Arbiter.Worker.Cron

A cron schedule. Built with cronJob, or cronJobInTimezone for a non-UTC one.

Cron tick overlap policy.

Bound on replay of missed ticks. Applies at startup and mid-flight.

Whether a tick is for the current minute or a replay of a past minute.

Build a CronJob evaluated in UTC. A bad expression returns Left. cronJobInTimezone is the local-time form. Set backfill and initiallyEnabled by record update.

cronJob "nightly-report" "0 3 * * *" SkipOverlap
  (\_kind _tick -> defaultJob (GenerateReport "nightly"))

Like cronJob but evaluated in a specific timezone. The tz name is validated eagerly against the bundled tzdata database.

Convert an OverlapPolicy to its text representation.

Parse an OverlapPolicy from text.

Check a cron patch before it is written. At tick time a bad override stops firing or falls back to the default.

updateCronScheduleUnchecked behind validateCronScheduleUpdate. Returns rows affected, 0 for an unknown name or an empty patch.

The first tick after now that sched matches in the given timezone. Nothing means UTC. An unknown tz name returns Nothing.

nextRunInTimezone over an unparsed expression. A bad one returns Nothing.

Format a UTCTime as YYYY-MM-DDTHH:MM for dedup key buckets.

Look up an IANA tz name in the bundled tzdata database.

Match a cron schedule against a UTC tick in the given timezone. Nothing means UTC. An unknown tz name returns False. A fixed-time schedule skips the second reading of a repeated local hour. A wildcard one runs through both.

Enumerate all minute-boundary times from start through end (inclusive). Both start and end should be truncated to minute boundaries.

Truncate a UTCTime to the current minute (zero out seconds).

Minutes to evaluate for a processCronCatchUp call. Returns [] when the watermark is at or past currentTick.

The dedup key for a schedule's tick. An AllowOverlap key includes the UTC tick minute.

Delay in microseconds until the next minute boundary, clamped to zero through maxTickDelay.

The scheduler's logger with the gates its repeating failures report through.

A CronLog with no gate tripped, for one scheduler run.

Scheduler entry point. Exits when the worker state becomes ShuttingDown.

Scheduler catch-up step. Each tick commits independently. Backfill ticks acquire a per-schedule advisory lock for their transaction.

A failed tick is logged and skipped once a later tick fires. The watermark of a Backfill schedule stays behind a failed newest tick, and the next pass retries it.

Claim and fire every schedule with a pending run request. A SkipOverlap schedule reuses its constant dedup key, so its manual run is skipped while one of its jobs is active.

The claim and the insert are atomic. If either fails the other rolls back.

Upsert the default expression, overlap, timezone and initial enabled flag of each CronJob into the cron_schedules table. Preserves user overrides. An existing row keeps its enabled state.