SQLAlchemy Session Context Manager

sqlachemy_session_context.py

from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from contextlib import contextmanager

Base = declarative_base()

class User(Base):
    __tablename__ = "users"
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String)

engine = create_engine("sqlite:///:memory:")

Base.metadata.create_all(bind=engine)
SessionMaker = sessionmaker(bind=engine)

@contextmanager
def session_manager():
    """
    example : 
      with session_manager() as session:
        result = session.query(User).all()
        print(result)
    """
    
    session = SessionMaker()
    try:
        yield session
    except Exception as e:
        print("rollback transaction")
        session.rollback()
        raise
    finally:
        print("closing connection")
        session.close()