acrn-hypervisor/doc/tutorials/docbuild.rst

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ReStructuredText

.. _acrn_doc:
ACRN Documentation Generation
#############################
These instructions will walk you through generating the Project ACRN's
documentation and publishing it to https://projectacrn.github.io.
You can also use these instructions to generate the ACRN documentation
on your local system.
.. contents::
:local:
:depth: 1
Documentation Overview
**********************
Project ACRN content is written using the reStructuredText markup
language (``.rst`` file extension) with Sphinx extensions, and processed
using Sphinx to create a formatted stand-alone website. Developers can
view this content either in its raw form as .rst markup files, or you
can generate the HTML content and view it with a web browser directly on
your workstation.
You can read details about `reStructuredText`_, and `Sphinx`_ from
their respective websites.
The project's documentation contains the following items:
* ReStructuredText source files used to generate documentation found at the
http://projectacrn.github.io website. All of the reStructuredText sources
are found in the ``acrn-hypervisor/doc`` folder, or pulled in from sibling
folders (such as ``misc/``) by the build scripts.
* Doxygen-generated material used to create all API-specific documents
found at http://projectacrn.github.io/latest/api/. The documentation build
process uses doxygen to scan source files in the hypervisor and
device-model folders (as explained later).
.. image:: images/doc-gen-flow.png
:align: center
The reStructuredText files are processed by the Sphinx documentation system
and use the breathe extension for including the doxygen-generated API
material.
Set Up the Documentation Working Folders
****************************************
You'll need ``git`` installed to get the working folders set up:
* For an Ubuntu development system use:
.. code-block:: bash
sudo apt install git
We use the source header files to generate API documentation and we use
``github.io`` for publishing the generated documentation. Here's the
recommended folder setup for documentation contributions and generation:
.. code-block: none
projectacrn/
acrn-hypervisor/
devicemodel/
doc/
hypervisor/
misc/
The parent ``projectacrn folder`` is there because, if you have repo publishing
rights, we'll also be creating a publishing area later in these steps.
It's best if the ``acrn-hypervisor`` folder is an ssh clone of your personal
fork of the upstream project repos (though ``https`` clones work too and won't
require you to
`register your public SSH key with GitHub <https://github.com/settings/keys>`_):
#. Use your browser to visit https://github.com/projectacrn and do a
fork of the **acrn-hypervisor** repo to your personal GitHub account.)
.. image:: images/acrn-doc-fork.png
:align: center
#. At a command prompt, create the working folder and clone the acrn-hypervisor
repository to your local computer (and if you have publishing rights, the
``projectacrn.github.io`` repo). If you don't have publishing rights
you'll still be able to generate the documentation files locally, but not publish them:
.. code-block:: bash
cd ~
mkdir projectacrn && cd projectacrn
git clone git@github.com:<github-username>/projectacrn/acrn-hypervisor.git
#. For the cloned local repos, tell git about the upstream repo:
.. code-block:: bash
cd acrn-hypervisor
git remote add upstream git@github.com:projectacrn/acrn-hypervisor.git
After that, you'll have ``origin`` pointing to your cloned personal repo and
``upstream`` pointing to the project repo.
#. If you haven't done so already, be sure to configure git with your name
and email address for the ``signed-off-by`` line in your commit messages:
.. code-block:: bash
git config --global user.name "David Developer"
git config --global user.email "david.developer@company.com"
Install the Documentation Tools
*******************************
Our documentation processing has been tested to run with Python 3.6.3
and these other tools:
* breathe version: 4.23.0
* sphinx version: 3.2.1
* docutils version: 0.16
* sphinx-rtd-theme version: 0.5.0
* sphinx-tabs version: 1.3.0
* doxygen version: 1.8.13
Depending on your Linux version, install the needed tools. You may get a
different (newer) version of doxygen noted above that may also work.
For Ubuntu use:
.. code-block:: bash
sudo apt install doxygen python3-pip \
python3-wheel make graphviz xsltproc
Then use ``pip3`` to install the remaining Python-based tools:
.. code-block:: bash
cd ~/projectacrn/acrn-hypervisor/doc
pip3 install --user -r scripts/requirements.txt
Use this command to add ``$HOME/.local/bin`` to the front of your ``PATH`` so the system will
find expected versions of these Python utilities such as ``sphinx-build`` and
``breathe``:
.. code-block:: bash
printf "\nexport PATH=\$HOME/.local/bin:\$PATH" >> ~/.bashrc
.. important::
You will need to open a new terminal for this change to take effect.
Adding this to your ``~/.bashrc`` file ensures it is set by default.
And with that you're ready to generate the documentation.
.. note::
We've provided a script you can run to show what versions of the
documentation building tools are installed and compare with the
tool versions shown above.::
doc/scripts/show-versions.py
Extra Tools for Generating PDF
==============================
While the primary output for ACRN documentation is for an HTML website, you can
also generate a PDF version of the documentation. A few extra tools are needed
only if you want to create PDF output. For Ubuntu users add these additional
packages:
.. code-block:: bash
sudo apt install texlive-latex-recommended texlive-fonts-recommended \
texlive-latex-extra latexmk texlive-xetex xindy
Documentation Presentation Theme
********************************
Sphinx supports easy customization of the generated HTML documentation
appearance through the use of themes. Replace the theme files and do
another ``make html`` and the output layout and style is changed. The
sphinx build system creates document cache information that attempts to
expedite documentation rebuilds, but occasionally can cause an unexpected error or
warning to be generated. Doing a ``make clean`` to create a clean
generation environment and a ``make html`` again generally fixes these issues.
The ``read-the-docs`` theme is installed as part of the
``requirements.txt`` list above. Tweaks to the standard
``read-the-docs`` appearance are added by using CSS
and JavaScript customization found in ``doc/static``, and
theme template overrides found in ``doc/_templates``.
Run the Documentation Processors
********************************
The ``acrn-hypervisor/doc`` directory has all the ``.rst`` source files, extra
tools, and ``Makefile`` for generating a local copy of the ACRN technical
documentation. (Some additional ``.rst`` files and other material is extracted
or generated from the ``/misc`` folder as part of the ``Makefile``.)
.. code-block:: bash
cd ~/projectacrn/acrn-hypervisor/doc
make html
Depending on your development system, it will take less than two minutes to
collect and generate the HTML content. When done, you can view the HTML
output with your browser started at
``~/projectacrn/acrn-hypervisor/doc/_build/html/index.html``. You can
also ``cd`` to the ``_build/html`` folder and run a local web server
with the command:
.. code-block:: bash
cd _build/html
python3 -m http.server
and use your web browser to open the URL: ``http://localhost:8000``.
Generate PDF Output
===================
After the HTML content is generated, it leaves artifacts behind that you can
use to generate PDF output using the Sphinx ``latex`` builder. This
builder initially creates LaTeX output in the ``_build/latex`` folder and then
uses the ``latexmk`` tool to create the final ``acrn.pdf`` file in the same
folder. This process automatically makes a few passes over the content to create the index
and resolve intra-document hyperlinks, and produces plenty of progress messages along the
way. The Sphinx-generated output for tables and code blocks also yields many "underfill"
and "overfill" messages from the ``latex`` builder that can't be easily
suppressed or fixed. Because of that, we recommend running this PDF generation
with the ``-silent`` options, like this (after you've run ``make html``:
.. code-block:: bash
make latexpdf LATEXMKOPTS="-silent"
For convenience, we've also created a make target called ``pdf`` that will first
generate the HTML content and then make the PDF file in one step:
.. code-block:: bash
make pdf
This make target runs quietly, and then verifies that no unexpected message from
the build process are produced (using the :ref:`message filtering process
<filter_expected>` explained below. Either way, when the build completes, the
generated PDF file is in ``_build/latex/acrn.pdf``.
Publish Content
***************
If you have merge rights to the projectacrn repo called
``projectacrn.github.io``, you can update the public project documentation
found at https://projectacrn.github.io.
You'll need to do a one-time clone of the upstream repo (we publish
directly to the upstream repo rather than to a personal forked copy):
.. code-block:: bash
cd ~/projectacrn
git clone git@github.com:projectacrn/projectacrn.github.io.git
Then, after you've verified the generated HTML from ``make html`` looks
good, you can push directly to the publishing site with:
.. code-block:: bash
make publish
This uses git commands to synchronize the new content with what's
already published and will delete files in the publishing repo's
**latest** folder that are no longer needed. New or changed files from
the newly-generated HTML content are added to the GitHub pages
publishing repo. The public site at https://projectacrn.github.io will
be updated by the `GitHub pages system
<https://guides.github.com/features/pages/>`_, typically within a few
minutes.
Document Versioning
*******************
The https://projectacrn.github.io site has a document version selector
at the top of the left nav panel. The contents of this version
selector are defined in the ``conf.py`` sphinx configuration file,
specifically:
.. code-block:: python
:emphasize-lines: 5-6
html_context = {
'current_version': current_version,
'docs_title': docs_title,
'is_release': is_release,
'versions': ( ("latest", "/latest/"),
("2.3", "/2.3/"),
("2.2", "/2.2/"),
("2.1", "/2.1/"),
("2.0", "/2.0/"),
("1.6.1", "/1.6.1/"),
("1.6", "/1.6/"),
("1.5", "/1.5/"),
("1.4", "/1.4/"),
("1.0", "/1.0/"), # keep 1.0
)
}
As new versions of ACRN documentation are added, update this
``versions`` selection list to include the version number and publishing
folder. Note that there's no direct selection to go to a newer version
from an older one, without going to ``latest`` first.
By default, documentation build and publishing both assume we're generating
documentation for the main branch and publishing to the ``/latest/``
area on https://projectacrn.github.io. When we're generating the
documentation for a tagged version (e.g., 2.3), check out that version
of the repo, and add some extra flags to the ``make`` commands:
.. code-block:: bash
cd ~/projectacrn/acrn-hypervisor/doc
git checkout v2.3
make clean
make DOC_TAG=release RELEASE=2.3 html
make DOC_TAG=release RELEASE=2.3 publish
.. _filter_expected:
Filter Expected Warnings
************************
Alas, there are some known issues with the doxygen/Sphinx/Breathe
processing that generates warnings for some constructs, in particular
around unnamed structures in nested unions or structs.
While these issues are being considered for fixing in
Sphinx/Breathe, we've added a post-processing filter on the output of
the documentation build process to check for "expected" messages from the
generation process output.
The output from the Sphinx build is processed by the Python script
``scripts/filter-known-issues.py`` together with a set of filter
configuration files in the ``.known-issues/doc`` folder. (This
filtering is done as part of the ``Makefile``.)
If you're contributing components included in the ACRN API
documentation and run across these warnings, you can include filtering
them out as "expected" warnings by adding or editing a conf file in the
``.known-issues/doc`` folder, following the example of other conf files
found there.
.. _reStructuredText: http://sphinx-doc.org/rest.html
.. _Sphinx: http://sphinx-doc.org/