Sample after_flush_postexec session event

sa_flush_postexec.py

from __future__ import print_function
import sqlalchemy as sa
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

engine = sa.create_engine('sqlite:///:memory:', echo=True)

Base = declarative_base()


class Person(Base):

    __tablename__ = 'person'

    person_id = sa.Column(sa.Integer, primary_key=True)
    name = sa.Column(sa.Unicode)

    def __repr__(self):
        return "<Person {}>".format(self.name)


Base.metadata.create_all(engine)

Session = sessionmaker(bind=engine)
session = Session()


p = Person(name="P Body")


@sa.event.listens_for(session, "after_flush_postexec")
def handle_after_flush_postexec(session, flush_context):

    print("In handler, p: {}".format(p))
    renamed = session.info.pop('RENAMED', False)

    if not renamed:
        p.name += "*"
        session.info['RENAMED'] = True

session.add(p)
session.flush()

print("session.dirty: {}".format(session.dirty))
print("session.info: {}".format(session.info))