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# Copyright (c) 2011 X.commerce, a business unit of eBay Inc.
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Piston Cloud Computing, Inc.
# Copyright 2012 Cloudscaling Group, Inc.
# 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.
"""
SQLAlchemy models.
"""
import six
from oslo_utils import timeutils
from sqlalchemy import Column
from sqlalchemy import DateTime
from sqlalchemy.orm import object_mapper
from oslo_db.sqlalchemy import types
class ModelBase(six.Iterator):
"""Base class for models."""
__table_initialized__ = False
def save(self, session):
"""Save this object."""
# NOTE(boris-42): This part of code should be look like:
# session.add(self)
# session.flush()
# But there is a bug in sqlalchemy and eventlet that
# raises NoneType exception if there is no running
# transaction and rollback is called. As long as
# sqlalchemy has this bug we have to create transaction
# explicitly.
with session.begin(subtransactions=True):
session.add(self)
session.flush()
def __setitem__(self, key, value):
setattr(self, key, value)
def __getitem__(self, key):
return getattr(self, key)
def __contains__(self, key):
# Don't use hasattr() because hasattr() catches any exception, not only
# AttributeError. We want to passthrough SQLAlchemy exceptions
# (ex: sqlalchemy.orm.exc.DetachedInstanceError).
try:
getattr(self, key)
except AttributeError:
return False
else:
return True
def get(self, key, default=None):
return getattr(self, key, default)
@property
def _extra_keys(self):
"""Specifies custom fields
Subclasses can override this property to return a list
of custom fields that should be included in their dict
representation.
For reference check tests/db/sqlalchemy/test_models.py
"""
return []
def __iter__(self):
columns = list(dict(object_mapper(self).columns).keys())
# NOTE(russellb): Allow models to specify other keys that can be looked
# up, beyond the actual db columns. An example would be the 'name'
# property for an Instance.
columns.extend(self._extra_keys)
return ModelIterator(self, iter(columns))
def update(self, values):
"""Make the model object behave like a dict."""
for k, v in values.items():
setattr(self, k, v)
def _as_dict(self):
"""Make the model object behave like a dict.
Includes attributes from joins.
"""
local = dict((key, value) for key, value in self)
joined = dict([(k, v) for k, v in self.__dict__.items()
if not k[0] == '_'])
local.update(joined)
return local
def iteritems(self):
"""Make the model object behave like a dict."""
return self._as_dict().items()
def items(self):
"""Make the model object behave like a dict."""
return self._as_dict().items()
def keys(self):
"""Make the model object behave like a dict."""
return [key for key, value in self.iteritems()]
class ModelIterator(six.Iterator):
def __init__(self, model, columns):
self.model = model
self.i = columns
def __iter__(self):
return self
# In Python 3, __next__() has replaced next().
def __next__(self):
n = six.advance_iterator(self.i)
return n, getattr(self.model, n)
class TimestampMixin(object):
created_at = Column(DateTime, default=lambda: timeutils.utcnow())
updated_at = Column(DateTime, onupdate=lambda: timeutils.utcnow())
class SoftDeleteMixin(object):
deleted_at = Column(DateTime)
deleted = Column(types.SoftDeleteInteger, default=0)
def soft_delete(self, session):
"""Mark this object as deleted."""
self.deleted = self.id
self.deleted_at = timeutils.utcnow()
self.save(session=session)
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