Imports github.com/cenkalti/backoff github.com/mholt/caddy github.com/mholt/caddy/caddytls github.com/mholt/certmagic github.com/pkg/errors go.etcd.io/etcd/client Standard library imports bytes context crypto/rand crypto/sha1 encoding/base64 encoding/json fmt io/ioutil log net/url os path strings time