Letsencrypt/goについて、ここに記述してください。

https://ericchiang.github.io/go/tls/lets/encrypt/letsencrypt/2015/11/13/a-letsencrypt-client-for-go.html

In preperation for the Public Beta in December, I’ve written a simple client in Go which you can go get on GitHub.

This post uses that client to take you through the workflow of signing up, completing challenges, and requesting certificates. Let’s Encrypt!

For these examples, I’ve spun up a Let’s Encrypt server in dev mode on my local machine, made some edits to the server’s configuration,
and added an entry to my /etc/hosts. See details here if you want to follow along.