Another AUR Helper (incomplete)

AUR is the Arch User Repository, where anyone can upload a PKGBUILD and supplementary sources to allow others to build their own packages for use in the Arch Linux distribution.

I made an incomplete AUR Helper in Python, and decided to put it in a public repository. It's messy, and it requires a significant amount of set-up, but it works for me. It always builds in a CHROOT, and it lets the user check the PKGBUILD (by default) prior to building. There is no automatic dependency management. That must be done in the config. An example config is provided.

Things to know before using the helper

Sometimes if a package prompts a user to select between alternate package dependencies, makechrootpkg will fail to select one by default (it will constantly output "y" to stdin when a selection requires an integer). This means you will need to check the logs as it is building a package to make sure this kind of soft-lock doesn't happen. Use tail -f LOG_FILE for example. If such a soft-lock happens, Ctrl-C the helper, and explicitly set a dependency in the TOML config file in a "other_deps" array for the package like so:

[[entry]]
name = "sway-git"
aur_deps = [
    "wlroots-git",
    "swaybg-git"
]
other_deps = [
    "mesa"
]

Setting up the AUR Helper

The AUR Helper requires several things:

• A CHROOT to build in.
• A "checking GNUPG" directory that contains the GPG public keys that will be checked when building the PKGBUILD.
• A "singing GNUPG" directory that contains the GPG private key that will sign the built packages and repository database.
• SUDO privileges to be able to use makechrootpkg.
• /etc/pacman.conf must be configured to use the custom repository's packages if pacman -U will not be used.

Dependencies

The devtools package is required.

The python-toml package is required for the Python script to run.

Create the CHROOT

Use /usr/bin/mkarchroot to create your CHROOT in a directory.

mkarchroot $HOME/mychroot/root base base-devel ccache sccache cmake ninja

You must refer to the CHROOT as $HOME/mychroot if you used the same name as in the previous example.

Set up the GNUPG dirs

Checking GNUPG

Just create the directory anywhere, and store it in the config.toml. You must manually add public keys to it if a package requires checking source files with GNUPG.

GNUPGHOME=$HOME/myCheckingGNUPGDir gpg --recv-keys A_DEV_KEYS_FINGERPRINT

Note that gpg may not automatically create the GNUPGHOME directory.

Signing GNUPG

You will need to set up a GPG public/private key pair. GNUPG always respects the GNUPGHOME environment variable as the .gnupg dir, so set the variable first, create the directory, then set up your keys. The keys will be used to sign the packages you build and the custom repository that stores the package metadata.

Set the signing_gpg_key_fp variable in the config to the output fingerprint from of:

GNUPGHOME=mySigningGNUPGDir gpg --fingerprint

Note that you must remove the spaces between each part of the fingerprint, like in the example config.

Keep note of the password you store for this GNUPG key, as you will enter it every time you use the Python script.

Set up the config dir

See the example_config.toml for more configuration. It should be commented enough for figuring out how to use it.

Setting up the Repository

Create a directory for where you will store built packages and the repository.

The name of the repo must be similar to the repo specified in the config.

For example, if your repo's name is MyAURRepo, then repo should be set to .../MyAURRepo.db.tar.

You must also create symlinks such that MyAURRepo.db points to MyAURRepo.db.tar and MyAURRepo.files points to MyAURRepo.files.tar.

The Python script should automatically make a relative (not absolute) symlink to MyAURRepo.db.tar.sig with the name MyAURRepo.db.sig after signing (which should happen after each package is built and signed). Note the name doesn't have to be MyAURRepo, but is based on the repo variable set in the config.

To use the repository, you can add an entry to your /etc/pacman.conf with the following:

[MyAURRepo]
SigLevel = Required TrustAll
Include = file:///home/MyAURRepoDirectory

Note that SigLevel is set expecting the MyAURRepo.db file to be signed (the Python script usually signs the .db file after a package has been successfully built).

Making your system trust the new Repository

Export the public key from your signingGPGDirectory.

GNUPGHOME=mySigningGNUPGDir gpg --export MySigningKeyName > $HOME/MySigningKey.pub

Use pacman-key to add and trust it.

sudo pacman-key -a $HOME/MySigningKey.pub

First check that the name is unique:

sudo pacman-key --finger MySigningKeyName

Then trust it:

sudo pacman-key --lsign-key MySigningKeyName

After these steps, pacman should now trust the packages and repository signed by the GPG key you set up.

Using the AUR Helper

Typically, you will invoke:

./update.py --config my_config.toml

If you want to build in the CHROOT without updating the CHROOT, add the --no-update flag.

If you want to check only specific packages in the list of packages in the config use something like -p <package-name>. You can use -p <package_name> multiple times if you want to check a handful of packages only.

If you want to not skip a package marked with skip_branch_up_to_date in the config, then use --no-skip <package-name>, and the script will act as if skip_branch_up_to_date was not specified for the named package.

When building, the script will not directly output to the terminal it is run in, but rather appends to log files in the log directory specified in the config. To see the output while building, you can use something like:

tail -f $MY_LOG_DIR/google-chrome_stdout_2022-06-02_05-27-49_UTC

It may be helpful to periodically clear out the logs directory in between invocations of the AUR Helper script.

It is recommended to use the script with a prepared config.

Other Notes

By default, makechrootpkg does not verify integrity of files in the PKGBUILD. Use the makechrootpkg_noskipinteg.hook to modify the makechrootpkg script to not skip integrity checks.

update.py now does integrity checks before building with makechrootpkg. It is no longer necessary to modify the /usr/bin/makechrootpkg because the integrity checks are done separately.

If the hook was used previously, remove it from /etc/pacman.d/hooks and reinstall devtools.

link_cargo_registry

If you have .cargo/registry and .cargo/git in your home directory, and you don't want to re-download the Rust registry every time you update a Rust package, you can specify link_cargo_registry = true for a package in your config (see ion-git in the example_config.toml) and that will bind-mount these two directories into the chroot, which will share your local Rust cache with the chroot.