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# Copyright (c) 2013 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.
"""Metadata cache.
Files within the cache as passed to hook commands invoked by
os-collect-command.
The cache also stores the last version of a file in order to detect changes
that occur - hook commands are only automatically invoked when one or more
metadata sources have changed things.
The last version of a file is available under $FILENAME.last.
"""
import json
import os
import shutil
import tempfile
from oslo_config import cfg
def get_path(name):
return os.path.join(cfg.CONF.cachedir, '%s.json' % name)
def store(name, content):
if not os.path.exists(cfg.CONF.cachedir):
os.mkdir(cfg.CONF.cachedir)
changed = False
dest_path = get_path(name)
orig_path = '%s.orig' % dest_path
last_path = '%s.last' % dest_path
with tempfile.NamedTemporaryFile(
dir=cfg.CONF.cachedir,
delete=False) as new:
new.write(json.dumps(content, indent=1).encode('utf-8'))
new.flush()
if not os.path.exists(orig_path):
shutil.copy(new.name, orig_path)
changed = True
os.rename(new.name, dest_path)
if not changed:
if os.path.exists(last_path):
with open(last_path) as then:
then_value = json.load(then)
if then_value != content:
changed = True
else:
changed = True
return (changed, dest_path)
def commit(name):
dest_path = get_path(name)
if os.path.exists(dest_path):
shutil.copy(dest_path, '%s.last' % dest_path)
def store_meta_list(name, data_keys):
'''Store a json list of the files that should be present after store.'''
final_list = [get_path(k) for k in data_keys]
dest = get_path(name)
with tempfile.NamedTemporaryFile(prefix='tmp_meta_list.',
dir=os.path.dirname(dest),
delete=False) as out:
out.write(json.dumps(final_list).encode('utf-8'))
os.rename(out.name, dest)
return dest
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