The firmware publishes status/heartbeat, system/alerts, system/info and
status/playback with retain=true. On every backend (re)connect - every
restart and every uvicorn --reload - the broker replays the last message on
each of those topics for every device that ever connected. We handled those
replays as if they had just happened:
- heartbeats: a row with received_at=now() for every device, so devices
that have been dead for months showed ONLINE for 90s after each restart
and got pinged. ~770k such rows exist locally.
- boot_report: the last boot logged again as a new reboot (the phantom
PANIC entries on the Health tab).
- alerts / other info events: logged again as new occurrences.
MQTT delivers retain=1 only for replays caused by a new subscription; live
publishes always arrive with retain=0. The flag is now passed through to the
handlers and the WS broadcast:
- heartbeat: replays are not stored. A live heartbeat is.
- {"state":"offline"} heartbeat (LWT / graceful disconnect) is no longer
stored as a sign of life. It marks the device offline immediately in
a small in-memory set (mqtt/presence.py) used by /mqtt/status and the ping
loop; a later live heartbeat clears it. Replayed offline markers also mark
offline, since a retained message is the device's last word.
- boot_report: live -> always a new boot. Replay -> stored only if it
differs from the device's latest boot row (i.e. we missed it while down).
- alerts: replay still syncs the current-alert row; history gets a row on a
live alert (even an identical repeat - faults recur) or on a replay that
changes state. Replaces the 98dd16b rule that dropped identical live alerts.
- other info events: replays are not logged.
- Frontend (DeviceList, DeviceDetail, LogsTab) ignores retained WS messages
for live updates, and flips a device offline on the offline marker instead
of marking it online.
Verified locally after a backend restart: only the 7 actually-live devices
got new heartbeat rows (none from the replays), and no boot/alert/info rows
were created.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
React + Vite
This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
Currently, two official plugins are available:
- @vitejs/plugin-react uses Babel (or oxc when used in rolldown-vite) for Fast Refresh
- @vitejs/plugin-react-swc uses SWC for Fast Refresh
React Compiler
The React Compiler is not enabled on this template because of its impact on dev & build performances. To add it, see this documentation.
Expanding the ESLint configuration
If you are developing a production application, we recommend using TypeScript with type-aware lint rules enabled. Check out the TS template for information on how to integrate TypeScript and typescript-eslint in your project.