shaving zfs snapshots

zfssnap.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# ZFS スナップショットをルールに従ってdestroyします

# Copyright 2011 Takeshi Matsubara ([email protected])
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.
   
import sys
import subprocess
import time
import getopt

def usage(code = 1, errmsg = 'Error'):
	print >>sys.stderr, """
%s

Usage: %s [-vq] filesystem | xargs -n 1 -p zfs destroy

Options:
    -v  Verbose Output (to stderr)
    -q  Supress Output (to stdout)
""" % (errmsg, sys.argv[0])
	sys.exit(code)

try:
	(opts, args) = getopt.getopt(sys.argv[1:], 'vq')
except getopt.GetoptError, err:
	usage(2, str(err))

opts0 = dict(opts)
opt_v = True if '-v' in opts0 else False
opt_q = True if '-q' in opts0 else False
if len(args) == 0:
	usage(2, 'No filesystem specified')

cmd = 'zfs list -t snapshot -o name,creation -s creation -r'.split()
cmd.append(args[0])

p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
output = p.communicate()[0]

if p.returncode <> 0:
	print >>sys.stderr, 'zfs command exits with error %d' % p.returncode
	sys.exit(p.returncode)

skip = 1
today = time.time() / 86400
last = 0

# 1週間前まではなにもdestroyしない
period1 = today - 7
# 1ヶ月前までは、1日に1個のsnapshotを残す
period2 = today - 30
# 3ヶ月前までは、1週に1個のsnapshotを残す
period3 = today - 90
# 1年前までは、1月に1個のsnapshotを残す
period4 = today - 365
# それ以前のsnapshotは全部destroyする

for line in output.splitlines():
	if skip > 0: skip -= 1; continue;

	(name, creation) = line.split(None, 1)
	d = time.mktime(time.strptime(creation, '%a %b %d %H:%M %Y')) / 86400

	dst = False
	if d < period4:
		dst = True
	elif d < period3 and last + 30 >= d:
		dst = True
	elif d < period2 and last + 7 >= d:
		dst = True
	elif d < period1 and last >= d:
		dst = True
	if dst == False:
		last = d
	if dst and not opt_q:
		print "%s" % name
	if opt_v:
		msg = 'destroy' if dst else 'keep   '
		print >>sys.stderr, '%s, %s %s' % (msg, name, creation)