Session Manager

class falcon_sqla.Manager(engine, session_cls=<class 'falcon_sqla.session.RequestSession'>, binds=None)

A manager for SQLAlchemy sessions.

This manager allows registering multiple SQLAlchemy engines, specifying if they are read-write or read-only or write-only capable.

Parameters:

• engine (Engine) – An instance of a SQLAlchemy Engine, usually obtained with its create_engine function. This engine is added as read-write.

• session_cls (type, optional) – Session class used by this engine to create the session. Should be a subclass of SQLAlchemy Session class. Defaults to RequestSession.

• binds (dict, optional) – A dictionary that allows specifying custom binds on a per-entity basis in the session. See also https://docs.sqlalchemy.org/en/13/orm/session_api.html#sqlalchemy.orm.session.Session.params.binds. Defaults to None.

add_engine(engine, role='r')

Adds a new engine with the specified role.

Parameters:

• engine (Engine) – An instance of a SQLAlchemy Engine.

• role ({'r', 'rw', 'w'}, optional) – The role of the engine (‘r’: read-ony, ‘rw’: read-write, ‘w’: write-only). Defaults to ‘r’.

get_bind(req, resp, session, mapper, clause)

Choose the appropriate bind for the given request session.

This method is not used directly, it’s called by the session instance if multiple engines are defined.

get_session(req=None, resp=None)

Returns a new session object.

property middleware

Create a new Middleware instance connected to this manager.

property read_engines

A tuple of read capable engines.

session_scope(req=None, resp=None)

Provide a transactional scope around a series of operations.

Based on the session_scope() recipe from https://docs.sqlalchemy.org/orm/session_basics.html.

property write_engines

A tuple of write capable engines.