Source code for heat.engine.template_files

#    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
#    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.

import collections
import weakref

from heat.common import context
from heat.common import exception
from heat.common.i18n import _
from heat.db.sqlalchemy import api as db_api
from heat.objects import raw_template_files

_d = weakref.WeakValueDictionary()

[docs]class ReadOnlyDict(dict): def __setitem__(self, key): raise ValueError("Attempted to write to internal TemplateFiles cache")
[docs]class TemplateFiles(collections.Mapping): def __init__(self, files): self.files = None self.files_id = None if files is None: return if isinstance(files, TemplateFiles): self.files_id = files.files_id self.files = files.files return if isinstance(files, int): self.files_id = files if self.files_id in _d: self.files = _d[self.files_id] return if not isinstance(files, dict): raise ValueError(_('Expected dict, got %(cname)s for files, ' '(value is %(val)s)') % {'cname': files.__class__, 'val': str(files)}) # the dict has not been persisted as a raw_template_files DB obj # yet, so no self.files_id self.files = ReadOnlyDict(files) def __getitem__(self, key): self._refresh_if_needed() if self.files is None: raise KeyError return self.files[key] def __setitem__(self, key, value): self.update({key: value}) def __len__(self): self._refresh_if_needed() if not self.files: return 0 return len(self.files) def __contains__(self, key): self._refresh_if_needed() if not self.files: return False return key in self.files def __iter__(self): self._refresh_if_needed() if self.files is None: return iter(ReadOnlyDict({})) return iter(self.files) def _refresh_if_needed(self): # retrieve files from DB if needed if self.files_id is None: return if self.files_id in _d: self.files = _d[self.files_id] return self._refresh() def _refresh(self): ctxt = context.get_admin_context() rtf_obj = db_api.raw_template_files_get(ctxt, self.files_id) _files_dict = ReadOnlyDict(rtf_obj.files) self.files = _files_dict _d[self.files_id] = _files_dict
[docs] def store(self, ctxt): if not self.files or self.files_id is not None: # Do not to persist an empty raw_template_files obj. If we # already have a not null self.files_id, the (immutable) # raw_templated_object has already been persisted so just # return the id. return self.files_id rtf_obj = raw_template_files.RawTemplateFiles.create( ctxt, {'files': self.files}) self.files_id = _d[self.files_id] = self.files return self.files_id
[docs] def update(self, files): # Sets up the next call to store() to create a new # raw_template_files DB obj. It seems like we *could* just # update the existing raw_template_files obj, but the problem # with that is other heat-engine processes' _d dictionaries # would have stale data for a given with # no way of knowing whether that data should be refreshed or # not. So, just avoid the potential for weird race conditions # and create another DB obj in the next store(). if len(files) == 0: return if not isinstance(files, dict): raise ValueError(_('Expected dict, got %(cname)s for files, ' '(value is %(val)s)') % {'cname': files.__class__, 'val': str(files)}) self._refresh_if_needed() if self.files: new_files = self.files.copy() new_files.update(files) else: new_files = files self.files_id = None # not persisted yet self.files = ReadOnlyDict(new_files)
[docs]def get_files_from_container(cnxt, files_container, files=None): if files is None: files = {} else: files = files.copy() swift_plugin = cnxt.clients.client_plugin('swift') if not swift_plugin: raise exception.ClientNotAvailable(client_name='swift') new_files = swift_plugin.get_files_from_container(files_container, list(files.keys())) new_files.update(files) return new_files