Documentation

Since Fedora contributors live around the world and don’t often have the opportunity to meet in person, it’s important to maintain up-to-date high quality documentation for all our projects. Our preferred documentation tool is Sphinx. In fact, this documentation is written using Sphinx!

A project’s documentation should at a minimum contain:

  • An introduction to the project
  • A user guide
  • A contributor guide
  • API documentation.

The easiest way to maintain up-to-date documentation is to include the majority of the documentation in the code itself. Sphinx includes several extensions to turn Python documentation into HTML pages.

Note

Improving documentation is a great way to get involved in a project. When adding new documentation or cleaning up existing documentation, please follow the guidelines below.

Style

Sphinx supports three different documentation styles. By default, Sphinx expects ReStructuredText. However, it has included an extension to support the Google style and the NumPy style since version 1.3. The style of the documentation blocks is left up to the individual project, but it should document the choice and be consistent.

Introduction

The project introduction should be easy to find - preferably it should be the documentation’s index page. It should provide an overview of the project and should be easy for a complete new-comer to understand.

User Guide

Have a clear user guide that covers most, if not all, features of the project as well as potential use cases. Keep in mind that your users may be non- technical as well as technical. Some users will want to use the project’s web interface, while others are interested in the API and the documentation should make it easy for both types of users to find the documentation for them.

Contributor Guide

Documenting how to start contributing makes it much easier for new contributors to get involved. This is a good place to cover the expectations about code style, documentation, tests, etc.

API Documentation

All APIs should be documented. Users should never have to consult the source code to use the project’s API.

Python

Python API documentation is easily generated by using the autodoc extension. Following these steps will create rich HTML, PDF, EPUB, or man format documentation:

  1. All modules should contain a documentation block at the top of the file that describes the module’s purpose and documents module-level attributes it provides as part of its public interface. In the case of a package’s __init__.py, this should document the package’s purpose.
  2. All classes should have documentation blocks that describe their purpose, any attributes they have, and example usage if appropriate.
  3. All methods and functions should have documentation blocks that describe their purpose, the arguments they accept, the types of those arguments, and example usage if appropriate.
  4. Make use of Sphinx’s cross-referencing feature. This will generate links between objects in the documentation.

HTTP APIs

Many projects provide an HTTP-based API. Use sphinxcontrib-httpdomain to produce the HTTP interface documentation. This task is made significantly easier if the project using a web framework that sphinxcontrib-httpdomain supports, like Flask. In that case, all you need to do is add the sphinxcontrib-httpdomain ReStructuredText directives to the functions or classes that provide the Flask endpoints.

After that, all you need to do is use the autoflask ReStructuredText directive.

Release Notes and ChangeLog

The release notes (or the changelog) can be managed using towncrier. It can build a release notes files by assembling items that would be written in separate files by each pull request (or commit). This way, the different commits will not conflict by writing in the same changelog file, and a link to the issue, the pull request or the commit is automatically inserted.

In your project root, add a pyproject.toml file with a tool.towncrier section similar to the one in fedora-messaging.

Create a news directory where the news items will be written, and in there create a _template.rst file with a content similar to the one in fedora-messaging.

Of course, replace fedora_messaging and the project URL by yours, where applicable.

Then create a docs/changelog.rst file (location configured in the pyproject.toml file) with the follwing content:

=============
Release Notes
=============

.. towncrier release notes start

Then each commit can add a file in the news folder to document the change. The file has the source.type name format, where type is one of:

  • feature: for new features
  • bug: for bug fixes
  • api: for API changes
  • dev: for development-related changes
  • author: for contributor names
  • other: for other changes

And where the source part of the filename is:

  • 42 when the change is described in issue 42
  • PR42 when the change has been implemented in pull request 42, and there is no associated issue
  • Cabcdef when the change has been implemented in changeset abcdef, and there is no associated issue or pull request.
  • username for contributors (author extention). It should be the username part of their commits’ email address.

A preview of the release notes can be generated with towncrier --draft.

When running towncrier, the tool will write the changelog file and remove the individual news fragments. These changes can then be committed as part of the release commit.