https://nginxstore.com/blog/api-gateway/%ec%b5%9c%ec%8b%a0-api%ec%97%90%ec%84%9c-api-gateway-%ec%86%8d%eb%8f%84%ea%b0%80-%ec%a4%91%ec%9a%94%ed%95%9c-%ec%9d%b4%ec%9c%a0/