Base Class for SQLAlchemy Models

base.py

import datetime
import re
import uuid

from sqlalchemy import MetaData, func, DateTime, UUID, text
from sqlalchemy.ext.asyncio import AsyncAttrs
from sqlalchemy.orm import declarative_base, Mapped, mapped_column

POSTGRES_INDEXES_NAMING_CONVENTION = {
    "ix": "%(column_0_label)s_idx",
    "uq": "%(table_name)s_%(column_0_name)s_key",
    "ck": "%(table_name)s_%(constraint_name)s_check",
    "fk": "%(table_name)s_%(column_0_name)s_fkey",
    "pk": "%(table_name)s_pkey",
}
metadata = MetaData(naming_convention=POSTGRES_INDEXES_NAMING_CONVENTION)

DeclarativeBase = declarative_base(metadata=metadata)


class Base(AsyncAttrs, DeclarativeBase):
    """Base class for all models."""

    __abstract__ = True

    # id: Mapped[uuid.UUID] = mapped_column(
    #     UUID(as_uuid=True),
    #     primary_key=True,
    #     server_default=text("gen_random_uuid()"),
    #     unique=True,
    # )

    created_at: Mapped[datetime.datetime] = mapped_column(
        DateTime(timezone=True),
        default=datetime.datetime.now(datetime.UTC),
        server_default=func.current_timestamp(),
    )
    updated_at: Mapped[datetime.datetime] = mapped_column(
        DateTime(timezone=True),
        default=datetime.datetime.now(datetime.UTC),
        onupdate=datetime.datetime.now(datetime.UTC),
    )

    def __init_subclass__(cls, **kwargs):
        """Set the table name to the lowercase version of the class name if not set."""
        if not cls.__dict__.get("__tablename__", None):
            cls.__tablename__ = re.sub(r"(?<!^)(?=[A-Z])", "_", cls.__name__).lower()
        super().__init_subclass__(**kwargs)