thermograph/deploy/thermograph.env.example
Emi Griffith 1838527854 Gate the subscription notifier to one worker (#161)
Prod runs 3 uvicorn workers, but the in-process subscription notifier was
started in every worker's lifespan (it was written assuming a single-worker
deploy). Its sweep fetches recent-forecast/archive data from Open-Meteo on a
15-min timer independent of any request, so running it 3× tripled the
background upstream load against a shared quota — the source of the overnight
429/503 rate-limit errors in logs/errors, and 3× redundant subscription scans.

Elect one worker to own the notifier via a non-blocking exclusive flock on a
lockfile (THERMOGRAPH_SINGLETON_LOCK): the first worker wins and holds the fd
for its lifetime; others stand down; the OS releases the lock if the leader
dies, so a restart re-elects cleanly. Unset (single worker / dev / tests)
always wins, so behavior there is unchanged. Mirrors the shared-metrics store's
env-selected cross-worker coordination.

The neighbor warmer stays per-worker on purpose: each worker drains its own
request-fed queue, so gating it would leave non-leader queues undrained.

- backend/singleton.py: flock-based leader election (claim()).
- backend/app.py: gate notify.start() on singleton.claim().
- deploy/thermograph.service: default THERMOGRAPH_SINGLETON_LOCK to
  data/notifier.lock (needs the unit reinstalled on prod to take effect).
- deploy/thermograph.env.example: document it alongside WORKERS.
- Tests: leader election — single-worker default, first-wins, idempotent
  re-claim, second-holder stands down, re-election after release. 183 passed.

Co-authored-by: root <root@vmi3417050.contaboserver.net>
2026-07-17 12:54:55 +00:00

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# Copy to /etc/thermograph.env on the VPS and edit.
# Read by the systemd unit (EnvironmentFile).
# Port uvicorn binds on loopback. Caddy proxies to this. Keep 8137 unless it clashes.
PORT=8137
# Number of uvicorn worker processes. More than 1 stops a single slow upstream fetch
# (e.g. a cache-miss weather lookup) from blocking every other request — the cause of
# past brief outages. Prod runs 3; leave unset (defaults to 1) on a small box. Workers
# share one metrics store (THERMOGRAPH_METRICS_DB, defaulted in the systemd unit) so the
# ops dashboard still sees the whole picture, and elect one leader for the subscription
# notifier via a lockfile (THERMOGRAPH_SINGLETON_LOCK, also defaulted in the unit) so its
# timer-driven upstream sweep runs once, not once per worker. ~200 MB RAM per worker.
WORKERS=3
# Base path the app is served under.
# / -> app at the domain root (Thermograph owns the whole domain —
# this is what the Caddyfile expects: thermograph.org proxies "/")
# /thermograph -> app under a sub-path (share the host with other apps, e.g. a
# portfolio at the root)
THERMOGRAPH_BASE=/
# --- SEO: search-engine verification + IndexNow ---------------------------------
# Ownership-verification tokens, rendered as <meta> tags in every page's <head>.
# Google Search Console → add property https://thermograph.org → "HTML tag" method
# → paste just the content="…" value below. (Or verify via DNS TXT and skip this.)
#THERMOGRAPH_GOOGLE_VERIFY=
# Bing Webmaster Tools → add site → "HTML Meta Tag" (msvalidate.01) → paste the
# content value. (Bing can also import verification from Google Search Console.)
#THERMOGRAPH_BING_VERIFY=
# IndexNow key (Bing/DuckDuckGo/Yandex instant re-crawl). Auto-generated to
# data/indexnow_key.txt on first use; set here to pin a specific key.
#THERMOGRAPH_INDEXNOW_KEY=
# Public site URL for IndexNow. The deploy hook auto-pings IndexNow after a
# successful deploy, but only when the URL set changed (a new/removed city), so
# code-only deploys don't resubmit. `make indexnow` forces a full submit.
THERMOGRAPH_BASE_URL=https://thermograph.org
# --- Web Push (VAPID) -----------------------------------------------------------
# Keys that sign push notifications. If unset, the app generates a pair into
# data/vapid.json on first run — fine as long as that file PERSISTS (it lives in the
# writable data dir and survives deploys). PIN them here to be safe: if the keys ever
# change, every existing browser subscription silently stops receiving (the push
# service rejects with 401/403), and users must toggle alerts off/on to re-subscribe.
# Generate a pair: cd backend && ../.venv/bin/python -c "import push,json; k=push._generate(); print('PRIVATE=',k['private_key']); print('PUBLIC=',k['public_key'])"
#THERMOGRAPH_VAPID_PRIVATE_KEY=
#THERMOGRAPH_VAPID_PUBLIC_KEY=
# Contact (mailto: or https URL) sent to push services in the VAPID claim.
#THERMOGRAPH_VAPID_CONTACT=mailto:you@example.com