Using custom themes with Yaydoc to build documentation

What is Yaydoc?

Yaydoc aims to be a one stop solution for all your documentation needs. It is continuously integrated to your repository and builds the site on each commit. One of it’s primary aim is to minimize user configuration. It is currently in active development.

Why Themes?

Themes gives the user ability to generate visually different sites with the same markup documents without any configuration. It is one of the many features Yaydoc inherits from sphinx.

Now sphinx comes with 10 built in themes but there are much more custom themes available on PyPI, the official Python package repository. To use these custom themes, sphinx requires some setup. But Yaydoc being an automated system needs to performs those tasks automatically.

To use a custom theme which has been installed, sphinx needs to know the name of the theme and where to find it. We do that by specifying two variables in the sphinx configuration file. html_theme and html_theme_path respectively. Custom themes provide a method that can be called to get the html_theme_path of the theme. Usually that method is named get_html_theme_path . But that is not always the case. We have no way find the appropriate method automatically.

So how do we get the path of an installed theme just by it’s name and how do we add it to the generated configuration file.

The configuration file is generated by the sphinx-quickstart command which Yaydoc uses to initialize the documentation directory. We can override the default generated files by providing our own project templates. The templates are based on the Jinja2 template engine.

Firstly, I replaced

html_theme = ‘alabaster’

With

html_theme = ‘{{ html_theme }}’

This provides us the ability to pass the name of the theme as a parameter to sphinx-quickstart. Now the user has an option to choose between 10 built-in themes. For custom themes however there is a different story. I had to solve two major issues.

  • The name of the package and the theme may differ.
  • We also need the absolute path to the theme.

The following code snippet solves the above mentioned problems.

{% if html_theme in (['alabaster', 'classic', 'sphinxdoc', 'scrolls',
'agogo', 'traditional', 'nature', 'haiku',
'pyramid', 'bizstyle'])
%}
# Theme is builtin. Just set the name
html_theme = '{{ html_theme }}'
{% else %}
# Theme is a custom python package. Lets install it.
import pip
exitcode = pip.main(['install', '{{ html_theme }}'])
if exitcode:
    # Non-zero exit code
    print("""{0} is not available on pypi. Please ensure the theme can be installed using 'pip install {0}'.""".format('{{ html_theme }}'), file=sys.stderr)
else:
    import {{ html_theme }}
    def get_path_to_theme():
        package_path = os.path.dirname({{ html_theme }}.__file__)
        for root, dirs, files in os.walk(package_path):
            if 'theme.conf' in files:
                return root
    path_to_theme = get_path_to_theme()
    if path_to_theme is None:
        print("\n{0} does not appear to be a sphinx theme.".format('{{ html_theme }}'), file=sys.stderr)
        html_theme = 'alabaster'
    else:
        html_theme = os.path.basename(path_to_theme)
        html_theme_path = [os.path.abspath(os.path.join(path_to_theme, os.pardir))]
{% endif %}

It performs the following tasks in order:

  • It first checks if the provided theme is one of the built in themes. If that is indeed the case, we just set the html_theme config value to the name of the theme.
  • Otherwise, It installs the package using pip.
  • Now __file__ has a special meaning in python. It returns us the path of the module. We use it to get the path of the installed package.
  • Now each sphinx theme must have a file named `theme.conf` which defines several properties of the theme. We do a recursive search for that file.
  • We set html_theme to be the name of the directory which contains that file, and html_theme_path to be it’s parent directory.

Now let’s see everything in action. Here are four pages created by Yaydocs from a single markup document with no user configuration.

 

Now you can choose between many of the themes available on PyPI. You can even create your own theme. Follow this blog to get more insights and latest news about Yaydoc.

 

Generating a documentation site from markup documents with Sphinx and Pandoc

Generating a fully fledged website from a set of markup documents is no easy feat. But thanks to the wonderful tool sphinx, it certainly makes the task easier. Sphinx does the heavy lifting of generating a website with built in javascript based search. But sometimes it’s not enough.

This week we were faced with two issues related to documentation generation on loklak_server and susi_server. First let me give you some context. Now sphinx requires an index.rst file within /docs/  which it uses to generate the first page of the site. A very obvious way to fill it which helps us avoid unnecessary duplication is to use the include directive of reStructuredText to include the README file from the root of the repository.

This leads to the following two problems:

  • Include directive can only properly include a reStructuredText, not a markdown document. Given a markdown document, it tries to parse the markdown as  reStructuredText which leads to errors.
  • Any relative links in README break when it is included in another folder.

To fix the first issue, I used pypandoc, a thin wrapper around Pandoc. Pandoc is a wonderful command line tool which allows us to convert documents from one markup format to another. From the official Pandoc website itself,

If you need to convert files from one markup format into another, pandoc is your swiss-army knife.

pypandoc requires a working installation of Pandoc, which can be downloaded and installed automatically using a single line of code.

pypandoc.download_pandoc()

This gives us a cross-platform way to download pandoc without worrying about the current platform. Now, pypandoc leaves the installer in the current working directory after download, which is fine locally, but creates a problem when run on remote systems like Travis. The installer could get committed accidently to the repository. To solve this, I had to take a look at source code for pypandoc and call an internal method, which pypandoc basically uses to set the name of the installer. I use that method to find out the name of the file and then delete it after installation is over. This is one of many benefits of open-source projects. Had pypandoc not been open source, I would not have been able to do that.

url = pypandoc.pandoc_download._get_pandoc_urls()[0][pf]
filename = url.split(‘/’)[-1]
os.remove(filename)

Here pf is the current platform which can be one of ‘win32’, ‘linux’, or ‘darwin’.

Now let’s take a look at our second issue. To solve that, I used regular expressions to capture any relative links. Capturing links were easy. All links in reStructuredText are in the same following format.

`Title <url>`__

Similarly links in markdown are in the following format

[Title](url)

Regular expressions were the perfect candidate to solve this. To detect which links was relative and need to be fixed, I checked which links start with the \docs\ directory and then all I had to do was remove the \docs prefix from those links.

A note about loklak and susi server project

Loklak is a server application which is able to collect messages from various sources, including twitter.

SUSI AI is an intelligent Open Source personal assistant. It is capable of chat and voice interaction and by using APIs to perform actions such as music playback, making to-do lists, setting alarms, streaming podcasts, playing audiobooks, and providing weather, traffic, and other real time information