# Why is the DLR shut today?

A single-page site that displays one randomly chosen message in the centre of
the screen. The message changes on every page load and whenever the
**Check again** button is pressed.

The site is themed around the Docklands Light Railway colour scheme, with a
toggle between:

- **Modern colours** — the current DLR turquoise/teal branding.
- **Original colours** — the 1987 DLR red-and-blue livery.

The chosen theme is remembered between visits via `localStorage`.

## Adding messages

Edit `messages.js` and fill the `MESSAGES` array with your own reasons — one
string per entry. Entries are inserted as plain text. Until you add some, the
page shows a fallback prompt.

## Running

It is a static site with no build step. Open `index.html` in a browser, or
serve the directory with any static file server, for example:

```sh
python3 -m http.server
```

## Container

The site is packaged as a container based on `nginxinc/nginx-unprivileged`. It
runs as a non-root user and listens on port **8080**, serving the static files
and exposing a `/healthz` endpoint. It is designed to sit behind an external
reverse proxy that terminates TLS and routes by host.

Build and run locally:

```sh
docker build -t dlr .
docker run --rm -p 8080:8080 dlr
# then browse http://localhost:8080
```

## CI

`.gitea/workflows/build-and-publish.yml` builds the container with Gitea Actions
on every push to `main` and on pull requests. Pull requests build the image but
do not push. The registry host is derived from the Gitea server URL. Images are
built for `linux/amd64` and `linux/arm64` (armv8) and published as a single
multi-arch manifest; the arm64 build runs under QEMU emulation.

Authentication requires a Personal Access Token with package read/write scope,
because the automatically provided `GITEA_TOKEN` does not carry container
registry write permission on most Gitea instances. Create the token under an
account with write access to the target package namespace, then store it as a
repository Actions secret named `PACKAGES_TOKEN`.

### Automatic releases

The published image is `<gitea-host>/<owner>/<repo>`. Releases are derived from
[Conventional Commits](https://www.conventionalcommits.org/). On each push to
`main`, the workflow inspects the commits since the last `v*` tag and computes
the next version:

- `feat:` → minor bump,
- `fix:` / `perf:` → patch bump,
- `!` or `BREAKING CHANGE` → major bump,
- anything else (`chore`, `ci`, `docs`, `build`) → no release.

When a release is warranted, the image is published with `X.Y.Z`, `X.Y`, `X` and
`latest` tags, and the workflow records an annotated `vX.Y.Z` git tag so the next
release is computed from it. Pushes to `main` that warrant no release are
published under a `sha-<short>` tag only, so `latest` always points at the most
recent release rather than the newest commit.

Recording the release tag requires the workflow's `contents: write` permission;
if the instance forbids the automatic token from pushing, supply a PAT with
repository write scope and push the tag with it instead.

## Dependency updates

`renovate.json` configures Renovate to keep dependencies current:

- the Dockerfile base image,
- the actions used in the Gitea workflow,
- versioned front-end dependencies referenced in HTML.

There are currently no external front-end dependencies. When one is added via a
CDN, Renovate will track it if it is either annotated with a comment, e.g.

```html
<!-- renovate: datasource=npm depName=bootstrap -->
<link href="https://cdn.example.com/bootstrap@5.3.3/dist/css/bootstrap.min.css" rel="stylesheet">
```

or referenced through a versioned jsDelivr / unpkg npm URL, which is detected
automatically.

Renovate is configured to commit updates as `fix(deps): …`. Each merged Renovate
PR therefore registers as a patch-level change, so the release workflow above
cuts a new patch release and tags the image automatically.

## Files

| File                                  | Purpose                                          |
| ------------------------------------- | ------------------------------------------------ |
| `index.html`                          | Page structure.                                  |
| `styles.css`                          | Both colour schemes, selected via `data-theme`.  |
| `messages.js`                         | The list of messages (fill this in).             |
| `script.js`                           | Random message selection and the theme toggle.   |
| `Dockerfile` / `default.conf`         | Container image and nginx static-serving config. |
| `.gitea/workflows/`                   | Gitea Actions build-and-publish pipeline.        |
| `renovate.json`                       | Renovate dependency-update configuration.         |