Development and Contributing¶
This document describes the development process of KIWI and how you can be part of it. This description applies to version 9.19.13.
The core appliance builder is developed in Python and follows the test driven development rules.
If you want to implement a bigger feature, consider opening an issue on
GitHub first to discuss the changes. Or join the discussion in the
#kiwi channel on Riot.im.
Fork the upstream KIWI repository¶
On GitHub, navigate to: https://github.com/OSInside/kiwi
In the top-right corner of the page, click Fork.
Create a local clone of the forked KIWI repository¶
$ git clone https://github.com/YOUR-USERNAME/kiwi $ git remote add upstream https://github.com/OSInside/kiwi.git
Install Required Operating System Packages¶
KIWI requires the following additional packages which are not provided by pip:
- XML processing libraries
- Python header files, GCC compiler and glibc-devel header files
Required for python modules that hooks into shared library context
- Spell Checking library
Provided by the
ShellCheck script linter.
- ISO creation program
- LaTeX documentation build environment
A full LaTeX installation is required to build the PDF documentation 1.
The above mentioned system packages will be installed by calling the
install_devel_packages.sh helper script from the checked out Git
repository as follows:
$ sudo helper/install_devel_packages.sh
The helper script checks for the package managers
dnf and associates a distribution with it. If you use a
distribution that does not use one of those package managers
the script will not install any packages and exit with an
error message. In this case we recommend to take a look at
the package list encoded in the script and adapt to your
distribution and package manager as needed.
Create a Python Virtual Development Environment¶
The following commands initializes and activates a development environment for Python 3:
$ tox -e devel $ source .tox/3/bin/activate
The commands above automatically creates the application script called kiwi-ng, which allows you to run KIWI from the Python sources inside the virtual environment:
$ kiwi-ng --help
$PATH will not be taken into account when calling
KIWI via sudo! Use the absolute path to the KIWI executable
to run an actual build using your local changes:
$ sudo $PWD/.tox/3/bin/kiwi-ng system build ...
To leave the development mode, run:
To resume your work, cd into your local Git repository and call:
$ source .tox/3/bin/activate
Running the Unit Tests¶
We use tox to run the unit tests. Tox sets up its own
virtualenvs inside the
.tox directory for multiple Python versions
and should thus not be invoked from inside your development virtualenv.
Before submitting your changes via a pull request, ensure that all tests pass and that the code has the required test coverage via the command:
We also include
pytest-xdist in the development virtualenv which allows
to run the unit tests in parallel. It is turned off by default but can be
$ tox "-n NUMBER_OF_PROCESSES"
where you can insert an arbitrary number as
NUMBER_OF_PROCESSES (or a
shell command like
$(nproc)). Note that the double quotes around
NUMBER_OF_PROCESSES are required (otherwise tox will consume
this command line flag instead of forwarding it to pytest).
The previous call would run the unit tests for different Python versions, check the source code for errors and build the documentation.
If you want to see the available targets, use the option
-l to let
tox print a list of them:
$ tox -l
To only run a special target, use the
-e option. The following
example runs the test cases for the Python 3.6 interpreter only:
$ tox -e unit_py3_6
Create a Branch for each Feature or Bugfix¶
Code changes should be done in an extra Git branch. This allows for creating GitHub pull requests in a clean way. See also: Collaborating with issues and pull requests
$ git checkout -b my-topic-branch
Make and commit your changes.
You can make multiple commits which is generally useful to give your changes a clear structure and to allow us to better review your work.
Your work is important and must be signed to ensure the integrity of the repository and the code. Thus we recommend to setup a signing key as documented in Signing Git Patches.
$ git commit -S -a
Once everything is done, push your local branch to your forked repository and create a pull request into the upstream repository.
$ git push origin my-topic-branch
Thank you much for contributing to KIWI. Your time and work effort is very much appreciated!
KIWI follows the general PEP8 guidelines with the following exceptions:
We do not use free functions at all. Even utility functions must be part of a class, but should be either prefixed with the
@staticmethoddecorators (whichever is more appropriate).
Do not set module and class level variables, put these into the classes’
The names of constants are not written in all capital letters.
We do not use type hints (yet) as the current code base needs to maintain Python 2 compatibility.
KIWI uses Sphinx for the API and user documentation.
In order to build the HTML documentation call:
tox -e doc
or to build the full documentation (including a PDF generated by LaTeX 3):
tox -e packagedoc
Document all your classes, methods, their parameters and their types using the standard reStructuredText syntax as supported by Sphinx, an example class is documented as follows:
class Example: """ **Example class** :param str param: A parameter :param bool : Source file name to compress :param list supported_zipper: List of supported compression tools :attr Optional[str] attr: A class attribute """ def __init__(self, param, param_w_default=False): self.attr = param if param_w_default else None def method(self, param): """ A method that takes a parameter. :param list param: a parameter :return: whether param is very long :rtype: bool """ return len(param) > 50
Try to stick to the following guidelines when documenting source code:
Classes should be documented directly in their main docstring and not in
Document every function parameter and every public attribute including their types.
Only public methods should be documented, private methods don’t have to, unless they are complex and it is not easy to grasp what they do (which should be avoided anyway).
Please also document any user-facing changes that you implementing
(e.g. adding a new build type) in the user documentation, which can be
doc/source. General documentation should be put into the
working_with_kiwi/ subfolder, whereas documentation about more
specialized topics would belong into the
Adhere to a line limit of 75 characters when writing the user facing documentation 2.
The following sections provides further information about the repository integrity, version, package and documentation management.
Signing Git Patches¶
To ensure the integrity of the repository and the code base, patches sent for inclusion should be signed with a GPG key.
To prepare Git to sign commits, follow these instructions:
Create a key suitable for signing (it is not recommended to use existing keys to not mix it with your email environment):
$ gpg2 --expert --full-gen-key
Either choose a RSA key for signing (option
(4)) or an ECC key for signing (option
(10)). For a RSA key choose a key size of 4096 bits and for a ECC key choose Curve 25519 (option
(1)). Enter a reasonable validity period (we recommend 2 to 5 years). Complete the key generation by entering your name and email address.
Add the key ID to your git configuration, by running the following git config commands:
$ git config --local user.signingkey $YOUR_SIGN_KEY_ID $ git config --local commit.gpgSign true
Omitting the flag
--localwill make these settings global for all repositories (they will be added to
~/.gitconfig). You can find your signkey’s ID via:
$ gpg2 --list-keys --keyid-format long $YOUR_EMAIL pub rsa4096/AABBCCDDEEFF0011 2019-04-26 [S] [expires: 2021-04-16] AAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBB uid [ultimate] YOU <$YOUR_EMAIL>
The key’s ID in this case would be
AABBCCDDEEFF0011. Note that your signkey will have only a
[S]after the creation date, not a
[SC](then you are looking at your ordinary GPG key that can also encrypt).
Bumping the Version¶
The KIWI project follows the Semantic Versioning scheme. We use the bumpversion tool for consistent versioning.
Follow these instructions to bump the major, minor, or patch part of the KIWI version. Ensure that your repository is clean (i.e. no modified and unknown files exist) beforehand running bumpversion.
For backwards-compatible bug fixes:
$ bumpversion patch
For additional functionality in a backwards-compatible manner. When changed, the patch level is reset to zero:
$ bumpversion minor
For incompatible API changes. When changed, the patch and minor levels are reset to zero:
$ bumpversion major
Creating a RPM Package¶
We provide a template for a RPM spec file in
package/python-kiwi-spec-template alongside with a rpmlint
configuration file and an automatically updated
To create the necessary files to build a RPM package via
$ make build
The sources are collected in the
dist/ directory. These can be
directly build it with rpmbuild, fedpkg, or submitted
to the Open Build Service using osc.
Sphinx requires a plethora of additional LaTeX packages. Unfortunately there is currently no comprehensive list available. On Ubuntu/Debian installing
texlive-latex-extrashould be sufficient. For Fedora, consult the package list from
Configure your editor to automatically break lines and/or reformat paragraphs. For Emacs you can use
M-x set-fill-column RET 75and
M-x auto-fill-mode RETfor automatic filling of paragraphs in conjunction with
M-x fill-paragraph(usually bound to
M-q) to reformat a paragraph to adhere to the current column width. For editing reStructuredText we recommend
rst-mode(built-in to Emacs since version
23.1). Vim users can set the text width via
:tw 75and then use the commands
Requires a full LaTeX installation.