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Copyright 2011-2016 Josiah Carlson
Released under the LGPL license version 2.1 and version 3 (you can choose
which you'd like to be bound under).
Description
===========
This package intends to offer a method of parsing crontab schedule entries and
determining when an item should next be run. More specifically, it calculates
a delay in seconds from when the .next() method is called to when the item
should next be executed.
Comparing the below chart to http://en.wikipedia.org/wiki/Cron#CRON_expression
you will note that W and # symbols are not supported.
============= =========== ================= ===========================
Field Name Mandatory Allowed Values Allowed Special Characters
============= =========== ================= ===========================
Minutes Yes 0-59 \* / , -
Hours Yes 0-23 \* / , -
Day of month Yes 1-31 \* / , - ? L
Month Yes 1-12 or JAN-DEC \* / , -
Day of week Yes 0-6 or SUN-SAT \* / , - ? L
Year No 1970-2099 \* / , -
============= =========== ================= ===========================
Sample individual crontab fields
================================
Examples of supported entries are as follows::
*
*/5
7/8
3-25/7
3,7,9
0-10,30-40/5
For month or day of week entries, 3 letter abbreviations of the month or day
can be used to the left of any optional / where a number could be used.
For days of the week::
mon-fri
sun-thu/2
For month::
apr-jul
mar-sep/3
Example uses
============
::
>>> from crontab import CronTab
>>> from datetime import datetime
>>> # define the crontab for 25 minutes past the hour every hour
... entry = CronTab('25 * * * *')
>>> # find the delay from when this was run (around 11:13AM)
... entry.next()
720.81637899999998
>>> # find the delay from when it was last scheduled
... entry.next(datetime(2011, 7, 17, 11, 25))
3600.0
Notes
=====
At most one of 'day of week' or 'day of month' can be a value other than '?'
or '*'. We violate spec here and allow '*' to be an alias for '?', in the case
where one of those values is specified (seeing as some platforms don't support
'?').
This module also supports the convenient aliases::
@yearly
@annually
@monthly
@weekly
@daily
@hourly
Example full crontab entries and their meanings::
30 */2 * * * -> 30 minutes past the hour every 2 hours
15,45 23 * * * -> 11:15PM and 11:45PM every day
0 1 ? * SUN -> 1AM every Sunday
0 1 * * SUN -> 1AM every Sunday (same as above)
0 0 1 jan/2 * 2011-2013 ->
midnight on January 1, 2011 and the first of every odd month until
the end of 2013
24 7 L * * -> 7:24 AM on the last day of every month
24 7 * * L5 -> 7:24 AM on the last friday of every month
24 7 * * Lwed-fri ->
7:24 AM on the last wednesday, thursday, and friday of every month