# Aimee OS Build Container Images

This repository contains the build scripts for the container images that
provide the build environment for Aimee OS projects.  Most projects will use
the _build/build-{target}_ image, which contains a cross-compiler toolchain for
the _{target}_ system (e.g. _aarch64-unknown-linux-gnu_) with Rust support, as
well as several other tools for compiling software and creating bootable OS
images.


## Container Images

There are several images in the collection:

```
gentoo/stage3 †
build/base
└── build/cross-aarch64-unknown-linux-gnu
    └── build/build-aarch64-unknown-linux-gnu ‡
```

† The _gentoo/stage3_ image contains an unmodified Gentoo stage3 system.  It is
used to bootstrap the _build/base_ image.

‡ Although the _build/build-{target}_ image is initially populated from the
corresponding _build/cross-{target}_ image, the final image is "squashed" into
a single layer to minimize download size.


## Git Branches

To enable building images in Jenkins without building all of the preceding
images, each image has its own Jenkins job.  Since Jenkins does not support
(auto discovering) multiple jobs in a single Git repository branch, the build
scripts for the images are tracked in separate branches.  Each branch is named
like _{image}/{sub-branch}_, where _{image}_ is the short name of the image
(e.g. `base`, `cross`, etc) and _{sub-branch}_ is an arbitrary name (e.g.
_main_).

* _base/main_: This branch is responsible for building _gentoo/stage3_ and
  _build/base_.
* _cross/main_: This branch contains the build script for
  _build/cross-{target}_.
* _build/main_: This branch builds _build/build-{target}_.

In addition to the per-image branches, there is also _lib/{sub-branch}_.
Code shared by multiple image build scripts is tracked here.  Build scripts
expect the shared code to be available in the `lib` directory, which is
generally populated using a Git worktree, e.g.:

```sh
git worktree add lib lib/main
```

The _main_ branch itself is empty except for this README.