def db_sync(engine, abs_path, version=None, init_version=0, sanity_check=True):
"""Upgrade or downgrade a database.
Function runs the upgrade() or downgrade() functions in change scripts.
:param engine: SQLAlchemy engine instance for a given database
:param abs_path: Absolute path to migrate repository.
:param version: Database will upgrade/downgrade until this version.
If None - database will update to the latest
available version.
:param init_version: Initial database version
:param sanity_check: Require schema sanity checking for all tables
"""
if version is not None:
try:
version = int(version)
except ValueError:
raise exception.DbMigrationError(
message=("version should be an integer"))
current_version = db_version(engine, abs_path, init_version)
repository = _find_migrate_repo(abs_path)
if sanity_check:
_db_schema_sanity_check(engine)
if version is None or version > current_version:
return versioning_api.upgrade(engine, repository, version)
else:
return versioning_api.downgrade(engine, repository, version)
def _find_migrate_repo(abs_path):
"""Get the project's change script repository
:param abs_path: Absolute path to migrate repository
"""
if not os.path.exists(abs_path):
raise exception.DbMigrationError("Path %s not found" % abs_path)
return Repository(abs_path)
def get_manager():
storage_db = CONF['storage:sqlalchemy'].connection
pool_manager_cache_db = CONF['pool_manager_cache:sqlalchemy'].connection
if storage_db == pool_manager_cache_db:
raise exception.DbMigrationError(
message=("Pool Manager Cache requires its own database."
" Please check your config file."))
else:
return utils.get_migration_manager(REPOSITORY, pool_manager_cache_db)
def create_schema(config=None, engine=None):
"""Create database schema from models description.
Can be used for initial installation instead of upgrade('head').
"""
if engine is None:
engine = enginefacade.get_legacy_facade().get_engine()
# NOTE(viktors): If we will use metadata.create_all() for non empty db
# schema, it will only add the new tables, but leave
# existing as is. So we should avoid of this situation.
if version(engine=engine) is not None:
raise db_exc.DbMigrationError("DB schema is already under version"
" control. Use upgrade() instead")
models.Base.metadata.create_all(engine)
stamp('head', config=config)
def upgrade(self, revision):
"""Upgrade database with all available backends."""
# a revision exists only in a single plugin. Until we reached it, we
# should upgrade to the plugins' heads.
# revision=None is a special case meaning latest revision.
rev_in_plugins = [p.has_revision(revision) for p in self._plugins]
if not any(rev_in_plugins) and revision is not None:
raise exception.DbMigrationError('Revision does not exist')
results = []
for plugin, has_revision in zip(self._plugins, rev_in_plugins):
if not has_revision or revision is None:
results.append(plugin.upgrade(None))
else:
results.append(plugin.upgrade(revision))
break
return results
def schema_create(self, config=None, engine=None):
"""Create database schema from models description.
Can be used for initial installation instead of upgrade('head').
:param config: Instance of alembic config
:param engine: Instance of DB engine
"""
engine = engine or get_engine()
# NOTE(viktors): If we will use metadata.create_all() for non empty db
# schema, it will only add the new tables, but leave
# existing as is. So we should avoid of this situation.
if self.schema_revision(engine=engine) is not None:
raise db_exc.DbMigrationError("DB schema is already under version"
" control. Use upgrade() instead")
models.BASE.metadata.create_all(engine)
self.schema_stamp("head", config=config)
def downgrade(self, revision):
"""Downgrade database with available backends."""
# a revision exists only in a single plugin. Until we reached it, we
# should upgrade to the plugins' first revision.
# revision=None is a special case meaning initial revision.
rev_in_plugins = [p.has_revision(revision) for p in self._plugins]
if not any(rev_in_plugins) and revision is not None:
raise exception.DbMigrationError('Revision does not exist')
# downgrading should be performed in reversed order
results = []
for plugin, has_revision in zip(reversed(self._plugins),
reversed(rev_in_plugins)):
if not has_revision or revision is None:
results.append(plugin.downgrade(None))
else:
results.append(plugin.downgrade(revision))
break
return results
def db_version(engine, abs_path, init_version):
"""Show the current version of the repository.
:param engine: SQLAlchemy engine instance for a given database
:param abs_path: Absolute path to migrate repository
:param version: Initial database version
"""
repository = _find_migrate_repo(abs_path)
try:
return versioning_api.db_version(engine, repository)
except versioning_exceptions.DatabaseNotControlledError:
meta = sqlalchemy.MetaData()
meta.reflect(bind=engine)
tables = meta.tables
if len(tables) == 0 or 'alembic_version' in tables:
db_version_control(engine, abs_path, version=init_version)
return versioning_api.db_version(engine, repository)
else:
raise exception.DbMigrationError(message=(
"The database is not under version control, but has "
"tables. Please stamp the current version of the schema "
"manually."))
