migrations/env.py

import sys
from pathlib import Path
from logging.config import fileConfig

from sqlalchemy import pool
from alembic import context

# Add the project root to sys.path so we can import the backend package
root_path = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(root_path))

# Import database models and settings
from backend.app.models import Base
from backend.app.core.database import DATABASE_URL

# 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.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# add your model's MetaData object here
target_metadata = Base.metadata

def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode."""
    url = DATABASE_URL
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

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


def run_migrations_online() -> None:
    """Run migrations in 'online' mode."""
    # Create the engine dynamically from our DATABASE_URL
    from sqlalchemy import create_engine
    connectable = create_engine(DATABASE_URL, poolclass=pool.NullPool)

    with connectable.connect() as connection:
        context.configure(
            connection=connection, target_metadata=target_metadata
        )

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


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