Overview

Locks prevent concurrent or overly frequent operations that could overload the database or trigger duplicate runners.

ActionScheduler_Lock defines the lock interface, and ActionScheduler_OptionLock is the default implementation.

Lock lifecycle

• Acquire: ActionScheduler_Lock::set( $lock_type )
• Check: ActionScheduler_Lock::is_locked( $lock_type )
• Expiry: ActionScheduler_Lock::get_expiration( $lock_type )
• Duration: ActionScheduler_Lock::get_duration( $lock_type ) (default 60 seconds)

Default lock class

ActionScheduler_Lock::instance() instantiates the lock class using:

• Filter: action_scheduler_lock_class (default ActionScheduler_OptionLock)

Default lock duration

ActionScheduler_Lock::get_duration() uses:

• Filter: action_scheduler_lock_duration (default MINUTE_IN_SECONDS)

Option-based lock implementation

ActionScheduler_OptionLock stores lock values in wp_options:

• Key: action_scheduler_lock_{lock_type}
• Value: uniqid() . '|' . ( time() + duration )

The lock is acquired using an atomic update of the option value, ensuring a lock cannot be stolen if another process updated it first.

Async request lock usage

The queue runner uses a lock of type async-request-runner to ensure async dispatch runs at most once per lock duration during shutdown requests.

Hooks & Filters

Filters

• action_scheduler_lock_class
• action_scheduler_lock_duration