Symfony 7.4 Lock Component

GitHub: https://github.com/symfony/lock Docs: https://symfony.com/doc/7.4/components/lock.html

Quick Reference

Installation

bash

composer require symfony/lock

Basic Usage

php

use Symfony\Component\Lock\LockFactory;
use Symfony\Component\Lock\Store\SemaphoreStore;

$store = new SemaphoreStore();
$factory = new LockFactory($store);

$lock = $factory->createLock('pdf-creation');

if ($lock->acquire()) {
    // Exclusive access to "pdf-creation" resource
    $lock->release();
}

Blocking Lock

php

$lock = $factory->createLock('pdf-creation');
$lock->acquire(true); // Blocks until acquired

Expiring Lock with TTL

php

$lock = $factory->createLock('pdf-creation', ttl: 30);

if ($lock->acquire()) {
    try {
        while (!$finished) {
            performPartialWork();
            $lock->refresh(); // Reset TTL
        }
    } finally {
        $lock->release();
    }
}

Shared (Readers-Writer) Lock

php

$lock = $factory->createLock('resource');
$lock->acquireRead();       // Read lock (concurrent readers allowed)
$lock->acquire();           // Promote to write lock
$lock->acquireRead();       // Demote back to read lock

Disable Auto-Release

php

$lock = $factory->createLock('resource', 3600, autoRelease: false);

Serializing Locks Across Processes

php

use Symfony\Component\Lock\Key;

$key = new Key('article.'.$article->getId());
$lock = $factory->createLockFromKey($key, 300, autoRelease: false);
$lock->acquire(true);
// Pass $key to another process via message bus

Available Stores

Store	Scope	Blocking	Expiring	Sharing
FlockStore	local	yes	no	yes
SemaphoreStore	local	yes	no	no
RedisStore	remote	retry	yes	yes
MemcachedStore	remote	retry	yes	no
PdoStore	remote	retry	yes	no
DoctrineDbalStore	remote	retry	yes	no
PostgreSqlStore	remote	yes	no	yes
DoctrineDbalPostgreSqlStore	remote	yes	no	yes
MongoDbStore	remote	retry	yes	no
ZookeeperStore	remote	retry	no	no
CombinedStore	remote	varies	varies	varies
DynamoDbStore	remote	retry	yes	no
InMemoryStore	local	-	-	-

Common Store Setup

php

// FlockStore (filesystem)
$store = new FlockStore('/var/stores');

// RedisStore
$redis = new \Redis();
$redis->connect('localhost');
$store = new RedisStore($redis);

// PostgreSqlStore (advisory locks, no table needed)
$store = new PostgreSqlStore('pgsql:host=localhost;dbname=app');

// CombinedStore (high availability)
$store = new CombinedStore($stores, new ConsensusStrategy());

LockInterface Methods

•acquire(bool $blocking = false): bool - Acquire exclusive lock
•acquireRead(bool $blocking = false): bool - Acquire shared read lock
•release(): void - Release the lock
•isAcquired(): bool - Check if lock is held
•refresh(float|null $ttl = null): void - Reset TTL
•getRemainingLifetime(): float|null - Seconds until expiry
•isExpired(): bool - Check if lock expired

Full Documentation

See references/lock.md for complete store configuration, strategies, serialization details, and reliability considerations.