[Unit]
Description=Thermograph (FastAPI/uvicorn)
After=network-online.target
Wants=network-online.target

[Service]
Type=exec
User=deploy
Group=deploy
# The repo checkout. uvicorn is run from backend/ so `app:app` resolves.
WorkingDirectory=/opt/thermograph/backend
# Defaults; /etc/thermograph.env (below) overrides. WORKERS is how many uvicorn
# worker processes to run — prod sets WORKERS=3 there; a single-worker box can leave
# it. Multiple workers each keep their own in-process state, so metrics go to a shared
# SQLite DB (THERMOGRAPH_METRICS_DB) that every worker tallies into — otherwise the ops
# dashboard, polling one random worker, would see only a fraction of the traffic.
Environment=WORKERS=1
Environment=THERMOGRAPH_METRICS_DB=/opt/thermograph/data/metrics.db
# THERMOGRAPH_BASE, PORT, WORKERS, etc. See deploy/thermograph.env.example.
EnvironmentFile=/etc/thermograph.env
# Clear the shared metrics DB on each (re)start so the dashboard's "since start" tallies
# reflect the running workers, matching how the old in-process counters behaved.
ExecStartPre=/usr/bin/rm -f /opt/thermograph/data/metrics.db /opt/thermograph/data/metrics.db-wal /opt/thermograph/data/metrics.db-shm
# Bind loopback only — Caddy terminates TLS and reverse-proxies to us.
ExecStart=/opt/thermograph/.venv/bin/uvicorn app:app --host 127.0.0.1 --port ${PORT} --workers ${WORKERS}
Restart=on-failure
RestartSec=2
# Hardening
NoNewPrivileges=true
PrivateTmp=true
ProtectSystem=full
ProtectHome=read-only
# The parquet cache must stay writable across deploys.
ReadWritePaths=/opt/thermograph/data /opt/thermograph/logs

[Install]
WantedBy=multi-user.target