JezK
Edit File: env.py
import logging from logging.config import fileConfig from sqlalchemy import MetaData from flask import current_app from alembic import context USE_TWOPHASE = False # this is the Alembic Config object, which provides # access to the values within the .ini file in use. config = context.config # Interpret the config file for Python logging. # This line sets up loggers basically. fileConfig(config.config_file_name) logger = logging.getLogger('alembic.env') def get_engine(bind_key=None): try: # this works with Flask-SQLAlchemy<3 and Alchemical return current_app.extensions['migrate'].db.get_engine(bind=bind_key) except TypeError: # this works with Flask-SQLAlchemy>=3 return current_app.extensions['migrate'].db.engines.get(bind_key) def get_engine_url(bind_key=None): try: return get_engine(bind_key).url.render_as_string( hide_password=False).replace('%', '%%') except AttributeError: return str(get_engine(bind_key).url).replace('%', '%%') # add your model's MetaData object here # for 'autogenerate' support # from myapp import mymodel # target_metadata = mymodel.Base.metadata config.set_main_option('sqlalchemy.url', get_engine_url()) bind_names = [] if current_app.config.get('SQLALCHEMY_BINDS') is not None: bind_names = list(current_app.config['SQLALCHEMY_BINDS'].keys()) else: get_bind_names = getattr(current_app.extensions['migrate'].db, 'bind_names', None) if get_bind_names: bind_names = get_bind_names() for bind in bind_names: context.config.set_section_option( bind, "sqlalchemy.url", get_engine_url(bind_key=bind)) target_db = current_app.extensions['migrate'].db # other values from the config, defined by the needs of env.py, # can be acquired: # my_important_option = config.get_main_option("my_important_option") # ... etc. def get_metadata(bind): """Return the metadata for a bind.""" if bind == '': bind = None if hasattr(target_db, 'metadatas'): return target_db.metadatas[bind] # legacy, less flexible implementation m = MetaData() for t in target_db.metadata.tables.values(): if t.info.get('bind_key') == bind: t.tometadata(m) return m def run_migrations_offline(): """Run migrations in 'offline' mode. This configures the context with just a URL and not an Engine, though an Engine is acceptable here as well. By skipping the Engine creation we don't even need a DBAPI to be available. Calls to context.execute() here emit the given string to the script output. """ # for the --sql use case, run migrations for each URL into # individual files. engines = { '': { 'url': context.config.get_main_option('sqlalchemy.url') } } for name in bind_names: engines[name] = rec = {} rec['url'] = context.config.get_section_option(name, "sqlalchemy.url") for name, rec in engines.items(): logger.info("Migrating database %s" % (name or '<default>')) file_ = "%s.sql" % name logger.info("Writing output to %s" % file_) with open(file_, 'w') as buffer: context.configure( url=rec['url'], output_buffer=buffer, target_metadata=get_metadata(name), literal_binds=True, ) with context.begin_transaction(): context.run_migrations(engine_name=name) 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. """ # this callback is used to prevent an auto-migration from being generated # when there are no changes to the schema # reference: http://alembic.zzzcomputing.com/en/latest/cookbook.html def process_revision_directives(context, revision, directives): if getattr(config.cmd_opts, 'autogenerate', False): script = directives[0] if len(script.upgrade_ops_list) >= len(bind_names) + 1: empty = True for upgrade_ops in script.upgrade_ops_list: if not upgrade_ops.is_empty(): empty = False if empty: directives[:] = [] logger.info('No changes in schema detected.') # for the direct-to-DB use case, start a transaction on all # engines, then run all migrations, then commit all transactions. engines = { '': {'engine': get_engine()} } for name in bind_names: engines[name] = rec = {} rec['engine'] = get_engine(bind_key=name) for name, rec in engines.items(): engine = rec['engine'] rec['connection'] = conn = engine.connect() if USE_TWOPHASE: rec['transaction'] = conn.begin_twophase() else: rec['transaction'] = conn.begin() try: for name, rec in engines.items(): logger.info("Migrating database %s" % (name or '<default>')) context.configure( connection=rec['connection'], upgrade_token="%s_upgrades" % name, downgrade_token="%s_downgrades" % name, target_metadata=get_metadata(name), process_revision_directives=process_revision_directives, **current_app.extensions['migrate'].configure_args ) context.run_migrations(engine_name=name) if USE_TWOPHASE: for rec in engines.values(): rec['transaction'].prepare() for rec in engines.values(): rec['transaction'].commit() except: # noqa: E722 for rec in engines.values(): rec['transaction'].rollback() raise finally: for rec in engines.values(): rec['connection'].close() if context.is_offline_mode(): run_migrations_offline() else: run_migrations_online()