mtrview 0.4.3

Human-friendly dashboard for mtr2mqtt summary topics

mtrview

mtrview is a small standalone web dashboard for retained JSON summaries published by mtr2mqtt. mtr2mqtt writes the measurement summaries to MQTT; mtrview subscribes to those topics and turns the latest values into a simple human-friendly dashboard.

The app subscribes to summary topics such as summary/<receiver>, keeps the latest summary per receiver in memory, normalizes transmitter readings, and serves a dark auto-updating dashboard at http://localhost:8000/.

MQTT input

By default mtrview subscribes to:

summary/#

Each retained message should be a JSON object with a receiver, an updated_at timestamp, and a transmitters mapping. Transmitter metadata may be partial; missing location, zone, quantity, description, unit, or battery fields are displayed with sensible placeholders instead of failing.

Configuration

Settings are read from environment variables:

Variable	Default
MTRVIEW_MQTT_HOST	localhost
MTRVIEW_MQTT_PORT	1883
MTRVIEW_MQTT_USERNAME	unset
MTRVIEW_MQTT_PASSWORD	unset
MTRVIEW_MQTT_TOPICS	summary/#
MTRVIEW_MQTT_MAX_PAYLOAD_BYTES	1048576
MTRVIEW_MQTT_MAX_RECEIVERS	128
MTRVIEW_MQTT_MAX_TRANSMITTERS_PER_SUMMARY	1000
MTRVIEW_MQTT_MAX_FIELD_LENGTH	512
MTRVIEW_HTTP_HOST	0.0.0.0
MTRVIEW_HTTP_PORT	8000
MTRVIEW_REFRESH_INTERVAL_SECONDS	20
MTRVIEW_DISPLAY_TIMEZONE	UTC
MTRVIEW_UPDATE_CHECK_ENABLED	true
MTRVIEW_UPDATE_CHECK_URL	GitHub latest release API
MTRVIEW_UPDATE_CHECK_INTERVAL_SECONDS	21600

See .env.example for a copyable starting point.

Local run

uv sync --group dev
uv run mtrview

Then open http://localhost:8000/.

Useful endpoints:

• GET / - dashboard
• GET /api/summary - normalized JSON for all receivers and transmitters
• GET /health - health status

Docker

docker build -t mtrview .
docker run --rm -p 8000:8000 \
  -e MTRVIEW_MQTT_HOST=host.docker.internal \
  -e MTRVIEW_MQTT_TOPICS=summary/# \
  mtrview

Published Docker images support linux/amd64, linux/arm64, linux/arm/v7, and linux/arm/v6 for Pi Zero-class 32-bit ARM devices. The image intentionally uses Uvicorn without optional native performance extras so old Raspberry Pi targets can install dependencies without a compiler and the runtime image stays small.

Dashboard

The UI is server-rendered first, with a small vanilla JavaScript refresh loop that fetches /api/summary. It includes summary counts, MQTT connection state, search, status/zone/receiver filters, card and compact table views, and a priority section for non-online readings. Transmitter battery state is shown in the card, table, and detail views when present. Battery labels are derived from voltage: full at 3.1 V or higher, good at 2.9-3.0 V, medium at 2.7-2.8 V, low at 2.6 V, and critical at 2.5 V or lower.

MQTT summaries that exceed the configured payload, receiver, transmitter, or string-field limits are ignored and logged so malformed or oversized retained messages cannot grow dashboard memory and CPU use without bound.

The dashboard footer shows the running mtrview version. By default the browser asks /api/version for update status, and the server checks the latest GitHub release with a six-hour cache. Set MTRVIEW_UPDATE_CHECK_ENABLED=false to disable outbound update checks, or set MTRVIEW_UPDATE_CHECK_URL to another compatible JSON endpoint that exposes tag_name or name.

Development

make install
make verify

Individual checks:

uv run pytest
uv run ruff check .

Releases

Releases are managed by GitHub Actions using Conventional Commits and semantic-release. Merges to master can create GitHub releases, publish the Python package to PyPI, and publish multi-arch Docker images to Docker Hub as tvallas/mtrview.