CRM/Core/Lock.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 4.7                                                |
   5  +--------------------------------------------------------------------+
   6  | Copyright CiviCRM LLC (c) 2004-2015                                |
   7  +--------------------------------------------------------------------+
   8  | This file is a part of CiviCRM.                                    |
   9  |                                                                    |
  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
  11  | under the terms of the GNU Affero General Public License           |
  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  13  |                                                                    |
  14  | CiviCRM is distributed in the hope that it will be useful, but     |
  15  | WITHOUT ANY WARRANTY; without even the implied warranty of         |
  16  | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
  17  | See the GNU Affero General Public License for more details.        |
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  19  | You should have received a copy of the GNU Affero General Public   |
  20  | License and the CiviCRM Licensing Exception along                  |
  21  | with this program; if not, contact CiviCRM LLC                     |
  22  | at info[AT]civicrm[DOT]org. If you have questions about the        |
  23  | GNU Affero General Public License or the licensing of CiviCRM,     |
  24  | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
  25  +--------------------------------------------------------------------+
  26  */
  27
  28 /**
  29  *
  30  * @package CRM
  31  * @copyright CiviCRM LLC (c) 2004-2015
  32  * $Id$
  33  *
  34  */
  35 class CRM_Core_Lock implements \Civi\Core\Lock\LockInterface {
  36
  37   static $jobLog = FALSE;
  38
  39   // lets have a 3 second timeout for now
  40   const TIMEOUT = 3;
  41
  42   protected $_hasLock = FALSE;
  43
  44   protected $_name;
  45
  46   /**
  47    * Use MySQL's GET_LOCK(). Locks are shared across all Civi instances
  48    * on the same MySQL server.
  49    *
  50    * @param string $name
  51    *   Symbolic name for the lock. Names generally look like
  52    *   "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
  53    *
  54    *   Categories: worker|data|cache|...
  55    *   Component: core|mailing|member|contribute|...
  56    * @return \Civi\Core\Lock\LockInterface
  57    */
  58   public static function createGlobalLock($name) {
  59     return new static($name, NULL, TRUE);
  60   }
  61
  62   /**
  63    * Use MySQL's GET_LOCK(), but apply prefixes to the lock names.
  64    * Locks are unique to each instance of Civi.
  65    *
  66    * @param string $name
  67    *   Symbolic name for the lock. Names generally look like
  68    *   "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
  69    *
  70    *   Categories: worker|data|cache|...
  71    *   Component: core|mailing|member|contribute|...
  72    * @return \Civi\Core\Lock\LockInterface
  73    */
  74   public static function createScopedLock($name) {
  75     return new static($name);
  76   }
  77
  78   /**
  79    * Use MySQL's GET_LOCK(), but conditionally apply prefixes to the lock names
  80    * (if civimail_server_wide_lock is disabled).
  81    *
  82    * @param string $name
  83    *   Symbolic name for the lock. Names generally look like
  84    *   "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
  85    *
  86    *   Categories: worker|data|cache|...
  87    *   Component: core|mailing|member|contribute|...
  88    * @return \Civi\Core\Lock\LockInterface
  89    * @deprecated
  90    */
  91   public static function createCivimailLock($name) {
  92     $serverWideLock = \CRM_Core_BAO_Setting::getItem(
  93       \CRM_Core_BAO_Setting::MAILING_PREFERENCES_NAME,
  94       'civimail_server_wide_lock'
  95     );
  96     return new static($name, NULL, $serverWideLock);
  97   }
  98
  99   /**
 100    * Initialize the constants used during lock acquire / release
 101    *
 102    * @param string $name
 103    *   Symbolic name for the lock. Names generally look like
 104    *   "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
 105    *
 106    *   Categories: worker|data|cache|...
 107    *   Component: core|mailing|member|contribute|...
 108    * @param int $timeout
 109    *   The number of seconds to wait to get the lock. 1 if not set.
 110    * @param bool $serverWideLock
 111    *   Should this lock be applicable across your entire mysql server.
 112    *   this is useful if you have multiple sites running on the same
 113    *   mysql server and you want to limit the number of parallel cron
 114    *   jobs - CRM-91XX
 115    */
 116   public function __construct($name, $timeout = NULL, $serverWideLock = FALSE) {
 117     $config = CRM_Core_Config::singleton();
 118     $dsnArray = DB::parseDSN($config->dsn);
 119     $database = $dsnArray['database'];
 120     $domainID = CRM_Core_Config::domainID();
 121     if ($serverWideLock) {
 122       $this->_name = $name;
 123     }
 124     else {
 125       $this->_name = $database . '.' . $domainID . '.' . $name;
 126     }
 127     if (defined('CIVICRM_LOCK_DEBUG')) {
 128       CRM_Core_Error::debug_log_message('trying to construct lock for ' . $this->_name);
 129     }
 130     $this->_timeout = $timeout !== NULL ? $timeout : self::TIMEOUT;
 131   }
 132
 133   public function __destruct() {
 134     $this->release();
 135   }
 136
 137   /**
 138    * Acquire lock.
 139    *
 140    * @param int $timeout
 141    *
 142    * @return bool
 143    * @throws \CRM_Core_Exception
 144    */
 145   public function acquire($timeout = NULL) {
 146     if (!$this->_hasLock) {
 147       if (self::$jobLog && CRM_Core_DAO::singleValueQuery("SELECT IS_USED_LOCK( '" . self::$jobLog . "')")) {
 148         return $this->hackyHandleBrokenCode(self::$jobLog);
 149       }
 150
 151       $query = "SELECT GET_LOCK( %1, %2 )";
 152       $params = array(
 153         1 => array($this->_name, 'String'),
 154         2 => array($timeout ? $timeout : $this->_timeout, 'Integer'),
 155       );
 156       $res = CRM_Core_DAO::singleValueQuery($query, $params);
 157       if ($res) {
 158         if (defined('CIVICRM_LOCK_DEBUG')) {
 159           CRM_Core_Error::debug_log_message('acquire lock for ' . $this->_name);
 160         }
 161         $this->_hasLock = TRUE;
 162         if (stristr($this->_name, 'data.mailing.job.')) {
 163           self::$jobLog = $this->_name;
 164         }
 165       }
 166       else {
 167         if (defined('CIVICRM_LOCK_DEBUG')) {
 168           CRM_Core_Error::debug_log_message('failed to acquire lock for ' . $this->_name);
 169         }
 170       }
 171     }
 172     return $this->_hasLock;
 173   }
 174
 175   /**
 176    * @return null|string
 177    */
 178   public function release() {
 179     if ($this->_hasLock) {
 180       if (defined('CIVICRM_LOCK_DEBUG')) {
 181         CRM_Core_Error::debug_log_message('release lock for ' . $this->_name);
 182       }
 183       $this->_hasLock = FALSE;
 184
 185       if (self::$jobLog == $this->_name) {
 186         self::$jobLog = FALSE;
 187       }
 188
 189       $query = "SELECT RELEASE_LOCK( %1 )";
 190       $params = array(1 => array($this->_name, 'String'));
 191       return CRM_Core_DAO::singleValueQuery($query, $params);
 192     }
 193   }
 194
 195   /**
 196    * @return null|string
 197    */
 198   public function isFree() {
 199     $query = "SELECT IS_FREE_LOCK( %1 )";
 200     $params = array(1 => array($this->_name, 'String'));
 201     return CRM_Core_DAO::singleValueQuery($query, $params);
 202   }
 203
 204   /**
 205    * @return bool
 206    */
 207   public function isAcquired() {
 208     return $this->_hasLock;
 209   }
 210
 211   /**
 212    * CRM-12856 locks were originally set up for jobs, but the concept was extended to caching & groups without
 213    * understanding that would undermine the job locks (because grabbing a lock implicitly releases existing ones)
 214    * this is all a big hack to mitigate the impact of that - but should not be seen as a fix. Not sure correct fix
 215    * but maybe locks should be used more selectively? Or else we need to handle is some cool way that Tim is yet to write :-)
 216    * if we are running in the context of the cron log then we would rather die (or at least let our process die)
 217    * than release that lock - so if the attempt is being made by setCache or something relatively trivial
 218    * we'll just return TRUE, but if it's another job then we will crash as that seems 'safer'
 219    *
 220    * @param string $jobLog
 221    * @throws CRM_Core_Exception
 222    * @return bool
 223    */
 224   public function hackyHandleBrokenCode($jobLog) {
 225     if (stristr($this->_name, 'job')) {
 226       CRM_Core_Error::debug_log_message('lock acquisition for ' . $this->_name . ' attempted when ' . $jobLog . ' is not released');
 227       throw new CRM_Core_Exception('lock acquisition for ' . $this->_name . ' attempted when ' . $jobLog . ' is not released');
 228     }
 229     if (defined('CIVICRM_LOCK_DEBUG')) {
 230       CRM_Core_Error::debug_log_message('(CRM-12856) faking lock for ' . $this->_name);
 231     }
 232     $this->_hasLock = TRUE;
 233     return TRUE;
 234   }
 235
 236 }