CRM/Queue/Queue.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | Copyright CiviCRM LLC. All rights reserved.                        |
   5  |                                                                    |
   6  | This work is published under the GNU AGPLv3 license with some      |
   7  | permitted exceptions and without any warranty. For full license    |
   8  | and copyright information, see https://civicrm.org/licensing       |
   9  +--------------------------------------------------------------------+
  10  */
  11
  12 /**
  13  * A queue is an object (usually backed by some persistent data store)
  14  * which stores a list of tasks or messages for use by other processes.
  15  *
  16  * This would ideally be an interface, but it's handy to specify the
  17  * "function __construct()" and the "$name" handling
  18  *
  19  * Note: This interface closely parallels the DrupalQueueInterface.
  20  */
  21 abstract class CRM_Queue_Queue {
  22
  23   /**
  24    * @var string
  25    */
  26   private $_name;
  27
  28   /**
  29    * @var array{name: string, type: string, runner: string, batch_limit: int, lease_time: ?int, retry_limit: int, retry_interval: ?int}
  30    * @see \CRM_Queue_Service::create()
  31    */
  32   protected $queueSpec;
  33
  34   /**
  35    * Create a reference to queue. After constructing the queue, one should
  36    * usually call createQueue (if it's a new queue) or loadQueue (if it's
  37    * known to be an existing queue).
  38    *
  39    * @param array{name: string, type: string, runner: string, batch_limit: int, lease_time: ?int, retry_limit: int, retry_interval: ?int} $queueSpec
  40    *   Ex: ['name' => 'my-import', 'type' => 'SqlParallel']
  41    *   The full definition of queueSpec is defined in CRM_Queue_Service.
  42    * @see \CRM_Queue_Service::create()
  43    */
  44   public function __construct($queueSpec) {
  45     $this->_name = $queueSpec['name'];
  46     $this->queueSpec = $queueSpec;
  47   }
  48
  49   /**
  50    * Determine the string name of this queue.
  51    *
  52    * @return string
  53    */
  54   public function getName() {
  55     return $this->_name;
  56   }
  57
  58   /**
  59    * Get a property from the queueSpec.
  60    *
  61    * @param string $field
  62    * @return mixed|null
  63    */
  64   public function getSpec(string $field) {
  65     return $this->queueSpec[$field] ?? NULL;
  66   }
  67
  68   /**
  69    * Perform any registation or resource-allocation for a new queue
  70    */
  71   abstract public function createQueue();
  72
  73   /**
  74    * Perform any loading or pre-fetch for an existing queue.
  75    */
  76   abstract public function loadQueue();
  77
  78   /**
  79    * Release any resources claimed by the queue (memory, DB rows, etc)
  80    */
  81   abstract public function deleteQueue();
  82
  83   /**
  84    * Check if the queue exists.
  85    *
  86    * @return bool
  87    */
  88   abstract public function existsQueue();
  89
  90   /**
  91    * Add a new item to the queue.
  92    *
  93    * @param mixed $data
  94    *   Serializable PHP object or array.
  95    * @param array $options
  96    *   Queue-dependent options; for example, if this is a
  97    *   priority-queue, then $options might specify the item's priority.
  98    */
  99   abstract public function createItem($data, $options = []);
 100
 101   /**
 102    * Determine number of items remaining in the queue.
 103    *
 104    * @return int
 105    */
 106   abstract public function numberOfItems();
 107
 108   /**
 109    * Get the next item.
 110    *
 111    * @param int $lease_time
 112    *   Seconds.
 113    *
 114    * @return object
 115    *   with key 'data' that matches the inputted data
 116    */
 117   abstract public function claimItem($lease_time = 3600);
 118
 119   /**
 120    * Get the next item, even if there's an active lease
 121    *
 122    * @param int $lease_time
 123    *   Seconds.
 124    *
 125    * @return object
 126    *   with key 'data' that matches the inputted data
 127    */
 128   abstract public function stealItem($lease_time = 3600);
 129
 130   /**
 131    * Remove an item from the queue.
 132    *
 133    * @param object $item
 134    *   The item returned by claimItem.
 135    */
 136   abstract public function deleteItem($item);
 137
 138   /**
 139    * Return an item that could not be processed.
 140    *
 141    * @param object $item
 142    *   The item returned by claimItem.
 143    */
 144   abstract public function releaseItem($item);
 145
 146 }