from contextlib import contextmanager

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker

from src import config


engine = create_engine(config.DB_CONNECTION_URI, pool_pre_ping=True, query_cache_size=0)
_session_maker = sessionmaker(bind=engine, expire_on_commit=False)
_scoped_session = scoped_session(_session_maker)
_session = _scoped_session()


@contextmanager
def db_session():
    try:
        yield _session
        _session.commit()
    except Exception:
        _session.rollback()
        raise