SQLAlchemy query counter

query_counter.py

from sqlalchemy import engine_from_config, event
from sqlalchemy.orm import sessionmaker


def query_count_hook(
        conn, cursor, statement, parameters, context, executemany,
):
    info = conn.info
    info['query_count'] = info.get('query_count', 0) + 1


engine = engine_from_config(settings, prefix='sqlalchemy.')
dbmaker = sessionmaker(bind=engine)
event.listen(engine, 'after_cursor_execute', query_count_hook)


def session(request):
    """
    Create SQLAlchemy session for each web request.

    """
    session = dbmaker()

    def cleanup(request):
        """
        Destroy session after web request.

        """
        conn_info = session.connection().info
        print(conn_info.get('query_count', 0))
        conn_info['query_count'] = 0
        if request.exception is not None:
            session.rollback()
        else:
            session.commit()
        session.close()

    request.add_finished_callback(cleanup)
    return session