Manages one Caddyfile entry per subdomain (URL -> IP:Port, plus optional
HTTP Basic Auth) and applies changes with a hot-reload through the Caddy
admin API, so an edit is live in ~0.3s with no restart and no certificate
churn.
Safety properties:
- every change is validated by the real Caddy binary before it is written
- a rejected reload restores the previous Caddyfile
- site blocks containing directives cadprox does not model are preserved
byte-for-byte, shown read-only, and never rewritten
- the Caddyfile is the only source of state, so a hand-edited file cannot
silently diverge from what the UI shows
- password hashes never leave the server; the session cookie is HttpOnly
and SameSite=Strict, and mutating requests need a custom header
app.py is a single standard-library file. The image is built on caddy:2.11.4
so validation, adaptation and hashing use the same binary that serves
traffic, which is why basic-auth hashes are bcrypt: Caddy's argon2id hashes
load fine but its basic-auth provider only verifies bcrypt.
Tests: 28 unit tests (Caddy-backed ones skip without the binary) and a 32
assertion end-to-end script that runs against a throwaway Caddy.
