Lockable Behavior for CakePHP

Simple concurrancy locking for any Model using MySQL's GET_LOCK() and RELEASE_LOCK(). It requires use of MySQL.

Install the Plugin

cd yourprojectroot
git clone https://github.com/AudiologyHoldings/Lockable-CakePHP.git app/Plugin/Lockable

Add the following to your app/Config/bootstrap.php

CakePlugin::load('Lockable');

Run the Unit Tests

cd yourprojectroot
cake test Lockable Model/Behavior/LockableBehavior

Add to your Model

<?php
// my Model file
public $actsAs = array(
	// LockableBehavior added with default config
	'Lockable.Lockable' => array(),
);

Configuration is simple, just pass in whatever options you want to over-ride from the default config...

<?php
// my Model file
public $actsAs = array(
	'Lockable.Lockable',
);

Use from your Model

<?php
// my Model file
public function somethingWithFullModelLocking() {
	$this->lock(1);
	//
	// ... do whatever you need ...
	//
	$this->unlock(1);
	return 'done';
}
public function somethingRequiringRecordSpecificLocking($record) {
	if (empty($record[$this->alias][$this->primaryKey])) {
		throw new OutOfBoundsException('Missing primary key')
	}
	$this->lock($record[$this->alias][$this->primaryKey]);
	//
	// ... do whatever you need ...
	//
	$this->unlock($record[$this->alias][$this->primaryKey]);
	return 'done';
}

While a lock exists, no other process can obtain that lock.

The when attempting to obtain that lock, it is "blocking" (meaning we wait and keep trying to obtain the lock).

• if unlock is not called, The lock dissappears after the process has completed

Common Uses

If you have a cron or process which can run on multiple servers at the same time, you can run into race conditions.