2e79681670
Currently, sqlalchemy.ModelBase.__contains__() catches any exception,
and by doing that, it hides real bugs. For example, a Nova unit test
raises the following error, but __contains__() simply returns False:
sqlalchemy.orm.exc.DetachedInstanceError: Parent instance
<InstanceExtra at 0x7fea635bc5f8> is not bound to a Session;
deferred load operation of attribute 'pci_requests' cannot proceed
On Python 3, hasattr() calls getattr(): it returns True if getattr()
succeeds, False if getattr() raises an AttributeError, or passes
through the exception, if getattr() failed for a different reason.
On Python 2, hasattr() also calls getattr(), but it catches *any*
exception.
This change replaces hasattr() with getattr(), and it only catches
AttributeError as Python 3, so passes through sqlalchemy exceptions.
Add an unit test to test the new behaviour.
Closes-Bug: #1469225
Change-Id: If9c3ccc03f1dc9746936b0b83ea132508491e577
149 lines
4.7 KiB
Python
149 lines
4.7 KiB
Python
# Copyright (c) 2011 X.commerce, a business unit of eBay Inc.
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# Copyright 2011 Piston Cloud Computing, Inc.
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# Copyright 2012 Cloudscaling Group, Inc.
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# All Rights Reserved.
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#
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# 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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SQLAlchemy models.
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"""
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import six
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from oslo_utils import timeutils
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from sqlalchemy import Column, Integer
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from sqlalchemy import DateTime
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from sqlalchemy.orm import object_mapper
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class ModelBase(six.Iterator):
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"""Base class for models."""
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__table_initialized__ = False
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def save(self, session):
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"""Save this object."""
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# NOTE(boris-42): This part of code should be look like:
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# session.add(self)
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# session.flush()
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# But there is a bug in sqlalchemy and eventlet that
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# raises NoneType exception if there is no running
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# transaction and rollback is called. As long as
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# sqlalchemy has this bug we have to create transaction
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# explicitly.
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with session.begin(subtransactions=True):
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session.add(self)
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session.flush()
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def __setitem__(self, key, value):
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setattr(self, key, value)
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def __getitem__(self, key):
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return getattr(self, key)
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def __contains__(self, key):
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# Don't use hasattr() because hasattr() catches any exception, not only
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# AttributeError. We want to passthrough SQLAlchemy exceptions
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# (ex: sqlalchemy.orm.exc.DetachedInstanceError).
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try:
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getattr(self, key)
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except AttributeError:
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return False
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else:
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return True
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def get(self, key, default=None):
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return getattr(self, key, default)
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@property
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def _extra_keys(self):
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"""Specifies custom fields
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Subclasses can override this property to return a list
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of custom fields that should be included in their dict
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representation.
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For reference check tests/db/sqlalchemy/test_models.py
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"""
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return []
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def __iter__(self):
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columns = list(dict(object_mapper(self).columns).keys())
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# NOTE(russellb): Allow models to specify other keys that can be looked
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# up, beyond the actual db columns. An example would be the 'name'
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# property for an Instance.
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columns.extend(self._extra_keys)
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return ModelIterator(self, iter(columns))
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def update(self, values):
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"""Make the model object behave like a dict."""
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for k, v in six.iteritems(values):
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setattr(self, k, v)
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def _as_dict(self):
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"""Make the model object behave like a dict.
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Includes attributes from joins.
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"""
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local = dict((key, value) for key, value in self)
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joined = dict([(k, v) for k, v in six.iteritems(self.__dict__)
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if not k[0] == '_'])
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local.update(joined)
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return local
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def iteritems(self):
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"""Make the model object behave like a dict."""
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return six.iteritems(self._as_dict())
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def items(self):
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"""Make the model object behave like a dict."""
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return self._as_dict().items()
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def keys(self):
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"""Make the model object behave like a dict."""
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return [key for key, value in self.iteritems()]
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class ModelIterator(six.Iterator):
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def __init__(self, model, columns):
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self.model = model
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self.i = columns
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def __iter__(self):
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return self
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# In Python 3, __next__() has replaced next().
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def __next__(self):
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n = six.advance_iterator(self.i)
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return n, getattr(self.model, n)
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class TimestampMixin(object):
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created_at = Column(DateTime, default=lambda: timeutils.utcnow())
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updated_at = Column(DateTime, onupdate=lambda: timeutils.utcnow())
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class SoftDeleteMixin(object):
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deleted_at = Column(DateTime)
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deleted = Column(Integer, default=0)
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def soft_delete(self, session):
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"""Mark this object as deleted."""
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self.deleted = self.id
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self.deleted_at = timeutils.utcnow()
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self.save(session=session)
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