3 +--------------------------------------------------------------------+
4 | Copyright CiviCRM LLC. All rights reserved. |
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 +--------------------------------------------------------------------+
15 * @copyright CiviCRM LLC https://civicrm.org/licensing
19 class CRM_Core_Lock
implements \Civi\Core\Lock\LockInterface
{
22 * This variable (despite it's name) roughly translates to 'lock that we actually care about'.
24 * Prior to version 5.7.5 mysql only supports a single named lock. This variable is
25 * part of the skullduggery involved in 'say it's no so Frank'.
27 * See further comments on the aquire function.
31 public static $jobLog = FALSE;
34 * lets have a 3 second timeout for now
41 protected $_hasLock = FALSE;
48 * Use MySQL's GET_LOCK(). Locks are shared across all Civi instances
49 * on the same MySQL server.
52 * Symbolic name for the lock. Names generally look like
53 * "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
55 * Categories: worker|data|cache|...
56 * Component: core|mailing|member|contribute|...
57 * @return \Civi\Core\Lock\LockInterface
59 public static function createGlobalLock($name) {
60 return new static($name, NULL, TRUE);
64 * Use MySQL's GET_LOCK(), but apply prefixes to the lock names.
65 * Locks are unique to each instance of Civi.
68 * Symbolic name for the lock. Names generally look like
69 * "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
71 * Categories: worker|data|cache|...
72 * Component: core|mailing|member|contribute|...
73 * @return \Civi\Core\Lock\LockInterface
75 public static function createScopedLock($name) {
76 return new static($name);
80 * Use MySQL's GET_LOCK(), but conditionally apply prefixes to the lock names
81 * (if civimail_server_wide_lock is disabled).
84 * Symbolic name for the lock. Names generally look like
85 * "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
87 * Categories: worker|data|cache|...
88 * Component: core|mailing|member|contribute|...
89 * @return \Civi\Core\Lock\LockInterface
92 public static function createCivimailLock($name) {
93 $serverWideLock = \Civi
::settings()->get('civimail_server_wide_lock');
94 return new static($name, NULL, $serverWideLock);
98 * Initialize the constants used during lock acquire / release
100 * @param string $name
101 * Symbolic name for the lock. Names generally look like
102 * "worker.mailing.EmailProcessor" ("{category}.{component}.{AdhocName}").
104 * Categories: worker|data|cache|...
105 * Component: core|mailing|member|contribute|...
106 * @param int $timeout
107 * The number of seconds to wait to get the lock. 1 if not set.
108 * @param bool $serverWideLock
109 * Should this lock be applicable across your entire mysql server.
110 * this is useful if you have multiple sites running on the same
111 * mysql server and you want to limit the number of parallel cron
114 public function __construct($name, $timeout = NULL, $serverWideLock = FALSE) {
115 $config = CRM_Core_Config
::singleton();
116 $dsnArray = DB
::parseDSN($config->dsn
);
117 $database = $dsnArray['database'];
118 $domainID = CRM_Core_Config
::domainID();
119 if ($serverWideLock) {
120 $this->_name
= $name;
123 $this->_name
= $database . '.' . $domainID . '.' . $name;
125 // MySQL 5.7 doesn't like long lock names so creating a lock id
126 $this->_id
= sha1($this->_name
);
127 if (defined('CIVICRM_LOCK_DEBUG')) {
128 CRM_Core_Error
::debug_log_message('trying to construct lock for ' . $this->_name
. '(' . $this->_id
. ')');
130 $this->_timeout
= $timeout !== NULL ?
$timeout : self
::TIMEOUT
;
133 public function __destruct() {
140 * The advantage of mysql locks is that they can be used across processes. However, only one
141 * can be used at once within a process. An attempt to use a second one within a process
142 * prior to mysql 5.7.5 results in the first being released.
144 * The process here is
145 * 1) first attempt to grab a lock for a mailing job - self::jobLog will be populated with the
146 * lock id & a mysql lock will be created for the ID.
148 * If a second function in the same process attempts to grab the lock it will enter the hackyHandleBrokenCode routine
149 * which says 'I won't break a mailing lock for you but if you are not a civimail send process I'll let you
150 * pretend you have a lock already and you can go ahead with whatever you were doing under the delusion you
153 * @todo bypass hackyHandleBrokenCode for mysql version 5.7.5+
155 * If a second function in a separate process attempts to grab the lock already in use it should be rejected,
156 * but it appears it IS allowed to grab a different lock & unlike in the same process the first lock won't be released.
158 * All this means CiviMail locks are first class citizens & any other process gets a 'best effort lock'.
160 * @todo document naming convention for CiviMail locks as this is key to ensuring they work properly.
162 * @param int $timeout
165 * @throws \CRM_Core_Exception
167 public function acquire($timeout = NULL) {
168 if (!$this->_hasLock
) {
169 if (!CRM_Utils_SQL
::supportsMultipleLocks() && self
::$jobLog && CRM_Core_DAO
::singleValueQuery("SELECT IS_USED_LOCK( '" . self
::$jobLog . "')")) {
170 return $this->hackyHandleBrokenCode(self
::$jobLog);
173 $query = "SELECT GET_LOCK( %1, %2 )";
175 1 => [$this->_id
, 'String'],
176 2 => [$timeout ?
$timeout : $this->_timeout
, 'Integer'],
178 $res = CRM_Core_DAO
::singleValueQuery($query, $params);
180 if (defined('CIVICRM_LOCK_DEBUG')) {
181 CRM_Core_Error
::debug_log_message('acquire lock for ' . $this->_name
. '(' . $this->_id
. ')');
183 $this->_hasLock
= TRUE;
184 if (stristr($this->_name
, 'data.mailing.job.')) {
185 self
::$jobLog = $this->_id
;
189 if (defined('CIVICRM_LOCK_DEBUG')) {
190 CRM_Core_Error
::debug_log_message('failed to acquire lock for ' . $this->_name
. '(' . $this->_id
. ')');
194 return $this->_hasLock
;
198 * @return null|string
200 public function release() {
201 if ($this->_hasLock
) {
202 if (defined('CIVICRM_LOCK_DEBUG')) {
203 CRM_Core_Error
::debug_log_message('release lock for ' . $this->_name
. '(' . $this->_id
. ')');
205 $this->_hasLock
= FALSE;
207 if (self
::$jobLog == $this->_id
) {
208 self
::$jobLog = FALSE;
211 $query = "SELECT RELEASE_LOCK( %1 )";
212 $params = [1 => [$this->_id
, 'String']];
213 return CRM_Core_DAO
::singleValueQuery($query, $params);
218 * @return null|string
220 public function isFree() {
221 $query = "SELECT IS_FREE_LOCK( %1 )";
222 $params = [1 => [$this->_id
, 'String']];
223 return CRM_Core_DAO
::singleValueQuery($query, $params);
229 public function isAcquired() {
230 return $this->_hasLock
;
234 * CRM-12856 locks were originally set up for jobs, but the concept was extended to caching & groups without
235 * understanding that would undermine the job locks (because grabbing a lock implicitly releases existing ones)
236 * this is all a big hack to mitigate the impact of that - but should not be seen as a fix. Not sure correct fix
237 * but maybe locks should be used more selectively? Or else we need to handle is some cool way that Tim is yet to write :-)
238 * if we are running in the context of the cron log then we would rather die (or at least let our process die)
239 * than release that lock - so if the attempt is being made by setCache or something relatively trivial
240 * we'll just return TRUE, but if it's another job then we will crash as that seems 'safer'
242 * @param string $jobLog
243 * @throws CRM_Core_Exception
246 public function hackyHandleBrokenCode($jobLog) {
247 if (stristr($this->_name
, 'job')) {
248 CRM_Core_Error
::debug_log_message('lock acquisition for ' . $this->_name
. '(' . $this->_id
. ')' . ' attempted when ' . $jobLog . ' is not released');
249 throw new CRM_Core_Exception('lock acquisition for ' . $this->_name
. '(' . $this->_id
. ')' . ' attempted when ' . $jobLog . ' is not released');
251 if (defined('CIVICRM_LOCK_DEBUG')) {
252 CRM_Core_Error
::debug_log_message('(CRM-12856) faking lock for ' . $this->_name
. '(' . $this->_id
. ')');
254 $this->_hasLock
= TRUE;