over the last few days I had a look into the CentOS mirrorlist code (used to run mirrorlist[.]centos[.]org) at https://github.com/CentOS/mirrorlists-code
I found it very difficult to set up and it lacks good documentation.
So I came up with an alternative implementation, now available at https://github.com/stevemeier/mirrorlist
It’s written entirely in Go, supports different database backends, has REST-Style endpoints and easily serves 3.000+ requests per second (on my test box).
I hope this is a useful contribution to the project. PRs to improve it are welcome.