Python Continuous Documentation

Introduction

If you own a Python library that uses Sphinx formatted docstrings, it's easy to get started turning these docstrings into beautiful HTML, hosted on GitHub Pages, updated every time you push to GitHub.

This repository is intended to be a working example of this method, check out the docs.

This tutorial uses Travis CI, but there is an older version written for Jenkins.

Why not use ReadTheDocs?

Please do! This tutorial simply provides an alternative.

Setting Up Your Project

Installation

As always, I suggest using a virtualenv for local Python development. Inside your virtualenv, run:

pip install sphinx

Setup

Create a doc directory in your project, we'll add it to git later:

mkdir -p doc
cd doc

Create the basic configuration and file structure:

sphinx-quickstart

There are several questions you need to give a non-default answer to:

> Separate source and build directories (y/N) [n]: y
> Project name: yourproject
> Author name(s): Your Name
> Project version: 1.2.3
> autodoc: automatically insert docstrings from modules (y/N) [n]: y
> intersphinx: link between Sphinx documentation of different projects (y/N) [n]: y

Creating the Doc Layout

When running sphinx-quickstart, you specified index.rst as the starting point for your documentation pages. With Sphinx, you'll need every page linked either directly or indirectly from index.rst using the .. toctree:: directive. Let's consider the following Python package:

docpkg/__init__.py
docpkg/main.py
docpkg/config.py

One package, three modules. Replace your index.rst with the following:

``docpkg`` Package
==================

.. automodule:: docpkg
   :members:

-------------------

**Sub-Modules:**

.. toctree::

   docpkg.main
   docpkg.config

Now we're going to create two more files, docpkg.main.rst and docpkg.config.rst. I'll give you docpkg.main.rst, create docpkg.config.rst the same way:

``docpkg.main`` Module
========================

.. automodule:: docpkg.main
   :members:

As you add more modules to your project, they need to be added to the documentation structure. You can obviously put more than one .. automodule:: on a page, at your discretion.

Building the Docs Locally

Once you have your doc layout created, you can build your documentation from the doc/ directory with:

make html

Try navigating to doc/build/html/index.html in your browser!

Add Documentation Requirements

I usually keep a doc/requirements.txt file around so that I don't have to hard-code the dependencies necessary to build the documentation anywhere. For now, this may only contain one:

sphinx

In the future, you might add others with themes or sphinx extensions.

Committing to Git

The entire doc/ directory tree does not necessarily need to be put into git. The following should suffice:

git add doc/requirements.txt doc/Makefile doc/source/conf.py doc/source/*.rst
git commit

Creating GitHub Pages Branch

GitHub will generate a GitHub Pages site for any repository that has a gh-pages branch. Let's set ours up now:

git checkout --orphan gh-pages
git rm -rf .

Now let's add the .nojekyll file. This tells GitHub that our content does not use Jekyll for rendering. Finally, commit and push:

touch .nojekyll
git add .nojekyll
git commit -m 'initial commit'
git push origin gh-pages

Setting up Travis CI

Thus far we have only built docs locally. We will now configure Travis CI to build and deploy the docs any time we merge changes to our default branch. It does so by committing the files under doc/build/html into the gh-pages branch and pushing using your GitHub Personal Access Token.

All the steps below operate on the .travis.yml file in your project repository. It is assumed that you have already setup Travis to build your project, otherwise start there.

Setting the Version

Because Python projects usually declare their version in setup.py, we want Sphinx to look there to find the project version so our API docs reflect the correct value.

In doc/source/conf.py, you likely see this value:

release = '1.2.3'

Replace that line with one that reads the version correctly:

import pkg_resources

# Read the project version from setup.py
release = pkg_resources.require(project)[0].version

Building the Docs

To start, we need to make sure our build has Sphinx and other doc dependencies installed, so add a new install step:

install:
  - travis_retry pip install -U -r doc/requirements.txt
  # ...

Next, add an after_success step to build the docs:

after_success:
  - make -C doc html
  # ...

Deploying to GitHub Pages

Travis can deploy to GitHub Pages on build with the simple addition of a deploy section:

deploy:
  provider: pages
  skip_cleanup: true
  github_token: $GITHUB_TOKEN
  keep_history: true
  on:
    branch: main  # the default branch name
  local_dir: doc/build/html

If you have not already, turn on GitHub Pages for your repository using the gh-pages branch under Settings → GitHub Pages.

Setting Your GitHub Token

This step should be taken very carefully!

First, you should have a token with repo scope, so that Travis may access and update your gh-pages branch. You will need to copy this token shortly.

Navigate to your project settings in Travis. Under the Environment Variables section, add a new variable:

Change main if that is not the name of your default branch. Be absolutely sure not to check Display value in build log or your API token may be leaked and should be deleted.

Commit

Commit and push your .travis.yml updates, and watch your Travis build logs to watch it in action. If all goes well, your project's GitHub Pages site should be now contain your latest and greatest API documentation.

🎉