mg4/web

Nils' MG4 — car server

Next.js app, self-hosted at car.stinnesbeck.com: the ingest API the car writes to, the ABRP forwarder, and a phone-shaped dashboard for reading the history back. Data lives in InfluxDB 2. Based on upstream's Vercel/MongoDB app in FatihsMG4.

car ──live telemetry───▶ server ──▶ ABRP  api.iternio.com/1/tlm/send
    ──daily chunks─────▶   │
    ──charging sessions▶   ▼
                       InfluxDB 2

Credentials

	Who holds it	What it opens
INGEST_TOKEN	the car, entered in the app	the write endpoints, and the car's own history read
DASHBOARD_PASSWORD	you, in a browser	the dashboard and the GET /v1/history reads
ABRP_API_KEY, ABRP_USER_TOKEN	only the server	forwarding live telemetry to ABRP

The ABRP credentials never reach the car. A missing or empty one switches forwarding off.

Environment variables

See .env.example. In Kubernetes they come from the Secret in ../k8s/.

Name	Notes
INFLUX_URL, INFLUX_TOKEN, INFLUX_ORG, INFLUX_BUCKET	bucket defaults to mg4; the token needs read/write on it
INGEST_TOKEN	at least 24 characters, or every write is refused: openssl rand -hex 32
DASHBOARD_PASSWORD	at least 8 characters, or login is refused outright
SESSION_SECRET	openssl rand -hex 32; rotating it signs every browser out
ABRP_API_KEY, ABRP_USER_TOKEN	optional; both needed to forward
ABRP_MIN_INTERVAL_SECONDS	default 5

Endpoints

Write, Authorization: Bearer <INGEST_TOKEN>:

• POST /v1/telemetry — { installationId, samples: [...] }, up to 500 samples in ABRP's tlm field names and units (utc in epoch seconds; flags as 0/1 or booleans). Stored, then the newest sample is forwarded to ABRP if it is under 5 minutes old.
• PUT /v1/consumption/daily — one delta chunk of a day's consumption.
• PUT /v1/charging-sessions/:sessionId

Read:

• GET /v1/consumption/history/:installationId — ingest token; the car reads its own totals back.
• GET /v1/history/:installationId/consumption, .../charging — session cookie or Authorization: Bearer <DASHBOARD_PASSWORD>.

GET /v1/health is unauthenticated and returns {"status":"ok"}.

Storage

One bucket, installationId tag on every point:

Measurement	Timestamp	Tags	Fields
telemetry	sample utc	—	the ABRP fields that were sent
consumption_chunk	recordedAt	date	km, kwh, hours, socDrop, sohPercent
charging_session	startedAt	sessionId	endedAtMs, duration, energy, cost, start/end SOC
charging_curve	point time	sessionId	powerKw, socPercent

A point with the same measurement, tags and timestamp replaces the earlier one, so the car's retries are idempotent: a cached chunk is re-sent with its original recordedAt. Days and the lifetime total are summed from the chunks when read. All numbers are written as floats, because InfluxDB fixes a field's type on first write.

Local development

nix develop                  # from the repository root: Node 22 and InfluxDB 2
cp .env.example .env.local   # Next loads .env.local automatically
npm install
npm run dev
npm test                     # validation, aggregation and forwarding rules; no database

Container image

podman build -t git.stinnesbeck.com/nils/mg4-server:<version> .
podman push git.stinnesbeck.com/nils/mg4-server:<version>

The build runs the unit tests. The image runs as UID 10001 and listens on port 3000.