Alembic --autogenerate producing empty migration

Question

I am trying to use `Alembic` for the first time and want to use `--autogenerate` feature described here My project structure looks like ``` project/ configuration/ __init__.py dev.py test.py core/ app/ models/ __init__.py user.py db/ alembic/ versions/ env.py alembic.ini ``` I am using `Flask` and `SQLAlchemy` and their `Flask-SQLAlchemy` extension. my model `User` looks like ``` class User(UserMixin, db.Model): __tablename__ = 'users' # noinspection PyShadowingBuiltins uuid = Column('uuid', GUID(), default=uuid.uuid4, primary_key=True, unique=True) email = Column('email', String, nullable=False, unique=True) _password = Column('password', String, nullable=False) created_on = Column('created_on', sa.types.DateTime(timezone=True), default=datetime.utcnow()) last_login = Column('last_login', sa.types.DateTime(timezone=True), onupdate=datetime.utcnow()) ``` As described here, I modified `env.py` to look like ``` from configuration import app alembic_config = config.get_section(config.con…

Accepted Answer

As per @zzzeek, after I included the following in my `env.py`, I was able to work with `--autogenerate` option

in `env.py` under `run_migrations_online()`

```
from configuration import app
from core.expense.models import user # added my model here

alembic_config = config.get_section(config.config_ini_section)
alembic_config['sqlalchemy.url'] = app.config['SQLALCHEMY_DATABASE_URI']
engine = engine_from_config(
    alembic_config,
    prefix='sqlalchemy.',
    poolclass=pool.NullPool)
```

then I ran `alembic revision --autogenerate -m "Added initial table"` and got

```
def upgrade():
    ### commands auto generated by Alembic - please adjust! ###
    op.create_table('users',
    sa.Column('uuid', sa.GUID(), nullable=False),
    sa.Column('email', sa.String(), nullable=False),
    sa.Column('password', sa.String(), nullable=False),
    sa.Column('created_on', sa.DateTime(timezone=True), nullable=True),
    sa.Column('last_login', sa.DateTime(timezone=True), nullable=True),
    sa.PrimaryKeyConstraint('uuid'),
    sa.UniqueConstraint('email'),
    sa.UniqueConstraint('uuid')
    )
    ### end Alembic commands ###
```

Thank you Michael for all your help!

Alembic --autogenerate producing empty migration

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