Files
wild-pc/docs/findings-lakehouse.md
Paul Payne 4840cbe72a feat: castle UX fixes from the lakehouse adoption test
Driven by adopting lakehouse (an existing daemon that bundles its own SPA) —
see docs/findings-lakehouse.md.

#3 deploy reloads the gateway. castle deploy regenerated the Caddyfile but
   left the running Caddy on the old config, so new proxy routes were silently
   dead. Deploy now reloads the gateway when it's running.

#1 castle expose <program>. Turns an adopted program into a service
   (run/port/health/proxy/systemd) in one command — the missing
   daemon-to-service step. Flags: --port --health --path --run --port-env
   --host --no-proxy.

#2 port_env mapping. A service can declare expose.http.internal.port_env so
   castle sets the env var the program actually reads (e.g. lakehoused reads
   LAKEHOUSED_DAEMON_PORT, not castle's convention LAKEHOUSE_PORT). Castle now
   genuinely drives an adopted daemon's bind port.

#4a auto-base for react-vite. The build passes VITE_BASE = the gateway serve
   prefix (/<name>/, or / for castle-app); vite.config reads it. A castle-built
   frontend now works at its subpath with no hand-tuned base. castle-app's
   vite.config updated as the reference.

#4b host-based routing. proxy.caddy.host routes a whole hostname to the backend
   root via a host matcher inside the :9000 site, so a root-based SPA (base="/")
   serves unchanged — the fix for proxying an app castle can't rebuild. Caddyfile
   now emits 'auto_https off' (HTTP-only gateway on a non-standard port).

Nit: activate skips the editable reinstall when the tool is already on PATH.

Tests: core 94, cli 24, api 52; ruff + app build clean. Verified live: lakehouse
runs under systemd, API at /lakehouse, full UI (SPA boots) via host routing.
2026-06-14 13:16:34 -07:00

4.4 KiB

Findings — adopting lakehouse as a castle service

A completeness/UX test: take an existing daemon (/data/repos/lakehouse, a FastAPI lakehoused server on port 8420 that bundles its own SPA, normally started by a bespoke lakehouse start) and bring it fully under castle — systemd-managed, health-checked, proxied, on the dashboard.

What worked cleanly

  • castle add auto-detected behavior: daemon + stack: python-fastapi from the pyproject (fastapi/uvicorn in deps).
  • Adding the service via the config API (PUT /config/services/lakehouse) validated and persisted correctly.
  • castle deploy lakehouse produced a correct systemd unit, registry entry, and Caddy route, and auto-installed the editable package.
  • castle service enable lakehouse started it and enabled it on boot.
  • Health probe (direct 127.0.0.1:8420) and dashboard data (program / service / deployment / active) were all correct.

Gaps found

#1 — No CLI/app path to create a service from an adopted daemon (High)

castle add writes a daemon-behavior program, but there is no command to turn it into a running service (port, health, proxy, systemd). We had to hand the service block to the config API. Worse: castle install <daemon> on a program with no service silently falls through to the tool install path (uv tool install) instead of running it — a dead end.

Fix: castle expose <program> [--port --health --path] to scaffold a service entry from an existing program. (App needs an equivalent "add service" flow — tracked separately.)

#2 — castle can't actually configure an adopted program's port / data dir (Medium)

The generated unit injects castle's convention vars LAKEHOUSE_PORT=8420 and LAKEHOUSE_DATA_DIR=…, but lakehoused reads LAKEHOUSED_DAEMON_PORT and its own storage paths — it ignores both. The port "worked" only because 8420 is the daemon's built-in default and we declared the same value. Castle's convention assumes a castle-aware program; an adopted one doesn't read <PREFIX>_PORT.

Fix: let a service declare which env var carries the port, e.g. expose.http.port_env: LAKEHOUSED_DAEMON_PORT, so castle sets that to the configured port and genuinely drives the bind. (defaults.env is the manual workaround.)

#3 — castle deploy regenerates the Caddyfile but never reloads Caddy (High, bug)

Deploy wrote the new /lakehouse route to the Caddyfile on disk but didn't reload the running gateway, so every /lakehouse/* request fell through to the castle-app catch-all and returned the dashboard's index.html (a misleading 200). castle service enable doesn't reload either, and the deploy output never mentions castle gateway reload.

Fix: castle deploy (and service enable) reload the gateway when proxy routes changed.

#4 — Path-prefix proxying breaks root-based SPAs (Medium, architectural)

lakehoused's bundled webapp is built with Vite base: "/" — its index.html references assets at absolute /assets/…. Proxied at /lakehouse/, the browser requests /assets/… (no prefix), which hits the castle-app catch-all → the UI can't boot. The API works through the gateway; the UI only works directly at :8420/.

Two distinct cases, because Vite bakes base in at build time (a runtime env in the unit is too late to rebase a pre-built bundle):

  • Case A — frontends castle builds (the react-vite stack, served by file_server). Castle runs pnpm build and knows the serve prefix, so it can pass --base=/<prefix>/ automatically. Today power-graph-app only works because its base was hand-set to match. Fix: derive the build --base from the serve path prefix.
  • Case B — adopted daemons that self-serve a root SPA (lakehouse). Castle never runs their build, so it can't pass --base. The clean answer is host-based routing (lakehouse.civil.lan → :8420) so base: "/" stays valid — also a generally useful castle capability. Fix: support proxy-by-hostname in the Caddyfile generator + manifest.

Nits

  • Redundant editable reinstall: castle deploy installs the package, then castle install/activate may uv tool install it again.
  • Entry-point discovery: the service's run.program had to be lakehoused, not lakehouse — the package ships two console scripts and castle gives no hint which is the server. Surfacing a package's [project.scripts] would help.