Feature: #104126 - Add configuration setting to define backend-locking file

See forge#104126

Description

TYPO3 supports the ability to lock the backend for maintenance reasons. This is controlled with a LOCK_BACKEND file that was previously stored in typo3conf/.

With Important: #104126 - Drop "typo3conf" directory from system status check and backend locking this directory is no longer needed, so now the location to this file can be adjusted via the new configuration setting $GLOBALS['TYPO3_CONF_VARS']['BE']['lockBackendFile'] .

When empty, it falls back to a file LOCK_BACKEND, which is now stored by default in:

  • var/lock/ for Composer Mode
  • config/ for Legacy Mode

If you previously manually maintained the LOCK_BACKEND file (for example via deployment or other maintenance automation), please either adjust your automations to the new file location, or change the setting to the desired file location, or at best use the CLI commands vendor/bin/typo3 backend:lock and vendor/bin/typo3 backend:unlock.

The backend locking functionality is now contained in a distinct service class \TYPO3\CMS\Backend\Authentication\BackendLocker to allow future flexibility.

When upgrading an installation to Composer Mode with a locked backend in effect, please ensure your backend can remain locked by moving (or copying) the file to the new location var/lock/.

Remember, if you want locked backend state to persist between deployments, ensure that the used directory (var/lock by default) is shared between deployment releases.

Impact

The location for LOCK_BACKEND to lock (and unlock) the backend can now be controlled by maintainers of a TYPO3 installation, and has moved outside of typo3conf/ by default to either var/lock/ (Composer) or config/ (Legacy).