Cron schedule

A Cron schedule runs a Workflow on a time-based schedule (a cron expression + timezone), with a catch-up policy for runs missed while the process was down: skip (ignore them) or run-all (replay them, up to a bound).

Interfaces

Rust

Authored declaratively as a cron Trigger in a package:

#[trigger(on = "daily_report", cron = "0 9 * * *", timezone = "UTC")]
struct DailyReport;

Python

Managed at the runner API — register and manage schedules at runtime; read operations return dicts:

runner = cloaca.DefaultRunner("postgresql://…")

schedule_id = runner.register_cron_workflow(
    "daily_report",   # workflow name
    "0 9 * * *",      # cron expression
    "UTC",            # timezone
)
runner.list_cron_schedules(enabled_only=True)   # list[dict]
runner.set_cron_schedule_enabled(schedule_id, False)
runner.delete_cron_schedule(schedule_id)

Key facts

• Expression format: standard 5-field cron (minute hour day month weekday) with an optional leading seconds field (6-field, e.g. */3 * * * * * = every 3 seconds). Parsed by the croner crate with seconds-optional enabled; evaluated timezone-aware (CronEvaluator in cloacina-workflow).
• Catch-up policy: skip or run-all (run-all is bounded by a max-catchup count).
• Schedule dicts (Python): id, workflow_name, cron_expression, timezone, enabled, catchup_policy, next_run_at, last_run_at, created_at, updated_at.
• Parity: Python packages can also declare cron triggers — @cloaca.trigger(on="...", cron="...", timezone="...") (added in CLOACI-T-0688; the reconciler routes cron-bearing triggers to the cron scheduler). Note cloacinactl package new offers a cron scaffold for Rust only — hand-author the decorator in a Python package.

See also

• Trigger · Cron scheduling (design)