2021-02-07 14:02:31 +01:00

68 lines
2.0 KiB
Python

import re
class ThinnerRule:
"""a thinning schedule rule for Thinner"""
TIME_NAMES = {
'y': 3600 * 24 * 365.25,
'm': 3600 * 24 * 30,
'w': 3600 * 24 * 7,
'd': 3600 * 24,
'h': 3600,
'min': 60,
's': 1,
}
TIME_DESC = {
'y': 'year',
'm': 'month',
'w': 'week',
'd': 'day',
'h': 'hour',
'min': 'minute',
's': 'second',
}
def __init__(self, rule_str):
"""parse scheduling string
example:
daily snapshot, remove after a week: 1d1w
weekly snapshot, remove after a month: 1w1m
monthly snapshot, remove after 6 months: 1m6m
yearly snapshot, remove after 2 year: 1y2y
keep all snapshots, remove after a day 1s1d
keep nothing: 1s1s
"""
rule_str = rule_str.lower()
matches = re.findall("([0-9]*)([a-z]*)([0-9]*)([a-z]*)", rule_str)[0]
period_amount = int(matches[0])
period_unit = matches[1]
ttl_amount = int(matches[2])
ttl_unit = matches[3]
if period_unit not in self.TIME_NAMES:
raise (Exception("Invalid period string in schedule: '{}'".format(rule_str)))
if ttl_unit not in self.TIME_NAMES:
raise (Exception("Invalid ttl string in schedule: '{}'".format(rule_str)))
self.period = period_amount * self.TIME_NAMES[period_unit]
self.ttl = ttl_amount * self.TIME_NAMES[ttl_unit]
if self.period > self.ttl:
raise (Exception("Period cant be longer than ttl in schedule: '{}'".format(rule_str)))
self.rule_str = rule_str
self.human_str = "Keep every {} {}{}, delete after {} {}{}.".format(
period_amount, self.TIME_DESC[period_unit], period_amount != 1 and "s" or "", ttl_amount,
self.TIME_DESC[ttl_unit], ttl_amount != 1 and "s" or "")
def __str__(self):
"""get schedule as a schedule string"""
return self.rule_str