rrb_cleanup_helper

#!/usr/bin/env python

import sys
import os
import os.path
import datetime

def execRule(now, rule, backups):
  if len(backups) < rule[1]:
    del backups[:]
    print >> sys.stderr, "Rule", rule, "keeps all"
    return

  optDts = [now - datetime.timedelta(days=y) * rule[0] / rule[1] \
    for y in sorted(range(rule[1]))]
  for optDt in optDts:
    diffs = []
    for backup in backups:
      diffs.append((abs(optDt - backup[0]), backup[0], backup[1]))
    diffs.sort()
    print >> sys.stderr, "Rule", rule, "tries to get", \
      optDt.strftime("%Y-%m-%dT%H:%M:%S"), "and keeps", diffs[0][2]
    backups.remove((diffs[0][1], diffs[0][2]))

def main(argv=None):
  if not argv:
    argv = sys.argv

  if len(argv) < 5 or len(argv) % 2 != 0:
    print >> sys.stderr, "Usage: " + argv[0] + " dir rule1_days rule1_nr [...]"

  baseDir = argv[1]
  rules = map(lambda x: (int(x[0]), int(x[1])), zip(*[iter(argv[2:])]*2))

  dirs = os.listdir(baseDir)
  backups = []

  for dir in dirs:
    try:
      dt = datetime.datetime.strptime(dir, "%Y-%m-%dT%H:%M:%S")
    except ValueError:
      continue
    backups.append((dt, dir))
  backups.sort(reverse=True)

  now = datetime.datetime.now()

  for rule in rules:
    execRule(now, rule, backups)

  # Print backups to be deleted.
  for backup in backups:
    sys.stdout.write(os.path.join(baseDir, backup[1]) + '\0')

if __name__ == '__main__':
  main()