59 lines
1.7 KiB
Python
59 lines
1.7 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 cache: dictionary to hold opaque cache.
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:param filename: the file path to read.
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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 cache: dictionary to hold opaque cache.
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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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