Big Clock

A fullscreen, dark-mode clock with live weather, designed to run on a wall-mounted display. Single HTML file served by nginx inside Docker, deployed via Portainer on a home server.

Features

• Large 12-hour clock with AM/PM indicator
• Current weather + 5-day forecast via Open-Meteo (no API key required)
• Temperature accent colors: blue (cold) → green (mild) → amber (warm) → red (hot)
• Inline SVG weather icons (no external assets)
• Auto-reloads connected browsers when a new version is deployed

URL parameters

All parameters are optional. Without any, the clock defaults to Seattle weather in imperial units.

Parameter	Example	Effect
lat + lon	?lat=47.6&lon=-122.3	Weather for specific coordinates
name	&name=Seattle,+WA	Display name shown above the weather card
city	?city=Berlin	Geocode a city name via Open-Meteo
tz	&tz=America/Los_Angeles	Timezone for the coordinates
units	?units=metric	metric for °C/km/h, default is imperial (°F/mph)
geo	?geo=1	Use browser geolocation

Tech stack

• Frontend: Single index.html — no build step, no framework, no external JS
• Fonts: Inter via Google Fonts
• Weather API: Open-Meteo (free, no key)
• Server: nginx:alpine Docker image
• Orchestration: Docker Compose (compose.yml)
• Deployment: Portainer Git stack (see below)

Local development

Option 1 — Python (fastest, no Docker required):

python3 -m http.server 8080
# Open http://localhost:8080

Option 2 — Docker Compose (matches production):

docker compose up --build
# Open http://localhost:8088

Deployment

The app runs as a Portainer Git stack on a home server. Portainer polls this GitHub repo every 5 minutes. When it detects a new commit on main, it pulls the repo and runs docker compose up --build.

How a deploy flows end-to-end

1. Edit index.html
2. Update build-version.txt (e.g. release-YYYYMMDD) — this is the deploy trigger
3. Commit and push to main
4. Within 5 minutes, Portainer detects the new commit and rebuilds the Docker image
5. The Dockerfile copies build-version.txt into the image as /version.txt
6. The page polls /version.txt every 15 seconds; when the value changes, it auto-reloads all open browser tabs

Why build-version.txt matters

Portainer rebuilds the image from scratch on each detected change, but Docker's layer cache would serve a stale version.txt if no tracked file changed in that layer. Updating build-version.txt busts the cache for the COPY build-version.txt layer, guaranteeing the new version string lands inside the container.

File structure

index.html          — entire application (clock + weather + auto-reload logic)
build-version.txt   — bumped on each deploy to bust Docker cache and trigger client reload
Dockerfile          — copies index.html and build-version.txt into nginx:alpine
compose.yml         — Docker Compose config; used by Portainer as the Git stack entry point