|
|
| Line 1: |
Line 1: |
| {{DISPLAYTITLE:Fedora Packaging Guidelines for Python}}
| |
| <div style="float: right; margin-left: 0.5em" class="toclimit-2">__TOC__</div>
| |
|
| |
| == Python Version Support ==
| |
|
| |
| In Fedora we have multiple Python runtimes, one for each supported major Python release. At this point that's one for python2.x and one for python3.x. If a piece of software supports python3, it must be packaged for python3. If it supports python2 as well, it may be packaged for python2. If it supports only python2 then (obviously) it must not be packaged for python3.
| |
|
| |
| == Multiple Python Runtimes ==
| |
|
| |
| Each runtime corresponds to a binary of the form <code>/usr/bin/python$MAJOR.$MINOR</code>. One of these python runtimes is the "system runtime" which is what is run when invoking <code>/usr/bin/python</code>. On Fedora 27, for example, this is a link to <code>/usr/bin/python2</code> (which itself is a link to <code>/usr/bin/python2.7</code>).
| |
|
| |
| However, packages in Fedora MUST NOT depend on where <code>/usr/bin/python</code> happens to point but instead MUST call the proper executable for the needed python major version directly, either <code>/usr/bin/python2</code> or <code>/usr/bin/python3</code> as appropriate. As a result of that <code>/usr/bin/python</code> (as well as <code>/usr/bin/env python</code> and similar) MUST NOT be used in shebang lines or as a dependency of a package.
| |
|
| |
| All python runtimes have a virtual provide for <code>python(abi) = $MAJOR-$MINOR</code>. For example, the python-3.4 runtime package has:
| |
| $ rpm -q --provides python3 |grep -i abi
| |
| python(abi) = 3.4
| |
|
| |
| python modules using these runtimes should have a corresponding "Requires" line on the python runtime that they are used with. This is done automatically for files below <code>/usr/lib[^/]*/python${PYVER}</code>
| |
|
| |
| Mirroring the policy for regular packages, the Python-version-specific subpackages of your package MUST NOT be removed in a release branch of Fedora.
| |
|
| |
| == Dependencies ==
| |
| Packages building for Python2 will need <code>BuildRequires: python2-devel</code>.
| |
| Packages building for Python3 will need <code>BuildRequires: python3-devel</code>.
| |
| Packages building for for both will need build-time dependencies on both.
| |
|
| |
| Packages MUST NOT have dependencies (either build-time or runtime) on packages named with the unversioned <code>python-</code> prefix unless no properly versioned package exists. Dependencies on Python packages instead MUST use names beginning with <code>python2-</code> or <code>python3-</code> as appropriate.
| |
|
| |
| == Provides ==
| |
| Using a fictional module named "example", the subpackage containing the python2 version '''must''' provide <code>python2-example</code>. This is of course always the case if the subpackage is named <code>python2-example</code> (as in the examples below). If the subpackage has some other name then then <code>Provides: python2-example</code> must be added explicitly (but see the <code>%python_provide</code> macro below).
| |
|
| |
| The python3 subpackage '''must''' provide <code>python3-example</code>. However, as the naming guidelines mandate that the python3 subpackage be named <code>python3-example</code>, this will happen automatically.
| |
|
| |
| === The %python_provide macro ===
| |
|
| |
| In addition, the subpackage corresponding to the current system runtime '''must''' provide <code>Provides: python-example</code>. However, the system version of python in Fedora will almost certainly change at some point in the future.
| |
|
| |
| To avoid having to alter every python module package when this change happens, and to allow the same spec to build for releases with different system versions of python, a convenient <code>%python_provide</code> macro is provided. When given (as an argument) the name of the current subpackage, it will evaluate to either the proper <code>Provide:</code> line or nothing at all as appropriate for the version of the system runtime. Thus if the package follows the suggested subpackage naming scheme as shown in the below example, placing this macro in the definition of each subpackage will guarantee that the necessary <code>Provide:</code> line appears where it should, and does not appear where it shouldn't.
| |
|
| |
| If <code>%python_provide</code> is called with an argument beginning with <code>python2-</code>, it will also generate a suitable <code>Obsoletes:</code> line for the unversioned <code>python-</code> package. This facilitate renaming those unversioned subpackages.
| |
|
| |
| Finally, if the macro called with an argument like <code>python-example</code> (no python major version in the name) then it will evaluate to either <code>Provides: python2-example</code> or <code>Provides: python3-example</code> depending on the version of the current system runtime.
| |
|
| |
| == Automatic Provides with a standardized name ==
| |
|
| |
| Since Fedora 25, when building a Python package, RPM looks for <code>.dist-info</code> and <code>.egg-info</code> files or directories in the <code>%files</code> sections of all packages. If one or more are found, RPM parses them to find the '''standardized name''' (i.e. dist name, name on PyPI) of the packaged software, and then automatically creates two <code>Provides:</code> tags in the following format:
| |
|
| |
| <pre>
| |
| Provides: pythonX.Ydist(CANONICAL_STANDARDIZED_NAME)
| |
| Provides: pythonXdist(CANONICAL_STANDARDIZED_NAME)
| |
| </pre>
| |
|
| |
| The <code>X</code> and <code>X.Y</code> are the Python version used (usually 2.7 or 3.5 and higher), and between the parentheses is the name of the software in a '''canonical format''' used by Python tools and services such as setuptools, pip and PyPI. The canonical name is obtained by switching the standardized name to lower case and converting all runs of non-alphanumeric characters to single “-” characters. Example: “The $$$ Tree” becomes “the-tree”.
| |
|
| |
| === Requires and BuildRequires with standardized names ===
| |
|
| |
| Starting with Fedora 26, these Provides tags can be used to list Requires and BuildRequires of a package using the ''standardized names'' (i.e. dist name, name on PyPI) of Python modules. To make it easier, you can use macros <code>%{py2_dist}</code> and <code>%{py3_dist}</code> that accept one or more parameters: the ''standardized name(s)'' of the desired Python software. They will convert the name(s) to the ''canonical format'' and create the proper <code>pythonXdist(...)</code> tag(s).
| |
|
| |
| In addition, you can use the %{py_dist_name} macro that simply transforms any ''standardized name'' to the ''canonical format''.
| |
|
| |
| For example:
| |
|
| |
| <pre>
| |
| BuildRequires: %{py2_dist PyMySQL} >= 0.7.5
| |
| # => BuildRequires: python2dist(pymysql) >= 0.7.5
| |
|
| |
| Requires: %{py3_dist virtualenv pyPEG2}
| |
| # => Requires: python3dist(virtualenv) python3dist(pypeg2)
| |
|
| |
| %{py_dist_name 0-._.-._.-._.-._.-._.-._.-0}
| |
| # => 0-0
| |
| </pre>
| |
|
| |
| == Macros == | | == Macros == |
| The following macros are defined for you: | | The following macros are defined for you: |
| Line 77: |
Line 4: |
| !Macro!!Normal Definition!!Notes | | !Macro!!Normal Definition!!Notes |
| |- | | |- |
| |__python||/usr/bin/python||Prohibited (see the note bellow this macro list) | | |__python||<code>%{__python2}</code>||Default Python interpreter. Currently links to Python2 interpreter |
| |- | | |- |
| |__python2||/usr/bin/python2||Python 2 interpreter | | |__python2||/usr/bin/python2||Python 2 interpreter. Also the current default python interpreter |
| |- | | |- |
| |__python3||/usr/bin/python3||Python 3 interpreter | | |__python3||/usr/bin/python3||Python 3 interpreter |
| |- | | |- |
| |python_provide|| (Lua script) ||Given a package name, evaluates to either <code>Provides: python-example</code> or nothing at all depending on the version of the system runtime. See [[Packaging:Python#The_.25python_provide_macro|here]] for an example. | | |python_provide|| (Lua script) ||Given a package name, evaluates to either <code>Provides: python-example</code> or nothing at all depending on the version of the system runtime. See [[Packaging:Python#The_.25python_provide_macro|here]] for an example. |
| | |- |
| | |python_sitelib||<code>%{python2_sitelib}</code>||Where pure python modules are installed for the default Python implementation |
| | |- |
| | |python_sitearch||<code>%{python2_sitearch}</code>||Where python extension modules that are compiled C are installed for the default Python implementation |
| |- | | |- |
| |py2_dist|| (Lua script) ||Introduced in Fedora 25. Given a standardized name (i.e. dist name, name on PyPI) of Python software, it will convert it to a canonical format, and evaluates to <code>python2dist(CANONICAL_NAME)</code>, which is useful when listing dependencies. See [[Packaging:Python#Automatic_Provides_with_a_standardized_name|above]] for more information. | | |py2_dist|| (Lua script) ||Introduced in Fedora 25. Given a standardized name (i.e. dist name, name on PyPI) of Python software, it will convert it to a canonical format, and evaluates to <code>python2dist(CANONICAL_NAME)</code>, which is useful when listing dependencies. See [[Packaging:Python#Automatic_Provides_with_a_standardized_name|above]] for more information. |
| Line 108: |
Line 39: |
|
| |
|
| {{admon/note|The generic %{_python} macros| | | {{admon/note|The generic %{_python} macros| |
| The unversioned macros, <code>%{__python}</code>, <code>%{python_sitelib}</code>, and <code>%{python_sitearch}</code> are generic macros that point to or use <code>/usr/bin/python</code>. Since <code>/usr/bin/python</code> invocation is prohibited and deprecated in RPM build, you shall never use those macros unless you manually set <code>%{__python}</code> to either <code>%{__python2}</code> or <code>%{__python3}</code>. | | The unversioned macros, <code>%{__python}</code>, <code>%{python_sitelib}</code>, and <code>%{python_sitearch}</code> are generic macros that will always point to the default implementation. You may only use them with applications that need to choose to use the system's default version of python. (Currently this is the python2 interpreter.) |
| | This is future proofing for the time when things will be switched over to python3 by default instead of python2. |
| You should use <code>%{__python2}</code>, <code>%{python2_sitelib}</code>, and <code>%{python2_sitearch}</code> to explicitly reference the python2 interpreter instead. | | You should use <code>%{__python2}</code>, <code>%{python2_sitelib}</code>, and <code>%{python2_sitearch}</code> to explicitly reference the python2 interpreter instead. |
| }} | | }} |
| Line 127: |
Line 59: |
| * It ensures that the packages are installed correctly on multilib architectures. | | * It ensures that the packages are installed correctly on multilib architectures. |
| * Using these macros instead of hardcoding the directory in the specfile ensures your spec remains compatible with the installed python version even if the directory structure changes radically (for instance, if <code>python2_sitelib</code> moves into <code>%{_datadir}</code>). | | * Using these macros instead of hardcoding the directory in the specfile ensures your spec remains compatible with the installed python version even if the directory structure changes radically (for instance, if <code>python2_sitelib</code> moves into <code>%{_datadir}</code>). |
|
| |
| == Files to include ==
| |
| When packaging python modules, several types of files are included:
| |
| * *.py source files because they are used when generating tracebacks.
| |
| * *.pyc and *.pyo byte compiled files (and, if present, the enclosing __pycache__ directory in most cases).
| |
| ** Python will try to create them at runtime if they don't exist which leads to spurious SELinux AVC denials in the logs.
| |
| ** If the system administrator invokes python with -OO, .pyos will be created with no docstrings. This can break some programs.
| |
| * *.egg-info files or directories. If these 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.
| |
|
| |
| The source files must be included in the same package as the byte compiled versions.
| |
|
| |
| == Byte compiling ==
| |
|
| |
| Python will automatically try to byte compile files when it runs in order to speed up startup the next time it is run. These files are saved in files with the extension of .pyc (compiled python) or .pyo (optimized compiled python). With current versions of python 3, these files will be located inside a directory named <code>__pycache__</code>. Older versions of python will simply place them alongside the .py files.
| |
|
| |
| The .pyc and .pyo files contain byte code that is portable across OSes. If you do not include them in your packages, python will try (and generally fail) to create them when the user runs the program. If the system administrator runs the program, then the files will be successfully written, causing stray .pyc and .pyo files which will not be removed when the package is removed. To prevent that the byte compiled files need to be compiled and included in the <code>%files</code> section. Normally, byte compilation is done for you by the <code>brp-python-bytecompile</code> script. This script runs after the <code>%install</code> section of the spec file has been processed and byte compiles any .py files that it finds (this recompilation puts the proper filesystem paths into the modules otherwise tracebacks would include the <code>%{buildroot}</code> in them).
| |
|
| |
| You must include in your package the .pyc and .pyo files. If the build process creates a __pycache__ directory in a subdirectory of %{python3_sitearch} or %{python3_sitelib}, you must also include all items in the __pycache__ directory. (You should not include the directories %{python3_sitearch}/__pycache__ or %{python3_sitelib}/__pycache__ because they are already owned by the python3-libs package.)
| |
|
| |
| All that you need to do is include the files in the <code>%files</code> section (replacing %{python3_sitelib} with the appropriate macro for your package):
| |
|
| |
| <pre>
| |
| %files
| |
| %{python3_sitelib}/foo/
| |
| </pre>
| |
|
| |
| or, if the python code installs directly into %{python3_sitelib}:
| |
|
| |
| <pre>
| |
| %files
| |
| %{python3_sitelib}/foo.py
| |
| %{python3_sitelib}/__pycache__/*
| |
| </pre>
| |
|
| |
| {{admon/warning|Avoid INSTALLED_FILES|python's distutils has an <code>INSTALLED_FILES</code> feature that lists which files are installed when you run <code>%py_install</code>. Do not use it for packaging as that will not list the directories which need to be specified in the <code>%files</code> section as well. Using globs in the <code>%files</code> section is simpler and safer.}}
| |
|
| |
| {{admon/warning|Including egg info|When you run <code>%py_install</code> in any current Fedora, distutils generates a <code>.egg-info</code> file with metadata about the python module that is installed. These files need to be included as well. (See [[#Packaging_eggs_and_setuptools_concerns|Packaging:Python_Eggs]] )}}
| |
|
| |
| === Optimization ===
| |
|
| |
| Fedora packages running with python < 3.5 (including any version of python 2) '''must not''' invoke python with the <code>-OO</code> option or set the environment variable <code>PYTHONOPTIMIZE</code> to 2 or greater. (Using -O or <code>PYTHONOPTIMIZE</code> less than 2 is fine, though unnecessary.)
| |
|
| |
| Similarly, any <code>.pyo</code> shipped in a Fedora package for python < 3.5 '''must not''' have been byte compiled using optimization level 2 or higher.
| |
|
| |
| === Manual byte compilation ===
| |
| For more details on the internals of byte compilation, please see [[Packaging:Python_Appendix#Manual_byte_compilation|the appendix]].
| |
|
| |
| == Common SRPM vs split SRPMs ==
| |
|
| |
| Many times when you package a python module you will want to create a module for python2 and a module for python3. Both versions should be built from the same SRPM. An exception to this would be if the two versions are distributed as separate archives and do not follow the same release schedule.
| |
|
| |
| {{admon/warning|Use of the <code>%python_provide</code> macro|When building more than once from the same spec file, you must not have a <code>%files</code> section. Instead you must build one subpackage for each python runtime and use the <code>%python_provide</code> macro as shown in the example specfile below.}}
| |
|
| |
| == Example common spec file ==
| |
|
| |
| The following is a very simple spec file for a module building for both python2
| |
| and python3. It builds both versions in the same directory; this is possible
| |
| because the build products for different versions of Python usually do not conflict.
| |
|
| |
| There are cases where it is not possible to build in a single directory. Most
| |
| commonly this happens when the sources are modified during the build process to
| |
| convert them from python2 to python3 using the the <code>2to3</code> tool. In
| |
| that case, please see [[Packaging:Python_Appendix#Using_separate_build_directories|the appendix]].
| |
|
| |
| As you can see in the <code>%install</code> section below, the order in which
| |
| you do the python2 versus python3 install can sometimes matter. You need to be
| |
| aware of when the install is writing to the same file in both packages (in this
| |
| example, a script in <code>%{_bindir}</code> and make sure that you're getting
| |
| the version you expect.
| |
|
| |
| <pre>
| |
| %global srcname example
| |
| %global sum An example python module
| |
|
| |
| Name: python-%{srcname}
| |
| Version: 1.2.3
| |
| Release: 1%{?dist}
| |
| Summary: %{sum}
| |
|
| |
| License: MIT
| |
| URL: https://pypi.python.org/pypi/%{srcname}
| |
| Source0: https://files.pythonhosted.org/packages/source/e/%{srcname}/%{srcname}-%{version}.tar.gz
| |
|
| |
| BuildArch: noarch
| |
| BuildRequires: python2-devel python3-devel
| |
|
| |
| %description
| |
| An python module which provides a convenient example.
| |
|
| |
| %package -n python2-%{srcname}
| |
| Summary: %{sum}
| |
| %{?python_provide:%python_provide python2-%{srcname}}
| |
|
| |
| %description -n python2-%{srcname}
| |
| An python module which provides a convenient example.
| |
|
| |
|
| |
| %package -n python3-%{srcname}
| |
| Summary: %{sum}
| |
| %{?python_provide:%python_provide python3-%{srcname}}
| |
|
| |
| %description -n python3-%{srcname}
| |
| An python module which provides a convenient example.
| |
|
| |
|
| |
| %prep
| |
| %autosetup -n %{srcname}-%{version}
| |
|
| |
| %build
| |
| %py2_build
| |
| %py3_build
| |
|
| |
| %install
| |
| # Must do the python2 install first because the scripts in /usr/bin are
| |
| # overwritten with every setup.py install, and in general we want the
| |
| # python3 version to be the default.
| |
| # If, however, we're installing separate executables for python2 and python3,
| |
| # the order needs to be reversed so the unversioned executable is the python2 one.
| |
| %py2_install
| |
| %py3_install
| |
|
| |
| %check
| |
| %{__python2} setup.py test
| |
| %{__python3} setup.py test
| |
|
| |
| # Note that there is no %%files section for the unversioned python module if we are building for several python runtimes
| |
| %files -n python2-%{srcname}
| |
| %license COPYING
| |
| %doc README.rst
| |
| %{python2_sitelib}/*
| |
|
| |
| %files -n python3-%{srcname}
| |
| %license COPYING
| |
| %doc README.rst
| |
| %{python3_sitelib}/*
| |
| %{_bindir}/sample-exec
| |
|
| |
| %changelog
| |
| </pre>
| |
|
| |
| == Avoiding collisions between the python 2 and python 3 stacks ==
| |
| The python 2 and python 3 stacks are intended to be fully-installable in parallel. When generalizing the package for both python 2 and python 3, it is important to ensure that two different built packages do not attempt to place different payloads into the same path.
| |
|
| |
| === Executables in <code>/usr/bin</code> ===
| |
| Many existing python packages install executables into <code>/usr/bin</code>.
| |
|
| |
| For example if we have a <code>console_scripts</code> in a <code>setup.py</code> shared between
| |
| python 2 and python 3 builds: these will spit out files in <code>/usr/bin/</code>,
| |
| and these will collide.
| |
|
| |
| For example <code>python-coverage</code> has a <code>setup.py</code> that contains:
| |
| <pre>
| |
| entry_points = {
| |
| 'console_scripts': [
| |
| 'coverage = coverage:main',
| |
| ]
| |
| },
| |
| </pre>
| |
|
| |
| which thus generates a <code>/usr/bin/coverage</code> executable (this is a python
| |
| script that runs another python script whilst generating code-coverage
| |
| information on the latter).
| |
|
| |
| Similarly for the 'scripts' clause; see e.g. <code>python-pygments</code>:
| |
| <code>Pygments-1.1.1/setup.py</code> has:
| |
| <pre>
| |
| scripts = ['pygmentize'],
| |
| </pre>
| |
| which generates a <code>/usr/bin/pygmentize</code> (this is a python script that leverages the pygments syntax-highlighting module, giving a simple command-line interface for generating syntax-highlighted files)
| |
|
| |
| If the executables provide the same functionality independent of whether they are run on top of Python 2 or Python 3, then only the Python 3 version of the executable should be packaged. Transitioning from python2 to python3 is left to individual package maintainers except for packages in Fedora's critical path. For these, we want to port to python3 versions in the same Fedora release if possible.
| |
|
| |
| Examples of this:
| |
| * <code>/usr/bin/pygmentize</code> ought to generate the same output regardless of whether it's implemented via Python 2 or Python 3, so only one version needs to be shipped.
| |
|
| |
| If the executables provide different functionality for Python 2 and Python 3, then both versions should be packaged.
| |
|
| |
| Examples of this:
| |
| * <code>/usr/bin/coverage</code> runs a python script, augmenting the interpreter with code-coverage information. Given that the interpreter itself is the thing being worked with, it's reasonable to package both versions of the executable.
| |
| * <code>/usr/bin/bpython</code> augments the interpreter with a "curses" interface. Again, it's reasonable to package both versions of this.
| |
| * <code>/usr/bin/easy_install</code> installs a module into one of the Python runtimes: we need a version for each runtime.
| |
|
| |
| === Naming ===
| |
| Many executables already contain a "-MAJOR.MINOR" suffix, for example <code>/usr/bin/easy_install-3.4</code>. These obviously can be used as-is, as they won't conflict.
| |
|
| |
| For other executables, the general rule is:
| |
| * If only one executable is to be shipped, then it owns its own slot and should use /usr/bin/python3 from Fedora 22 on.
| |
| * If executables are to be shipped for both python 2 and python 3:
| |
| ** Both python 2 and python 3 variants must provide symlinks with a '-X' and '-X.Y' suffix (python runtime major version, or python runtime major.minor version), unless upstream already provides appropriately versioned executables without the dash.
| |
| ** The unversioned executable '''must''' be the python2 version.
| |
| ** For example, the python3 version of "coverage" '''must''' ship executables <code>/usr/bin/coverage-3</code> and <code>/usr/bin/coverage-3.4</code> (assuming python3 is currently version 3.4), while the python2 version '''must''' provide <code>/usr/bin/coverage</code>, <code>/usr/bin/coverage-2</code> and <code>/usr/bin/coverage-2.7</code> (assuming python2 version 2.7).
| |
| ** For compatibility packages, the Python version is appended *after* the specific package version, for example <code>/usr/bin/coverage-v1.2-3</code> and <code>/usr/bin/coverage-v1.2-3.4</code> for python3-coverage1.2 compat package.
| |
| See [http://lists.fedoraproject.org/pipermail/devel/2010-January/129217.html this thread] and a newer thread [https://lists.fedoraproject.org/pipermail/packaging/2014-December/010360.html] for discussions of this.
| |
|
| |
| == Packaging eggs ==
| |
| Please see the Python eggs [[Packaging:Python_Eggs|guidelines]] for information specific to Python eggs.
| |
|
| |
| == Reviewer checklist ==
| |
| The following briefly summarizes the guidelines for reviewers to go over:
| |
| * '''Must''': If you build for more than one python runtime you must use the <code>%python_provide</code> macro.
| |
| * '''Must''': If you build for a single python runtime you must add <code>%python_provide python-$module</code> so that the current default python is provided from the unversioned python package.
| |
| * '''Must''': Python modules must be built from source. They cannot simply drop an egg from upstream into the proper directory. (See [[Packaging:Guidelines#No_inclusion_of_pre-built_binaries_or_libraries| prebuilt binaries Guidelines]] for details)
| |
| * '''Must''': Python modules must not download any dependencies during the build process.
| |
| * '''Must''': When building a compat package, it must install using easy_install -m so it won't conflict with the main package.
| |
| * '''Must''': When building multiple versions (for a compat package) one of the packages must contain a default version that is usable via "import MODULE" with no prior setup.
| |
| * '''Should''': A package which is used by another package via an egg interface should provide egg info.
| |
|
| |
| == Filtering Requires: and Provides: ==
| |
| RPM's dependency generator can often throw in additional dependencies and will often think packages provide functionality contrary to reality. To fix this, the dependency generator needs to be overriden so that the additional dependencies can be filtered out. See [[Packaging:AutoProvidesAndRequiresFiltering]] for details.
| |
|
| |
| [[Category:Packaging guidelines]]
| |
| [[Category:Python]]
| |
