class MongodbLock in MongoDB 8
Hierarchy
- class \Drupal\Core\Lock\LockBackendAbstract implements LockBackendInterface
- class \Drupal\mongodb\MongodbLock
Expanded class hierarchy of MongodbLock
1 string reference to 'MongodbLock'
1 service uses MongodbLock
File
- src/
MongodbLock.php, line 12 - Contains \Drupal\mongodb\MongodbLock.
Namespace
Drupal\mongodbView source
class MongodbLock extends LockBackendAbstract {
/**
* The mongodb factory registered as a service.
*
* @var \Drupal\mongodb\MongoCollectionFactory
*/
protected $mongo;
/**
* Construct the DatabaseFileUsageBackend.
*
* @param \Drupal\mongodb\MongoCollectionFactory $mongo
* The mongodb collection factory.
*/
public function __construct(MongoCollectionFactory $mongo) {
// __destruct() is causing problems with garbage collections, register a
// shutdown function instead.
drupal_register_shutdown_function(array(
$this,
'releaseAll',
));
$this->mongo = $mongo;
}
/**
* Acquires a lock.
*
* @param string $name
* Lock name. Limit of name's length is 255 characters.
* @param float $timeout = 30.0
* (optional) Lock lifetime in seconds.
*
* @return bool
*/
public function acquire($name, $timeout = 30.0) {
// Insure that the timeout is at least 1 ms.
$timeout = max($timeout, 0.001);
$expire = microtime(TRUE) + $timeout;
if (isset($this->locks[$name])) {
// Try to extend the expiration of a lock we already acquired.
$result = $this
->mongoCollection()
->update([
'_id' => $this
->mongoId($name),
], [
'expire' => $expire,
]);
$success = !empty($result['n']);
if (!$success) {
// The lock was broken.
unset($this->locks[$name]);
}
return $success;
}
else {
// Optimistically try to acquire the lock, then retry once if it fails.
// The first time through the loop cannot be a retry.
$retry = FALSE;
// We always want to do this code at least once.
do {
try {
$this
->mongoCollection()
->insert([
'_id' => $this
->mongoId($name),
'expire' => $expire,
]);
// We track all acquired locks in the global variable.
$this->locks[$name] = TRUE;
// We never need to try again.
$retry = FALSE;
} catch (\MongoDuplicateKeyException $e) {
// Suppress the error. If this is our first pass through the loop,
// then $retry is FALSE. In this case, the insert failed because some
// other request acquired the lock but did not release it. We decide
// whether to retry by checking lockMayBeAvailable(). This will clear
// the offending row from the database table in case it has expired.
$retry = $retry ? FALSE : $this
->lockMayBeAvailable($name);
}
// We only retry in case the first attempt failed, but we then broke
// an expired lock.
} while ($retry);
}
return isset($this->locks[$name]);
}
/**
* @param $name
* @return array
*/
protected function mongoId($name) {
return [
'name' => $name,
'value' => $this
->getLockId(),
];
}
/**
* Checks if a lock is available for acquiring.
*
* @param string $name
* Lock to acquire.
*
* @return bool
*/
public function lockMayBeAvailable($name) {
$lock = $this
->mongoCollection()
->findOne([
'_id.name' => $name,
]);
if (!$lock) {
return TRUE;
}
$expire = (double) $lock['expire'];
$now = microtime(TRUE);
if ($now > $expire) {
// We check two conditions to prevent a race condition where another
// request acquired the lock and set a new expire time. We add a small
// number to $expire to avoid errors with float to string conversion.
return (bool) $this
->mongoCollection()
->remove([
'_id.name' => $name,
'value' => $lock['value'],
'expire' => [
'$lte' => 0.0001 + $expire,
],
]);
}
return FALSE;
}
/**
* Releases the given lock.
*
* @param string $name
*/
public function release($name) {
unset($this->locks[$name]);
$this
->mongoCollection()
->remove([
'_id' => $this
->mongoId($name),
]);
}
/**
* Releases all locks for the given lock token identifier.
*
* @param string $lockId
* (optional) If none given, remove all locks from the current page.
* Defaults to NULL.
*/
public function releaseAll($lockId = NULL) {
// Only attempt to release locks if any were acquired.
if (!empty($this->locks)) {
$this->locks = array();
if (empty($lock_id)) {
$lock_id = $this
->getLockId();
}
$this
->mongoCollection()
->remove([
'_id.value' => $lock_id,
]);
}
}
/**
* @return \MongoCollection
*/
protected function mongoCollection() {
return $this->mongo
->get('semaphore');
}
}
Members
Name | Modifiers | Type | Description | Overrides |
---|---|---|---|---|
LockBackendAbstract:: |
protected | property | Current page lock token identifier. | |
LockBackendAbstract:: |
protected | property | Existing locks for this page. | |
LockBackendAbstract:: |
public | function |
Gets the unique page token for locks. Overrides LockBackendInterface:: |
|
LockBackendAbstract:: |
public | function |
Waits a short amount of time before a second lock acquire attempt. Overrides LockBackendInterface:: |
|
MongodbLock:: |
protected | property | The mongodb factory registered as a service. | |
MongodbLock:: |
public | function |
Acquires a lock. Overrides LockBackendInterface:: |
|
MongodbLock:: |
public | function |
Checks if a lock is available for acquiring. Overrides LockBackendInterface:: |
|
MongodbLock:: |
protected | function | ||
MongodbLock:: |
protected | function | ||
MongodbLock:: |
public | function |
Releases the given lock. Overrides LockBackendInterface:: |
|
MongodbLock:: |
public | function |
Releases all locks for the given lock token identifier. Overrides LockBackendInterface:: |
|
MongodbLock:: |
public | function | Construct the DatabaseFileUsageBackend. | 1 |