GrandFatherSon 1.3

用法

此模块需要datetime.date或datetime.datetime 对象作为输入。例如，假设您有每日备份 1999年全年需要轮换：

>>> import datetime
>>> start_date = datetime.date(1999, 1, 1)
>>> end_date = datetime.date(1999, 12, 31)
>>> backups = [start_date + datetime.timedelta(days=i)
...            for i in range((end_date - start_date).days + 1)]
>>> backups
[datetime.date(1999, 1, 1),
 datetime.date(1999, 1, 2),
 datetime.date(1999, 1, 3),
 ...
 datetime.date(1999, 12, 30),
 datetime.date(1999, 12, 31)]

假设每周六进行完整备份，增量备份 每天备份。一周或7天的增量备份应该 被保留。保留一个月或4周的完整备份。此外， 在三个月内，每个月都会保留第一次完整备份， 其他的被丢弃了。

这是一年中的最后一天，你想知道哪些备份 需要修剪：

>>> now = datetime.date(1999, 12, 31)

要查看将保留哪些文件，请使用dates_to_keep 功能：

>>> from grandfatherson import dates_to_keep, SATURDAY
>>> sorted(dates_to_keep(backups, days=7, weeks=4, months=3,
...                      firstweekday=SATURDAY, now=now))
[datetime.date(1999, 10, 1),
 datetime.date(1999, 11, 1),
 datetime.date(1999, 12, 1),
 datetime.date(1999, 12, 4),
 datetime.date(1999, 12, 11),
 datetime.date(1999, 12, 18),
 datetime.date(1999, 12, 25),
 datetime.date(1999, 12, 26),
 datetime.date(1999, 12, 27),
 datetime.date(1999, 12, 28),
 datetime.date(1999, 12, 29),
 datetime.date(1999, 12, 30),
 datetime.date(1999, 12, 31)]

如果不使用now参数，则默认使用 datetime.datetime.now()。

要查看应删除哪些文件，请使用dates_to_delete 功能：

>>> from grandfatherson import dates_to_delete, SATURDAY
>>> sorted(dates_to_delete(backups, days=7, weeks=4, months=3,
...                        firstweekday=SATURDAY, now=now))
[datetime.date(1999, 1, 1),
 ...
 datetime.date(1999, 9, 30),
 datetime.date(1999, 10, 2),
 ...
 datetime.date(1999, 10, 31),
 datetime.date(1999, 11, 2),
 ...
 datetime.date(1999, 11, 30),
 datetime.date(1999, 12, 2),
 datetime.date(1999, 12, 3),
 datetime.date(1999, 12, 5),
 ...
 datetime.date(1999, 12, 10),
 datetime.date(1999, 12, 12),
 ...
 datetime.date(1999, 12, 17),
 datetime.date(1999, 12, 19),
 ...
 datetime.date(1999, 12, 24)]

最后，如果需要旋转时间戳在 datetime格式，您可以使用相应的to_keep和 to_delete函数：

>>> now = datetime.datetime(1999, 12, 31, 23, 59, 59)
>>> start_datetime = datetime.datetime(1999, 12, 31, 0, 0, 0)
>>> end_datetime = datetime.datetime(1999, 12, 31, 23, 59, 59)
>>> backups = [start_datetime + datetime.timedelta(seconds=i)
...            for i
...            in range((end_datetime - start_datetime).seconds + 1)]
>>> backups
[datetime.datetime(1999, 12, 31, 0, 0),
 datetime.datetime(1999, 12, 31, 0, 0, 1),
 datetime.datetime(1999, 12, 31, 0, 0, 2),
 ...
 datetime.datetime(1999, 12, 31, 23, 59, 58),
 datetime.datetime(1999, 12, 31, 23, 59, 59)]

>>> from grandfatherson import to_keep
>>> sorted(to_keep(backups, hours=2, minutes=10, seconds=10, now=now))
[datetime.datetime(1999, 12, 31, 22, 0),
 datetime.datetime(1999, 12, 31, 23, 0),
 datetime.datetime(1999, 12, 31, 23, 50),
 ...
 datetime.datetime(1999, 12, 31, 23, 59),
 datetime.datetime(1999, 12, 31, 23, 59, 50),
 ...
 datetime.datetime(1999, 12, 31, 23, 59, 59)]

>>> from grandfatherson import to_delete
>>> sorted(to_delete(backups, hours=2, minutes=10, seconds=10, now=now))
[datetime.datetime(1999, 12, 31, 0, 0),
 ...
 datetime.datetime(1999, 12, 31, 21, 59, 59),
 datetime.datetime(1999, 12, 31, 22, 0, 1),
 ...
 datetime.datetime(1999, 12, 31, 22, 59, 59),
 datetime.datetime(1999, 12, 31, 23, 0, 1),
 ...
 datetime.datetime(1999, 12, 31, 23, 49, 59),
 datetime.datetime(1999, 12, 31, 23, 50, 1),
 ...
 datetime.datetime(1999, 12, 31, 23, 58, 59),
 datetime.datetime(1999, 12, 31, 23, 59, 1),
 ...
 datetime.datetime(1999, 12, 31, 23, 59, 49)]