app/migrations/env.py

import asyncio
from logging.config import fileConfig

from alembic import context
from sqlalchemy import engine_from_config, pool
from sqlalchemy.ext.asyncio import AsyncEngine

from app.core import config as app_config

# 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)  # type: ignore

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
from app.models.database.base import Base  # noqa

target_metadata = Base.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 get_database_uri():
    return app_config.settings.SQLALCHEMY_DATABASE_URI


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 = get_database_uri()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
        compare_server_default=True,
    )

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


def do_run_migrations(connection):
    context.configure(
        connection=connection, target_metadata=target_metadata, compare_type=True
    )

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


async 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.

    """
    configuration = config.get_section(config.config_ini_section)
    assert configuration
    configuration["sqlalchemy.url"] = get_database_uri()
    connectable = AsyncEngine(
        engine_from_config(
            configuration,
            prefix="sqlalchemy.",
            poolclass=pool.NullPool,
            future=True,
        )  # type: ignore
    )
    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)


if context.is_offline_mode():
    run_migrations_offline()
else:
    asyncio.run(run_migrations_online())