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[[Category:Packaging Policies]]

== Tools ==

=== bdist_rpm5 ===
The fastest way to pack a Python2 module for ROSA is to use bdist_rpm5 class extending standard [http://docs.python.org/distutils/builtdist.html#creating-rpm-packages bdist_rpm] and intended to create RPMv5 packages for ROSA. 

To use it, you should specify bdistr_rpm5 option for setup.py:
<pre>
python setup.py bdist_rpm5
</pre>

If everything goes fine, you will find ready-to-use SRPM inside the dist folder which contains spec file conforming to ROSA Python policy (and the rest of this document is just for your interest then).

If the tool fails to automatically detect values for some tags (license, description, etc.), it will set these fields to 'UNKNOWN' value.

Please look for 'UNKNOWN' words in the generated spec and fix them manually.

bdist_rpm5 for Python3 does not exist yet.

=== Py2pack ===
[http://pypi.python.org/pypi/py2pack Py2pack] script can be used to generate RPM spec file from Python modules using Python Package Index (PyPI). Currently py2pack can only generate spec files for OpenSUSE and Fedora, but one may use generated spec as a basis for the ROSA one.

== Rules ==

=== Naming ===
The name of a package with Python2 module 'foo' that provides an extension for Python2 library must be of the form {{pkg|python-foo}}, with foo being lower case. For packages with Python3 modules, 'python3' prefix should be used - {{pkg|python3-foo}}. If the upstream name 'foo' already contains "python", that should be dropped from the name.

Rationale: using a prefix is serving as a name space, and clearly shows how to find python modules.

Having everything in lower case is easier to read, and offers a consistent sorting.

'''Note:''' User-level applications written in Python do not need to follow these naming rules.

=== Tags ===
* For Python modules, group should be set to 'Development/Python'
* BuildArch must be noarch for pure Python packages

=== Build Requires ===
* 'python' or 'python3' requirement is added automatically once the rpmbuild detects you are using python to build your package. If spec file is created using bdist_rpm5, python-setuptool dependency is also added.
* All other dependencies should be added manually.
* Arch dependent packages (compiled extensions) should require (at least) python-devel (python3-devel for Python3 packages).

=== Requires ===
* Mandatory requirement python(abi) = VERSION is added automatically (by pythondeps.sh script)

== Rpm macro ==

The following macros are available for Python packagers: 
{|class='wikitable'
! Macro (Python2) !! Analogue for Python3 !! Description
|-
| {{macro|%py_ver}} || {{macro|%py3_ver}} || Get Python version (as reported by invoking 'python -V')
|-
| {{macro|%py_incdir}} || {{macro|%py3_incdir}} || Path to Python include files (necessary to compile C extensions)
|-
| {{macro|%py_puresitedir}} || {{macro|%py3_puresitedir}} || Directory for the installation of third-party extensions which are platform-independent (written in pure Python)
|-
| {{macro|%py_platsitedir}} || {{macro|%py3_platsitedir}} || Directory for the installation of third-party extensions which are platform-dependent (C extensions)
|-
| {{macro|%py_platlibdir}} || N/A yet || Platform-dependent directory for the installation for the standard library
|-
| {{macro|%py_purelibdir}} || N/A yet || Platform-independent directory for the installation for the standard library
|-
| {{macro|%py_prefix}} || {{macro|%py3_prefix}} || Site-specific directory prefix where the platform independent Python files are installed (sys.prefix)
|-
| {{macro|%py_compile(O)}} || N/A yet || Create .pyc files, dropping existing ones, if any. If -O option is specified, the same is performed for .pyo files.
|}

'''%py_(pure|plat)(site|lib)dir''' are intended to be used instead of single '''%py_(site|lib)dir''' in order to place pure Python modules (that are architecture independent) in the same place on all hardware platforms, while putting compiled C extensions to arch-specific folders. For example, pure Python modules will go to /usr/lib/python on both x86 and x86-64, while compiled extensions will go to /usr/lib/python/ on x86 and /usr/lib64/python/ on x86-64. This allows packaging software consisting of pure Python modules only as noarch packages suitable for installing on all platforms.

For those familiar with [http://docs.python.org/distutils/apiref.html#module-distutils.sysconfig Python distutils] - '''%py_(pure|plat)(site|lib)dir''' correspond to results of ''distutils.sysconfig.get_python_lib()'' with appropriate parameter (plat_specific, standard _lib).

See http://archives.mandrivalinux.com/cooker/2006-01/msg01404.php for more discussions.

=== Obsolete Macros ===
The following macros are also available but marked as obsolete and not recommended:
{|class='wikitable'
! Macro !! Description
|-
| {{macro|%py_libdir}} || The same as %py_purelibdir
|-
| {{macro|%py_sitedir}} || The same as %py_puresitedir
|-
| {{macro|%python_sitearch}} || The same as %py_platsitedir
|-
| {{macro|%python_sitelib}} || The same as %py_puresitedir
|-
| {{macro|%python_version}} || The same as %py_ver
|-
| {{macro|%py_requires(d)}} || Insert build dependency on python; if '-d' option is specified then add build dependency on python-devel, as well.<br/> For now, it is recommended to explicitly specify BuildRequires: python and  BuildRequires: python-devel.
|}

== pyc/pyo policy ==
Files should be compiled before rpm creation and includes as they will otherwise be created if a package is run as root, and therefore created weird bug ( ie, module removed but still here, unowned files ).

To compile the .py moudles, add the following macros to the beginning of the spec:

<pre>
%define python_compile_opt python -O -c "import compileall; compileall.compile_dir('.')"
%define python_compile     python -c "import compileall; compileall.compile_dir('.')"
</pre>

Then in the %install section:

<pre>
dir -d %{buildroot}%{py_platsitedir}/%{name}
%python_compile_opt
%python_compile
install *.pyc *.pyo %{buildroot}%{py_platsitedir}/%{name}
</pre>

This will create a directory for the software under the platform sitedir, compile the python modules, then copy them to the directory created before. You may use 'pushd directory' before that code and 'popd' after the code if the python modules are in a directory below the root of the tarball.

And finally in the %files section:

<pre>
%{py_platsitedir}/%{name}/*.pyc
%{py_platsitedir}/%{name}/*.pyo
</pre>

=== egg-info ===
If egg-info files or directories are generated by the module's build scripts they must be included in the package because they might be needed by other applications and modules at runtime. So the %files section should contain something like this:
<pre>
%{py_platsitedir}/%{name}-*.egg-info
</pre>

=== Automated setup ===
If you use automated setup and invoke something like 'python setup.py install', you may set PYTHONDONTWRITEBYTECODE to zero or empty value to keep all files generated during installation. In addition, you may ask python to record names of installed files and then use the recorded list in the %files section:

<pre>
%install
...
PYTHONDONTWRITEBYTECODE= python setup.py install --root=%{buildroot} --record=FILELIST
...

%files -f FILELIST
...
</pre>


== Example spec file ==
<pre>
%define module	mymodule
%define name	python-%{module}
%define version 1.0
%define release 1

Summary: 	Example module
Name: 	 	%{name}
Version: 	%{version}
Release: 	%{release}
Source:         %{module}-%{version}.tar.gz
URL:		http://mypage.org/mymodule
License:	Apache License
Group:		Development/Python
BuildRoot:	%{_tmppath}/%{name}-%{version}-%{release}-buildroot
BuildRequires:	python-devel
BuildArch:	noarch

%description
Example Python module

%prep
%setup -q

%install
rm -rf %{buildroot}
PYTHONDONTWRITEBYTECODE=  python setup.py install --root=%{buildroot} --record=FILELIST

%files -f FILELIST
%defattr(-,root,root)
%doc *.txt
</pre>

== Rebuild policy  ==
It is known that Python is not completely backward compatible (so if you update e.g. from 2.6 to 2.7, some modules may become broken). Due to this 'python(abi)' dependency is set to particular Python version. 

As a result, when Python itself is updated all dependent packages should be rebuilt to handle pick up the new version.

== Policy in other distributions ==
* [http://fedoraproject.org/wiki/Packaging/Python Fedora python packaging policy]
* [http://www.debian.org/doc/packaging-manuals/python-policy/ Debian python packaging policy]
* [http://en.opensuse.org/openSUSE:Packaging_Python OpenSUSE python packaging policy]

<hr>

{{message|This Policy is based on the [http://wiki.mandriva.com/en/Development/Tasks/Packaging/Policies/Python Mandriva Python Packaging Policy].}}