ifupdown2/ifupdown/utils.py

   1 #!/usr/bin/python
   2 #
   3 # Copyright 2014 Cumulus Networks, Inc. All rights reserved.
   4 # Author: Roopa Prabhu, roopa@cumulusnetworks.com
   5 #
   6 # utils --
   7 #    helper class
   8 #
   9 import os
  10 import fcntl
  11 import re
  12
  13 class utils():
  14
  15     @classmethod
  16     def importName(cls, modulename, name):
  17         """ Import a named object """
  18         try:
  19             module = __import__(modulename, globals(), locals(), [name])
  20         except ImportError:
  21             return None
  22         return getattr(module, name)
  23
  24     @classmethod
  25     def lockFile(cls, lockfile):
  26         try:
  27             fp = os.open(lockfile, os.O_CREAT | os.O_TRUNC | os.O_WRONLY)
  28             fcntl.flock(fp, fcntl.LOCK_EX | fcntl.LOCK_NB)
  29         except IOError:
  30             return False
  31         return True
  32
  33     @classmethod
  34     def parse_iface_range(cls, name):
  35         range_match = re.match("^([\w\.]+)\[([\d]+)-([\d]+)\]", name)
  36         if range_match:
  37             range_groups = range_match.groups()
  38             if range_groups[1] and range_groups[2]:
  39                 return (range_groups[0], int(range_groups[1], 10),
  40                         int(range_groups[2], 10))
  41         return None
  42
  43     @classmethod
  44     def expand_iface_range(cls, name):
  45         ifacenames = []
  46         iface_range = cls.parse_iface_range(name)
  47         if iface_range:
  48             for i in range(iface_range[1], iface_range[2]):
  49                 ifacenames.append('%s-%d' %(iface_range[0], i))
  50         return ifacenames
  51
  52