# How to deploy to Hugging Face Spaces

Push a new version of the site to the HF Space `Bani57/website`. Everything is git-based — there is no build button. The Space rebuilds its Docker image from whatever is on the `main` branch of its repo. For the rationale and full design see [`plans/deploy_huggingface_spaces.md`](../../plans/deploy_huggingface_spaces.md).

## Prerequisites

- The Space `Bani57/website` exists with **SDK = Docker**, **Hardware = CPU basic (free)**.
- Space secrets are set: `DJANGO_SECRET_KEY`, `DJANGO_DEBUG=False`, `DJANGO_ALLOWED_HOSTS=bani57-website.hf.space`.
- The HF Hub model repo `Bani57/checkpoints` exists and contains the current weights. See [Refreshing checkpoints](#refreshing-checkpoints) below.
- Local working tree is on the deployment branch (typically `master`) and tests pass.

## 1. Local container smoke test

Always reproduce production locally before pushing.

```bash
cp .env.example .env
python -c "import secrets; print('DJANGO_SECRET_KEY=' + secrets.token_urlsafe(50))" >> .env
docker compose up --build
```

First build is ~20–30 minutes (mamba solve, GPU torch, frontend bundle, checkpoint download). Subsequent builds reuse layer cache and the `checkpoints` named volume.

Open `http://localhost:7860` and walk through:

- Home page renders, nav works.
- `/cv` renders.
- Each demo page loads and a sample inference completes.
- A bogus URL (`/this/path/does/not/exist`) shows the [Lara Croft 404](../glossary.md#hf-space).
- `GET /api/v1/health` returns `200 ok`.

If anything fails, fix it locally — never push a broken image to the Space.

## 2. Push to the Space

Add the HF git remote (one-time):

```bash
git remote add hf https://huggingface.co/spaces/Bani57/website
```

Then for each release:

```bash
git push hf master:main
```

HF Spaces uses a `main` branch. The Space's Build Logs tab in the web UI shows live build progress. First-time build is again 20–30 min; incremental builds reuse layer cache and run in under 5 min if `requirements.txt` and `environment.yml` haven't changed.

## 3. Verify the live Space

After the build succeeds:

```bash
curl https://bani57-website.hf.space/api/v1/health
```

Then in a browser:

- Visit `https://bani57-website.hf.space`.
- Hard-refresh on a deep route (e.g. `https://bani57-website.hf.space/demos/coins`). The SPA catch-all should serve `index.html` and Vue Router should resolve the route.
- Visit `https://bani57-website.hf.space/foo/bar` and confirm the Lara 404 page appears.
- Run the Postman collection ([`docs/postman/`](../postman/)) against `https://bani57-website.hf.space/api/v1`.
- Watch the Space's Logs tab for the first 5 minutes. Confirm `[entrypoint] checkpoints ready` and a clean `gunicorn ... Listening at: http://0.0.0.0:7860`.

## 4. Rollback

Spaces are fully versioned by git:

```bash
git push hf <previous-good-sha>:main --force
```

Force-push triggers an image rebuild from the rolled-back commit. Checkpoints in the HF Hub model repo are immutable across rollbacks, so no data loss. Use this only when a regression is bad enough that fixing forward isn't practical.

## Refreshing checkpoints

Checkpoints live in `Bani57/checkpoints` on HF Hub, separate from the code repo. To publish new weights:

```bash
huggingface-cli login    # one-time, paste a write token
python scripts/upload_checkpoints.py --create
```

`--create` is safe to repeat; it's a no-op when the repo already exists. The script walks the local `src/research/.../checkpoints/` dirs and uploads every `*.tar` / `*.ckpt` / `*.pt` / `*.pth` / `*.bin` / `*.safetensors`. Existing files with matching hashes are skipped. Use `--dry-run` to list what would be sent before committing to the upload.

After a checkpoint refresh, restart the Space (Settings → "Restart this Space"). The container's entrypoint re-runs `snapshot_download` and picks up the new files.

## Configuring Space secrets

In the Space Settings → Variables and secrets:

- **Secrets** (encrypted, not exposed in logs):
  - `DJANGO_SECRET_KEY` — required. Generate with `python -c "import secrets; print(secrets.token_urlsafe(50))"`.
  - `HF_TOKEN` — strongly recommended. A read-scope token (huggingface.co/settings/tokens → New token → Read) lifts anonymous rate limits and roughly triples checkpoint download throughput on cold starts. Required only if the checkpoint repo is private.
- **Variables** (visible in logs and to viewers of the Space metadata):
  - `DJANGO_DEBUG=False`.
  - `DJANGO_ALLOWED_HOSTS=bani57-website.hf.space`.
  - `CORS_ALLOWED_ORIGINS=https://bani57-website.hf.space` (only matters if a third party calls `/api/v1` directly; the SPA itself is same-origin).
  - `TORCH_DEVICE=cpu` (override on a paid GPU SKU).

Changing a variable or secret triggers an automatic Space restart.

## Optional: persistent storage

Free Spaces have 50 GB ephemeral disk that resets on restart, so every cold start re-downloads ~5.4 GB of checkpoints. The first request after a restart waits for `snapshot_download` to finish. For ~$5/month, the Space's **Persistent Storage** tier puts `/data` on a permanent volume. To use it, set the variable `CHECKPOINTS_ROOT=/data/checkpoints` in the Space settings. The container's `entrypoint.sh` will write the snapshot there; subsequent restarts find it already populated. The default unifies `CHECKPOINTS_ROOT` with `RESEARCH_ROOT=/app/research`, so checkpoints land alongside the bundled research code on free tier — clean for one-shot deploys, costly to re-pull on every restart.

## See also

- [explanation/architecture.md](../explanation/architecture.md) — what the deployed container actually does.
- [explanation/inference-lifecycle.md](../explanation/inference-lifecycle.md) — boot sequence inside the container.
- [`plans/deploy_huggingface_spaces.md`](../../plans/deploy_huggingface_spaces.md) — the design doc that this guide implements.