name : dbmigrate_lib.py #!/opt/cloudlinux/venv/bin/python3 -bb # coding=utf-8 # # Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved # # Licensed under CLOUD LINUX LICENSE AGREEMENT # http://cloudlinux.com/docs/LICENSE.TXT import os import sys try: from alembic.migration import MigrationContext from alembic import config, command, script except ImportError as e: if __name__ == '__main__': # show message end exit if run as script print(f'Alembic Python library is not installed. Error: {e}') sys.exit(1) else: raise ALEMBIC_CONF = os.path.join(os.path.dirname(__file__), 'alembic.ini') def generate_revisions_chain(alembic_cfg): chain_ = [] script_ = script.ScriptDirectory.from_config(alembic_cfg) revision_pairs = {s.down_revision or 'base': s.revision for s in script_.walk_revisions()} curent_revision = 'base' while curent_revision: chain_.append(curent_revision) curent_revision = revision_pairs.get(curent_revision) return chain_ def get_database_version(engine): connection = engine.connect() context = MigrationContext.configure(connection) current_rev = context.get_current_revision() return current_rev or 'base' def migration_way(alembic_cfg, revision_from, revision_to): """ Check need migrate or downgrade to specific revisions :return bool: True - upgrade; False downgrade """ rev_chain = generate_revisions_chain(alembic_cfg) return rev_chain.index(revision_from) <= rev_chain.index(revision_to) def correct_script_location(alembic_cfg): """ correct script_location in alembic config for relative path support :param alembic_cfg: :return: """ location = alembic_cfg.get_section_option('alembic', 'script_location') here = alembic_cfg.get_section_option('alembic', 'here') location_corrected = os.path.abspath(os.path.join(here, location)) alembic_cfg.set_section_option( 'alembic', 'script_location', location_corrected) return alembic_cfg def get_orm_version(): alembic_version = getattr( __import__('lvestats.orm', fromlist=['alembic_version']), 'alembic_version', 'base') return alembic_version def alembic_migrate(engine, alembic_version=None, stamp=False, lve_stats_cfg=None): if alembic_version is None: alembic_version = get_orm_version() alembic_cfg = correct_script_location(config.Config(ALEMBIC_CONF)) alembic_cfg.attributes['lve-stats'] = lve_stats_cfg # pylint: disable=unsupported-assignment-operation with engine.begin() as connection: alembic_cfg.attributes['connection'] = connection # pylint: disable=unsupported-assignment-operation if stamp: # write revision version to database only command.stamp(alembic_cfg, alembic_version) else: database_version = get_database_version(engine) if migration_way(alembic_cfg, database_version, alembic_version): command.upgrade(alembic_cfg, alembic_version) else: command.downgrade(alembic_cfg, alembic_version)