If I'm not wrong, the SQLAlchemy official doc provides some examples to explain how to share a set of common columns, some common table options, or other mapped properties, across many classes. But I cannot find how to share common methods (e.g. your customized to_dict() method). This post will just show you a POC to achieve this goal by using Python Mixin. Continue reading
The concurrency model for SQLAlchemy's Session and AsyncSession is therefore Session per thread, AsyncSession per task.
The best way to ensure this use is by using the standard context manager pattern locally within the top level Python function that is inside the thread or task, which will ensure the lifespan of the Session or AsyncSession is maintained within a local scope.
For applications that benefit from having a "global" Session where it's not an option to pass the Session object to specific functions and methods which require it, the scoped_session approach can provide for a "thread local" Session object; see the section Contextual/Thread-local Sessions for background. Within the asyncio context, the async_scoped_session object is the asyncio analogue for scoped_session, however is more challenging to configure as it requires a custom "context" function.