def version(config=None, engine=None):
"""Current database version.
:returns: Database version
:rtype: string
"""
if engine is None:
engine = sqla_api.get_engine()
with engine.connect() as conn:
context = alembic_migration.MigrationContext.configure(conn)
return context.get_current_revision()
def run_migrations_online():
"""Run migrations in 'online' mode.
In this scenario we need to create an Engine
and associate a connection with the context.
"""
engine = sqla_api.get_engine()
with engine.connect() as connection:
context.configure(connection=connection,
target_metadata=target_metadata)
with context.begin_transaction():
context.run_migrations()
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 = sqla_api.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)