from __future__ import with_statement from alembic import context from sqlalchemy import engine_from_config, pool from logging.config import fileConfig # 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) # add your model's MetaData object here # for 'autogenerate' support # from myapp import mymodel # target_metadata = mymodel.Base.metadata from flask import current_app config.set_main_option( "sqlalchemy.url", current_app.config.get("SQLALCHEMY_DATABASE_URI") ) target_metadata = current_app.extensions["migrate"].db.metadata # 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 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. """ url = config.get_main_option("sqlalchemy.url") context.configure(url=url) with context.begin_transaction(): context.run_migrations() 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 = engine_from_config( config.get_section(config.config_ini_section), prefix="sqlalchemy.", poolclass=pool.NullPool, ) connection = engine.connect() context.configure( connection=connection, target_metadata=target_metadata, **current_app.extensions["migrate"].configure_args ) try: with context.begin_transaction(): context.run_migrations() finally: connection.close() if context.is_offline_mode(): run_migrations_offline() else: run_migrations_online()