Alembic support for multiple Postgres schemas

Question

How can I use Alembic\'s --autogenerate to migrate multiple Postgres schemas that are not hard-coded in the SQL Alchemy model? (mirror question of SQLA

Answer 1

This is a pretty old question, but for anyone who ran into the same problem, I solved it by using the following in my env.py:

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.

"""
connectable = engine_from_config(
    config.get_section(config.config_ini_section),
    prefix='sqlalchemy.',
    poolclass=pool.NullPool)

with connectable.connect() as connection:
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        include_schemas=True,
        version_table_schema=build  # <-- This is the relevant line
    )

    with context.begin_transaction():
        context.run_migrations()

where build is a string that defines the desired schema name. My use case is slightly different (multiple distributed builds with a single database containing multiple identical schemas), however I was running into the same problem of alembic not correctly detecting the schema I was attempting to connect to.

I use environment variables to determine the correct build, as it works quite well with Zappa.