CRM/Queue/Runner.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 4.6                                                |
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   6  | Copyright CiviCRM LLC (c) 2004-2014                                |
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  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
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  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
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  26 */
  27
  28 /**
  29  * The queue runner is a helper which runs all jobs in a queue.
  30  *
  31  * The queue runner is most useful for one-off queues (such as an upgrade);
  32  * if the intention is to develop a dedicated, long-running worker thread,
  33  * then one should consider writing a new queue consumer.
  34  */
  35 class CRM_Queue_Runner {
  36
  37   /**
  38    * The failed task should be discarded, and queue processing should continue.
  39    */
  40   const ERROR_CONTINUE = 1;
  41
  42   /**
  43    * The failed task should be kept in the queue, and queue processing should
  44    * abort.
  45    */
  46   const ERROR_ABORT = 2;
  47
  48   /**
  49    * @var string
  50    */
  51   public $title;
  52
  53   /**
  54    * @var CRM_Queue_Queue
  55    */
  56   public $queue;
  57   public $errorMode;
  58   public $isMinimal;
  59   public $onEnd;
  60   public $onEndUrl;
  61   public $pathPrefix;
  62   // queue-runner id; used for persistence
  63   public $qrid;
  64
  65   /**
  66    * @var array whether to display buttons, eg ('retry' => TRUE, 'skip' => FALSE)
  67    */
  68   public $buttons;
  69
  70   /**
  71    * @var CRM_Queue_TaskContext
  72    */
  73   public $taskCtx;
  74
  75   /**
  76    * Locate a previously-created instance of the queue-runner.
  77    *
  78    * @param string $qrid
  79    *   The queue-runner ID.
  80    *
  81    * @return CRM_Queue_Runner|NULL
  82    */
  83   public static function instance($qrid) {
  84     if (!empty($_SESSION['queueRunners'][$qrid])) {
  85       return unserialize($_SESSION['queueRunners'][$qrid]);
  86     }
  87     else {
  88       return NULL;
  89     }
  90   }
  91
  92   /**
  93    *
  94    * FIXME: parameter validation
  95    * FIXME: document signature of onEnd callback
  96    *
  97    * @param array $runnerSpec
  98    *   Array with keys:
  99    *   - queue: CRM_Queue_Queue
 100    *   - errorMode: int, ERROR_CONTINUE or ERROR_ABORT.
 101    *   - onEnd: mixed, a callback to update the UI after running; should be
 102    *     both callable and serializable.
 103    *   - onEndUrl: string, the URL to which one redirects.
 104    *   - pathPrefix: string, prepended to URLs for the web-runner;
 105    *     default: 'civicrm/queue'.
 106    */
 107   public function __construct($runnerSpec) {
 108     $this->title = CRM_Utils_Array::value('title', $runnerSpec, ts('Queue Runner'));
 109     $this->queue = $runnerSpec['queue'];
 110     $this->errorMode = CRM_Utils_Array::value('errorMode', $runnerSpec, self::ERROR_ABORT);
 111     $this->isMinimal = CRM_Utils_Array::value('isMinimal', $runnerSpec, FALSE);
 112     $this->onEnd = CRM_Utils_Array::value('onEnd', $runnerSpec, NULL);
 113     $this->onEndUrl = CRM_Utils_Array::value('onEndUrl', $runnerSpec, NULL);
 114     $this->pathPrefix = CRM_Utils_Array::value('pathPrefix', $runnerSpec, 'civicrm/queue');
 115     $this->buttons = CRM_Utils_Array::value('buttons', $runnerSpec, array('retry' => TRUE, 'skip' => TRUE));
 116     // perhaps this value should be randomized?
 117     $this->qrid = $this->queue->getName();
 118   }
 119
 120   /**
 121    * @return array
 122    */
 123   public function __sleep() {
 124     // exclude taskCtx
 125     return array(
 126       'title',
 127       'queue',
 128       'errorMode',
 129       'isMinimal',
 130       'onEnd',
 131       'onEndUrl',
 132       'pathPrefix',
 133       'qrid',
 134       'buttons',
 135     );
 136   }
 137
 138   /**
 139    * Redirect to the web-based queue-runner and evaluate all tasks in a queue.
 140    */
 141   public function runAllViaWeb() {
 142     $_SESSION['queueRunners'][$this->qrid] = serialize($this);
 143     $url = CRM_Utils_System::url($this->pathPrefix . '/runner', 'reset=1&qrid=' . urlencode($this->qrid));
 144     CRM_Utils_System::redirect($url);
 145     // TODO: evaluate items incrementally via AJAX polling, cleanup session
 146   }
 147
 148   /**
 149    * Immediately run all tasks in a queue (until either reaching the end
 150    * of the queue or encountering an error)
 151    *
 152    * If the runner has an onEndUrl, then this function will not return
 153    *
 154    * @return mixed
 155    *   TRUE if all tasks complete normally; otherwise, an array describing the
 156    *   failed task
 157    */
 158   public function runAll() {
 159     $taskResult = $this->formatTaskResult(TRUE);
 160     while ($taskResult['is_continue']) {
 161       // setRaiseException should't be necessary here, but there's a bug
 162       // somewhere which causes this setting to be lost.  Observed while
 163       // upgrading 4.0=>4.2.  This preference really shouldn't be a global
 164       // setting -- it should be more of a contextual/stack-based setting.
 165       // This should be appropriate because queue-runners are not used with
 166       // basic web pages -- they're used with CLI/REST/AJAX.
 167       $errorScope = CRM_Core_TemporaryErrorScope::useException();
 168       $taskResult = $this->runNext();
 169       $errorScope = NULL;
 170     }
 171
 172     if ($taskResult['numberOfItems'] == 0) {
 173       $result = $this->handleEnd();
 174       if (!empty($result['redirect_url'])) {
 175         CRM_Utils_System::redirect($result['redirect_url']);
 176       }
 177       return TRUE;
 178     }
 179     else {
 180       return $taskResult;
 181     }
 182   }
 183
 184   /**
 185    * Take the next item from the queue and attempt to run it.
 186    *
 187    * Individual tasks may also throw exceptions -- caller should watch for
 188    * exceptions.
 189    *
 190    * @param bool $useSteal
 191    *   Whether to steal active locks.
 192    *
 193    * @return array
 194    *   - is_error => bool,
 195    *   - is_continue => bool,
 196    *   - numberOfItems => int,
 197    *   - 'last_task_title' => $,
 198    *   - 'exception' => $
 199    */
 200   public function runNext($useSteal = FALSE) {
 201     if ($useSteal) {
 202       $item = $this->queue->stealItem();
 203     }
 204     else {
 205       $item = $this->queue->claimItem();
 206     }
 207
 208     if ($item) {
 209       $this->lastTaskTitle = $item->data->title;
 210
 211       $exception = NULL;
 212       try {
 213         $isOK = $item->data->run($this->getTaskContext());
 214         if (!$isOK) {
 215           $exception = new Exception('Task returned false');
 216         }
 217       } catch (Exception$e) {
 218         $isOK = FALSE;
 219         $exception = $e;
 220       }
 221
 222       if ($isOK) {
 223         $this->queue->deleteItem($item);
 224       }
 225       else {
 226         $this->releaseErrorItem($item);
 227       }
 228
 229       return $this->formatTaskResult($isOK, $exception);
 230     }
 231     else {
 232       return $this->formatTaskResult(FALSE, new Exception('Failed to claim next task'));
 233     }
 234   }
 235
 236   /**
 237    * Take the next item from the queue and attempt to run it.
 238    *
 239    * Individual tasks may also throw exceptions -- caller should watch for
 240    * exceptions.
 241    *
 242    * @param bool $useSteal
 243    *   Whether to steal active locks.
 244    *
 245    * @return array
 246    *   - is_error => bool,
 247    *   - is_continue => bool,
 248    *   - numberOfItems => int)
 249    */
 250   public function skipNext($useSteal = FALSE) {
 251     if ($useSteal) {
 252       $item = $this->queue->stealItem();
 253     }
 254     else {
 255       $item = $this->queue->claimItem();
 256     }
 257
 258     if ($item) {
 259       $this->lastTaskTitle = $item->data->title;
 260       $this->queue->deleteItem($item);
 261       return $this->formatTaskResult(TRUE);
 262     }
 263     else {
 264       return $this->formatTaskResult(FALSE, new Exception('Failed to claim next task'));
 265     }
 266   }
 267
 268   /**
 269    * Release an item in keeping with the error mode.
 270    *
 271    * @param object $item
 272    *   The item previously produced by Queue::claimItem.
 273    */
 274   protected function releaseErrorItem($item) {
 275     switch ($this->errorMode) {
 276       case self::ERROR_CONTINUE:
 277         $this->queue->deleteItem($item);
 278       case self::ERROR_ABORT:
 279       default:
 280         $this->queue->releaseItem($item);
 281     }
 282   }
 283
 284   /**
 285    * @return array
 286    *   - is_error => bool,
 287    *   - is_continue => bool,
 288    *   - numberOfItems => int,
 289    *   - redirect_url => string
 290    */
 291   public function handleEnd() {
 292     if (is_callable($this->onEnd)) {
 293       call_user_func($this->onEnd, $this->getTaskContext());
 294     }
 295     // Don't remove queueRunner until onEnd succeeds
 296     if (!empty($_SESSION['queueRunners'][$this->qrid])) {
 297       unset($_SESSION['queueRunners'][$this->qrid]);
 298     }
 299
 300     // Fallback; web UI does redirect in Javascript
 301     $result = array();
 302     $result['is_error'] = 0;
 303     $result['numberOfItems'] = 0;
 304     $result['is_continue'] = 0;
 305     if (!empty($this->onEndUrl)) {
 306       $result['redirect_url'] = $this->onEndUrl;
 307     }
 308     return $result;
 309   }
 310
 311   /**
 312    * Format a result record which describes whether the task completed.
 313    *
 314    * @param bool $isOK
 315    *   TRUE if the task completed successfully.
 316    * @param Exception|NULL $exception
 317    *   If applicable, an unhandled exception that arose during execution.
 318    *
 319    * @return array
 320    *   (is_error => bool, is_continue => bool, numberOfItems => int)
 321    */
 322   public function formatTaskResult($isOK, $exception = NULL) {
 323     $numberOfItems = $this->queue->numberOfItems();
 324
 325     $result = array();
 326     $result['is_error'] = $isOK ? 0 : 1;
 327     $result['exception'] = $exception;
 328     $result['last_task_title'] = isset($this->lastTaskTitle) ? $this->lastTaskTitle : '';
 329     $result['numberOfItems'] = $this->queue->numberOfItems();
 330     if ($result['numberOfItems'] <= 0) {
 331       // nothing to do
 332       $result['is_continue'] = 0;
 333     }
 334     elseif ($isOK) {
 335       // more tasks remain, and this task succeeded
 336       $result['is_continue'] = 1;
 337     }
 338     elseif ($this->errorMode == CRM_Queue_Runner::ERROR_CONTINUE) {
 339       // more tasks remain, and we can disregard this error
 340       $result['is_continue'] = 1;
 341     }
 342     else {
 343       // more tasks remain, but we can't disregard the error
 344       $result['is_continue'] = 0;
 345     }
 346
 347     return $result;
 348   }
 349
 350   /**
 351    * @return CRM_Queue_TaskContext
 352    */
 353   protected function getTaskContext() {
 354     if (!is_object($this->taskCtx)) {
 355       $this->taskCtx = new CRM_Queue_TaskContext();
 356       $this->taskCtx->queue = $this->queue;
 357       // $this->taskCtx->log = CRM_Core_Config::getLog();
 358       $this->taskCtx->log = CRM_Core_Error::createDebugLogger();
 359     }
 360     return $this->taskCtx;
 361   }
 362 }