APK Build Chroot tool

There are various build chains surrounding Alpine. Most solutions use containerization, QEMU, or other technologies; meanwhile I just wanted a simple way to build packages and install development utilities without shitting up my production system. abchr is an attempt to create a simple solution to my simple problem. It isn't very flexible, requires root access for chroot, and won't allow you to (easily) build for multiarch, but it works.

Installation

1. Create a directory and four subdirectories named bin, alpine, aports, and packages. Your tree should look like this:

   + abchr
     + bin
     + alpine
     + aports
     + packages
   

2. Clone the repo to the bin directory.
3. Run abchr-newchroot to populate the alpine directory with a new installation of Alpine Linux.
4. To ensure everything worked, run abchr abuild -h. You should see the help text for abuild, which should be installed in the chroot.

Usage

abchr-newchroot

This command downloads the latest apk-tools-static into the chroot and installs the basic packages necessary for a build environment. It also creates a user in the chroot with its UID set to the current user UID. Having this be your own UID is optimal as it lets you manupulate the chroot files easily.

If you run the script as root, the UID will not be populated automatically. Pass the desired UID and primary GID as arguments to the script for the user to be created correctly. In general, you should just run this as your normal user that you will be using when you interact with the chroot.

abchr

abchr does not accept any switches or options. The command simply sets up the chroot and starts whatever program is specified in its arguments―they are all passed as-is to the underlying shell in the chroot.

The aports directory is mounted into the chroot under the /home/abuild/aports directory, and if your shell is within that directory structure, you will be moved to that same location within the chroot. For example, if you want to build aports/testing/somepackage, all you need to do is cd into that directory and run abchr abuild -r. You will be moved into the chroot and placed into the directory /home/abuild/aports/testing/somepackage automatically, before the abuild -r command is run.

The upside of being a chroot is you can customize the installation however you like, including installing and configuring shells and other features. If on the same filesystem, you should also be able to hardlink (i.e. same inode) files from your normal user into the chroot, to have a generally unified userland.

Do recall that Alpine runs on Musl, so you may not be able to simply link binaries built for other C libs and have it work in the chroot.

Convenience links

abuild, abump, etc. are links to abchr provided for youe convenience. The script recognizes if it has been called with a name other than abchr, and will automatically prefix any passed arguments with the link name, so you don't have to explicitly type out abchr abuild or similar every time.

As such, adding the bin directory to your path will thus allow you to run abuild like you normally would and have it just work, as long as you're within the aports directory tree of course.

Convenience scripts

abchr-buildall

A shortcut to abchr buildrepo -ps testing. Pass arguments to it to build other trees than testing.

apkgvers

Prints the version numbers for all APKBUILD files in your repository. Useful when bumping versions with abump.

Why a subdirectory?

Git doesn't like it when there's a bazillion files in its directory, even if you .gitignore them. So, the repository's expected file structure must be set up manually.

License

This project is licensed under the Apache License, Version 2.0 (the "License"); you may not use it except in compliance with the License. A copy of the License is made available in the LICENSE file. You may also obtain a copy of the license at the Apache website.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.