85 lines
2.9 KiB
Python
85 lines
2.9 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 shall not be used by external projects. It will be moved
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to neutron-lib in due course, and then it can be used from there.
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"""
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import contextlib
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from neutron_lib.db import api as db_api
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from neutron_lib.db import utils as db_utils
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from oslo_log import log as logging
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from oslo_utils import excutils
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LOG = logging.getLogger(__name__)
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@contextlib.contextmanager
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def _noop_context_manager():
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yield
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def safe_creation(context, create_fn, delete_fn, create_bindings,
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transaction=True):
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'''This function wraps logic of object creation in safe atomic way.
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In case of exception, object is deleted.
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More information when this method could be used can be found in
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developer guide - Effective Neutron: Database interaction section.
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https://docs.openstack.org/neutron/latest/contributor/effective_neutron.html
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:param context: context
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:param create_fn: function without arguments that is called to create
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object and returns this object.
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:param delete_fn: function that is called to delete an object. It is
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called with object's id field as an argument.
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:param create_bindings: function that is called to create bindings for
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an object. It is called with object's id field as an argument.
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:param transaction: if true the whole operation will be wrapped in a
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transaction. if false, no transaction will be used.
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'''
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cm = (db_api.CONTEXT_WRITER.using(context)
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if transaction else _noop_context_manager())
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with cm:
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obj = create_fn()
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try:
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value = create_bindings(obj['id'])
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except Exception:
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with excutils.save_and_reraise_exception():
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try:
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delete_fn(obj['id'])
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except Exception as e:
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LOG.error("Cannot clean up created object %(obj)s. "
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"Exception: %(exc)s", {'obj': obj['id'],
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'exc': e})
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return obj, value
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def model_query(context, model):
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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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query_filter = (model.tenant_id == context.tenant_id)
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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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