

   */

  public function disconnect() {

    if (!is_resource($this->_connection)) {

      $this->connected = false;

    } else {

      $this->_write('quit');

      $this->connected = !fclose($this->_connection);

      if (!$this->connected) {

        $this->_connection = null;

      }

    }

    return !$this->connected;

  }

  /**

   * Pushes an error message to the logger, when one is configured.

   *

   * @param string $message The error message.

   * @return void

   */

  protected function _error($message) {

    if ($this->_config['logger']) {

      $this->_config['logger']->error($message);

    }

  }

  public function errors()

  {

    return $this->_config['logger'];

  }

  /**

   * Writes a packet to the socket. Prior to writing to the socket will

   * check for availability of the connection.

   *

   * @param string $data

   * @return integer|boolean number of written bytes or `false` on error.

   */

  protected function _write($data) {

    if (!$this->connected) {

      $message = 'No connecting found while writing data to socket.';

      throw new RuntimeException($message);

    }

    $data .= "\r\n";

    return fwrite($this->_connection, $data, strlen($data));

  }

  /**

   * Reads a packet from the socket. Prior to reading from the socket

   * will check for availability of the connection.

   *

   * @param integer $length Number of bytes to read.

   * @return string|boolean Data or `false` on error.

   */

  protected function _read($length = null) {

    if (!$this->connected) {

      $message = 'No connection found while reading data from socket.';

      throw new RuntimeException($message);

    }

    if ($length) {

      if (feof($this->_connection)) {

        return false;

      }

      $data = stream_get_contents($this->_connection, $length + 2);

      $meta = stream_get_meta_data($this->_connection);

      if ($meta['timed_out']) {

        $message = 'Connection timed out while reading data from socket.';

        throw new RuntimeException($message);

      }

      $packet = rtrim($data, "\r\n");

    } else {

      $packet = stream_get_line($this->_connection, 16384, "\r\n");

    }

    return $packet;

  }

  /* Producer Commands */

  /**

   * The `put` command is for any process that wants to insert a job into the queue.

   *

   * @param integer $pri Jobs with smaller priority values will be scheduled

   *    before jobs with larger priorities. The most urgent priority is

   *    0; the least urgent priority is 4294967295.

   * @param integer $delay Seconds to wait before putting the job in the

   *    ready queue. The job will be in the "delayed" state during this time.

   * @param integer $ttr Time to run - Number of seconds to allow a worker to

   *    run this job. The minimum ttr is 1.

   * @param string $data The job body.

   * @return integer|boolean `false` on error otherwise an integer indicating

   *     the job id.

   */

  public function put($pri, $delay, $ttr, $data) {

    $this->_write(sprintf("put %d %d %d %d\r\n%s", $pri, $delay, $ttr, strlen($data), $data));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'INSERTED':

      case 'BURIED':

        return (integer) strtok(' '); // job id

      case 'EXPECTED_CRLF':

      case 'JOB_TOO_BIG':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * The `use` command is for producers. Subsequent put commands will put

   * jobs into the tube specified by this command. If no use command has

   * been issued, jobs will be put into the tube named `default`.

   *

   * @param string $tube A name at most 200 bytes. It specifies the tube to

   *    use. If the tube does not exist, it will be created.

   * @return string|boolean `false` on error otherwise the name of the tube.

   */

  public function useTube($tube) {

    $this->_write(sprintf('use %s', $tube));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'USING':

        return strtok(' ');

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Pause a tube delaying any new job in it being reserved for a given time.

   *

   * @param string $tube The name of the tube to pause.

   * @param integer $delay Number of seconds to wait before reserving any more

   *    jobs from the queue.

   * @return boolean `false` on error otherwise `true`.

   */

  public function pauseTube($tube, $delay) {

    $this->_write(sprintf('pause-tube %s %d', $tube, $delay));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'PAUSED':

        return true;

      case 'NOT_FOUND':

      default:

        $this->_error($status);

        return false;

    }

  }

  /* Worker Commands */

  /**

   * Reserve a job (with a timeout).

   *

   * @param integer $timeout If given specifies number of seconds to wait for

   *    a job. `0` returns immediately.

   * @return array|false `false` on error otherwise an array holding job id

   *     and body.

   */

  public function reserve($timeout = null) {

    if (isset($timeout)) {

      $this->_write(sprintf('reserve-with-timeout %d', $timeout));

    } else {

      $this->_write('reserve');

    }

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'RESERVED':

        return [

          'id' => (integer) strtok(' '),

          'body' => $this->_read((integer) strtok(' '))

        ];

      case 'DEADLINE_SOON':

      case 'TIMED_OUT':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Removes a job from the server entirely.

   *

   * @param integer $id The id of the job.

   * @return boolean `false` on error, `true` on success.

   */

  public function delete($id) {

    $this->_write(sprintf('delete %d', $id));

    $status = $this->_read();

    switch ($status) {

      case 'DELETED':

        return true;

      case 'NOT_FOUND':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Puts a reserved job back into the ready queue.

   *

   * @param integer $id The id of the job.

   * @param integer $pri Priority to assign to the job.

   * @param integer $delay Number of seconds to wait before putting the job in the ready queue.

   * @return boolean `false` on error, `true` on success.

   */

  public function release($id, $pri, $delay) {

    $this->_write(sprintf('release %d %d %d', $id, $pri, $delay));

    $status = $this->_read();

    switch ($status) {

      case 'RELEASED':

      case 'BURIED':

        return true;

      case 'NOT_FOUND':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Puts a job into the `buried` state Buried jobs are put into a FIFO

   * linked list and will not be touched until a client kicks them.

   *

   * @param integer $id The id of the job.

   * @param integer $pri *New* priority to assign to the job.

   * @return boolean `false` on error, `true` on success.

   */

  public function bury($id, $pri) {

    $this->_write(sprintf('bury %d %d', $id, $pri));

    $status = $this->_read();

    switch ($status) {

      case 'BURIED':

        return true;

      case 'NOT_FOUND':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Allows a worker to request more time to work on a job.

   *

   * @param integer $id The id of the job.

   * @return boolean `false` on error, `true` on success.

   */

  public function touch($id) {

    $this->_write(sprintf('touch %d', $id));

    $status = $this->_read();

    switch ($status) {

      case 'TOUCHED':

        return true;

      case 'NOT_TOUCHED':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Adds the named tube to the watch list for the current connection.

   *

   * @param string $tube Name of tube to watch.

   * @return integer|boolean `false` on error otherwise number of tubes in watch list.

   */

  public function watch($tube) {

    $this->_write(sprintf('watch %s', $tube));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'WATCHING':

        return (integer) strtok(' ');

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Remove the named tube from the watch list.

   *

   * @param string $tube Name of tube to ignore.

   * @return integer|boolean `false` on error otherwise number of tubes in watch list.

   */

  public function ignore($tube) {

    $this->_write(sprintf('ignore %s', $tube));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'WATCHING':

        return (integer) strtok(' ');

      case 'NOT_IGNORED':

      default:

        $this->_error($status);

        return false;

    }

  }

  /* Other Commands */

  /**

   * Inspect a job by its id.

   *

   * @param integer $id The id of the job.

   * @return string|boolean `false` on error otherwise the body of the job.

   */

  public function peek($id) {

    $this->_write(sprintf('peek %d', $id));

    return $this->_peekRead();

  }

  /**

   * Inspect the next ready job.

   *

   * @return string|boolean `false` on error otherwise the body of the job.

   */

  public function peekReady() {

    $this->_write('peek-ready');

    return $this->_peekRead();

  }

  /**

   * Inspect the job with the shortest delay left.

   *

   * @return string|boolean `false` on error otherwise the body of the job.

   */

  public function peekDelayed() {

    $this->_write('peek-delayed');

    return $this->_peekRead();

  }

  /**

   * Inspect the next job in the list of buried jobs.

   *

   * @return string|boolean `false` on error otherwise the body of the job.

   */

  public function peekBuried() {

    $this->_write('peek-buried');

    return $this->_peekRead();

  }

  /**

   * Handles response for all peek methods.

   *

   * @return string|boolean `false` on error otherwise the body of the job.

   */

  protected function _peekRead() {

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'FOUND':

        return [

          'id' => (integer) strtok(' '),

          'body' => $this->_read((integer) strtok(' '))

        ];

      case 'NOT_FOUND':

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Moves jobs into the ready queue (applies to the current tube).

   *

   * If there are buried jobs those get kicked only otherwise delayed

   * jobs get kicked.

   *

   * @param integer $bound Upper bound on the number of jobs to kick.

   * @return integer|boolean False on error otherwise number of jobs kicked.

   */

  public function kick($bound) {

    $this->_write(sprintf('kick %d', $bound));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'KICKED':

        return (integer) strtok(' ');

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * This is a variant of the kick command that operates with a single

   * job identified by its job id. If the given job id exists and is in a

   * buried or delayed state, it will be moved to the ready queue of the

   * the same tube where it currently belongs.

   *

   * @param integer $id The job id.

   * @return boolean `false` on error `true` otherwise.

   */

  public function kickJob($id) {

    $this->_write(sprintf('kick-job %d', $id));

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'KICKED':

        return true;

      case 'NOT_FOUND':

      default:

        $this->_error($status);

        return false;

    }

  }

  /* Stats Commands */

  /**

   * Gives statistical information about the specified job if it exists.

   *

   * @param integer $id The job id.

   * @return string|boolean `false` on error otherwise a string with a yaml formatted dictionary.

   */

  public function statsJob($id) {

    $this->_write(sprintf('stats-job %d', $id));

    return $this->_statsRead();

  }

  /**

   * Gives statistical information about the specified tube if it exists.

   *

   * @param string $tube Name of the tube.

   * @return string|boolean `false` on error otherwise a string with a yaml formatted dictionary.

   */

  public function statsTube($tube) {

    $this->_write(sprintf('stats-tube %s', $tube));

    return $this->_statsRead();

  }

  /**

   * Gives statistical information about the system as a whole.

   *

   * @return string|boolean `false` on error otherwise a string with a yaml formatted dictionary.

   */

  public function stats() {

    $this->_write('stats');

    return $this->_statsRead();

  }

  /**

   * Returns a list of all existing tubes.

   *

   * @return string|boolean `false` on error otherwise a string with a yaml formatted list.

   */

  public function listTubes() {

    $this->_write('list-tubes');

    return $this->_statsRead();

  }

  /**

   * Returns the tube currently being used by the producer.

   *

   * @return string|boolean `false` on error otherwise a string with the name of the tube.

   */

  public function listTubeUsed() {

    $this->_write('list-tube-used');

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'USING':

        return strtok(' ');

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Returns a list of tubes currently being watched by the worker.

   *

   * @return string|boolean `false` on error otherwise a string with a yaml formatted list.

   */

  public function listTubesWatched() {

    $this->_write('list-tubes-watched');

    return $this->_statsRead();

  }

  /**

   * Handles responses for all stat methods.

   *

   * @param boolean $decode Whether to decode data before returning it or not. Default is `true`.

   * @return array|string|boolean `false` on error otherwise statistical data.

   */

  protected function _statsRead($decode = true) {

    $status = strtok($this->_read(), ' ');

    switch ($status) {

      case 'OK':

        $data = $this->_read((integer) strtok(' '));

        return $decode ? $this->_decode($data) : $data;

      default:

        $this->_error($status);

        return false;

    }

  }

  /**

   * Decodes YAML data. This is a super naive decoder which just works on

   * a subset of YAML which is commonly returned by beanstalk.

   *

   * @param string $data The data in YAML format, can be either a list or a dictionary.

   * @return array An (associative) array of the converted data.

   */

  protected function _decode($data) {

    $data = array_slice(explode("\n", $data), 1);

    $result = [];

    foreach ($data as $key => $value) {

      if ($value[0] === '-') {

        $value = ltrim($value, '- ');

      } elseif (strpos($value, ':') !== false) {

        list($key, $value) = explode(':', $value);

        $value = ltrim($value, ' ');

      }

      if (is_numeric($value)) {

        $value = (integer) $value == $value ? (integer) $value : (float) $value;

      }

      $result[$key] = $value;

    }

    return $result;

  }

}

?>