thermograph/backend/daemon

thermograph-daemon

Single Go binary that owns the backend's long-lived stateful I/O: the Discord gateway connection (IDENTIFY/RESUME/heartbeat/reconnect backoff) and the recurring-job timers (warm-cities, IndexNow). It replaces the two in-process background jobs web/app.py used to run under leader election — one daemon replica makes the single-connection invariant a deployment fact instead of a runtime election.

The Go/Python split

Go here owns no climate or grading logic. Grading depends on polars and the parquet cache, and the slash-command path deliberately shares one grade builder with the API so bot grades and API grades never drift. So anything data-shaped is a POST back into the Python app's internal-only routes:

Route	Purpose
POST /internal/discord/grade	{"query": "phoenix"} → gateway-ready Discord message JSON, relayed to Discord verbatim
POST /internal/jobs/warm-cities	trigger the warm-cities job
POST /internal/jobs/indexnow	trigger the IndexNow check-and-submit

Every request carries X-Thermograph-Internal-Token. Caddy never routes /internal/* to the backend, so the token is defence in depth, not the only control. If THERMOGRAPH_INTERNAL_TOKEN is unset, the Python side disables the routes and this daemon refuses to start (fail closed on both ends).

Configuration (env)

Var	Required	Meaning
THERMOGRAPH_INTERNAL_TOKEN	yes	shared secret for the internal routes
THERMOGRAPH_API_BASE_INTERNAL	yes	backend base URL, e.g. http://web:8137
THERMOGRAPH_DISCORD_BOT	no	1/true/yes/on enables the gateway
THERMOGRAPH_DISCORD_BOT_TOKEN	no	bot token (gateway stays off without it)
THERMOGRAPH_WARM_CITIES_INTERVAL_HOURS	no	default 24; malformed → default
THERMOGRAPH_INDEXNOW_INTERVAL_HOURS	no	default 6; malformed → default

Run locally

cd backend/daemon
go build ./... && go vet ./... && go test ./...

THERMOGRAPH_INTERNAL_TOKEN=dev-token \
THERMOGRAPH_API_BASE_INTERNAL=http://localhost:8137 \
go run .

Deployed as /usr/local/bin/thermograph-daemon in the backend image.