파이썬 싱글톤 구현 https://bitcodic.tistory.com/89
중복데이터 제거 https://steemit.com/kr/@yjiq150/mysql
데몬으로 실행 https://stackoverflow.com/questions/45168300/how-do-you-keep-your-airflow-scheduler-running-in-aws-ec2-while-exiting-ssh
