tacker/tacker/db/db_base.py
Kanagaraj Manickam 30a1d2464b Enables soft deletion for VIM, VNFD and VNF
implements blueprint: audit-support

Change-Id: Ia73389d76f7112fa7849a4904b3b2f32089406f0
Co-Authored-By: Vishwanath Jayaraman <vishwanathj@hotmail.com>
2016-08-20 04:23:30 +00:00

204 lines
8.4 KiB
Python

# Copyright (c) 2012 OpenStack Foundation.
# All Rights Reserved.
#
# 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.
import weakref
from six import iteritems
from sqlalchemy import sql
from tacker.common import exceptions as n_exc
from tacker.db import sqlalchemyutils
class CommonDbMixin(object):
"""Common methods used in core and service plugins."""
# Plugins, mixin classes implementing extension will register
# hooks into the dict below for "augmenting" the "core way" of
# building a query for retrieving objects from a model class.
# To this aim, the register_model_query_hook and unregister_query_hook
# from this class should be invoked
_model_query_hooks = {}
# This dictionary will store methods for extending attributes of
# api resources. Mixins can use this dict for adding their own methods
# TODO(salvatore-orlando): Avoid using class-level variables
_dict_extend_functions = {}
@classmethod
def register_model_query_hook(cls, model, name, query_hook, filter_hook,
result_filters=None):
"""Register a hook to be invoked when a query is executed.
Add the hooks to the _model_query_hooks dict. Models are the keys
of this dict, whereas the value is another dict mapping hook names to
callables performing the hook.
Each hook has a "query" component, used to build the query expression
and a "filter" component, which is used to build the filter expression.
Query hooks take as input the query being built and return a
transformed query expression.
Filter hooks take as input the filter expression being built and return
a transformed filter expression
"""
model_hooks = cls._model_query_hooks.get(model)
if not model_hooks:
# add key to dict
model_hooks = {}
cls._model_query_hooks[model] = model_hooks
model_hooks[name] = {'query': query_hook, 'filter': filter_hook,
'result_filters': result_filters}
@property
def safe_reference(self):
"""Return a weakref to the instance.
Minimize the potential for the instance persisting
unnecessarily in memory by returning a weakref proxy that
won't prevent deallocation.
"""
return weakref.proxy(self)
def _model_query(self, context, model):
query = context.session.query(model)
# define basic filter condition for model query
# NOTE(jkoelker) non-admin queries are scoped to their tenant_id
# NOTE(salvatore-orlando): unless the model allows for shared objects
query_filter = None
if not context.is_admin and hasattr(model, 'tenant_id'):
if hasattr(model, 'shared'):
query_filter = ((model.tenant_id == context.tenant_id) |
(model.shared == sql.true()))
else:
query_filter = (model.tenant_id == context.tenant_id)
# Execute query hooks registered from mixins and plugins
for _name, hooks in iteritems(self._model_query_hooks.get(model, {})):
query_hook = hooks.get('query')
if isinstance(query_hook, basestring):
query_hook = getattr(self, query_hook, None)
if query_hook:
query = query_hook(context, model, query)
filter_hook = hooks.get('filter')
if isinstance(filter_hook, basestring):
filter_hook = getattr(self, filter_hook, None)
if filter_hook:
query_filter = filter_hook(context, model, query_filter)
# NOTE(salvatore-orlando): 'if query_filter' will try to evaluate the
# condition, raising an exception
if query_filter is not None:
query = query.filter(query_filter)
# Don't list the deleted entries
if hasattr(model, 'deleted_at'):
query = query.filter_by(deleted_at=None)
return query
def _fields(self, resource, fields):
if fields:
return dict(((key, item) for key, item in resource.items()
if key in fields))
return resource
def _get_tenant_id_for_create(self, context, resource):
if context.is_admin and 'tenant_id' in resource:
tenant_id = resource['tenant_id']
elif ('tenant_id' in resource and
resource['tenant_id'] != context.tenant_id):
reason = _('Cannot create resource for another tenant')
raise n_exc.AdminRequired(reason=reason)
else:
tenant_id = context.tenant_id
return tenant_id
def _get_by_id(self, context, model, id):
query = self._model_query(context, model)
return query.filter(model.id == id).one()
def _apply_filters_to_query(self, query, model, filters):
if filters:
for key, value in iteritems(filters):
column = getattr(model, key, None)
if column:
query = query.filter(column.in_(value))
for _name, hooks in iteritems(
self._model_query_hooks.get(model, {})):
result_filter = hooks.get('result_filters', None)
if isinstance(result_filter, basestring):
result_filter = getattr(self, result_filter, None)
if result_filter:
query = result_filter(query, filters)
return query
def _apply_dict_extend_functions(self, resource_type,
response, db_object):
for func in self._dict_extend_functions.get(
resource_type, []):
args = (response, db_object)
if isinstance(func, basestring):
func = getattr(self, func, None)
else:
# must call unbound method - use self as 1st argument
args = (self,) + args
if func:
func(*args)
def _get_collection_query(self, context, model, filters=None,
sorts=None, limit=None, marker_obj=None,
page_reverse=False):
collection = self._model_query(context, model)
collection = self._apply_filters_to_query(collection, model, filters)
if limit and page_reverse and sorts:
sorts = [(s[0], not s[1]) for s in sorts]
collection = sqlalchemyutils.paginate_query(collection, model, limit,
sorts,
marker_obj=marker_obj)
return collection
def _get_collection(self, context, model, dict_func, filters=None,
fields=None, sorts=None, limit=None, marker_obj=None,
page_reverse=False):
query = self._get_collection_query(context, model, filters=filters,
sorts=sorts,
limit=limit,
marker_obj=marker_obj,
page_reverse=page_reverse)
items = [dict_func(c, fields) for c in query]
if limit and page_reverse:
items.reverse()
return items
def _get_collection_count(self, context, model, filters=None):
return self._get_collection_query(context, model, filters).count()
def _get_marker_obj(self, context, resource, limit, marker):
if limit and marker:
return getattr(self, '_get_%s' % resource)(context, marker)
return None
def _filter_non_model_columns(self, data, model):
"""Removes attributes from data.
Remove all the attributes from data which are not columns of
the model passed as second parameter.
"""
columns = [c.name for c in model.__table__.columns]
return dict((k, v) for (k, v) in
iteritems(data) if k in columns)