4bdefc2041
Smart hooks may want to perform delta analysis on metadata, and tests want to be able to tell if the cache is updated it's previous state, so we should make the presence and name of the old versions of the files a stable interface. Change-Id: Ia29c1ef9e10308d6461dae7823c5f497f6b90122
77 lines
2.2 KiB
Python
77 lines
2.2 KiB
Python
# Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Metadata cache.
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Files within the cache as passed to hook commands invoked by
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os-collect-command.
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The cache also stores the last version of a file in order to detect changes
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that occur - hook commands are only automatically invoked when one or more
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metadata sources have changed things.
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The last version of a file is available under $FILENAME.last.
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"""
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import json
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import os
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import shutil
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import tempfile
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from oslo.config import cfg
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def get_path(name):
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return os.path.join(cfg.CONF.cachedir, '%s.json' % name)
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def store(name, content):
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if not os.path.exists(cfg.CONF.cachedir):
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os.mkdir(cfg.CONF.cachedir)
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changed = False
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dest_path = get_path(name)
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orig_path = '%s.orig' % dest_path
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last_path = '%s.last' % dest_path
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with tempfile.NamedTemporaryFile(
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dir=cfg.CONF.cachedir,
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delete=False) as new:
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new.write(json.dumps(content, indent=1))
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new.flush()
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if not os.path.exists(orig_path):
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shutil.copy(new.name, orig_path)
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changed = True
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os.rename(new.name, dest_path)
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if not changed:
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with open(dest_path) as now:
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if os.path.exists(last_path):
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with open(last_path) as then:
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for now_line in now:
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then_line = then.next()
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if then_line != now_line:
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changed = True
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break
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else:
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changed = True
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return (changed, dest_path)
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def commit(name):
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dest_path = get_path(name)
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if os.path.exists(dest_path):
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shutil.copy(dest_path, '%s.last' % dest_path)
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