Gary Kotton 07bbf797fc Parse linuxbridge plugins using openstack.common.cfg
Implements the blueprint use-common-cfg

In order for the linuxbridge plugin to use the rpc code soon to be merged into
openstack-common, we need to parse our configuration using cfg. Here we
make the most simple, backwards compatible change in that direction.

The same is relevant for the openvswitch implementation

Fixes after comments.

Change-Id: I70fc1898a802cb4198f72741453283d114added2
2012-05-29 09:54:29 -04:00

127 lines
4.0 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2012 OpenStack LLC.
#
# 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.
class ParseError(Exception):
def __init__(self, message, lineno, line):
self.msg = message
self.line = line
self.lineno = lineno
def __str__(self):
return 'at line %d, %s: %r' % (self.lineno, self.msg, self.line)
class BaseParser(object):
lineno = 0
parse_exc = ParseError
def _assignment(self, key, value):
self.assignment(key, value)
return None, []
def _get_section(self, line):
if line[-1] != ']':
return self.error_no_section_end_bracket(line)
if len(line) <= 2:
return self.error_no_section_name(line)
return line[1:-1]
def _split_key_value(self, line):
colon = line.find(':')
equal = line.find('=')
if colon < 0 and equal < 0:
return self.error_invalid_assignment(line)
if colon < 0 or (equal >= 0 and equal < colon):
key, value = line[:equal], line[equal + 1:]
else:
key, value = line[:colon], line[colon + 1:]
return key.strip(), [value.strip()]
def parse(self, lineiter):
key = None
value = []
for line in lineiter:
self.lineno += 1
line = line.rstrip()
if not line:
# Blank line, ends multi-line values
if key:
key, value = self._assignment(key, value)
continue
elif line[0] in (' ', '\t'):
# Continuation of previous assignment
if key is None:
self.error_unexpected_continuation(line)
else:
value.append(line.lstrip())
continue
if key:
# Flush previous assignment, if any
key, value = self._assignment(key, value)
if line[0] == '[':
# Section start
section = self._get_section(line)
if section:
self.new_section(section)
elif line[0] in '#;':
self.comment(line[1:].lstrip())
else:
key, value = self._split_key_value(line)
if not key:
return self.error_empty_key(line)
if key:
# Flush previous assignment, if any
self._assignment(key, value)
def assignment(self, key, value):
"""Called when a full assignment is parsed"""
raise NotImplementedError()
def new_section(self, section):
"""Called when a new section is started"""
raise NotImplementedError()
def comment(self, comment):
"""Called when a comment is parsed"""
pass
def error_invalid_assignment(self, line):
raise self.parse_exc("No ':' or '=' found in assignment",
self.lineno, line)
def error_empty_key(self, line):
raise self.parse_exc('Key cannot be empty', self.lineno, line)
def error_unexpected_continuation(self, line):
raise self.parse_exc('Unexpected continuation line',
self.lineno, line)
def error_no_section_end_bracket(self, line):
raise self.parse_exc('Invalid section (must end with ])',
self.lineno, line)
def error_no_section_name(self, line):
raise self.parse_exc('Empty section name', self.lineno, line)