7ee4f409e1
Instead of having a library have a global (and not garbage collectable) file cache that is only used by enforcers and no other code have the file cache be per-enforcer so that it can be garbage collected when the enforcer drops from the scope its used in. This also removes one more usage of global state with instance specific state, which makes things easier to test and easier to isolate problems in (the less things that can be 'touched at a distance' the better). Change-Id: I208b08ae00e0337b594ece0f2b335d4de9f7392b
56 lines
1.6 KiB
Python
56 lines
1.6 KiB
Python
# Copyright 2011 OpenStack Foundation.
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# All Rights Reserved.
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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 logging
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import os
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LOG = logging.getLogger(__name__)
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def read_cached_file(cache, filename, force_reload=False):
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"""Read from a file if it has been modified.
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:param force_reload: Whether to reload the file.
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:returns: A tuple with a boolean specifying if the data is fresh
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or not.
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"""
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if force_reload:
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delete_cached_file(cache, filename)
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reloaded = False
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mtime = os.path.getmtime(filename)
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cache_info = cache.setdefault(filename, {})
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if not cache_info or mtime > cache_info.get('mtime', 0):
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LOG.debug("Reloading cached file %s", filename)
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with open(filename) as fap:
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cache_info['data'] = fap.read()
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cache_info['mtime'] = mtime
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reloaded = True
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return (reloaded, cache_info['data'])
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def delete_cached_file(cache, filename):
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"""Delete cached file if present.
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:param filename: filename to delete
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"""
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try:
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del cache[filename]
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except KeyError:
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pass
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