charm-swift-storage/hooks/charmhelpers/core/fstab.py
2014-06-19 11:11:47 +01:00

117 lines
3.3 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
__author__ = 'Jorge Niedbalski R. <jorge.niedbalski@canonical.com>'
import os
class Fstab(file):
"""This class extends file in order to implement a file reader/writer
for file `/etc/fstab`
"""
class Entry(object):
"""Entry class represents a non-comment line on the `/etc/fstab` file
"""
def __init__(self, device, mountpoint, filesystem,
options, d=0, p=0):
self.device = device
self.mountpoint = mountpoint
self.filesystem = filesystem
if not options:
options = "defaults"
self.options = options
self.d = d
self.p = p
def __eq__(self, o):
return str(self) == str(o)
def __str__(self):
return "{} {} {} {} {} {}".format(self.device,
self.mountpoint,
self.filesystem,
self.options,
self.d,
self.p)
DEFAULT_PATH = os.path.join(os.path.sep, 'etc', 'fstab')
def __init__(self, path=None):
if path:
self._path = path
else:
self._path = self.DEFAULT_PATH
file.__init__(self, self._path, 'r+')
def _hydrate_entry(self, line):
# NOTE: use split with no arguments to split on any
# whitespace including tabs
return Fstab.Entry(*filter(
lambda x: x not in ('', None),
line.strip("\n").split()))
@property
def entries(self):
self.seek(0)
for line in self.readlines():
try:
if not line.startswith("#"):
yield self._hydrate_entry(line)
except ValueError:
pass
def get_entry_by_attr(self, attr, value):
for entry in self.entries:
e_attr = getattr(entry, attr)
if e_attr == value:
return entry
return None
def add_entry(self, entry):
if self.get_entry_by_attr('device', entry.device):
return False
self.write(str(entry) + '\n')
self.truncate()
return entry
def remove_entry(self, entry):
self.seek(0)
lines = self.readlines()
found = False
for index, line in enumerate(lines):
if not line.startswith("#"):
if self._hydrate_entry(line) == entry:
found = True
break
if not found:
return False
lines.remove(line)
self.seek(0)
self.write(''.join(lines))
self.truncate()
return True
@classmethod
def remove_by_mountpoint(cls, mountpoint, path=None):
fstab = cls(path=path)
entry = fstab.get_entry_by_attr('mountpoint', mountpoint)
if entry:
return fstab.remove_entry(entry)
return False
@classmethod
def add(cls, device, mountpoint, filesystem, options=None, path=None):
return cls(path=path).add_entry(Fstab.Entry(device,
mountpoint, filesystem,
options=options))