This is scertec, a Let's Encrypt ACME client that stores certs in setec and a Go client library that reads those certs back out of setec at serving time via a tls.Config.GetCertificate hook.
It only supports ACME DNS challenges using Amazon Route53.
Directories involved:
.(packagescertec): the client library that gets certs from setecscertecd(packagescertecd): the ACME client code that runs either in the foreground once or in the background as an HTTP server, keeping the certs refreshed in seteccmd/scertecd: a littlepackage mainwrapper around the earlier item.