5aad62cbc0
This commit introduces a new method 'get_values' in neutron_lib.db.model_query module. Callers can leverage this method to fetch specific field of a OVO. Related patch in Neutron: https://review.openstack.org/#/c/610182/ Change-Id: I524c7101fa2dcbc5bd78587bf1fc8107faca70b5
330 lines
14 KiB
Python
330 lines
14 KiB
Python
# 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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"""
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NOTE: This module is a temporary shim until networking projects move to
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versioned objects at which point this module shouldn't be needed.
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"""
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from oslo_db.sqlalchemy import utils as sa_utils
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from sqlalchemy import sql, or_, and_
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from sqlalchemy.ext import associationproxy
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from neutron_lib._i18n import _
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from neutron_lib.api import attributes
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from neutron_lib.db import utils as db_utils
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from neutron_lib import exceptions as n_exc
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from neutron_lib.objects import utils as obj_utils
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from neutron_lib.utils import helpers
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# Classes implementing extensions will register hooks into this dictionary
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# for "augmenting" the "core way" of building a query for retrieving objects
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# from a model class. Hooks are registered by invoking register_hook().
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_model_query_hooks = {
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# model1 : {
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# hook1: {
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# 'query': query_hook,
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# 'filter': filter_hook,
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# 'result_filters': result_filters
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# },
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# hook2: {
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# 'query': query_hook,
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# 'filter': filter_hook,
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# 'result_filters': result_filters
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# },
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# ...
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# },
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# model2 : {
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# hook1: {
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# 'query': query_hook,
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# 'filter': filter_hook,
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# 'result_filters': result_filters
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# },
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# hook2: {
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# 'query': query_hook,
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# 'filter': filter_hook,
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# 'result_filters': result_filters
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# },
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# ...
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# },
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# ...
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}
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def register_hook(model, name, query_hook, filter_hook,
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result_filters=None):
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"""Register a hook to be invoked when a query is executed.
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Adds the hook components to the _model_query_hooks dict. Models are the
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keys of this dict, whereas the value is another dict mapping hook names
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to callables performing the hook.
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:param model: The DB Model that the hook applies to.
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:param name: A name for the hook.
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:param query_hook: The method to be called to augment the query.
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:param filter_hook: A method to be called to augment the query filter.
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:param result_filters: A Method to be called to filter the query result.
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:returns: None.
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"""
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if callable(query_hook):
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query_hook = helpers.make_weak_ref(query_hook)
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if callable(filter_hook):
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filter_hook = helpers.make_weak_ref(filter_hook)
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if callable(result_filters):
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result_filters = helpers.make_weak_ref(result_filters)
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_model_query_hooks.setdefault(model, {})[name] = {
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'query': query_hook,
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'filter': filter_hook,
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'result_filters': result_filters
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}
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def get_hooks(model):
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"""Retrieve the model query hooks for a model.
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:param model: The DB Model to look up for query hooks.
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:returns: list of hooks
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"""
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return _model_query_hooks.get(model, {}).values()
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def query_with_hooks(context, model, field=None):
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"""Query with hooks using the said context and model.
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:param context: The context to use for the DB session.
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:param model: The model to query.
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:param field: The column.
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:returns: The query with hooks applied to it.
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"""
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if field:
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if hasattr(model, field):
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field = getattr(model, field)
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else:
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msg = _("'%s' is not supported as field") % field
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raise n_exc.InvalidInput(error_message=msg)
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query = context.session.query(field)
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else:
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query = context.session.query(model)
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# define basic filter condition for model query
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query_filter = None
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if db_utils.model_query_scope_is_project(context, model):
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if hasattr(model, 'rbac_entries'):
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query = query.outerjoin(model.rbac_entries)
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rbac_model = model.rbac_entries.property.mapper.class_
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query_filter = (
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(model.tenant_id == context.tenant_id) |
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((rbac_model.action == 'access_as_shared') &
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((rbac_model.target_tenant == context.tenant_id) |
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(rbac_model.target_tenant == '*'))))
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elif hasattr(model, 'shared'):
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query_filter = ((model.tenant_id == context.tenant_id) |
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(model.shared == sql.true()))
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else:
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query_filter = (model.tenant_id == context.tenant_id)
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# Execute query hooks registered from mixins and plugins
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for hook in get_hooks(model):
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query_hook = helpers.resolve_ref(hook.get('query'))
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if query_hook:
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query = query_hook(context, model, query)
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filter_hook = helpers.resolve_ref(hook.get('filter'))
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if filter_hook:
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query_filter = filter_hook(context, model, query_filter)
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# NOTE(salvatore-orlando): 'if query_filter' will try to evaluate the
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# condition, raising an exception
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if query_filter is not None:
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query = query.filter(query_filter)
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return query
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def get_by_id(context, model, object_id):
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"""Query the said model with the given context for a specific object.
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:param context: The context to use in the query.
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:param model: The model to query.
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:param object_id: The ID of the object to query for.
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:returns: The object with the give object_id for the said model.
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"""
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query = query_with_hooks(context=context, model=model)
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return query.filter(model.id == object_id).one()
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def apply_filters(query, model, filters, context=None):
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"""Apply filters to a query.
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:param query: The query to apply filters to.
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:param model: The model for the query.
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:param filters: The filters to apply.
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:param context: The context to use for the DB session.
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:returns: The query with filters applied to it.
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"""
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if filters:
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for key, value in filters.items():
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column = getattr(model, key, None)
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# NOTE(kevinbenton): if column is a hybrid property that
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# references another expression, attempting to convert to
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# a boolean will fail so we must compare to None.
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# See "An Important Expression Language Gotcha" in:
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# docs.sqlalchemy.org/en/rel_0_9/changelog/migration_06.html
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if column is not None:
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if not value:
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query = query.filter(sql.false())
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return query
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if isinstance(column, associationproxy.AssociationProxy):
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# association proxies don't support in_ so we have to
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# do multiple equals matches
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query = query.filter(
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or_(*[column == v for v in value]))
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elif isinstance(value, obj_utils.FilterObj):
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query = query.filter(value.filter(column))
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elif None in value:
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# in_() operator does not support NULL element so we have
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# to do multiple equals matches
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query = query.filter(
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or_(*[column == v for v in value]))
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else:
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query = query.filter(column.in_(value))
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elif key == 'shared' and hasattr(model, 'rbac_entries'):
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# translate a filter on shared into a query against the
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# object's rbac entries
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rbac = model.rbac_entries.property.mapper.class_
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matches = [rbac.target_tenant == '*']
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if context:
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matches.append(rbac.target_tenant == context.tenant_id)
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# any 'access_as_shared' records that match the
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# wildcard or requesting tenant
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is_shared = and_(rbac.action == 'access_as_shared',
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or_(*matches))
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if not value[0]:
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# NOTE(kevinbenton): we need to find objects that don't
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# have an entry that matches the criteria above so
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# we use a subquery to exclude them.
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# We can't just filter the inverse of the query above
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# because that will still give us a network shared to
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# our tenant (or wildcard) if it's shared to another
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# tenant.
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# This is the column joining the table to rbac via
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# the object_id. We can't just use model.id because
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# subnets join on network.id so we have to inspect the
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# relationship.
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join_cols = model.rbac_entries.property.local_columns
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oid_col = list(join_cols)[0]
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is_shared = ~oid_col.in_(
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query.session.query(rbac.object_id).filter(is_shared)
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)
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elif (not context or
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not db_utils.model_query_scope_is_project(
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context, model)):
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# we only want to join if we aren't using the subquery
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# and if we aren't already joined because this is a
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# scoped query
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query = query.outerjoin(model.rbac_entries)
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query = query.filter(is_shared)
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for hook in get_hooks(model):
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result_filter = helpers.resolve_ref(
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hook.get('result_filters', None))
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if result_filter:
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query = result_filter(query, filters)
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return query
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def get_collection_query(context, model, filters=None, sorts=None, limit=None,
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marker_obj=None, page_reverse=False):
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"""Get a collection query.
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:param context: The context to use for the DB session.
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:param model: The model to use.
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:param filters: The filters to apply in the query.
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:param sorts: The sort keys to use.
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:param limit: The limit associated with the query.
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:param marker_obj: The marker object if applicable.
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:param page_reverse: If reverse paging should be used.
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:returns: A paginated query for the said model.
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"""
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collection = query_with_hooks(context, model)
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collection = apply_filters(collection, model, filters, context)
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if sorts:
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sort_keys = db_utils.get_and_validate_sort_keys(sorts, model)
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sort_dirs = db_utils.get_sort_dirs(sorts, page_reverse)
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# we always want deterministic results for sorted queries
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# so add unique keys to limit queries when present.
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# (http://docs.sqlalchemy.org/en/latest/orm/
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# loading_relationships.html#subqueryload-ordering)
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# (http://docs.sqlalchemy.org/en/latest/faq/
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# ormconfiguration.html#faq-subqueryload-limit-sort)
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for k in _unique_keys(model):
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if k not in sort_keys:
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sort_keys.append(k)
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sort_dirs.append('asc')
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collection = sa_utils.paginate_query(collection, model, limit,
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marker=marker_obj,
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sort_keys=sort_keys,
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sort_dirs=sort_dirs)
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return collection
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def _unique_keys(model):
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# just grab first set of unique keys and use them.
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# if model has no unqiue sets, 'paginate_query' will
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# warn if sorting is unstable
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uk_sets = sa_utils.get_unique_keys(model)
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return uk_sets[0] if uk_sets else []
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def get_collection(context, model, dict_func,
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filters=None, fields=None,
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sorts=None, limit=None, marker_obj=None,
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page_reverse=False):
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"""Get a collection for a said model.
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:param context: The context to use for the DB session.
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:param model: The model for the collection.
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:param dict_func: The function used to build the collection dict.
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:param filters: The filters to apply.
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:param fields: The fields to collect.
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:param sorts: The sort keys to use.
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:param limit: The limit for the query if applicable.
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:param marker_obj: The marker object if applicable.
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:param page_reverse: If reverse paging should be used.
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:returns: A list of dicts where each dict is an object in the collection.
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"""
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query = get_collection_query(context, model,
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filters=filters, sorts=sorts,
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limit=limit, marker_obj=marker_obj,
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page_reverse=page_reverse)
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items = [
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attributes.populate_project_info(
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dict_func(c, fields) if dict_func else c)
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for c in query
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]
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if limit and page_reverse:
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items.reverse()
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return items
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def get_values(context, model, field, filters=None):
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query = query_with_hooks(context, model, field=field)
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query = apply_filters(query, model, filters, context)
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return [c[0] for c in query]
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def get_collection_count(context, model, filters=None):
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"""Get the count for a specific collection.
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:param context: The context to use for the DB session.
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:param model: The model for the query.
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:param filters: The filters to apply.
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:returns: The number of objects for said model with filters applied.
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"""
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return get_collection_query(context, model, filters).count()
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