blazar/climate/context.py
Yuriy Taraday ea0c144b13 Refactor context module to make it more flexible
- context data is stored in a dictionary now, so any key is allowed;
- list of allowed key for certain context is stored in special class
  variable;
- methods "current" and "elevated" of ClimateContext class are
  accessible from module level;
- moved to usage of threading.local instead of emulating one in code (as
  long as we use eventlet's monkey-patching, it's specific local() will
  be used).

Change-Id: I3c79c9cd0d16dfb5c61208f2aa71b5c59f3f40f3
2013-11-25 14:10:23 +04:00

99 lines
2.6 KiB
Python

# Copyright (c) 2013 Mirantis Inc.
#
# 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.
import threading
class BaseContext(object):
_elements = set()
_context_stack = threading.local()
def __init__(self, __mapping=None, **kwargs):
if __mapping is None:
self.__values = dict(**kwargs)
else:
if isinstance(__mapping, BaseContext):
__mapping = __mapping.__values
self.__values = dict(__mapping)
self.__values.update(**kwargs)
bad_keys = set(self.__values) - self._elements
if bad_keys:
raise TypeError("Only %s keys are supported. %s given" %
(tuple(self._elements), tuple(bad_keys)))
def __getattr__(self, name):
try:
return self.__values[name]
except KeyError:
if name in self._elements:
return None
else:
raise AttributeError(name)
def __enter__(self):
try:
stack = self._context_stack.stack
except AttributeError:
stack = []
self._context_stack.stack = stack
stack.append(self)
return self
def __exit__(self, exc_type, exc_val, exc_tb):
res = self._context_stack.stack.pop()
assert res is self, "self should be the top element of the stack"
@classmethod
def current(cls):
try:
return cls._context_stack.stack[-1]
except (AttributeError, IndexError):
raise RuntimeError("Context isn't available here")
# NOTE(yorik-sar): as long as oslo.rpc requires this
def to_dict(self):
return self.__values
class ClimateContext(BaseContext):
_elements = set([
"user_id",
"tenant_id",
"auth_token",
"service_catalog",
"user_name",
"tenant_name",
"roles",
"is_admin",
])
@classmethod
def elevated(cls):
try:
ctx = cls.current()
except RuntimeError:
ctx = None
return cls(ctx, is_admin=True)
def current():
return ClimateContext.current()
def elevated():
return ClimateContext.elevated()