WeatherLink Bridge

A Python service that polls the Davis WeatherLink v2 API and forwards personal weather station observations to Weather Underground and Windy. It is a clean rewrite of the original Node.js app, adding robust configuration management, Prometheus metrics, and a production-ready container image.

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Architecture

WeatherLink API
      |
      v
WeatherLinkCollector  (httpx, X-Api-Secret header)
      |
      v
WeatherObservation    (canonical imperial fields, Pydantic v2)
      |
      +----> FieldMapper(wunderground.yaml) --> WundergroundPublisher --> WU HTTPS API
      |
      +----> FieldMapper(windy.yaml)        --> WindyPublisher        --> Windy v2 API
                  (unit transforms: °F→°C, mph→m/s, inHg→Pa, in→mm)

Prometheus /metrics on METRICS_PORT (default 8080)
  - wl_fetch_total, publish_total, collection_run_total
  - observation_value (per-field gauge)
  - last_successful_cycle_timestamp  <-- liveness signal

Publishers are registered via PublisherFactory — adding a new destination (CWOP, PWSWeather, …) requires only a new YAML sensor map and a publisher class.

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Quickstart

Prerequisites: Python 3.12+, uv.

# Clone and install
git clone https://github.com/rodenj1/weatherlink-bridge.git
cd weatherlink-bridge

# Copy the example env file and fill in your credentials
cp .env.example .env
$EDITOR .env

# Run directly (reads .env automatically)
uv run weatherlink-bridge

# Or install into a venv and run the console script
uv sync
weatherlink-bridge --version
weatherlink-bridge

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Configuration Reference

All configuration is via environment variables (or a .env file in the working directory). Nested settings use the __ delimiter.

Variable	Required	Default	Description
WEATHERLINK__API_KEY	Yes	—	WeatherLink v2 API key
WEATHERLINK__API_SECRET	Yes	—	WeatherLink v2 API secret
WEATHERLINK__STATION_ID	Yes	—	WeatherLink station ID
WUNDERGROUND__ENABLED	No	false	Enable Weather Underground publishing
WUNDERGROUND__STATION_ID	No	""	WU PWS station ID (e.g. KCASANDI123)
WUNDERGROUND__PASSWORD	No	""	WU station key / password
WINDY__ENABLED	No	false	Enable Windy publishing
WINDY__STATION_ID	No	""	Windy station ID (numeric)
WINDY__PASSWORD	No	""	Windy station password (see note below)
UPDATE_INTERVAL_MINS	No	5	Poll interval in minutes (minimum 5)
METRICS_PORT	No	8080	TCP port for Prometheus /metrics
LOG_LEVEL	No	INFO	Log verbosity (DEBUG, INFO, WARNING, ERROR)

Windy credentials note

Windy uses a per-station password for uploads, not the management API key. Find it at stations.windy.com under My Stations → Station settings → Key/Password. Set this value in WINDY__PASSWORD.

Weather Underground credentials note

WU needs the station ID (WUNDERGROUND__STATION_ID, e.g. KCASANDI123) and the station key / password (WUNDERGROUND__PASSWORD). Both are found in the WU device management dashboard.

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Running with Docker

Single container

# Pull the latest image
docker pull ghcr.io/rodenj1/weatherlink-bridge:latest

# Run with a .env file
docker run --rm --env-file .env -p 8080:8080 ghcr.io/rodenj1/weatherlink-bridge:latest

docker-compose

cp .env.example .env
$EDITOR .env          # fill in real credentials
docker compose up -d
# metrics available at http://localhost:8080/metrics

The image is published to ghcr.io/rodenj1/weatherlink-bridge for both linux/amd64 and linux/arm64 (suitable for Raspberry Pi / ARM homelab).

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Running on Kubernetes

Manifests are under deploy/k8s/.

# 1. Create the namespace
kubectl create namespace weather

# 2. Copy the secret example, fill in real values, apply
cp deploy/k8s/secret.example.yaml deploy/k8s/secret.yaml
$EDITOR deploy/k8s/secret.yaml   # add real credentials
kubectl apply -f deploy/k8s/secret.yaml

# 3. Apply the rest
kubectl apply -f deploy/k8s/deployment.yaml
kubectl apply -f deploy/k8s/service.yaml

# Verify
kubectl -n weather get pods
kubectl -n weather logs -f deployment/weatherlink-bridge

Do not commit secret.yaml with real values. Use Sealed Secrets or a secrets manager to encrypt before committing.

The Deployment is intentionally replicas: 1 — two replicas would double-upload every observation to WU and Windy.

Liveness and readiness probes

Both probes hit GET /metrics on port 8080. The liveness probe also lets you monitor last_successful_cycle_timestamp in Prometheus — if that gauge is older than 2 * update_interval_seconds, the service may be stalled.

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Metrics

The service exposes Prometheus metrics at http://<host>:8080/metrics.

Metric	Type	Description
wl_fetch_total	Counter	WeatherLink fetch attempts (status=success|error)
wl_fetch_duration_seconds	Histogram	WeatherLink API latency
publish_total	Counter	Publisher attempts (publisher=wu|windy, status=success|failure|skipped)
publish_duration_seconds	Histogram	Publisher call latency
collection_run_total	Counter	Full cycle outcomes (status=success|partial|error)
collection_run_duration_seconds	Histogram	Full cycle duration
observation_value	Gauge	Latest numeric field value per field + station
last_successful_cycle_timestamp	Gauge	Unix timestamp of last successful fetch (liveness signal)
update_interval_seconds	Gauge	Configured poll interval
weatherlink_bridge_info	Info	App version

Liveness vs freshness

• Liveness (last_successful_cycle_timestamp): advances after every successful WeatherLink fetch, regardless of publisher outcomes. Alert if time() - last_successful_cycle_timestamp > 2 * update_interval_seconds.
• Publisher health: monitor publish_total{status="failure"} separately. Publisher failures do not gate liveness — a rate-limited or temporarily unavailable WU/Windy should not restart the pod.

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Migration from the Node.js version

Old environment variable	New environment variable	Notes
WEATHERLINK_API_KEY	WEATHERLINK__API_KEY	Delimiter changed (_ → __)
WEATHERLINK_API_SECRECT	WEATHERLINK__API_SECRET	Typo fixed (SECRECT → SECRET)
WEATHERLINK_STATION_ID	WEATHERLINK__STATION_ID	Delimiter changed
WUNDERGROUND_ID	WUNDERGROUND__STATION_ID	Renamed for clarity
WUNDERGROUND_KEY	WUNDERGROUND__PASSWORD	Renamed; this is the station password
UPDATE_INTERVAL_MINS	UPDATE_INTERVAL_MINS	Unchanged
PORT	METRICS_PORT	Renamed; default is now 8080

Sensor map: sensor_map.json is replaced by YAML files in config/sensor_maps/ (wunderground.yaml, windy.yaml). The YAML format supports field transforms (unit conversions) and is checked into version control.

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Development

# Install all deps including dev tools
uv sync

# Run tests with coverage
uv run pytest

# Lint + format check
uv run ruff check src tests
uv run ruff format --check src tests

# Type-check
uv run pyright src
uv run mypy src

# Pre-commit hooks (runs on every commit)
uv run pre-commit install
uv run pre-commit run --all-files

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License

MIT — see LICENSE.