Documentation Build Instructions
================================

The `website documentation`_ for Clear Linux* OS for Intel Architecture 
should be written in :abbr:`ReStructuredText (ReST)` AKA ``.rst``, which 
makes it easy to build parsable, command-line readable, indexed, and 
search-friendly documentation and APIs with `Sphinx`_.


.. _requirements:

Requirements
------------

To build documentation with Sphinx, ensure your system has these prerequisites:

* `GNU make`_
* `Python`_
* `PIP`_

The instructions for installing these varies according to OS. On a basic
out-of-the-box Ubuntu-like OS (which usually has Python installed by default),
check your python version

you might need something like:

.. code-block:: console

   $ sudo apt-get install python-pip
   $ sudo pip install -U sphinx sphinx-autobuild



.. code-block:: console

   $ python -c 'print __import__("sphinx").__version__'
     1.3.1


We have confirmed Sphinx installed.  The next step is to clone Gitlab
repo to our local machine.


.. code-block:: console

	$ git clone git@clrgitlab.intel.com:clr-documentation/project-docs.git
	Cloning into 'project-docs'...



**Note**:  If the first time you've cloned ``project-docs`` is following
along with these instructions, you may skip this section; go straight 
ahead to the :ref:`Run make` section. However, if you cloned an earlier 
version and ran into trouble generating HTML documentation locally, try 
the steps documented here.

Before running Sphinx, we may need to correct some of the problems in the 
legacy Gitlab repo. Running :command:`make` straightaway from the root of 
our clone won't work.  We need to delete the existing :file:`conf.py` file 
and also rename the existing index file so it can generate a new one with 
the correct parameters. Some files in the Gitlab repo are remnant of a build 
on a Windows box, and they don't quite work on Linux.

.. code-block:: console

	$ cd project-docs/
	$ ls
	make.bat  Makefile  source/
	$ rm -rf Makefile make.bat
	$ rm -rf source/conf.py
	$ mv source/index.rst source/oldindex.rst

In the cloned source directory, we have all the ``.rst`` files needed to 
build the docs. We run a native instance of :command:`sphinx-quickstart`. 
The program will run you through a series of questions. The main things to be
conscious of here are:

* Tell it to use the existing :file:`source/` directory as the Root path for
  the documentation; this is where it looks to find what it needs to generate
  the HTML.
* It's better to tell it to **not** separate the source and build directories;
  if you answer "y" here, Sphinx will generate *another* :file:`source/` directory,
  which can be confusing.  
* Running quickstart also creates a :file:`_static` directory where you
  should put all images, screenshots, and other content that is linked as static
  content. The builder has been known to complain about this directory if it exists
  already, but it's easy to fix. 
* It is only necessary to run the builder **once**.

What follows here is a log from a successful :command:`sphinx-quickstart` build
started from within an older clone of the :file:`project-docs/` directory.  Blank
answers indicate default.

.. code-block:: console

   $ sphinx-quickstart
   Welcome to the Sphinx 1.3.1 quickstart utility.

   Please enter values for the following settings (just press Enter to
   accept a default value, if one is given in brackets).

   Enter the root path for documentation.
   > Root path for the documentation [.]: source/

   You have two options for placing the build directory for Sphinx output.
   Either, you use a directory "_build" within the root path, or you separate
   "source" and "build" directories within the root path.
   > Separate source and build directories (y/n) [n]: n

   Inside the root directory, two more directories will be created; "_templates"
   for custom HTML templates and "_static" for custom stylesheets and other static
   files. You can enter another prefix (such as ".") to replace the underscore.
   > Name prefix for templates and static dir [_]:

   The project name will occur in several places in the built documentation.
   > Project name: ClearLinux Docs
   > Author name(s): Intel OTC

   Sphinx has the notion of a "version" and a "release" for the
   software. Each version can have multiple releases. For example, for
   Python the version is something like 2.5 or 3.0, while the release is
   something like 2.5.1 or 3.0a1.  If you don't need this dual structure,
   just set both to the same value.
   > Project version: 1.0.0
   > Project release [1.0.0]: 1.0.0

   If the documents are to be written in a language other than English,
   you can select a language here by its language code. Sphinx will then
   translate text that it generates into that language.

   For a list of supported codes, see
   http://sphinx-doc.org/config.html#confval-language.
   > Project language [en]: en

   The file name suffix for source files. Commonly, this is either ".txt"
   or ".rst".  Only files with this suffix are considered documents.
   > Source file suffix [.rst]: .rst

   One document is special in that it is considered the top node of the
   "contents tree", that is, it is the root of the hierarchical structure
   of the documents. Normally, this is "index", but if your "index"
   document is a custom template, you can also set this to another filename.
   > Name of your master document (without suffix) [index]:

   Sphinx can also add configuration for epub output:
   > Do you want to use the epub builder (y/n) [n]: n

   Please indicate if you want to use one of the following Sphinx extensions:
   > autodoc: automatically insert docstrings from modules (y/n) [n]: n
   > doctest: automatically test code snippets in doctest blocks (y/n) [n]: n
   > intersphinx: link between Sphinx documentation of different projects (y/n) [n]: n
   > todo: write "todo" entries that can be shown or hidden on build (y/n) [n]: n
   > coverage: checks for documentation coverage (y/n) [n]: n
   > pngmath: include math, rendered as PNG images (y/n) [n]: n
   > mathjax: include math, rendered in the browser by MathJax (y/n) [n]: y
   > ifconfig: conditional inclusion of content based on config values (y/n) [n]: y
   > viewcode: include links to the source code of documented Python objects (y/n) [n]: y

   A Makefile and a Windows command file can be generated for you so that you
   only have to run e.g. "make html" instead of invoking sphinx-build
   directly.
   > Create Makefile? (y/n) [y]: y
   > Create Windows command file? (y/n) [n]: n

   Creating file source/conf.py.
   Creating file source/index.rst.
   Creating file source/Makefile.

   Finished: An initial directory structure has been created.

   You should now populate your master file source/index.rst and create other
   documentation source files. Use the Makefile to build the docs, like so:
	    make builder
   where "builder" is one of the supported builders, e.g. html, latex or
   linkcheck.


.. _run_make:

Run make
--------

Finally are we ready to run :command:`make`. Be sure to :command:`cd` to the
:file:`source/` directory where your ``.rst`` files are (or will be), before 
running :command:`make` ``html``, or the doc format of your choice.

.. code-block:: console

   $ make html
   >
   sphinx-build -b html -d _build/doctrees   . _build/html
   Running Sphinx v1.3.1
   making output directory...
   .
   .
   .
   build succeeded, 0 warnings.

   Build finished. The HTML pages are in _build/html.

Open one of the .html pages in a web browser to view the rendered 
documentation. If needed, you can copy the contents of the oldindex.rst
into the generated index file, re-run :command:`make`, to generate the 
new HTML, and your local Table of Contents should update accordingly.

For tips on how to contribute documentation formatted in the .rst style
needed to integrate beautifully on the clearlinux.org website, please see
 `Theming Sphinx`_.


.. _website documentation:  https://clearlinux.org/documentation
.. _Sphinx: http://sphinx-doc.org/
.. _GNU make: https://www.gnu.org/software/make/
.. _Python: https://www.python.org/
.. _PIP: https://pypi.python.org/pypi/pip/
.. _Theming Sphinx: https://github.com/otcshare/tcs-hub/blob/master/theming-sphinx.rst