# android-builder

Native `linux/arm64` Android build toolchain for CI, published to the Gitea
container registry at `git.helu.ca/r/android`.

App repos consume this image to build signed release artifacts. Instrumented
tests are **not** part of this toolchain — by design, CI builds are promotions
of code already tested in Dev (on Apple silicon, where the emulator runs
natively). The OCI Ampere (aarch64) runner has no `/dev/kvm` (the guest VM
boots at EL1, so KVM can't access HYP/EL2), so there's no accelerated emulator
here — and we don't need one.

## What's in the image

- Eclipse Temurin JDK 21 (native arm64)
- Android cmdline-tools, platform, and build-tools — **baked in**, so prod
  builds don't depend on Google's download endpoint at job time
- `git`, `curl`, `unzip`

Pinned versions live as `ARG`s at the top of the `Dockerfile`:

| ARG                     | Default     | Where to check |
| ----------------------- | ----------- | -------------- |
| `CMDLINE_TOOLS_VERSION` | `13114758`  | https://developer.android.com/studio#command-line-tools-only |
| `BUILD_TOOLS_VERSION`   | `35.0.0`    | SDK Manager / release notes |
| `PLATFORM_VERSION`      | `android-35`| your app's `compileSdk` |

`aapt2` and the build-tools binaries ship native arm64 for 35.x, so packaging
runs without emulation.

## Tagging model

The whole point of owning this image is that **app repos pin a tag and a new
toolchain never lands in a prod build by accident.**

- **Immutable** — a git tag like `2026.06` produces `git.helu.ca/r/android:2026.06`.
  This is what app repos pin to.
- **Moving** — pushes to `main` (and any tag build) refresh
  `git.helu.ca/r/android:latest` for convenience. Don't pin prod builds to this.

## Cutting a new toolchain

1. Update the `ARG` defaults in the `Dockerfile` if you're moving SDK/tool
   versions. Verify `CMDLINE_TOOLS_VERSION` against the link above — a stale
   number 404s the image build.
2. Commit to `main`. The workflow builds and pushes `:latest`; confirm it's green.
3. Tag the release with the year-month you want app repos to reference:
   ```
   git tag 2026.06
   git push origin 2026.06
   ```
   This publishes the immutable `git.helu.ca/r/android:2026.06`.
4. Roll app repos forward deliberately by bumping their pinned tag (see below)
   — one at a time if you want to validate, all at once if you trust the bump.

## Using it in an app repo

Drop `.gitea/workflows/build.yml` (the template alongside this repo) into the
app and pin the toolchain:

```yaml
jobs:
  build:
    runs-on: [self-hosted, arm64]
    container:
      image: git.helu.ca/r/android:2026.06
      credentials:
        username: ${{ gitea.actor }}
        password: ${{ secrets.GITEA_TOKEN }}
```

The build task is selectable: `assembleRelease` (APK, the default) or
`bundleRelease` (AAB — only needed for Google Play distribution).

### Required secrets in each app repo (or org-level)

Signing happens at job time; nothing sensitive lives in the repo or the image.

| Secret              | What it is |
| ------------------- | ---------- |
| `KEYSTORE_BASE64`   | release keystore, base64-encoded: `base64 -w0 release.keystore` |
| `KEYSTORE_PASSWORD` | keystore password |
| `KEY_ALIAS`         | signing key alias |
| `KEY_PASSWORD`      | key password |

`GITEA_TOKEN` needs `write:package` here (to push) and `read:package` in app
repos (to pull). The built-in token usually covers this; if your instance
scopes it tightly, use a PAT.

## First-run sequencing

The image must exist in the registry before any app workflow can pull it.
So: cut and push `2026.06` from this repo first, confirm it's in the registry,
*then* the app workflows that pin it will resolve.