This simple webfinger implementation just redirects a single webfinger address to another server. I use it to allow people to find my mastodon profile via my personal server.
Example usage:
$ redirect-webfinger --acct=jelmer@jelmer.uk \ --mastodon-server=mastodon.cloud \ --mastodon-user=jelmer
The only URL it exposes is /.well-known/webfinger, which you would probably want to expose via your reverse HTTP proxy.
Or using docker/podman:
$ podman run ghcr.io/jelmer/redirect-webfinger \ -e ACCT=jelmer@jelmer.uk \ -e MASTODON_SERVER=mastodon.cloud \ -e MASTODON_USER=jelmer