read.markets/alembic/env.py

"""Alembic environment — DB URL is sourced from app/config.Settings at runtime
so we keep secrets out of alembic.ini. Async engine is used in 'online' mode."""
from __future__ import annotations

import asyncio
from logging.config import fileConfig

from alembic import context
from sqlalchemy import pool
from sqlalchemy.engine import Connection
from sqlalchemy.ext.asyncio import async_engine_from_config

from app.config import get_settings
from app.db import Base
# Import models so that Base.metadata is populated.
from app import models  # noqa: F401

config = context.config

# Inject the real DB URL from Settings.
config.set_main_option("sqlalchemy.url", get_settings().DATABASE_URL)

if config.config_file_name is not None:
    # disable_existing_loggers=False is essential: the app applies
    # migrations in-process at startup (see app.main lifespan), so the
    # default True would disable uvicorn's already-configured loggers —
    # silencing access logs and 500 tracebacks for the whole process.
    fileConfig(config.config_file_name, disable_existing_loggers=False)

target_metadata = Base.metadata


def run_migrations_offline() -> None:
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
    )
    with context.begin_transaction():
        context.run_migrations()


def do_run_migrations(connection: Connection) -> None:
    # render_as_batch is required for SQLite, which doesn't support
    # most ALTER COLUMN / ADD CONSTRAINT operations natively. With
    # batch mode enabled, Alembic emits a copy-and-rename dance under
    # SQLite while still producing plain ALTER on MariaDB / Postgres,
    # so prod migrations are unchanged. Detect via the dialect name.
    render_as_batch = connection.dialect.name == "sqlite"
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        compare_type=True,
        render_as_batch=render_as_batch,
    )
    with context.begin_transaction():
        context.run_migrations()


async def run_migrations_online() -> None:
    connectable = async_engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )
    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)
    await connectable.dispose()


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