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165 lines
7.0 KiB
165 lines
7.0 KiB
<?php |
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/* |
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* This file is part of the Symfony package. |
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* |
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* (c) Fabien Potencier <fabien@symfony.com> |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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*/ |
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namespace Symfony\Component\Cache; |
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use Psr\Log\LoggerInterface; |
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use Symfony\Contracts\Cache\CacheInterface; |
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use Symfony\Contracts\Cache\ItemInterface; |
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/** |
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* LockRegistry is used internally by existing adapters to protect against cache stampede. |
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* |
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* It does so by wrapping the computation of items in a pool of locks. |
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* Foreach each apps, there can be at most 20 concurrent processes that |
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* compute items at the same time and only one per cache-key. |
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* |
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* @author Nicolas Grekas <p@tchwork.com> |
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*/ |
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final class LockRegistry |
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{ |
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private static $openedFiles = []; |
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private static $lockedFiles; |
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private static $signalingException; |
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private static $signalingCallback; |
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/** |
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* The number of items in this list controls the max number of concurrent processes. |
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*/ |
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private static $files = [ |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AbstractAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AbstractTagAwareAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AdapterInterface.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ApcuAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ArrayAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ChainAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'CouchbaseBucketAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'CouchbaseCollectionAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'DoctrineAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'DoctrineDbalAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'FilesystemAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'FilesystemTagAwareAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'MemcachedAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'NullAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ParameterNormalizer.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PdoAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PhpArrayAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PhpFilesAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ProxyAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'Psr16Adapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'RedisAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'RedisTagAwareAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TagAwareAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TagAwareAdapterInterface.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TraceableAdapter.php', |
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__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TraceableTagAwareAdapter.php', |
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]; |
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/** |
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* Defines a set of existing files that will be used as keys to acquire locks. |
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* |
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* @return array The previously defined set of files |
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*/ |
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public static function setFiles(array $files): array |
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{ |
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$previousFiles = self::$files; |
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self::$files = $files; |
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foreach (self::$openedFiles as $file) { |
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if ($file) { |
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flock($file, \LOCK_UN); |
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fclose($file); |
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} |
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} |
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self::$openedFiles = self::$lockedFiles = []; |
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return $previousFiles; |
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} |
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public static function compute(callable $callback, ItemInterface $item, bool &$save, CacheInterface $pool, \Closure $setMetadata = null, LoggerInterface $logger = null) |
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{ |
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if ('\\' === \DIRECTORY_SEPARATOR && null === self::$lockedFiles) { |
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// disable locking on Windows by default |
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self::$files = self::$lockedFiles = []; |
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} |
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$key = self::$files ? abs(crc32($item->getKey())) % \count(self::$files) : -1; |
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if ($key < 0 || self::$lockedFiles || !$lock = self::open($key)) { |
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return $callback($item, $save); |
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} |
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self::$signalingException ?? self::$signalingException = unserialize("O:9:\"Exception\":1:{s:16:\"\0Exception\0trace\";a:0:{}}"); |
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self::$signalingCallback ?? self::$signalingCallback = function () { throw self::$signalingException; }; |
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while (true) { |
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try { |
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$locked = false; |
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// race to get the lock in non-blocking mode |
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$locked = flock($lock, \LOCK_EX | \LOCK_NB, $wouldBlock); |
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if ($locked || !$wouldBlock) { |
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$logger && $logger->info(sprintf('Lock %s, now computing item "{key}"', $locked ? 'acquired' : 'not supported'), ['key' => $item->getKey()]); |
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self::$lockedFiles[$key] = true; |
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$value = $callback($item, $save); |
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if ($save) { |
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if ($setMetadata) { |
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$setMetadata($item); |
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} |
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$pool->save($item->set($value)); |
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$save = false; |
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} |
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return $value; |
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} |
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// if we failed the race, retry locking in blocking mode to wait for the winner |
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$logger && $logger->info('Item "{key}" is locked, waiting for it to be released', ['key' => $item->getKey()]); |
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flock($lock, \LOCK_SH); |
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} finally { |
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flock($lock, \LOCK_UN); |
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unset(self::$lockedFiles[$key]); |
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} |
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try { |
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$value = $pool->get($item->getKey(), self::$signalingCallback, 0); |
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$logger && $logger->info('Item "{key}" retrieved after lock was released', ['key' => $item->getKey()]); |
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$save = false; |
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return $value; |
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} catch (\Exception $e) { |
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if (self::$signalingException !== $e) { |
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throw $e; |
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} |
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$logger && $logger->info('Item "{key}" not found while lock was released, now retrying', ['key' => $item->getKey()]); |
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} |
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} |
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return null; |
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} |
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private static function open(int $key) |
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{ |
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if (null !== $h = self::$openedFiles[$key] ?? null) { |
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return $h; |
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} |
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set_error_handler(function () {}); |
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try { |
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$h = fopen(self::$files[$key], 'r+'); |
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} finally { |
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restore_error_handler(); |
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} |
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return self::$openedFiles[$key] = $h ?: @fopen(self::$files[$key], 'r'); |
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} |
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}
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