Introduction

This guide describes how to create documentation for the Open Network Automation Platform (ONAP). ONAP projects create a variety of content depending on the nature of the project. For example projects delivering a platform component may have different types of content than a project that creates libraries for a software development kit. The content from each project may be used together as a reference for that project and/or be used in documents that are tailored to a specific user audience and tasks they are performing.

Much of the content in this document is derived from similar documentation processes used in other Linux Foundation Projects including OPNFV and Open Daylight.

End to End View

ONAP documentation is stored in git repositories, changes are managed with gerrit reviews, and published documents generated when there is a change in any source used to build the documentation.

Authors create source for documents in reStructured Text (RST) that is rendered to HTML and published on Readthedocs.io. The developer Wiki or other web sites can reference these rendered documents directly allowing projects to easily maintain current release documentation.

Why reStructuredText/Sphinx?

In the past, standard documentation methods included ad-hoc Word documents, PDFs, poorly organized Wikis, and other, often closed, tools like Adobe FrameMaker. The rise of DevOps, Agile, and Continuous Integration, however, created a paradigm shift for those who care about documentation because:

  1. Documentation must be tightly coupled with code/product releases. In many cases, particularly with open-source products, many different versions of the same code can be installed in various production environments. DevOps personnel must have access to the correct version of documentation.
  2. Resources are often tight, volunteers scarce. With a large software base like ONAP, a small team of technical writers, even if they are also developers, cannot keep up with a constantly changing, large code base. Therefore, those closest to the code should document it as best they can, and let professional writers edit for style, grammar, and consistency.

Plain-text formatting syntaxes, such as reStructuredText, Markdown, and Textile, are a good choice for documentation because:

  1. They are editor agnostic
  2. The source is nearly as easy to read as the rendered text
  3. Documentation can be treated exactly as source code is (e.g. versioned, diff’ed, associated with commit messages that can be included in rendered docs)
  4. Shallow learning curve

The documentation team chose reStructuredText largely because of Sphinx, a Python-based documentation build system, which uses reStructuredText natively. In a code base as large as ONAP’s, cross-referencing between component documentation was deemed critical. Sphinx and reStructuredText have built-in functionality that makes collating and cross-referencing component documentation easier.

Which docs should go where?

Frequently, developers ask where documentation should be created. Should they always use reStructuredText/Sphinx? Not necessarily. Is the wiki appropriate for anything at all? Yes.

It’s really up to the development team. Here is a simple rule:

The more tightly coupled the documentation is to a particular version of the code, the more likely it is that it should be stored with the code in reStructuredText.

The doc team encourages component teams to store as much documentation as reStructuredText as possible because:

  1. It is easier to edit component documentation for grammar, spelling, clarity, and consistency.
  2. A consistent formatting syntax across components will allow flexibility in producing different kinds of output.
  3. It is easier to re-organize the documentation.
  4. Wiki articles tend to grow in size and not maintained making it hard to find current information.

Structure

A top level master document structure is used to organize all documents created by ONAP projects and this resides in the gerrit doc repository. Complete documents or guides may reside here and reference parts of source for documentation from other project repositories. Other ONAP projects will provide content that is referenced from this structure.

docs
├── guides
│   ├── onap-developer
│   │   ├── apiref
│   │   ├── architecture
│   │   ├── developing
│   │   ├── how-to-use-docs
│   │   ├── settingup
│   │   ├── tutorials
│   │   └── use-cases
│   ├── onap-provider
│   └── onap-user
├── release
└── templates
    ├── collections
    └── sections

Source Files

All documentation for project repositories should be structured and stored in or below <your_project_repo>/docs/ directory as Restructured Text. ONAP jenkins jobs that verify and merge documentation are triggered by RST file changes in the top level docs directory and below.

Licensing

All contributions to the ONAP project are done in accordance with the ONAP licensing requirements. Documentation in ONAP is contributed in accordance with the Creative Commons 4.0 license. All documentation files need to be licensed using the text below. The license may be applied in the first lines of all contributed RST files:

.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
.. Copyright YEAR ONAP or COMPANY or INDIVIDUAL

These lines will not be rendered in the html and pdf files.

When there are subsequent, significant contributions to a source file from a different contributor, a new copyright line may be appended after the last existing copyright line.