Unit Of Work Abstractions

Classes

Instruction

SqlAlchemy

This package provides a small abstraction layer over the UOW (Unit of Work) pattern for working with sqlalchemy.

• uowabc.sa.SaSessionUnitOfWork – A class that contains an async_sessionmaker[AsyncSession] and automatically calls .commit or .rollback when the context is closed.
• uowabc.sa.SaSessionRepository – A base repository containing an AsyncSession, extending the functionality of SaSessionUnitOfWork.
• uowabc.sa.CrudSaSessionRepository – A repository based on SaSessionRepository, designed to work with DeclarativeBase and implements basic CRUD methods.

import uowabc.sa
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
from sqlalchemy.orm import DeclarativeBase


class Row(DeclarativeBase):
    __tablename__ = 'rows'

    id = Column(Integer, primary_key=True, autoincrement=True)


# First step - Declaring the UOW

engine = create_async_engine('...')
session_maker = async_sessionmaker(engine, expire_on_commit=False)

class DatabaseSaUow(uowabc.sa.SaSessionUnitOfWork):
    def __init__(self) -> None:
        super().__init__(session_maker)

# Second step - Defining the repository

class RowsRepository(uowabc.sa.CrudSaSessionRepository[DatabaseSaUow, Row]):
    UowType = DatabaseSaUow
    model = Row

    async def get_row_count(self) -> int:
        result = await self.session.execute(select(func.count()).select_from(self.model))
        count = result.scalar_one()
        return count

# Step three - Execution

async def example_1():
    # Sequentially create the UOW and the repository

    async with DatabaseSaUow() as uow:
        async with RowsRepository(uow) as rows_repository:
            await rows_repository.get_row_count()

async def example_2(uow: DatabaseSaUow):
    # Initialize the repository by passing an already created UOW
    # The UOW must be "started" (the context manager must be invoked)

    async with RowsRepository(uow) as rows_repository:
        await rows_repository.get_row_count()

async def example_3():
    # Initialize the repository without a pre-created UOW
    # The UOW will be automatically created

    async with RowsRepository() as rows_repository:
        await rows_repository.get_row_count()

Dependencies

This module uses types introduced in python 3.12

Contribute

Issue Tracker: https://gitlab.com/rocshers/python/uow-abstractions/-/issues
Source Code: https://gitlab.com/rocshers/python/uow-abstractions

Before adding changes:

make install-dev

After changes:

make format test