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btcprice/README.md
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# btcprice
Bitcoin price tracker UI. Serves an HTML page with live price updates streamed from
[btcdata](../btcdata), which this server proxies over WebSocket and renders as HTML fragments
for HTMX.
## Quick Start
```bash
# Start btcdata first (provides price data)
cd ../btcdata && make run
# Local dev — creates .venv and installs requirements on first run
make run # starts on port 4000
make tailwind # watch Tailwind CSS (separate terminal)
```
Optionally `cp .env.example .env` to override `BTCDATA_URL`; without it the code default
(`http://localhost:4100`) applies. `make run-local` requires a `.env` defining
`BTCDATA_LOCAL_URL`.
Run the test suite with `make test`. Test-only packages are kept in `requirements-dev.txt` and are
not installed in the production image.
## Docker
`docker compose up -d` starts **btcprice only** — it does not bring up btcdata. Both compose
files attach to the external `btc-network`, so create it once and start btcdata separately:
```bash
docker network create btc-network # once
cd ../btcdata && docker compose up -d
cd ../btcprice && docker compose up -d
```
| Service | Local dev | Docker |
|----------|----------------|---------------------------------------|
| btcprice | localhost:4000 | localhost:4041 (container port 4040) |
| btcdata | localhost:4100 | localhost:4102 |
Inside `btc-network`, btcprice reaches btcdata as `http://btcdata:4102`.
## CI images
Pushes to the `main` branch and tags matching `v*` run
`.gitea/workflows/build.yml`. The workflow tests the application and publishes linux/amd64 images
to `harbor.pmagnus.cloud/btcprice/btcprice`. Branch builds receive an immutable
`main-<UTC timestamp>` tag (for Flux selection) and a SHA-qualified companion tag; release tags
receive the version without `v` and a SHA-qualified companion tag. The image embeds the short Git
SHA, available from `/api/version`.
The workflow requires the repository secrets `HARBOR_ROBOT_USER` and `HARBOR_ROBOT_TOKEN`. It only
pushes images and intentionally has no Kubernetes credentials.
## Legacy deployment (citadel)
```bash
./deploy-citadel.sh
```
Same method as `../elprice/deploy-citadel.sh`: builds the image locally for the target's
architecture (citadel is x86_64 → `linux/amd64`), copies `docker-compose.citadel.yml` and
`.env.citadel` to `/home/pmp/apps/btcprice` on the host as `docker-compose.yml` / `.env`,
pipes the image over SSH with `docker save | docker load`, and runs
`docker compose up -d --no-build`. No registry involved.
Deployed btcprice listens on **http://192.168.50.195:4041** and proxies to the btcdata running
on citadel as well. Both attach to the external `btc-network` there, so `BTCDATA_URL` is
`http://btcdata:4102` (set in `.env.citadel`) — the service name inside the network, not a LAN
address. The deploy script creates `btc-network` on the host if it does not exist yet.
Overridable: `BTCPRICE_DEPLOY_HOST`, `BTCPRICE_DEPLOY_DIR`, `BTCPRICE_IMAGE_NAME`,
`BTCPRICE_PLATFORM`, `BTCPRICE_NETWORK`.
## Environment Variables
| Variable | Default | Description |
|---|---|---|
| `BTCDATA_URL` | `http://localhost:4100` | btcdata service URL the server proxies to |
| `APP_VERSION` | `development` | Build identifier returned by `/api/version` |
| `BTCDATA_LOCAL_URL` | — | Used by `make run-local` instead of `BTCDATA_URL` |
| `DOCKER_BTCDATA_PORT` | `4102` | btcdata's port inside `btc-network` (local compose only) |
| `BTCPRICE_PORT` | `4041` | Host port in the citadel deployment (`.env.citadel`) |
The HTTP port is not configurable via environment: `make run` hardcodes 4000 and the Docker
image's `CMD` hardcodes 4040.
## Health endpoints
- `/api/health` is a process-only liveness check and remains healthy during a btcdata outage.
- `/api/ready` checks `${BTCDATA_URL}/api/health` with a three-second timeout and returns 503 when
btcdata is unavailable.
- `/api/version` returns the build SHA embedded by CI.
## How It Works
The browser loads a page with HTMX and the WebSocket extension, which connects back to
**btcprice** at `/ws/price` and `/ws/strike` — the browser never contacts btcdata directly.
Each of those endpoints opens an upstream WebSocket to btcdata (`/api/price/ws` and
`/api/strike/ws`), converts each JSON message to an HTML fragment (`price_json_to_html`,
`strike_json_to_html`), and forwards it to the browser. HTMX swaps the received
`<div id="price-display">` / `<div id="strike-display">` into the DOM. Price changes are
color-coded (green up, red down). Reconnection is handled by HTMX.
## Tech Stack
Python · FastAPI · Uvicorn · websockets · HTMX · Tailwind CSS v4
The Clojure implementation this replaced is on the `clojure` branch.