mirror of
https://github.com/MODSetter/SurfSense.git
synced 2026-05-29 19:35:20 +02:00
37 lines
1.3 KiB
Python
37 lines
1.3 KiB
Python
"""Cron math for the ``schedule`` trigger: validate + advance ``next_fire_at``."""
|
|
|
|
from __future__ import annotations
|
|
|
|
from datetime import UTC, datetime
|
|
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
|
|
|
|
from croniter import CroniterBadCronError, croniter
|
|
|
|
|
|
class InvalidCronError(ValueError):
|
|
"""Raised when a cron expression or timezone fails validation."""
|
|
|
|
|
|
def validate_cron(cron: str, timezone: str) -> None:
|
|
"""Raise ``InvalidCronError`` if cron or timezone are unusable."""
|
|
try:
|
|
ZoneInfo(timezone)
|
|
except ZoneInfoNotFoundError as exc:
|
|
raise InvalidCronError(f"unknown timezone {timezone!r}") from exc
|
|
|
|
try:
|
|
croniter(cron)
|
|
except (CroniterBadCronError, ValueError) as exc:
|
|
raise InvalidCronError(f"invalid cron {cron!r}: {exc}") from exc
|
|
|
|
|
|
def compute_next_fire_at(cron: str, timezone: str, *, after: datetime) -> datetime:
|
|
"""Return the next moment matching ``cron`` in ``timezone`` strictly after ``after``.
|
|
|
|
The result is normalized to UTC for storage. ``after`` is converted into the
|
|
given timezone before evaluation so DST and IANA rules apply correctly.
|
|
"""
|
|
tz = ZoneInfo(timezone)
|
|
base = after.astimezone(tz) if after.tzinfo else after.replace(tzinfo=UTC).astimezone(tz)
|
|
nxt: datetime = croniter(cron, base).get_next(datetime)
|
|
return nxt.astimezone(UTC)
|