123 lines
3.2 KiB
Python
123 lines
3.2 KiB
Python
# Copyright 2014 Huawei Technologies Co. Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Provider interface to manipulate database."""
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import logging
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from contextlib import contextmanager
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from sqlalchemy import create_engine
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from sqlalchemy.orm import scoped_session
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from sqlalchemy.orm import sessionmaker
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from threading import local
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from compass.db import model
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from compass.utils import setting_wrapper as setting
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ENGINE = create_engine(setting.SQLALCHEMY_DATABASE_URI, convert_unicode=True)
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SESSION = sessionmaker(autocommit=False, autoflush=False)
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SESSION.configure(bind=ENGINE)
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SCOPED_SESSION = scoped_session(SESSION)
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SESSION_HOLDER = local()
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model.BASE.query = SCOPED_SESSION.query_property()
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def init(database_url):
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"""Initialize database.
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:param database_url: string, database url.
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"""
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global ENGINE
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global SCOPED_SESSION
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ENGINE = create_engine(database_url, convert_unicode=True)
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SESSION.configure(bind=ENGINE)
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SCOPED_SESSION = scoped_session(SESSION)
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model.BASE.query = SCOPED_SESSION.query_property()
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def in_session():
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"""check if in database session scope."""
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if hasattr(SESSION_HOLDER, 'session'):
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return True
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else:
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return False
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@contextmanager
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def session():
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"""database session scope.
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.. note::
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To operate database, it should be called in database session.
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"""
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if hasattr(SESSION_HOLDER, 'session'):
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logging.error('we are already in session')
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raise Exception('session already exist')
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else:
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new_session = SCOPED_SESSION()
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SESSION_HOLDER.session = new_session
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try:
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yield new_session
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new_session.commit()
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except Exception as error:
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new_session.rollback()
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logging.error('failed to commit session')
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logging.exception(error)
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raise error
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finally:
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new_session.close()
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SCOPED_SESSION.remove()
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del SESSION_HOLDER.session
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def current_session():
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"""Get the current session scope when it is called.
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:return: database session.
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"""
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try:
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return SESSION_HOLDER.session
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except Exception as error:
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logging.error('It is not in the session scope')
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logging.exception(error)
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raise error
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def create_db():
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"""Create database."""
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model.BASE.metadata.create_all(bind=ENGINE)
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def drop_db():
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"""Drop database."""
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model.BASE.metadata.drop_all(bind=ENGINE)
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def create_table(table):
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"""Create table.
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:param table: Class of the Table defined in the model.
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"""
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table.__table__.create(bind=ENGINE, checkfirst=True)
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def drop_table(table):
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"""Drop table.
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:param table: Class of the Table defined in the model.
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"""
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table.__table__.drop(bind=ENGINE, checkfirst=True)
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