contributing.md

Contributing to the kernel_settings Linux System Role

Where to start

The first place to go is Contribute. This has all of the common information that all role developers need:

• Role structure and layout
• Development tools - How to run tests and checks
• Ansible recommended practices
• Basic git and github information
• How to create git commits and submit pull requests

Bugs and needed implementations are listed on Github Issues. Issues labeled with help wanted are likely to be suitable for new contributors!

Code is managed on Github, using Pull Requests.

Python Code

The Python code needs to be compatible with the Python versions supported by the role platform.

For example, see meta for the platforms supported by the role.

If the role provides Ansible modules (code in library/ or module_utils/) - these run on the managed node, and typically[1] use the default system python:

• EL6 - python 2.6
• EL7 - python 2.7 or python 3.6 in some cases
• EL8 - python 3.6
• EL9 - python 3.9

If the role provides some other sort of Ansible plugin such as a filter, test, etc. - these run on the control node and typically use whatever version of python that Ansible uses, which in many cases is not the system python, and may be a modularity release such as python311.

In general, it is a good idea to ensure the role python code works on all versions of python supported by tox-lsr from py36 on, and on py27 if the role supports EL7, and on py26 if the role supports EL6.[1]

[1] Advanced users may set ansible_python_interpreter to use a non-system python on the managed node, so it is a good idea to ensure your code has broad python version compatibility, and do not assume your code will only ever be run with the default system python.

Testing kernel_settings modules

It is recommended to use tox to set up your virtualenv for development/testing purposes:

dnf/yum install python-tox
tox -e py38

You can also use the virtualenv created by tox just like any other virtualenv created by python-virtualenv:

. .tox/env-py38/bin/activate
python
>>> import package.that.only.exists.in.venv

The unit tests and other tests are run by default when you use tox by itself or tox -e py38 for a specific python versioned environment. Note that other operating system packages may be required to be installed in order for tox to use pip to install python dependencies e.g. for python packages which have native components.

I would also strongly encourage you to use an IDE for development. For example, Visual Studio code python extension auto-discovers tests and allows you to run and debug unit tests. However, you may need to create a .env file like this, in order for code navigation, auto-completion, and test discovery to work correctly:

PYTHONPATH=/full/path/to/tuned:/full/path/to/linux-system-roles/kernel_settings/library

Testing the module

Ansible Module Development Guide

Using a tox python virtualenv from the kernel_settings directory:

. .tox/env-py38/bin/activate
TESTING=true [TEST_PROFILE=kernel_settings] python \
  library/kernel_settings.py args.json

looks for test profiles under tests/tuned/etc/tuned

to run the code in the debugger:

TESTING=true [TEST_PROFILE=kernel_settings] python -mpdb \
  library/kernel_settings.py args.json

Where args.json looks like this:

{
    "ANSIBLE_MODULE_ARGS": {
        "name": "kernel_settings",
        "sysctl": [
            {"name": "fs.inotify.max_user_watches", "value": 524288},
            {"name": "kernel.threads-max", "value": 30001}
        ],
        "sysfs": [
            {"name": "/sys/kernel/kexec_crash_size", "value": 337641472}
        ],
        "bootloader": [
            {"name": "cmdline", "value": [
                {"name": "mitigations", "value": "on"},
                {"name": "another"}
                ]
            }
        ],
        "selinux": [
            {"name": "avc_cache_threshold", "value": 512}
        ],
        "purge": false
    }
}