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OpenStack Study: policy.py**** CubicPower OpenStack Study ****
# Copyright (c) 2011 OpenStack Foundation # 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.""" import os.path from oslo.config import cfg from nova import exception from nova.openstack.common.gettextutils import _ from nova.openstack.common import policy from nova import utils policy_opts = [ cfg.StrOpt('policy_file', default='policy.json', help=_('JSON file representing policy')), cfg.StrOpt('policy_default_rule', default='default', help=_('Rule checked when requested rule is not found')), ] CONF = cfg.CONF CONF.register_opts(policy_opts) _POLICY_PATH = None _POLICY_CACHE = {}
**** CubicPower OpenStack Study **** def reset(): global _POLICY_PATH global _POLICY_CACHE _POLICY_PATH = None _POLICY_CACHE = {} policy.reset()
**** CubicPower OpenStack Study **** def init(): global _POLICY_PATH global _POLICY_CACHE if not _POLICY_PATH: _POLICY_PATH = CONF.policy_file if not os.path.exists(_POLICY_PATH): _POLICY_PATH = CONF.find_file(_POLICY_PATH) if not _POLICY_PATH: raise exception.ConfigNotFound(path=CONF.policy_file) utils.read_cached_file(_POLICY_PATH, _POLICY_CACHE, reload_func=_set_rules)
**** CubicPower OpenStack Study **** def _set_rules(data): default_rule = CONF.policy_default_rule policy.set_rules(policy.Rules.load_json(data, default_rule))
**** CubicPower OpenStack Study **** def enforce(context, action, target, do_raise=True): """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 target: 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}`` :param do_raise: if True (the default), raises PolicyNotAuthorized; if False, returns False :raises nova.exception.PolicyNotAuthorized: if verification fails and do_raise is True. :return: returns a non-False value (not necessarily "True") if authorized, and the exact value False if not authorized and do_raise is False. """ init() credentials = context.to_dict() # Add the exception arguments if asked to do a raise extra = {} if do_raise: extra.update(exc=exception.PolicyNotAuthorized, action=action) return policy.check(action, target, credentials, **extra)
**** CubicPower OpenStack Study **** def check_is_admin(context): """Whether or not roles contains 'admin' role according to policy setting. """ init() #the target is user-self credentials = context.to_dict() target = credentials return policy.check('context_is_admin', target, credentials) @policy.register('is_admin')
**** CubicPower OpenStack Study **** class IsAdminCheck(policy.Check): """An explicit check for is_admin."""
**** CubicPower OpenStack Study **** def __init__(self, kind, match): """Initialize the check.""" self.expected = (match.lower() == 'true') super(IsAdminCheck, self).__init__(kind, str(self.expected))
**** CubicPower OpenStack Study **** def __call__(self, target, creds): """Determine whether is_admin matches the requested value.""" return creds['is_admin'] == self.expected def get_rules(): return policy._rules
**** CubicPower OpenStack Study **** def get_rules(): return policy._rules
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