os-client-config/os_client_config/defaults.py
Joshua Harlow d597ee271e Update globals safely
The right way to update these globals is to use a lock
and ensure that nobody else is updating them at the same
time. Also update a temporary dictionary before setting
the global one so that nobody sees partial updates to the
global one.

This should help fix the thread-safety of shade (and other
tooling built ontop of this library).

Change-Id: Ie0e0369d98ba6a01edcbf447378a786eec3f13f9
2017-08-07 15:46:59 -07:00

53 lines
1.8 KiB
Python

# Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
#
# 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 json
import os
import threading
_json_path = os.path.join(
os.path.dirname(os.path.realpath(__file__)), 'defaults.json')
_defaults = None
_defaults_lock = threading.Lock()
def get_defaults():
global _defaults
if _defaults is not None:
return _defaults.copy()
with _defaults_lock:
if _defaults is not None:
# Did someone else just finish filling it?
return _defaults.copy()
# Python language specific defaults
# These are defaults related to use of python libraries, they are
# not qualities of a cloud.
#
# NOTE(harlowja): update a in-memory dict, before updating
# the global one so that other callers of get_defaults do not
# see the partially filled one.
tmp_defaults = dict(
api_timeout=None,
verify=True,
cacert=None,
cert=None,
key=None,
)
with open(_json_path, 'r') as json_file:
updates = json.load(json_file)
if updates is not None:
tmp_defaults.update(updates)
_defaults = tmp_defaults
return tmp_defaults.copy()