README

TYPO3 has three built-in Locking Strategies, that are chosen at runtime which fits best for the current system setup.

• SemaphoreLockStrategy
• SimpleLockStrategy
• FileLockStrategy

However, when dealing with a multi-tier system and a shared file system with multiple frontend nodes with a NFS filesystem, it is especially helpful to use a better suitable format. Redis is our weapon of choice for handling multi-node scenarios, and works just fine with TYPO3 and Caching.

This extension provides a Redis Locking mechanism to store the locks in a (shared) Redis database.

Requirements

This extension is available for TYPO3 v8+ LTS, and requires the PHP package php-redis as well as a Redis server.

Installation

Install this extension via composer composer require b13/distributed-locks or extensions.typo3.org / Extension Manager, and activate it in the Extension Manager.

Now add the following lines to your LocalConfiguration / AdditionalConfiguration to activate Redis Locking.

$GLOBALS['TYPO3_CONF_VARS']['SYS']['locking']['redis'] = [
    'hostname' => '127.0.0.1',
    'database' => 12
];

Other options:

'ttl' (numeric, default is 30sec)
'port' (numeric, default is 6379)
'password' (contains the password, necessary for secure authentication if required by redis)
'priority' (numeric, default is 95) - Set priority for this locking strategy. See LockingApi documentation.

Disabling it in certain contextes

If you have different TYPO3_CONTEXT or environments and you want to switch off the complete redis strategy (i.e. in your staging machine), you can set this in your LocalConfiguration / AdditionalConfiguration:

$GLOBALS['TYPO3_CONF_VARS']['SYS']['locking']['redis']['disabled'] = true;

Future Development

Should be switched to symfony/lock to allow distributed redis services and other lockers.

Credits & Background

Inspiration was taken from the now unmaintained extension "redis_lock_strategy" which we used several times, however with some drawbacks:

• No stable version for TYPO3 v9 in composer mode
• No maintainer available for releases anymore
• Destroying an object did not remove locks, ending in certain dead lock scenarios in broken scripts

Thanks to Alexander Miehe for the initial extension and the conceptual work.

Sharing our expertise

Find more TYPO3 extensions we have developed that help us deliver value in client projects. As part of the way we work, we focus on testing and best practices to ensure long-term performance, reliability, and results in all our code.