https://openresty.org/en/
https://github.com/openresty/
https://engineering.mercari.com/blog/entry/2016-05-25-170108/
https://qiita.com/nobuh/items/40ef50dd70fdf8a580e4
https://techblog.istyle.co.jp/archives/4136
https://blog.wnotes.net/posts/build-openresty-with-opentracing/