This is a cert-manager webhook handler generates DNS records for ACME DNS-01 challenges in the etcd schema expected by CoreDNS's etcd plugin. This allows a single public-facing CoreDNS and etcd instance to serve both external-dns and cert-manager records.
This repository is based on https://github.com/cert-manager/webhook-example.
Apparently this very similar project exists: https://github.com/ii/cert-manager-webhook-coredns-etcd