# Nix Runner for Gitea Actions

Custom Docker image for running Nix builds in CI.

## What's Included

- **Nix** with flakes enabled (`experimental-features = nix-command flakes`)
- **Node.js 20** for JavaScript-based GitHub Actions
- **Tools**: git, curl, jq, skopeo, bash, coreutils
- **Binary caches**:
  - `c3.mule-stork.ts.net:8501` (local cache proxy)
  - `cache.nixos.org` (official)

## Usage

In your workflow:

```yaml
jobs:
  build:
    runs-on: nix
    steps:
      - uses: actions/checkout@v4
      - run: nix build .#myPackage
```

The `nix` label is configured in `services/act-runner.hcl`.

## Current Version

**Tag**: `v4`
**Image**: `gitea.v.paler.net/alo/nix-runner:v4`

## Updating the Runner

### 1. Edit `flake.nix`

Make your changes, then bump the tag:

```nix
tag = "v5";  # was v4
```

### 2. Build

```bash
cd nix-runner
nix build
```

### 3. Push to Registry

```bash
skopeo copy --dest-authfile ~/.docker/config.json \
  docker-archive:result \
  docker://gitea.v.paler.net/alo/nix-runner:v5
```

### 4. Update act-runner

Edit `services/act-runner.hcl`:

```hcl
GITEA_RUNNER_LABELS = "ubuntu-latest:docker://node:20-bookworm,nix:docker://gitea.v.paler.net/alo/nix-runner:v5"
```

### 5. Re-register Runner

```bash
sudo rm /data/services/act-runner/.runner
nomad run services/act-runner.hcl
```

The runner will re-register with the new labels.

## Configuration

The image uses `NIX_CONFIG` environment variable for Nix settings:

```
experimental-features = nix-command flakes
sandbox = false
build-users-group =
substituters = http://c3.mule-stork.ts.net:8501 https://cache.nixos.org
trusted-public-keys = cache.nixos.org-1:... c3:...
```

## Troubleshooting

### Build fails with `build-users-group` error

The image runs as root without the nixbld group. This is handled by `build-users-group =` in NIX_CONFIG.

### Can't fetch from cache

Check that the runner container can reach `c3.mule-stork.ts.net:8501` (Tailscale network).

### Missing tool

Add it to `paths` in `flake.nix` and rebuild/push a new version.