Update the session context to the decorator？

[wu-clan]

It feels good.

from functools import wraps

def session_decorator(func):
    @wraps(func)
    async def wrapper(*args, **kwargs):
        async with async_db_session.begin() as db:
            return await func(db, *args, **kwargs)
    return wrapper

If use it, need to change a more practical method name.

[wu-clan]

Need to test

• services
• api (When used with the request method decorator)

[wu-clan]

Hi, @downdawn

What do you think?

[wu-clan]

Not all db operations require transactions

update async_db_session to async_session_maker

E.g.:

def async_session(func):
    """
    session 装饰器

    :param func:
    :return:
    """

    async def wrapper(*args, **kwargs):
        async with async_session_maker() as db:
            return await func(db, *args, **kwargs)

    return wrapper


def async_session_begin(func):
    """
    session 事务装饰器

    :param func:
    :return:
    """

    async def wrapper(*args, **kwargs):
        async with async_session_maker.begin() as db:
            return await func(db, *args, **kwargs)

    return wrapper

[downdawn]

Agree

async_session_begin or async_session_transaction

[wu-clan]

async_session_transaction looks better

[wu-clan]

Suspend the merger #20

When using this decorator, the IDE will lose parameter prompts and checks.

[downdawn]

Is there a screenshot?

[wu-clan]

No, You can check in pycharm

When using this decorator, in api functions, the caller will not be prompted for missing arguments, and there will be no error alert when using * mandatory formal parameters

[downdawn]

I see

This may be unsolvable, because the decorator cannot know which parameters the decorated function needs, and can only check whether these parameters exist by passing the parameter name.

[wu-clan]

Yes, this affects developers to some extent to do error checking

[downdawn]

May have to make a trade off

[downdawn]

Hi, @wu-clan

Why not just use：CurrentSession = Annotated[AsyncSession, Depends(get_db)]

And multi-table query will cause exception
sqlalchemy.exc.StatementError: (sqlalchemy.exc.MissingGreenlet) greenlet_spawn has not been called; can't call await_only() here. Was IO attempted in an unexpected place?

like the userinfo interface

[wu-clan]

This was an early question I had, but I can't remember the details

sqlalchemy/sqlalchemy#7835

[wu-clan]

Perhaps this needs attention as well

sqlalchemy/sqlalchemy#8176

[downdawn]

Help to evaluate the feasibility of this

async def get_db() -> AsyncSession:
    """
    session 生成器
    """
    async with async_db_session() as session:
        try:
            yield session
        except Exception as se:
            await session.rollback()
            raise se
        finally:
            await session.close()


async def get_db_transaction() -> AsyncSession:
    """
    session 生成器 事务
    """
    async with async_db_session.begin() as session:
        try:
            yield session
        except Exception as se:
            await session.rollback()
            raise se
        finally:
            await session.close()


# Session 依赖注入
CurrentSession = Annotated[AsyncSession, Depends(get_db)]
CurrentSessionTransaction = Annotated[AsyncSession, Depends(get_db_transaction)]

[wu-clan]

No need to include the yield in the context, just use yield async_db_session(), async_db_session.begin() is duplicated because begin() executes the session in the transaction, but await session.rollback() already exists

[wu-clan]

Please check：

• https://fastapi.tiangolo.com/zh/tutorial/dependencies/dependencies-with-yield/#using-context-managers-in-dependencies-with-yield
• https://docs.sqlalchemy.org/en/20/orm/extensions/asyncio.html#sqlalchemy.ext.asyncio.async_sessionmaker.begin

[wu-clan]

This solution has been abandoned.