web/app.py started two long-lived background jobs under a leader election: the
Discord gateway bot and an APScheduler. Both are stateful I/O loops -- reconnect,
RESUME, heartbeat, backoff, interval timers -- living inside an async web app
that also has to serve requests. This moves them into a single Go binary.
Go owns ONLY the stateful I/O. It owns no climate or grading logic: anything
needing data calls back into Python over a new internal-only HTTP surface
(/internal/discord/grade, /internal/jobs/warm-cities, /internal/jobs/indexnow).
Grading depends on polars and the parquet cache; reimplementing it in Go would
make the bot's grades drift from the API's, and the slash-command path
deliberately shares one grade builder so the two can never disagree. The grade
route returns gateway-ready JSON -- including the ephemeral-flag drop that
discord_bot.py used to do -- and Go relays those bytes verbatim without parsing
the embed.
Packaging: the binary is built by a golang:1.26 stage in the backend Dockerfile
and shipped in the SAME image, run as a second compose service off the SAME tag.
The daemon and backend share the /internal/* contract, so they must never skew
versions; one image makes that structural rather than a convention. Its
entrypoint bypasses entrypoint.sh -- the backend owns alembic, and two racing
migrators is a real hazard.
replicas: 1 in the Swarm stack is load-bearing. Discord permits exactly one
gateway connection per bot token; the pin replaces core/singleton.claim_leader
for this workload. update_config uses order: stop-first, since start-first would
briefly run two gateways. autoscale.sh targets ${STACK_NAME}_web only, so it
cannot scale this.
Security: the internal routes compare the token with hmac.compare_digest and the
whole router 404s when THERMOGRAPH_INTERNAL_TOKEN is unset -- fail closed, never
default open. Caddy only routes /api/*, /digest and /discord/interactions to the
backend, so /internal/* was never publicly reachable; the token is defence in
depth. The router mounts before the catch-all frontend proxy so /internal/*
cannot fall through to it. The daemon refuses to start without the token.
Behaviour preserved from the Python, with the reasoning carried into the Go
comments: non-privileged intents (no MESSAGE_CONTENT, so no portal review);
fatal close codes 4004/4010-4014 stop rather than loop; the bot-author and
self-author mention-loop guard; allowed_mentions locked to {"parse":[],
"replied_user":true} so a crafted query cannot turn a reply into an @everyone
ping; the first cron tick deferred one full interval rather than firing at boot,
since warm-cities already runs at deploy time; and no overlapping warm-cities
run, which would double-spend the archive-fetch quota.
Two deliberate improvements over the Python. A close intended for RESUME now
uses 4000 rather than 1000 -- Discord invalidates a session closed 1000/1001, so
the Python's default close silently defeated its own resume. And MESSAGE_CREATE
is handled on a bounded worker pool rather than an unbounded thread hand-off, so
a flood of mentions cannot spawn unbounded work against the backend.
A .dockerignore is added because a disposable backend/.venv was being swallowed
by COPY . /app/ and duplicated again by the chown layer, inflating the image to
1.8 GB; it builds at 578 MB.
Tests: 29 Go gateway tests covering every behaviour the deleted
test_discord_bot.py asserted, plus cron/config/apiclient suites; 10 new Python
tests for the internal routes (fail-closed, auth, flag drop, per-job 409 guard).
Full suite 359 passed / 7 skipped; go build, vet and test -race clean.
The cutover moved the host checkout's deploy tree to /opt/thermograph/infra/deploy/,
but the stack file's absolute bind sources (db init, env-entrypoint.sh, autoscale.sh)
still pointed at the old /opt/thermograph/deploy/ -- a service update kept the stale
mounts and new tasks failed with 'bind source path does not exist'.
/opt/thermograph becomes a monorepo checkout: deploy.sh gains INFRA_DIR (git
ops at the root, compose work cd'd into infra/), lock/tags/render paths move
under infra/deploy/, image-path defaults become emi/thermograph/backend|
frontend across compose, stack, and the tag-prune. docker-compose.yml pins
name: thermograph -- without it compose run from .../infra derives project
"infra" and recreates the whole stack beside the running one;
deploy-dev.sh pins COMPOSE_PROJECT_NAME=thermograph-dev (env wins over the
file key) to keep LAN dev's separate project.
