#!/usr/bin/python

# call rsnapshot daily/weekly/monthly regularly
# this should be called from cron very often (several times a day) to not miss
# a cycle when the machine is powered down for extended times.
#
# Author: Martin Pitt <martin@piware.de>
# License: Public Domain

import os, time, os.path, pwd, subprocess

user = pwd.getpwuid(os.getuid()).pw_name
rsnapshot_basedir = '/var/backups/' + user
rsnapshot_conffile = os.path.expanduser('~/.rsnapshotrc')
verbose = True

def days_mod(path):
    '''Return the number of days since the last modification of path.'''

    if os.path.exists(path):
        return (time.time() - os.stat(path).st_mtime)/86400.
    else:
        return time.time()/86400.

def rsnapshot(mode):
    argv = ['rsnapshot']
    if verbose:
        argv.append('-v')
    argv += ['-c', rsnapshot_conffile, mode]
    if verbose:
        print argv
    subprocess.call(argv)

# daily
if days_mod(os.path.join(rsnapshot_basedir, 'daily.0')) >= 1:
    rsnapshot('daily')
elif days_mod(os.path.join(rsnapshot_basedir, 'weekly.0')) >= 7:
    rsnapshot('weekly')
elif days_mod(os.path.join(rsnapshot_basedir, 'monthly.0')) >= 30:
    rsnapshot('monthly')