d597ee271e
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
37 lines
1.2 KiB
Python
37 lines
1.2 KiB
Python
# Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import json
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import os
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import threading
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_json_path = os.path.join(
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os.path.dirname(os.path.realpath(__file__)), 'constructors.json')
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_class_mapping = None
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_class_mapping_lock = threading.Lock()
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def get_constructor_mapping():
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global _class_mapping
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if _class_mapping is not None:
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return _class_mapping.copy()
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with _class_mapping_lock:
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if _class_mapping is not None:
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return _class_mapping.copy()
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tmp_class_mapping = {}
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with open(_json_path, 'r') as json_file:
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tmp_class_mapping.update(json.load(json_file))
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_class_mapping = tmp_class_mapping
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return tmp_class_mapping.copy()
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