Cron

A built-in background scheduler. Each job runs on its own thread, non-blocking.

-- Doc example: cron scheduler. Jobs run in the background; see the prose for cron_every.
-- Doctest just shows the registry starts empty (no jobs scheduled yet).
intent: "doc example: cron"

print("scheduled jobs: " + text(length(cron_list())))

test "the job registry starts empty"
    assert_eq(length(cron_list()), 0)

Scheduling

task sync_inventory()
    let data be http_get("https://api.warehouse.com/stock")
    share data as "inventory"

cron_every(300, sync_inventory)     -- every 5 minutes
cron_after(3600, send_reminder)     -- once, after 1 hour

Managing

cron_cancel("sync_inventory")       -- stop a job
let jobs be cron_list()             -- list all jobs
print(cron_status())                -- formatted status

Keeping jobs alive

Under run, jobs stop when the program ends (they're daemon threads). Use synsema serve to keep the process — and the schedule — running:

synsema serve scheduler.syn         -- "Serving N cron job(s). Press Ctrl+C to stop."