279 lines
10 KiB
Python
279 lines
10 KiB
Python
# coding: utf-8
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#
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# Copyright (c) 2013 OpenStack Foundation
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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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# Base on code in migrate/changeset/databases/sqlite.py which is under
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# the following license:
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#
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# The MIT License
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#
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# Copyright (c) 2009 Evan Rosson, Jan Dittberner, Domen Kožar
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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import os
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import re
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from migrate.changeset import ansisql
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from migrate.changeset.databases import sqlite
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from migrate import exceptions as versioning_exceptions
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from migrate.versioning import api as versioning_api
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from migrate.versioning.repository import Repository
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import sqlalchemy
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from sqlalchemy.schema import UniqueConstraint
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from heat.openstack.common.db import exception
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from heat.openstack.common.gettextutils import _
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def _get_unique_constraints(self, table):
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"""Retrieve information about existing unique constraints of the table
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This feature is needed for _recreate_table() to work properly.
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Unfortunately, it's not available in sqlalchemy 0.7.x/0.8.x.
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"""
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data = table.metadata.bind.execute(
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"""SELECT sql
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FROM sqlite_master
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WHERE
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type='table' AND
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name=:table_name""",
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table_name=table.name
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).fetchone()[0]
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UNIQUE_PATTERN = "CONSTRAINT (\w+) UNIQUE \(([^\)]+)\)"
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return [
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UniqueConstraint(
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*[getattr(table.columns, c.strip(' "')) for c in cols.split(",")],
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name=name
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)
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for name, cols in re.findall(UNIQUE_PATTERN, data)
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]
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def _recreate_table(self, table, column=None, delta=None, omit_uniques=None):
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"""Recreate the table properly
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Unlike the corresponding original method of sqlalchemy-migrate this one
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doesn't drop existing unique constraints when creating a new one.
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"""
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table_name = self.preparer.format_table(table)
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# we remove all indexes so as not to have
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# problems during copy and re-create
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for index in table.indexes:
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index.drop()
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# reflect existing unique constraints
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for uc in self._get_unique_constraints(table):
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table.append_constraint(uc)
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# omit given unique constraints when creating a new table if required
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table.constraints = set([
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cons for cons in table.constraints
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if omit_uniques is None or cons.name not in omit_uniques
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])
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self.append('ALTER TABLE %s RENAME TO migration_tmp' % table_name)
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self.execute()
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insertion_string = self._modify_table(table, column, delta)
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table.create(bind=self.connection)
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self.append(insertion_string % {'table_name': table_name})
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self.execute()
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self.append('DROP TABLE migration_tmp')
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self.execute()
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def _visit_migrate_unique_constraint(self, *p, **k):
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"""Drop the given unique constraint
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The corresponding original method of sqlalchemy-migrate just
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raises NotImplemented error
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"""
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self.recreate_table(p[0].table, omit_uniques=[p[0].name])
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def patch_migrate():
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"""A workaround for SQLite's inability to alter things
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SQLite abilities to alter tables are very limited (please read
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http://www.sqlite.org/lang_altertable.html for more details).
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E. g. one can't drop a column or a constraint in SQLite. The
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workaround for this is to recreate the original table omitting
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the corresponding constraint (or column).
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sqlalchemy-migrate library has recreate_table() method that
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implements this workaround, but it does it wrong:
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- information about unique constraints of a table
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is not retrieved. So if you have a table with one
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unique constraint and a migration adding another one
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you will end up with a table that has only the
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latter unique constraint, and the former will be lost
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- dropping of unique constraints is not supported at all
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The proper way to fix this is to provide a pull-request to
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sqlalchemy-migrate, but the project seems to be dead. So we
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can go on with monkey-patching of the lib at least for now.
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"""
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# this patch is needed to ensure that recreate_table() doesn't drop
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# existing unique constraints of the table when creating a new one
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helper_cls = sqlite.SQLiteHelper
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helper_cls.recreate_table = _recreate_table
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helper_cls._get_unique_constraints = _get_unique_constraints
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# this patch is needed to be able to drop existing unique constraints
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constraint_cls = sqlite.SQLiteConstraintDropper
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constraint_cls.visit_migrate_unique_constraint = \
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_visit_migrate_unique_constraint
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constraint_cls.__bases__ = (ansisql.ANSIColumnDropper,
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sqlite.SQLiteConstraintGenerator)
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def db_sync(engine, abs_path, version=None, init_version=0, sanity_check=True):
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"""Upgrade or downgrade a database.
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Function runs the upgrade() or downgrade() functions in change scripts.
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:param engine: SQLAlchemy engine instance for a given database
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:param abs_path: Absolute path to migrate repository.
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:param version: Database will upgrade/downgrade until this version.
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If None - database will update to the latest
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available version.
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:param init_version: Initial database version
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:param sanity_check: Require schema sanity checking for all tables
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"""
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if version is not None:
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try:
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version = int(version)
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except ValueError:
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raise exception.DbMigrationError(
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message=_("version should be an integer"))
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current_version = db_version(engine, abs_path, init_version)
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repository = _find_migrate_repo(abs_path)
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if sanity_check:
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_db_schema_sanity_check(engine)
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if version is None or version > current_version:
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return versioning_api.upgrade(engine, repository, version)
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else:
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return versioning_api.downgrade(engine, repository,
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version)
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def _db_schema_sanity_check(engine):
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"""Ensure all database tables were created with required parameters.
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:param engine: SQLAlchemy engine instance for a given database
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"""
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if engine.name == 'mysql':
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onlyutf8_sql = ('SELECT TABLE_NAME,TABLE_COLLATION '
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'from information_schema.TABLES '
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'where TABLE_SCHEMA=%s and '
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'TABLE_COLLATION NOT LIKE "%%utf8%%"')
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# NOTE(morganfainberg): exclude the sqlalchemy-migrate and alembic
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# versioning tables from the tables we need to verify utf8 status on.
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# Non-standard table names are not supported.
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EXCLUDED_TABLES = ['migrate_version', 'alembic_version']
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table_names = [res[0] for res in
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engine.execute(onlyutf8_sql, engine.url.database) if
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res[0].lower() not in EXCLUDED_TABLES]
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if len(table_names) > 0:
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raise ValueError(_('Tables "%s" have non utf8 collation, '
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'please make sure all tables are CHARSET=utf8'
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) % ','.join(table_names))
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def db_version(engine, abs_path, init_version):
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"""Show the current version of the repository.
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:param engine: SQLAlchemy engine instance for a given database
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:param abs_path: Absolute path to migrate repository
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:param version: Initial database version
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"""
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repository = _find_migrate_repo(abs_path)
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try:
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return versioning_api.db_version(engine, repository)
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except versioning_exceptions.DatabaseNotControlledError:
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meta = sqlalchemy.MetaData()
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meta.reflect(bind=engine)
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tables = meta.tables
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if len(tables) == 0 or 'alembic_version' in tables:
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db_version_control(engine, abs_path, version=init_version)
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return versioning_api.db_version(engine, repository)
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else:
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raise exception.DbMigrationError(
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message=_(
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"The database is not under version control, but has "
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"tables. Please stamp the current version of the schema "
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"manually."))
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def db_version_control(engine, abs_path, version=None):
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"""Mark a database as under this repository's version control.
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Once a database is under version control, schema changes should
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only be done via change scripts in this repository.
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:param engine: SQLAlchemy engine instance for a given database
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:param abs_path: Absolute path to migrate repository
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:param version: Initial database version
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"""
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repository = _find_migrate_repo(abs_path)
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versioning_api.version_control(engine, repository, version)
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return version
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def _find_migrate_repo(abs_path):
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"""Get the project's change script repository
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:param abs_path: Absolute path to migrate repository
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"""
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if not os.path.exists(abs_path):
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raise exception.DbMigrationError("Path %s not found" % abs_path)
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return Repository(abs_path)
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