I’m doing some experiments with airflow dags in docker container, and want to have a function that returns a db connection and cursor.

def db_connect():
    try:
        conn = pymysql.connect(
            host=CONFIG.get("db_host"),
            port=CONFIG.get("db_port"),
            user=CONFIG.get("db_user"),
            password=CONFIG.get("db_password"),
        )
        
        logger.info(
            "Database connection established: %(info)s"
            % {
                "info": conn.get_host_info(),
            }
        )
        cursor = conn.cursor()

        return conn, cursor
    except Exception as e:
        logger.error(
            "Failed to connect to database: %(error)s"
            % {
                "error": e,
            }
        )
        raise AirflowException("Database connection failed")

error:

TypeError: Object of type tuple is not JSON serializable

I have tried the exact same code in the local environment and it works fine.