Summary

Introduces a new Lock component that provides distributed locking mechanisms to prevent race conditions when multiple processes access shared resources.

This was identified as a gap in CakePHP compared to other frameworks (Symfony Lock component, Laravel Cache::lock()). The implementation follows CakePHP's existing patterns from the Cache component.

Features

• LockInterface - defines the contract for lock engines
• LockInstance - immutable value object representing an acquired lock
• Lock - static facade for convenient access (similar to Cache)
• LockRegistry - registry for managing engine instances

Lock Engines

Key Capabilities

• Non-blocking acquire() and blocking acquireBlocking() with timeout
• Lock refresh to extend TTL for long-running operations
• Owner verification on release (prevents releasing others' locks)
• Force release for administrative purposes
• synchronized() helper for automatic lock/unlock around callbacks

Example Usage

// Configure
Lock::setConfig('default', [
    'className' => RedisLockEngine::class,
    'host' => '127.0.0.1',
]);

// Basic usage
$lock = Lock::acquire('my-resource');
if ($lock !== null) {
    try {
        // Critical section
    } finally {
        Lock::release($lock);
    }
}

// Blocking with timeout
$lock = Lock::acquireBlocking('payment-' . $orderId, ttl: 60, timeout: 10);

// Synchronized helper (auto-release)
$result = Lock::synchronized('my-resource', function () {
    return doExpensiveWork();
});

Namespace: Lock

Namespaces WITHOUT split packages (monolith-only):

• Command
• Controller
• Error
• Lock (the new one)
• Mailer
• Network
• Routing
• TestSuite
• View

This seems to fit, since we dont need its own package usually here.

Related Discussion

This addresses the gap identified when comparing CakePHP to other frameworks. See: Symfony Lock component, Laravel's atomic locks.

We could also make this a plugin. But it seems this could be a core feature.

PS: Symfony added 2 years after Lock also Semaphore functionality. I descoped that for now, could also be something added within the next 2 years if thats what people need/want.