internal-CA HTTPS forces every device to trust a private root, which breaks down
on some clients (Android browsers). acme mode instead obtains a real Let's Encrypt
wildcard cert (*.<domain>) via a DNS-01 challenge, so browsers trust it with zero
CA install — while services stay internal-only (no inbound exposure, no public A
records; only a transient _acme-challenge TXT touches the public zone, and LAN DNS
resolves the names to a private IP).
- Config: GatewayConfig/NodeConfig gain domain, acme_email, acme_dns_provider
(plumbed through load/save + registry + deploy, omitted-when-empty for
round-trip stability). tls stays the discriminator: off | internal | acme.
- Caddyfile generator: acme branch emits a global {email, acme_dns <provider>
{env.TOKEN}} block + one *.<domain> wildcard site with host matchers derived
from the service name (<name>.<domain>); path/static stay on :<port>. Shared
_host_matcher_block helper (reused by off-mode). CASTLE_ACME_STAGING=1 toggles
the LE staging CA; acme-without-domain falls back to HTTP with a warning.
- deploy(): _acme_preflight warns (never writes) when domain, the gateway-service
token env, or the CLOUDFLARE_API_TOKEN secret is missing.
- install.sh: opt-in --with-dns-plugin[=provider] builds a DNS-plugin Caddy via
xcaddy (pinned) to /usr/local/bin/caddy, which the gateway picks up on deploy.
- Tests: TestCaddyfileTlsAcme (global block, wildcard site, derived host matcher,
path routes on :port, staging toggle, no-domain fallback). Docs: gateway.tls
modes table + full acme/DNS-01 section (setup, wild-central LAN DNS, staging).
Paul Payne
121f970f14