dashboards/README.md

# Homelab Dashboards

Three dashboards, one domain, one process, one SQLite file:

| Page        | What it answers                                                                 | Source                                             |
| ----------- | ------------------------------------------------------------------------------- | -------------------------------------------------- |
| `/`         | Is anything wrong, and which dashboard do I need?                               | all of the below, one request                      |
| `/system`   | What are my machines doing — CPU, memory, disk, GPU, network, and the history of all of it | `agent/host_agent.py`, our own stdlib agent per host |
| `/llm`      | Tokens/sec, active sessions, queue depth, KV-cache pressure, latency percentiles | llama.cpp-family (gufo) + vLLM `/metrics`, read-only |
| `/ups`      | Battery health, runtime left, power events, and battery-test buttons             | NUT `upsd` on 3493 (its own wire protocol client)   |

No Prometheus, no Grafana, no CDN, no build step. Nothing is fetched from the internet at
runtime; every asset is served by this app.

Working on this repo? **[`AGENTS.md`](AGENTS.md)** holds the invariants (read-only by
construction, never invent a number, unconfigured ≠ broken), the locked decisions, the real
fleet facts, and the known gaps.

## Quickstart

```bash
uv sync --python 3.14                       # deps + the package, editable
cp .env.example .env                        # then edit
uv run dashboards                           # http://127.0.0.1:8090
uv run uvicorn dashboards.app:app --port 8090   # equivalent
uv run pytest                               # unit tests, no network needed
```

Developing against the real fleet from a laptop (agents stay unexposed — ssh forwards
them to localhost):

```bash
cp .env.dev.example .env.dev                # your ssh aliases + which ports
python3 - <<'PY'                            # push the agent to each host (once)
import shlex, subprocess, pathlib
for host in ("driveripper-ops", "deskwork-ops", "gateway-ops"):
    subprocess.run(["ssh", host, "mkdir -p ~/lab-agent"], check=True)
    subprocess.run(["scp", "agent/host_agent.py", f"{host}:~/lab-agent/"], check=True)
PY
./scripts/dev-tunnels.sh start              # 9121/9122/9123 -> each host's agent,
                                            # + DEV_FORWARDS -> upsd on 127.0.0.1:3494
set -a; . ./.env.dev; set +a
uv run dashboards                           # foreground
./scripts/dev-server.sh restart             # or backgrounded, with a pidfile + logs
```

`DEV_TUNNELS` starts the agent remotely and forwards it; `DEV_FORWARDS` forwards a service
that already listens there (upsd) — that is how the UPS page reads a real battery without
3493 being reachable from anywhere but this laptop.

## The host agent

`agent/host_agent.py` is one file, **stdlib only**, Python 3.10+. It reads `/proc`,
`/sys/block`, `/sys/class/drm` and `statvfs` and answers `GET /snapshot` as JSON.

```bash
python3 host_agent.py --once                                # print one snapshot, exit
python3 host_agent.py --host 0.0.0.0 --port 9120 --token-file /etc/dashboards-agent.token
sudo deploy/install-agent.sh                                # systemd unit + user + token
deploy/install-agent.sh --status                            # unit state and /health
sudo deploy/install-agent.sh --uninstall
```

It is read-only by construction: there is no code path that writes, and the HTTP server
only answers `GET`. Counters are reported as counters — the dashboard computes rates over
a labelled window, so the agent never has to remember who polled it last.

Binding off-loopback without a token is refused (exit 2) rather than warned about. Prefer
`--token-file` over `--token`: argv is world-readable through `ps`, and this token guards
hostname, mounts, disk and GPU models, and process names. `deploy/install-agent.sh` creates
a system user, generates a token once (re-runs reuse it; `--rotate-token` for a new one),
stores it `0600` root-owned, and runs the agent under `ProtectSystem=strict` with no
capabilities — enough to read `/proc`, `/sys` and `statvfs()` and nothing else.

## Configuration

Everything comes from the environment (see `.env.example` for the annotated list). At
startup a `.env` next to the checkout is loaded first if it exists — as a *seed*: a
variable the container, systemd unit, or your shell already set always wins. Point
`DASH_ENV_FILE` somewhere else to keep several installs on one box. `.env.example` is
documentation and is never loaded, and `scripts/dev-server.sh` exports `.env.dev` itself
(see the quickstart) because dev settings must not leak into a production process.

| Variable                              | Meaning                                                        |
| ------------------------------------- | -------------------------------------------------------------- |
| `HOST_TARGETS`                        | `name=url` per host running the agent; a bearer token may ride in the URL userinfo (`http://TOKEN@host:9120`) |
| `HOST_INTERVAL_SECONDS`               | poll interval for hosts (default 10)                            |
| `GUFO_BASE_URL` / `VLLM_BASE_URL`     | LLM engines; unset means *not deployed here*, and its half of the page disappears |
| `RATE_WINDOW_SECONDS`                 | the Δ window behind every measured token rate (default 10)      |
| `NUT_HOST` / `NUT_PORT`               | upsd address. Reads work unauthenticated in stock NUT           |
| `NUT_USER` / `NUT_PASSWORD`           | only needed for instant commands (battery tests)                |
| `NUT_ALLOW_ACTIONS`                   | `1` enables the one write endpoint in the app                   |
| `NUT_SIMULATE`                        | `1` replaces upsd with a **labelled** simulator (development only) |
| `DASH_READ_ONLY`                      | `1` disables every mutating endpoint regardless of other flags  |
| `DASH_DB`                             | SQLite path (default `data/dashboards.sqlite3`)                 |
| `RETAIN_RAW_HOURS` / `RETAIN_MINUTE_DAYS` / `RETAIN_HOUR_DAYS` | history rollup and pruning |

A source that is not configured answers `404 {"configured": false}` **without dialling**,
and the page says "not configured" instead of showing a red panel for something you never
installed.

## Architecture

```
agent/host_agent.py (each host)      gufo / vLLM            upsd (NUT)
        │ GET /snapshot                    │ GET /metrics           │ LIST UPS / LIST VAR
        ▼                                  ▼                        ▼
src/dashboards/collectors.py ────────────────────────────────────────────┐
        │  parse + Δcounter/Δt (rates.py)                                │
        ▼                                                                ▼
sources/host.py · sources/llm.py · sources/nut.py          poller.py (one task per source)
        │        samples                    events                      │
        ▼                                                                 ▼
store.py  ── SQLite (WAL): sample(source,host,metric,res,ts) + event ──  api.py  → web/
```

* `poller.py` — every source gets its own asyncio task, its own health record, and its own
  error handling. A dead host keeps its last good values and is labelled stale; it never
  blanks or blocks another source.
* `store.py` — raw samples roll up to 1-minute and 1-hour averages and the raw rows are
  pruned, so a year of history is a few hundred MB rather than a disk emergency.
* `web/` — four static pages, one stylesheet, hand-rolled SVG charts (`charts.js`). No
  framework, no CDN, no bundler.

## Testing

```bash
uv run pytest                                  # unit + API tests, fully mocked, no network
uv run pytest --cov                            # coverage gate
uv run pytest -m live --live                   # optional: real fleet / engines / upsd
uv run ruff check src tests agent && uv run pyright            # lint + types
./scripts/capture-fixtures.sh                  # re-record ground-truth captures
```

Test philosophy: **real captures as fixtures, mocks for behaviour.** Anything that must
match an upstream (`/proc` layouts, vLLM metric names, NUT protocol framing) is asserted
against a verbatim capture in `tests/fixtures/`; behaviour that needs a failure — upsd
refusing a command, an engine returning 500, a host rebooting — is a fake. The `live` tests
(`tests/test_live_fleet.py`) are the bridge: they SKIP unless you pass `--live`, each one
also skips when its source is unset, they drive the production code paths (`collectors.*`,
`NutMonitor.collect`) against whatever hardware is reachable, and they never write — a
battery test on live hardware is not a unit test.

## Battery-test buttons

Instant commands are the only mutating endpoint in the application (`POST /api/ups/command`)
and they are gated four times: `NUT_ALLOW_ACTIONS=1`, not `DASH_READ_ONLY`, an `upsd.users`
account that actually has the command, and a confirmation in the UI — destructive ones
(deep test, calibration, `load.off`) require typing `DANGER`. The server re-checks every
gate; hiding a button is not a safety control. Commands that would cut power are refused
outright while the UPS is already on battery.

Give the app a narrowly scoped NUT user instead of a god-mode one — per-command `instcmds`,
not `actions = -`:

```ini
# /etc/ups/upsd.users
[dashboards]
    password = "..."
    instcmds = test.battery.start.quick test.battery.start.deep test.battery.stop
```

Bind upsd to loopback (`LISTEN 127.0.0.1` in `upsd.conf`) and reach it with an ssh forward
(`DEV_FORWARDS`) or a tailnet address. `NUT_SIMULATE=1` stands in for upsd during
development; everything it produces is badged `SIMULATED`, and it is never the default.

## Deployment

`Containerfile` is a two-stage build: `uv.lock` is resolved in the builder (exactly the
versions the tests ran against) and the runtime stage is slim Python with nothing but the
venv in it. The host agent is copied in too, so one image can monitor the box it runs on.
In the deployment repo the pattern is the same as every other service: quadlet container +
env template + nginx/SNI on the single domain.

```bash
podman build -t dashboards .
podman run --rm -p 8090:8090 --env-file dashboards.env \
    -v dashboards-data:/var/lib/dashboards dashboards
```

It listens on `0.0.0.0:8090` as an unprivileged user, and the SQLite history lives in
`/var/lib/dashboards` — put a volume there or every restart forgets the charts. With no
sources configured `/api/health` answers `200 {"status": "empty"}`, so the container passes
its health probe before its env file is right instead of crash-looping.