Crontab schedule.

A Crontab can be used as the run_every value of a periodic task entry to add crontab(5)-like scheduling.

Like a cron(5)-job, you can specify units of time of when you’d like the task to execute. It’s a reasonably complete implementation of cron’s features, so it should provide a fair degree of scheduling needs.

You can specify a minute, an hour, a day of the week, a day of the month, and/or a month in the year in any of the following formats:

minute¶

• A (list of) integers from 0-59 that represent the minutes of an hour of when execution should occur; or

• A string representing a Crontab pattern. This may get pretty advanced, like minute='*/15' (for every quarter) or minute='1,13,30-45,50-59/2'.

hour¶

• A (list of) integers from 0-23 that represent the hours of a day of when execution should occur; or

• A string representing a Crontab pattern. This may get pretty advanced, like hour='*/3' (for every three hours) or hour='0,8-17/2' (at midnight, and every two hours during office hours).

day_of_week¶

• A (list of) integers from 0-6, where Sunday = 0 and Saturday = 6, that represent the days of a week that execution should occur.

• A string representing a Crontab pattern. This may get pretty advanced, like day_of_week='mon-fri' (for weekdays only). (Beware that day_of_week='*/2' does not literally mean ‘every two days’, but ‘every day that is divisible by two’!)

day_of_month¶

• A (list of) integers from 1-31 that represents the days of the month that execution should occur.

• A string representing a Crontab pattern. This may get pretty advanced, such as day_of_month='2-30/2' (for every even numbered day) or day_of_month='1-7,15-21' (for the first and third weeks of the month).

month_of_year¶

• A (list of) integers from 1-12 that represents the months of the year during which execution can occur.

• A string representing a Crontab pattern. This may get pretty advanced, such as month_of_year='*/3' (for the first month of every quarter) or month_of_year='2-12/2' (for every even numbered month).

nowfun¶

Function returning the current date and time (datetime).

app¶

The Celery app instance.

It’s important to realize that any day on which execution should occur must be represented by entries in all three of the day and month attributes. For example, if day_of_week is 0 and day_of_month is every seventh day, only months that begin on Sunday and are also in the month_of_year attribute will have execution events. Or, day_of_week is 1 and day_of_month is ‘1-7,15-21’ means every first and third Monday of every month present in month_of_year.

Constructors¶

crontab(minute: int | str | Iterable[int] = '*', ...)[source]

Initialize self. See help(type(self)) for accurate signature.

Public members¶

property app : Celery

classmethod from_string(crontab: str) → crontab[source]

Create a Crontab from a cron expression string. For example crontab.from_string('* * * * *').

is_due(last_run_at: datetime) → tuple[bool, datetime][source]

Return tuple of (is_due, next_time_to_run).

maybe_make_aware(dt: datetime, ...) → datetime

now() → datetime

remaining_delta(...) → tuple[datetime, Any, datetime][source]

remaining_estimate(...) → timedelta[source]

Estimate of next run time.

to_local(dt: datetime) → datetime

property tz : tzinfo

property utc_enabled : bool

Helper methods¶

__reduce__() → tuple[type, tuple[int | str | Iterable[int], int | str | Iterable[int], int | str | Iterable[int], int | str | Iterable[int], int | str | Iterable[int]], Any][source]

Helper for pickle.

Comparison operators¶

__eq__(other: Any) → bool[source]

Return self==value.

String representation¶

__repr__() → str[source]

Return repr(self).