nova/nova/policy.py

79 lines
2.4 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (c) 2011 OpenStack, LLC.
# All Rights Reserved.
#
# 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.
"""Policy Engine For Nova"""
from nova import exception
from nova import flags
from nova import utils
from nova.common import policy
FLAGS = flags.FLAGS
flags.DEFINE_string('policy_file', 'policy.json',
_('JSON file representing policy'))
_POLICY_PATH = None
_POLICY_CACHE = {}
def reset():
global _POLICY_PATH
global _POLICY_CACHE
_POLICY_PATH = None
_POLICY_CACHE = {}
policy.reset()
def init():
global _POLICY_PATH
global _POLICY_CACHE
if not _POLICY_PATH:
_POLICY_PATH = utils.find_config(FLAGS.policy_file)
data = utils.read_cached_file(_POLICY_PATH, _POLICY_CACHE,
reload_func=_set_brain)
def _set_brain(data):
policy.set_brain(policy.HttpBrain.load_json(data))
def enforce(context, action, target):
"""Verifies that the action is valid on the target in this context.
:param context: nova context
:param action: string representing the action to be checked
this should be colon separated for clarity.
i.e. compute:create_instance
compute:attach_volume
volume:attach_volume
:param object: dictionary representing the object of the action
for object creation this should be a dictionary representing the
location of the object e.g. {'project_id': context.project_id}
:raises: `nova.exception.PolicyNotAllowed` if verification fails.
"""
init()
match_list = ('rule:%s' % action,)
target_dict = target
credentials_dict = context.to_dict()
try:
policy.enforce(match_list, target_dict, credentials_dict)
except policy.NotAllowed:
raise exception.PolicyNotAllowed(action=action)