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[[Category:Package development]]
 
[[Category:Package development]]
[[it:Python Package Guidelines]]
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[[it:Python package guidelines]]
{{Package Guidelines}}
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[[ja:Python パッケージガイドライン]]
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[[pt:Python package guidelines]]
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[[zh-hans:Python package guidelines]]
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{{Package guidelines}}
 +
This document covers standards and guidelines on writing [[PKGBUILD]]s for [[Python]] software.
  
Writing [[PKGBUILD]]s for software written in [[Python]].
+
== Package naming ==
 +
 
 +
For [[Python#Python 3|Python 3]] library modules, use {{ic|python-''modulename''}}. Also use the prefix if the package provides a program that is strongly coupled to the Python ecosystem (e.g. ''pip'' or ''tox''). For other applications, use only the program name.
 +
 
 +
The same applies to Python 2 except that the prefix (if needed) is {{Ic|python2-}}.
  
== Package naming ==
+
{{Note|The package name should be entirely lowercase.}}
For libraries, use {{Ic|python-''modulename''}}. For applications, use the program name. In either case, the package name should be entirely lowercase.
+
 
 +
== Source ==
 +
 
 +
Download URLs linked from the PyPI website include an unpredictable hash that needs to be fetched from the PyPI website each time a package must be updated. This makes them unsuitable for use in a PKGBUILD. PyPI [https://github.com/pypa/pypi-legacy/issues/438#issuecomment-226940730 provides] an alternative stable scheme: [[PKGBUILD#source]] {{ic|1=source=()}} array should use the following URL templates:
 +
 
 +
;Source package:
 +
:{{ic|<nowiki>https://files.pythonhosted.org/packages/source/${_name::1}/${_name}/${_name}-${pkgver}.tar.gz</nowiki>}}
 +
;Bilingual wheel package (Python 2 and Python 3 compatible)
 +
:{{ic|<nowiki>https://files.pythonhosted.org/packages/py2.py3/${_name::1}/$_name/$_name-$pkgver-py2.py3-none-any.whl</nowiki>}}
 +
;Arch specific wheel package
 +
:in this example for {{ic|1=source_x86_64=('...')}}. Also {{ic|1=_py=py36}} can be used to not repeat the python version:
 +
:{{ic|<nowiki>https://files.pythonhosted.org/packages/$_py/${_name::1}/$_name/$_name-$pkgver-$_py-${_py}m-manylinux1_x86_64.whl</nowiki>}}
 +
 
 +
Note that a custom {{ic|'''_name'''}} variable is used instead of {{ic|pkgname}} since python packages are generally prefixed with {{ic|python-}}. This variable can generically be defined as follows:
 +
_name=${pkgname#python-}
 +
 
 +
== Installation methods ==
 +
 
 +
Python packages are generally installed using language-specific tools, such as [https://pip.pypa.io/ pip] or [https://setuptools.readthedocs.io/en/latest/easy_install.html easy_install], which are comparable to dedicated package managers in that they are designed to fetch the source files from an online repository (usually [https://pypi.org/ PyPI], the Python Package Index) and track the relevant files (for a detailed comparison between the two, see [https://packaging.python.org/pip_easy_install/#pip-vs-easy-install pip vs easy_install]).
 +
 
 +
However, for managing Python packages from within PKGBUILDs, the standard-provided [http://docs.python.org/library/distutils.html distutils] proves to be the most convenient solution since it uses the downloaded source package's {{ic|setup.py}} and easily installs files under {{ic|''$pkgdir''/usr/lib/python''<python version>''/site-packages/''$pkgname''}} directory.
 +
 
 +
=== distutils ===
 +
 
 +
A ''distutils'' PKGBUILD is usually quite simple:
 +
 
 +
build() {
 +
    ''python'' setup.py build
 +
}
 +
 +
package() {
 +
    ''python'' setup.py install --root="$pkgdir/" --optimize=1 --skip-build
 +
}
 +
 
 +
where:
 +
 
 +
* ''python'' is replaced with the proper binary, {{ic|python}} or {{ic|python2}}
 +
* {{ic|1=--root="$pkgdir/" }} prevents trying to directly install in the host system instead of inside the package file, which would result in a permission error
 +
* {{ic|1=--optimize=1}} compiles optimized bytecode files ({{ic|.pyo}} for Python 2, {{ic|opt-1.pyc}} for Python 3) so they can be tracked by [[pacman]].
 +
* {{ic|1=--skip-build}} optimizes away the unnecessary attempt to re-run the build steps already run in the {{ic|build()}} function.
 +
 
 +
=== setuptools ===
 +
 
 +
The Python packaging scene has largely migrated from ''distutils'' to ''setuptools'', which is actively developed and functions as a drop-in replacement import in {{ic|setup.py}}. The main difference for packagers is that ''setuptools'' is packaged separately from Python itself, and must be specified as a {{ic|makedepends}}.
 +
 
 +
If the resulting package includes executables which [https://setuptools.readthedocs.io/en/latest/setuptools.html#automatic-script-creation import the {{ic|pkg_resources}} module], then ''setuptools'' must be additionally specified as a {{ic|depends}} in the split {{ic|package_*()}} functions; alternatively, if the PKGBUILD only installs the Python package for a single version of Python, ''setuptools'' should be moved from {{ic|makedepends}} to {{ic|depends}}.
 +
 
 +
=== pip ===
 +
 
 +
If you need to use ''pip'' (provided by {{Pkg|python-pip}} and {{Pkg|python2-pip}}), ''e.g.'' for installing [https://github.com/pypa/wheel wheel] packages, remember to pass the following flags:
 +
 
 +
PIP_CONFIG_FILE=/dev/null pip install --isolated --root="$pkgdir" --ignore-installed --no-deps *.whl
 +
 
 +
* {{ic|PIP_CONFIG_FILE&#61;/dev/null}} ignores {{ic|{/etc,~/.config}/pip.conf}} that may be appending arbitrary flags to '''pip'''.
 +
* {{ic|--isolated}} ignores environment variables (and again {{ic|{/etc,~/.config}/pip/pip.conf}}) that may otherwise also be appending arbitrary flags to '''pip'''.
 +
* {{ic|--ignore-installed}} is necessary until https://github.com/pypa/pip/issues/3063 is resolved (otherwise '''pip''' skips the install in the presence of an earlier {{ic|--user}} install).
 +
* {{ic|--no-deps}} ensures, that dependencies do not get packaged together with the main package.
 +
 
 +
''pip'' doesn't know how to generate {{ic|.pyo}} files (see https://github.com/pypa/pip/issues/2209). In order to generate them manually after ''pip'' has installed the module, run:
  
Python 2 libraries should instead be named {{Ic|python2-''modulename''}}.
+
python -O -m compileall "${pkgdir}/path/to/module"
  
== File placement ==
+
{{Warning|Use of ''pip'' and/or wheel packages is discouraged in favor of setuptools source packages, and should only be used when the latter is not a viable option (for example, packages which '''only''' come with wheel sources, and therefore cannot be installed using setuptools).}}
Most Python packages are installed with the [http://docs.python.org/library/distutils.html distutils] system using '''setup.py''', which installs files under {{Ic|/usr/lib/python''<python version>''/site-packages/''pkgname''}} directory.
 
  
 
== Notes ==
 
== Notes ==
The {{Ic|1=--optimize=1}} parameter compiles {{Ic|.pyo}} files so they can be tracked by [[pacman]].
 
  
 
In most cases, you should put {{Ic|any}} in the {{Ic|arch}} array since most Python packages are architecture independent.
 
In most cases, you should put {{Ic|any}} in the {{Ic|arch}} array since most Python packages are architecture independent.
  
 
Please do not install a directory named just {{Ic|tests}}, as it easily conflicts with other Python packages (for example, {{Ic|/usr/lib/python2.7/site-packages/tests/}}).
 
Please do not install a directory named just {{Ic|tests}}, as it easily conflicts with other Python packages (for example, {{Ic|/usr/lib/python2.7/site-packages/tests/}}).
 
== Example ==
 
An example PKGBUILD can be found at {{Ic|/usr/share/pacman/PKGBUILD-python.proto}}, which is in the {{Pkg|abs}} package.
 

Latest revision as of 20:29, 16 June 2018

Package creation guidelines

CLRCrossEclipseFree PascalGNOMEGoHaskellJavaKDEKernelLispMinGWNode.jsNonfreeOCamlPerlPHPPythonRRubyVCSWebWine

This document covers standards and guidelines on writing PKGBUILDs for Python software.

Package naming

For Python 3 library modules, use python-modulename. Also use the prefix if the package provides a program that is strongly coupled to the Python ecosystem (e.g. pip or tox). For other applications, use only the program name.

The same applies to Python 2 except that the prefix (if needed) is python2-.

Note: The package name should be entirely lowercase.

Source

Download URLs linked from the PyPI website include an unpredictable hash that needs to be fetched from the PyPI website each time a package must be updated. This makes them unsuitable for use in a PKGBUILD. PyPI provides an alternative stable scheme: PKGBUILD#source source=() array should use the following URL templates:

Source package
https://files.pythonhosted.org/packages/source/${_name::1}/${_name}/${_name}-${pkgver}.tar.gz
Bilingual wheel package (Python 2 and Python 3 compatible)
https://files.pythonhosted.org/packages/py2.py3/${_name::1}/$_name/$_name-$pkgver-py2.py3-none-any.whl
Arch specific wheel package
in this example for source_x86_64=('...'). Also _py=py36 can be used to not repeat the python version:
https://files.pythonhosted.org/packages/$_py/${_name::1}/$_name/$_name-$pkgver-$_py-${_py}m-manylinux1_x86_64.whl

Note that a custom _name variable is used instead of pkgname since python packages are generally prefixed with python-. This variable can generically be defined as follows:

_name=${pkgname#python-}

Installation methods

Python packages are generally installed using language-specific tools, such as pip or easy_install, which are comparable to dedicated package managers in that they are designed to fetch the source files from an online repository (usually PyPI, the Python Package Index) and track the relevant files (for a detailed comparison between the two, see pip vs easy_install).

However, for managing Python packages from within PKGBUILDs, the standard-provided distutils proves to be the most convenient solution since it uses the downloaded source package's setup.py and easily installs files under $pkgdir/usr/lib/python<python version>/site-packages/$pkgname directory.

distutils

A distutils PKGBUILD is usually quite simple:

build() {
    python setup.py build
}

package() {
    python setup.py install --root="$pkgdir/" --optimize=1 --skip-build
}

where:

  • python is replaced with the proper binary, python or python2
  • --root="$pkgdir/" prevents trying to directly install in the host system instead of inside the package file, which would result in a permission error
  • --optimize=1 compiles optimized bytecode files (.pyo for Python 2, opt-1.pyc for Python 3) so they can be tracked by pacman.
  • --skip-build optimizes away the unnecessary attempt to re-run the build steps already run in the build() function.

setuptools

The Python packaging scene has largely migrated from distutils to setuptools, which is actively developed and functions as a drop-in replacement import in setup.py. The main difference for packagers is that setuptools is packaged separately from Python itself, and must be specified as a makedepends.

If the resulting package includes executables which import the pkg_resources module, then setuptools must be additionally specified as a depends in the split package_*() functions; alternatively, if the PKGBUILD only installs the Python package for a single version of Python, setuptools should be moved from makedepends to depends.

pip

If you need to use pip (provided by python-pip and python2-pip), e.g. for installing wheel packages, remember to pass the following flags:

PIP_CONFIG_FILE=/dev/null pip install --isolated --root="$pkgdir" --ignore-installed --no-deps *.whl
  • PIP_CONFIG_FILE=/dev/null ignores {/etc,~/.config}/pip.conf that may be appending arbitrary flags to pip.
  • --isolated ignores environment variables (and again {/etc,~/.config}/pip/pip.conf) that may otherwise also be appending arbitrary flags to pip.
  • --ignore-installed is necessary until https://github.com/pypa/pip/issues/3063 is resolved (otherwise pip skips the install in the presence of an earlier --user install).
  • --no-deps ensures, that dependencies do not get packaged together with the main package.

pip doesn't know how to generate .pyo files (see https://github.com/pypa/pip/issues/2209). In order to generate them manually after pip has installed the module, run:

python -O -m compileall "${pkgdir}/path/to/module"
Warning: Use of pip and/or wheel packages is discouraged in favor of setuptools source packages, and should only be used when the latter is not a viable option (for example, packages which only come with wheel sources, and therefore cannot be installed using setuptools).

Notes

In most cases, you should put any in the arch array since most Python packages are architecture independent.

Please do not install a directory named just tests, as it easily conflicts with other Python packages (for example, /usr/lib/python2.7/site-packages/tests/).