ccb_backup.py 文件源码

def now_minus_delta_time(delta_time_string):
    curr_datetime = datetime.datetime.now(pytz.UTC)
    slop = 15 * 60 # 15 minutes of "slop" allowed in determining new backup is needed
    # curr_datetime = datetime.datetime(2016, 1, 7, 10, 52, 23, tzinfo=pytz.UTC)
    match = re.match('([1-9][0-9]*)([smhdwMY])', delta_time_string)
    if match is None:
        return None
    num_units = int(match.group(1))
    unit_char = match.group(2)
    seconds_per_unit = {'s': 1, 'm': 60, 'h': 3600, 'd': 86400, 'w': 604800}
    if unit_char in seconds_per_unit:
        delta_secs = (int(seconds_per_unit[unit_char]) * num_units) - slop
        return curr_datetime - datetime.timedelta(seconds=delta_secs)
    elif unit_char == 'M':
        month = curr_datetime.month - 1 - num_units
        year = int(curr_datetime.year + month / 12)
        month = month % 12 + 1
        day = min(curr_datetime.day, calendar.monthrange(year, month)[1])
        return datetime.datetime(year, month, day, curr_datetime.hour, curr_datetime.minute, curr_datetime.second,
            tzinfo=pytz.UTC) - datetime.timedelta(seconds=slop)
    else: # unit_char == 'Y'
        return datetime.datetime(curr_datetime.year + num_units, curr_datetime.month, curr_datetime.day,
            curr_datetime.hour, curr_datetime.minute, curr_datetime.second, tzinfo=pytz.UTC) - \
            datetime.timedelta(seconds=slop)