help-center-docs/packaging/packaging-practices/en.md

+++ title = "Packaging Practices" lastmod = "2017-06-01T13:45:24+03:00" +++

Packaging Practices

The primary goal of ypkg is ease of maintenance. In order to do so we ensure packages in the binary repository adhere to a strict set of conventions and practices.

The next few sections will detail these.

Package naming

The ypkg tool does not allow for custom subpackages or subpackage naming, and will enforce its own policy. This can be eased somewhat through the use of patterns, however the available subpackage names are limited.

We request you use (where possible) the upstream source name for your package. Subpackage names (when generated) are constructed by using the name value first, then applying the subpackage name as such:

pkgname-$subpackage

Subpackages are fully automatic with ypkg, and are created based on file patterns. All subpackages automatically depend on the main package, to ensure correct operation. In the following explanations, $lib is used to refer to the host library directory, i.e. lib or lib64 (or lib32 on emul32 builds)

The devel subpackage

This is invariably created for packages that provide libraries and development headers. The following rules will result in files being placed in a devel subpackage:

/usr/include
/usr/$lib/lib*.so
/usr/$lib/lib*.a
/usr/share/man2/
/usr/share/man3/
/usr/share/pkgconfig
/usr/$lib/pkgconfig
/usr/share/cmake
/usr/share/vala

Note that for some packages, /usr/$lib/lib*.so files are not symlinks. In this instance, the main package will be broken with no library files present. This can quickly be determined by looking at the resulting .xml file generated after running the build. If this happens, simply override with patterns or set libsplit to “no”.

A note on static archives: Unless it is absolutely unavoidable, you should disable static libraries within your build. This is usually fixed by adding --disable-static to your configure routine. If *.a files are shown in your packaging request, it will be questioned, as they can pose a greater security risk if packages link against these static archives.

The docs subpackage

Currently there is only one pattern which is forced into a docs subpackage:

/usr/share/gtk-doc

If required, you can use patterns to move other files into the docs subpackage, making it smaller.

The 32bit subpackage

This subpackage is only generated during an emul32 build. The folowing paths will automatically be placed into a 32bit subpackage

/usr/lib32/lib*.so
/usr/lib32/lib*.so.*
/usr/lib32/lib*.a

Note the same static archive rules apply to 32bit packages. These packages aren’t as heavily split as we try to discourage their use, though they must be provided in some instances.

The utils subpackage

This is not an automatic subpackage, you must use patterns to utilise it. It is provided for instances that it may not be suitable to have binaries present, i.e. for a library package.

Maintenance

When submitting a change package.yml, it must be accompanied by its corresponding pspec_*.xml file, which was generated at build time. This machine file allows the repository maintainers to evaluate the package condition.

When providing a new version of a package, or a fix, always ensure you increment the release number by 1. This ensures that users of your package are correctly updated to the latest version.

Never submit a package without having first tested it, and ensuring it builds within solbuild, a clean chroot environment.

Generating a Package.yml

Making a package.yml file is not necessarily a manual process. In fact, once you have common setup, you already have a script capable of generating a package.yml file based on the source archive URL.

You can generate a package.yml by using common/Scripts/yauto.py URL_TO_ARCHIVE. We recommend creation an alias in your .bashrc or .zshrc, so you can access it wherever you are. For example:

alias fetchYml="$HOME/repository/common/Scripts/yauto.py"

Patching / extra files

Files that may be required during the build can be accessed via the $pkgfiles variable. Note that you must store your files in the ./files directory relative to your package.yml

Both patches and extra files (such as systemd units) are stored in this directory. Note that if your patch is to address a CVE, you must use the following naming scheme: ./files/security/cve-xxxx-xxxx.patch

Where xxxx-xxxx is replaced with the full CVE ID. Complying with this simple rule ensures that we can know at any time the security status of packages when using tools such as cve-check-tool

Solus tooling allows the use of ./files/security/cve-xxxx-xxxx.nopatch (which isn't applied in the build) to indicate that a CVE has been validated as not applicable to the Solus package. This can be because another patch resolves this CVE, or there is a false positive via cve-check-tool. The contents of the file can describe why it doesn't apply without requiring a patch (i.e. Resolved by cve-xxxx-xxxx.patch).

Applying a patch

It is common practice to apply the patch within the setup section of your build staging. We can achieve this using the %patch macro, and the $pkgfiles variable. In this example, the required file is located at ./files/0002-Sample-commit-2.patch

%patch -p1 < $pkgfiles/0002-Sample-commit-2.patch

Note you use the macro as you would normally use the patch command, however use of the macro ensures it performs a clean batch-mode patch.

If you are using compressed patches, i.e. for the bash or readline packages, you can pipe the call through zcat or similar:

zcat $pkgfiles/bash43-032.gz | %patch -p0

Handling multiple patches

In the event you need to apply multiple patches, such as a multitude of CVE patches, it may be sensible to use our %apply_patches macro, which will apply all the patches listed in a series file in your package's ./files folder. Example below:

security/cve-xxxx-xxxx.patch
fix-silliness.patch

Both of the files above will be applied using -p1. If you need to use stripping num, like -p4, you can do something like:

security/cve-xxxx-xxxx.patch -p4
fix-silliness.patch

Installing extra files

We recommend using patches where possible first, as they ensure correct maintainence and will be updated across package versions. If you must install extra files into the directory, please use the install command, ensuring you set the correct permissions. Again, files are accessible from the ./files/ directory, relative to package.yml.

This is an example of installing a custom profile file, seen in the bash package:

install -m 0644 $pkgfiles/profile $installdir/etc/profile

Build dependencies

Most software packages that you build will in one way or another, depend on another software package to provide specific functionality. This is usually achieved by using a library.

Any package that is submitted to our repositories is always built in a clean chroot environment, therefore any dependencies required to build that package in a reproducible and sane fashion, must be listed.

This is achieved by populating the builddeps key with a list of build dependencies. We support two kinds of build dependencies: explicitly named, or pkgconfig dependencies.

We prefer the use of pkgconfig dependencies. Most modern software will use the pkg-config tool (package configuration) to determine which files are required to build the current software. This may include compiler flags, library to link against and where the package headers are located.

An obvious advantage to supporting pkgconfig dependencies is that there is a 1:1 mapping between the name requested by the build and the name used within the package.yml. Instead of trying to hunt down the package providing that dependency, you simply list the same name. Any package in the repository will export information about the .pc files (for pkg-config) it contains, enabling you to use those as a build dependency.

A secondary advantage is that this allows for easily switching or replacing a providing package. When no pkgconfig name is available (some packages do not provide these, or it doesn’t make sense for them to), you may use the explicit package name. Always ensure you select the correct package, i.e. the -devel subpackage. This provides the necessary symlinks and headers to build packages.

Using pkgconfig dependencies

In the builddeps list, simply use the pkgconfig(name) syntax. For example, to add gtk+-3.0 to the build dependencies, we would do the following:

builddeps:
    - pkgconfig(gtk+-3.0)

At build time the appropriate provider package is selected, in this instance libgtk-3-devel

You can determine if there are pkgconfigs available from a -devel package by doing eopkg info (name) and looking for the Provides key.

Example:

$ eopkg info libgtk-3-devel

In output:

Provides: pkgconfig(gtk+-3.0) pkgconfig(gdk-3.0) pkgconfig(gdk-wayland-3.0) pkgconfig(gail-3.0) pkgconfig(gdk-x11-3.0) pkgconfig(gtk+-unix-print-3.0)
pkgconfig(gtk+-wayland-3.0) pkgconfig(gtk+-x11-3.0) 

Using explict named dependencies

As may be obvious, simply list the package name. Note we discourage this when a pkgconfig dependency is available.

builddeps:
    - stk-devel

Runtime dependencies

Runtime dependencies are extra packages that a package needs in order to function correctly. A common example of this is other libraries. Solus eopkg packages will automatically add any binary dependencies at runtime, so that you do not have to.

All devel subpackages automatically depend on their parent package. On top of this, if they provide a .pc pkg-config file, we export this information, and automatically determine the packages this particular package would need to be able to build against correctly. As such, the majority of dependencies for builds are automatically resolved.

In certain instances, binary dependencies aren’t enough. An example of this might be an extra Python package, or a font, something that is not accounted for by binary checks.

To account for this, you may add extra explicit runtime dependencies to your package. These are taken from the optional rundeps ypkg key.

This key uses the dict(s) type, and the default key is the current package name. You may express a different subpackage to apply dependencies to by using that name as a key, i.e. devel, or docs.

This would add the “python-gobject” runtime dependency to the main package:

rundeps:
    - python-gobject

This would add the same dependency, as well as adding it to the devel subpackage:

rundeps:
    - python-gobject
    - devel: python-gobject

Remember this uses the dict(s) type, which is very flexible. You can equally express this as follows (adding more deps as an example):

rundeps:
    - python-gobject
    - devel:
        - somepackage
        - someotherpackage

Patterns

In most instances, ypkg will assign the correct location for files, whether it be in the main name package, or a subpackage. However there may be instances where the default does not match the intended behaviour.

In these instances it is possible to override the default assignment by way of patterns. These are simply a list of paths or globs to ensure a particular file, or set of files, end up in the desired location.

The patterns key expects a dict(s) argument. The default key for each pattern is assumed to be the name of the package, so omitting the name would place files into the main package. The value should be a path or pattern you wish to match, ensuring files go to a specific location.

In this example from libjpeg-turbo, we move all documentation into the docs subpackage:

patterns:
    - docs: [/usr/share/man]

This example, taken from the wayland package, ensures the binaries from /usr/bin and the /usr/share/wayland are located in the devel subpackage:

patterns:
    - devel:
        - /usr/bin
        - /usr/share/wayland

Replace / rename

In some situations, it may be required to replace one package with another, or to rename an existing package. In these instances you should coordinate with a repository maintainer to ensure the replaced package is marked Obsolete within the index. This will ensure correct upgrade paths for users.

Note that to retire a package, you must also coordinate with a repository maintainer. An Obsolete package is removed by the package manager when the user upgrades. As such, correct upgrade paths need to be established.

The replaces ypkg key uses the dict(s) type, and the default key is assumed to be the current package name.

In this example, we rename the libgeoclue* packages to use the correct names, and ensure a working upgrade path.

replaces:
    - devel: libgeoclue-devel
    - libgeoclue

The name of this package is geoclue, and the new package names are now:

• geoclue
• geoclue-devel

Given the replaces values above, geoclue now replaces libgeoclue, and geoclue-devel replaces libgeoclue-devel. This is entirely transparent to the user, with a seamless update replacing the old packages with the new renamed packages.

The repository maintainer marked the old names as Obsolete in the index.