Documentation Guide

This guide provides details on how to contribute to the OpenDaylight documentation. OpenDaylight currently uses reStructuredText for documentation and Sphinx to build it. These documentation tools are widely used in open source communities to produce both HTML and PDF documentation and can be easily versioned alongside the code. reStructuredText also offers similar syntax to Markdown, which is familiar to many developers.

Style Guide

This section serves two purposes:

  1. A guide for those writing documentation.
  2. A guide for those reviewing documentation.

Note

When reviewing content, assuming that the content is usable, the documentation team is biased toward merging the content rather than blocking it due to relatively minor editorial issues.

Formatting Preferences

In general, when reviewing content, the documentation team ensures that it is comprehensible but tries not to be overly pedantic. Along those lines, while it is preferred that the following formatting preferences are followed, they are generally not an exclusive reason to give a “-1” reply to a patch in Gerrit:

  • No trailing whitespace
  • Line wrapping at something reasonable, that is, 72–100 characters

Key terms

  • Functionality: something useful a project provides abstractly
  • Feature: a Karaf feature that somebody could install
  • Project: a project within OpenDaylight; projects ship features to provide functionality
  • OpenDaylight: this refers to the software we release; use this in place of OpenDaylight controller, the OpenDaylight controller, not ODL, not ODC
    • Since there is a controller project within OpenDaylight, using other terms is hard.

Common writing style mistakes

  • In per-project user documentation, you should never say git clone, but should assume people have downloaded and installed the controller per the getting started guide and start with feature:install <something>
  • Avoid statements which are true about part of OpenDaylight, but not generally true.
    • For example: “OpenDaylight is a NETCONF controller.” It is, but that is not all it is.
  • In general, developer documentation should target external developers to your project so should talk about what APIs you have and how they could use them. It should not document how to contribute to your project.

Grammar Preferences

  • Avoid contractions: Use “cannot” instead of “can’t”, “it is” instead of “it’s”, and so on.

Word Choice

Note

The following word choice guidelines apply when using these terms in text. If these terms are used as part of a URL, class name, or any instance where modifying the case would create issues, use the exact capitalization and spacing associated with the URL or class name.

  • ACL: not Acl or acl

  • API: not api

  • ARP: not Arp or arp

  • datastore: not data store, Data Store, or DataStore (unless it is a class/object name)

  • IPsec, not IPSEC or ipsec

  • IPv4 or IPv6: not Ipv4, Ipv6, ipv4, ipv6, IPV4, or IPV6

  • Karaf: not karaf

  • Linux: not LINUX or linux

  • NETCONF: not Netconf or netconf

  • Neutron: not neutron

  • OSGi: not osgi or OSGI

  • Open vSwitch: not OpenvSwitch, OpenVSwitch, or Open V Switch.

  • OpenDaylight: not Opendaylight, Open Daylight, or OpenDayLight.

    Note

    Also, avoid Opendaylight abbreviations like ODL and ODC.

  • OpenFlow: not Openflow, Open Flow, or openflow.

  • OpenStack: not Open Stack or Openstack

  • QoS: not Qos, QOS, or qos

  • RESTCONF: not Restconf or restconf

  • RPC not Rpc or rpc

  • URL not Url or url

  • VM: not Vm or vm

  • YANG: not Yang or yang

reStructuredText-based Documentation

When using reStructuredText, follow the Python documentation style guidelines. See: https://docs.python.org/devguide/documenting.html

One of the best references for reStrucutedText syntax is the Sphinx Primer on reStructuredText.

To build and review the reStructuredText documentation locally, you must have the following packages installed locally:

  • python
  • python-tox

Note

Both packages should be available in most distribution package managers.

Then simply run tox and open the HTML produced by using your favorite web browser as follows:

git clone https://git.opendaylight.org/gerrit/docs
cd docs
git submodule update --init
tox
firefox docs/_build/html/index.html

Directory Structure

The directory structure for the reStructuredText documentation is rooted in the docs directory inside the docs git repository.

Note

There are guides hosted directly in the docs git repository and there are guides hosted in remote git repositories. Documentation hosted in remote git repositories are generally provided for project-specific information.

For example, here is the directory layout on June, 28th 2016:

$ tree -L 2
.
├── Makefile
├── conf.py
├── documentation.rst
├── getting-started-guide
│   ├── api.rst
│   ├── concepts_and_tools.rst
│   ├── experimental_features.rst
│   ├── index.rst
│   ├── installing_opendaylight.rst
│   ├── introduction.rst
│   ├── karaf_features.rst
│   ├── other_features.rst
│   ├── overview.rst
│   └── who_should_use.rst
├── index.rst
├── make.bat
├── opendaylight-with-openstack
│   ├── images
│   ├── index.rst
│   ├── openstack-with-gbp.rst
│   ├── openstack-with-ovsdb.rst
│   └── openstack-with-vtn.rst
└── submodules
    └── releng
        └── builder

The getting-started-guide and opendaylight-with-openstack directories correspond to two guides hosted in the docs repository, while the submodules/releng/builder directory houses documentation for the RelEng/Builder project.

Each guide includes an index.rst file, which uses a toctree directive that includes the other files associated with the guide. For example:

.. toctree::
   :maxdepth: 1

   getting-started-guide/index
   opendaylight-with-openstack/index
   submodules/releng/builder/docs/index

This example creates a table of contents on that page where each heading of the table of contents is the root of the files that are included.

Note

When including .rst files using the toctree directive, omit the .rst file extension at the end of the file name.

Adding a submodule

If you want to import a project underneath the documentation project so that the docs can be kept in the separate repo, you can do it by using the git submodule add command as follows:

git submodule add -b master ../integration/packaging docs/submodules/integration/packaging
git commit -s

Note

Most projects will not want to use -b master, but instead use the branch ., which tracks whatever branch of the documentation project you happen to be on.

Unfortunately, -b . does not work, so you have to manually edit the .gitmodules file to add branch = . and then commit it. For example:

<edit the .gitmodules file>
git add .gitmodules
git commit --amend

When you’re done you should have a git commit something like:

$ git show
commit 7943ce2cb41cd9d36ce93ee9003510ce3edd7fa9
Author: Daniel Farrell <dfarrell@redhat.com>
Date:   Fri Dec 23 14:45:44 2016 -0500

    Add Int/Pack to git submodules for RTD generation

    Change-Id: I64cd36ca044b8303cb7fc465b2d91470819a9fe6
    Signed-off-by: Daniel Farrell <dfarrell@redhat.com>

diff --git a/.gitmodules b/.gitmodules
index 91201bf6..b56e11c8 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -38,3 +38,7 @@
        path = docs/submodules/ovsdb
        url = ../ovsdb
        branch = .
+[submodule "docs/submodules/integration/packaging"]
+       path = docs/submodules/integration/packaging
+       url = ../integration/packaging
+       branch = master
diff --git a/docs/submodules/integration/packaging b/docs/submodules/integration/packaging
new file mode 160000
index 00000000..fd5a8185
--- /dev/null
+++ b/docs/submodules/integration/packaging
@@ -0,0 +1 @@
+Subproject commit fd5a81853e71d45945471d0f91bbdac1a1444386

As usual, you can push it to Gerrit with git review.

Important

It is critical that the Gerrit patch be merged before the git commit hash of the submodule changes. Otherwise, Gerrit is not able to automatically keep it up-to-date for you.

Documentation Layout and Style

As mentioned previously, OpenDaylight aims to follow the Python documentation style guidelines, which defines a few types of sections:

# with overline, for parts
* with overline, for chapters
=, for sections
-, for subsections
^, for subsubsections
", for paragraphs

OpenDaylight documentation is organized around the following structure based on that recommendation:

docs/index.rst                 -> entry point
docs/____-guide/index.rst      -> part
docs/____-guide/<chapter>.rst  -> chapter

In the ____-guide/index.rst we use the # with overline at the very top of the file to determine that it is a part and then within each chapter file we start the document with a section using * with overline to denote that it is the chapter heading and then everything in the rest of the chapter should use:

=, for sections
-, for subsections
^, for subsubsections
", for paragraphs

Referencing Sections

This section provides a quick primer for creating references in OpenDaylight documentation. For more information, refer to Cross-referencing documents.

Within a single document, you can reference another section simply by:

This is a reference to `The title of a section`_

Assuming that somewhere else in the same file, there a is a section title something like:

The title of a section
^^^^^^^^^^^^^^^^^^^^^^

It is typically better to use :ref: syntax and labels to provide links as they work across files and are resilient to sections being renamed. First, you need to create a label something like:

.. _a-label:

The title of a section
^^^^^^^^^^^^^^^^^^^^^^

Note

The underscore (_) before the label is required.

Then you can reference the section anywhere by simply doing:

This is a reference to :ref:`a-label`

or:

This is a reference to :ref:`a section I really liked <a-label>`

Note

When using :ref:-style links, you don’t need a trailing underscore (_).

Because the labels have to be unique, a best practice is to prefix the labels with the project name to help share the label space; for example, use sfc-user-guide instead of just user-guide.

Troubleshooting

Nested formatting does not work

As stated in the reStructuredText guide, inline markup for bold, italic, and fixed-width font cannot be nested. Furthermore, inline markup cannot be mixed with hyperlinks, so you cannot have a link with bold text.

This is tracked in a Docutils FAQ question, but there is no clear current plan to fix this.

Make sure you have cloned submodules

If you see an error like this:

./build-integration-robot-libdoc.sh: line 6: cd: submodules/integration/test/csit/libraries: No such file or directory
Resource file '*.robot' does not exist.

It means that you have not pulled down the git submodule for the integration/test project. The fastest way to do that is:

git submodule update --init

In some cases, you might wind up with submodules which are somehow out-of-sync. In that case, the easiest way to fix them is to delete the submodules directory and then re-clone the submodules:

rm -rf docs/submodules/
git submodule update --init

Warning

These steps delete any local changes or information you made in the submodules, which would only occur if you manually edited files in that directory.

Clear your tox directory and try again

Sometimes, tox will not detect when your requirements.txt file has changed and so will try to run things without the correct dependencies. This issue usually manifests as No module named X errors or an ExtensionError and can be fixed by deleting the .tox directory and building again:

rm -rf .tox
tox

Builds on Read the Docs

Read the Docs builds do not automatically clear the file structure between builds and clones. The result is that you may have to clean up the state of old runs of the build script.

As an example, refer to the following patch: https://git.opendaylight.org/gerrit/41679

This patch fixed the issue that caused builds to fail because they were taking too long removing directories associated with generated javadoc files that were present from previous runs.

Errors from Coala

As part of running tox, two environments run: coala which does a variety of reStructuredText (and other) linting, and docs, which runs Sphinx to build HTML and PDF documentation. You can run them independently by doing tox -ecoala or tox -edocs.

The coala linter for reStructuredText is not always the most helpful in explaining why it failed. So, here are some common ones. There should also be Jenkins Failure Cause Management rules that will highlight these for you.

Git Commit Message Errors

Coala checks that git commit messages adhere to the following rules:

  • Shortlog (1st line of commit message) is less than 50 characters
  • Shortlog (1st line of commit message) is in the imperative mood. For example, “Add foo unit test” is good, but “Adding foo unit test is bad”“
  • Body (all lines but 1st line of commit message) are less than 72 characters. Some exceptions seem to exist, such as for long URLs.

Some examples of those being logged are:

::
Project wide: | | [NORMAL] GitCommitBear: | | Shortlog of HEAD commit isn’t in imperative mood! Bad words are ‘Adding’
::
Project wide: | | [NORMAL] GitCommitBear: | | Body of HEAD commit contains too long lines. Commit body lines should not exceed 72 characters.
Error in “code-block” directive

If you see an error like this:

::
docs/gerrit.rst | 89| ···..·code-block::·bash | | [MAJOR] RSTcheckBear: | | (ERROR/3) Error in “code-block” directive:

It means that the relevant code-block is not valid for the language specified, in this case bash.

Note

If you do not specify a language, the default language is Python. If you want the code-block to not be an any particular language, instead use the :: directive. For example:

::
::
This is a code block that will not be parsed in any particluar langauge

Project Documentation Requirements

Submitting Documentation Outlines (M2)

  1. Determine the features your project will have and which ones will be ‘’user-facing’‘.

    • In general, a feature is user-facing if it creates functionality that a user would directly interact with.
    • For example, odl-openflowplugin-flow-services-ui is likely user-facing since it installs user-facing OpenFlow features, while odl-openflowplugin-flow-services is not because it provides only developer-facing features.
  2. Determine pieces of documentation that you need to provide based on the features your project will have and which ones will be user-facing.

    Note

    You might need to create multiple documents for the same kind of documentation. For example, the controller project will likely want to have a developer section for the config subsystem as well as for the MD-SAL.

  3. Clone the docs repo: git clone https://git.opendaylight.org/gerrit/docs

  4. For each piece of documentation find the corresponding template in the docs repo.

    • For user documentation: docs.git/docs/templates/template-user-guide.rst
    • For developer documentation: ddocs/templates/template-developer-guide.rst
    • For installation documentation (if any): docs/templates/template-install-guide.rst

    Note

    You can find the rendered templates here:

  5. Copy the template into the appropriate directory for your project.

    • For user documentation: docs.git/docs/user-guide/${feature-name}-user-guide.rst
    • For developer documentation: docs.git/docs/developer-guide/${feature-name}-developer-guide.rst
    • For installation documentation (if any): docs.git/docs/getting-started-guide/project-specific-guides/${project-name}.rst

    Note

    These naming conventions are not set in stone, but are used to maintain a consistent document taxonomy. If these conventions are not appropriate or do not make sense for a document in development, use the convention that you think is more appropriate and the documentation team will review it and give feedback on the gerrit patch.

  6. Edit the template to fill in the outline of what you will provide using the suggestions in the template. If you feel like a section is not needed, feel free to omit it.

  7. Link the template into the appropriate core .rst file.

    • For user documentation: docs.git/docs/user-guide/index.rst
    • For developer documentation: docs.git/docs/developer-guide/index.rst
    • For installation documentation (if any): docs.git/docs/getting-started-guide/project-specific-guides/index.rst
    • In each file, it should be pretty clear what line you need to add. In general if you have an .rst file project-name.rst, you include it by adding a new line project-name without the .rst at the end.
  8. Make sure the documentation project still builds.

  9. Commit and submit the patch.

    1. Commit using:

      git add --all && git commit -sm "Documentation outline for ${project-shortname}"
      
    2. Submit using:

      git review
      

      See the Git-review Workflow page if you don’t have git-review installed.

  10. Wait for the patch to be merged or to get feedback

    • If you get feedback, make the requested changes and resubmit the patch.
    • When you resubmit the patch, it is helpful if you also post a “+0” reply to the patch in Gerrit, stating what patch set you just submitted and what you fixed in the patch set.

Expected Output From Documentation Project

The expected output is (at least) 3 PDFs and equivalent web-based documentation:

  • User/Operator Guide
  • Developer Guide
  • Installation Guide

These guides will consist of “front matter” produced by the documentation group and the per-project/per-feature documentation provided by the projects.

Note

This requirement is intended for the person responsible for the documentation and should not be interpreted as preventing people not normally in the documentation group from helping with front matter nor preventing people from the documentation group from helping with per-project/per-feature documentation.

Project Documentation Requirements

Content Types

These are the expected kinds of documentation and target audiences for each kind.

  • User/Operator: for people looking to use the feature without writing code

    • Should include an overview of the project/feature
    • Should include description of availble configuration options and what they do
  • Developer: for people looking to use the feature in code without modifying it

    • Should include API documentation, such as, enunciate for REST, Javadoc for Java, ??? for RESTCONF/models
  • Contributor: for people looking to extend or modify the feature’s source code

    Note

    You can find this information on the wiki.

  • Installation: for people looking for instructions to install the feature after they have downloaded the ODL release

    Note

    The audience for this content is the same as User/Operator docs

    • For most projects, this will be just a list of top-level features and options
      • As an example, l2switch-switch as the top-level feature with the -rest and -ui options
      • Features should also note if the options should be checkboxes (that is, they can each be turned on/off independently) or a drop down (that is, at most one can be selected)
      • What other top-level features in the release are incompatible with each feature
      • This will likely be presented as a table in the documentation and the data will likely also be consumed by automated installers/configurators/downloaders
    • For some projects, there is extra installation instructions (for external components) and/or configuration
      • In that case, there will be a (sub)section in the documentation describing this process.
  • HowTo/Tutorial: walk throughs and examples that are not general-purpose documentation

    • Generally, these should be done as a (sub)section of either user/operator or developer documentation.
    • If they are especially long or complex, they may belong on their own
  • Release Notes:

    • Release notes are required as part of each project’s release review. They must also be translated into reStructuredText for inclusion in the formal documentation.

Requirements for projects

  • Projects must provide reStructuredText documentation including:
    • Developer documentation for every feature
      • Most projects will want to logically nest the documentation for individual features under a single project-wide chapter or section
      • The feature documentation can be provided as a single .rst file or multiple .rst files if the features fall into different groups
      • Feature documentation should start with appromimately 300 word overview of the project and include references to any automatically-generated API documentation as well as more general developer information (see Content Types).
    • User/Operator documentation for every every user-facing feature (if any)
      • This documentation should be per-feature, not per-project. Users should not have to know which project a feature came from.
      • Intimately related features can be documented together. For example, l2switch-switch, l2switch-switch-rest, and l2switch-switch-ui, can be documented as one noting the differences.
      • This documentation can be provided as a single .rst file or multiple .rst files if the features fall into different groups
    • Installation documentation
      • Most projects will simply provide a list of user-facing features and options. See Content Types above.
    • Release Notes (both on the wiki and reStructuredText) as part of the release review.
  • Documentation must be contributed to the docs repo (or possibly imported from the project’s own repo with tooling that is under development)
    • Projects may be encouraged to instead provide this from their own repository if the tooling is developed
    • Projects choosing to meet the requirement in this way must provide a patch to docs repo to import the project’s documentation
  • Projects must cooperate with the documentation group on edits and enhancements to documentation

Timeline for Deliverables from Projects

  • M2: Documentation Started

    The following tasks for documentation deliverables must be completed for the M2 readout:

    • The kinds of documentation that will be provided and for what features must be identified.

      Note

      Release Notes are not required until release reviews at RC2

    • The appropriate .rst files must be created in the docs repository (or their own repository if the tooling is available).

    • An outline for the expected documentation must be completed in those .rst files including the relevant (sub)sections and a sentence or two explaining what will be contained in these sections.

      Note

      If an outline is not provided, delivering actual documentation in the (sub)sections meets this requirement.

    • M2 readouts should include

      1. the list of kinds of documentation
      2. the list of corresponding .rst files and their location, including repo and path
      3. the list of commits creating those .rst files
      4. the current word counts of those .rst files
  • M3: Documentation Continues

    • The readout at M3 should include the word counts of all .rst files with links to commits
    • The goal is to have draft documentation complete at the M3 readout so that the documentation group can comment on it.
  • M4: Documentation Complete

    • All (sub)sections in all .rst files have complete, readable, usable content.
    • Ideally, there should have been some interaction with the documentation group about any suggested edits and enhancements
  • RC2: Release notes

    • Projects must provide release notes in .rst format pushed to integration (or locally in the project’s repository if the tooling is developed)