Overview

ActionScheduler_QueueRunner integrates with WP-Cron by registering a custom schedule and a cron hook that runs the queue.

Schedule and hook registration

On ActionScheduler_QueueRunner::init():

1. Registers a schedule:
   • Filter: cron_schedules
   • Schedule key: every_minute
   • Interval: 60 seconds
2. Ensures older scheduled hooks (without context) are removed:
   • Unschedules action_scheduler_run_queue with no context args if present.
3. Schedules the queue runner:
   • Hook: action_scheduler_run_queue
   • Arguments: array( 'WP Cron' )
   • Schedule filter: action_scheduler_run_schedule (default every_minute)
4. Hooks the queue runner method:
   • add_action( 'action_scheduler_run_queue', array( ActionScheduler_QueueRunner::instance(), 'run' ) )

Context handling

The run() method defaults its $context to WP Cron. WP-Cron runs pass 'WP Cron' as the context via the scheduled event arguments.

Spawn mechanism and async kickoff

WP-Cron handles the baseline schedule, but Action Scheduler can also trigger async requests to keep the queue moving (see async-request.md). The queue runner hooks into shutdown to determine if it should dispatch an async request.

Hooks & Filters

Filters

• cron_schedules (used to register every_minute)
• action_scheduler_run_schedule (controls cron schedule for the queue runner)

Actions

• action_scheduler_run_queue (the queue runner hook executed by WP-Cron)