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 as it is widely-used to provide both HTML and pdf documentation that can be easily versioned alongside the code. It also offers similar syntax to Markdown which is familiar to large numbers of people.

Style Guide

This section serves two purposes:

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

That being said, assuming that the content is usable, the bias should be toward merging it rather than blocking on relatively minor edits.

Formatting Preferences

In general, the documentation team has focused on trying to make sure that the instructions are comprehensible, but not being overly pedantic about these things. Along those lines, while we would prefer the following, generally they aren’t a reason to -1 in and of themselves:

  • No trailing whitespace
  • Line wrapping at something reasonable, i.e., 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 feautre: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 the like.

Things to get right with spacing and capitalization

Note that all of these apply when using them in text. If they are used as part of URL, class name, or something similar, use the actual capitalization and spacing.

  • ACL: not Acl or acl
  • API: not api
  • ARP: not Arp or arp
  • datastore: not data store, Data Store, or DataStore (unless it’s 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, etc.
  • OpenDaylight: not Opendaylight, Open Daylight, or OpenDayLight, etc.
    • also avoid abbreviations like ODL and ODC
  • OpenFlow: not Openflow, Open Flow, openflow, etc.
  • 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, we try to follow the python documentation style guide. See: https://docs.python.org/devguide/documenting.html

The best reference for reStrucutedText syntax seems to be the Sphinx Primer on reStructuredText.

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

  • python
  • python-tox

Which both should be available in most distribution’s package managers.

Then simply run tox and open the html produced via your favorite web browser as follows:

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

Note

Make sure to run tox -edocs and not just tox. See Make sure you run tox -edocs

Directory Structure

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

Below that there are guides hosted directly in the docs git repository and there are guides hosted in remote git repositories. Usually those are 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.

Inside each guide there is usually an index.rst file which then includes other files using a toctree directive. For example:

.. toctree::
   :maxdepth: 1

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

This 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 toctree omit the .rst 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 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 will make track whatever branch of the documentation project you happen to be on.

Unfortunately, -b . doesn’t work, so you have to manually edit the .gitmodules file to add branch = . and then commit it. Something like:

<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’s critical that the Gerrit patch be merged before the git commit hash of the submodule changes. Otherwise, Gerrit won’t be able to automatically keep it up-to-date for you.

Documentation Layout and Style

As mentioned previously we try to follow the python documentation style guide which defines a few types of sections:

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

We try to follow 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’s the chapter heading and then everything in the rest of the chapter should use:

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

Referencing Sections

It’s pretty common to want to reference another location in the OpenDaylight documentation and it’s pretty easy to do with reStructuredText. This is a quick primer, more information is in the Sphinx section on Cross-referencing arbitrary locations.

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’s 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, it usually makes sense to prefix the labels with the project name to help share the label space, e.g., sfc-user-guide instead of just user-guide.

Troubleshooting

Nested formatting doesn’t work

As stated in the reStructuredText guide, inline markup for bold, italic, and fixed-width can’t be nested. Further, it can’t be mixed with hyperlinks, so you can’t have bold text link somewhere.

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

Make sure you’ve 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 haven’t 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 and in that case, the easiest way to fix it is delete the submodules directory and then re-clone the submodules:

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

Warning

This will delete any local changes or information you made in the submodules. This should only be the case if you manually edited files in that directory.

Make sure you run tox -edocs

If you see an error like:

ERROR:   docs: could not install deps [-rrequirements.txt]; v = InvocationError('/Users/ckd/git-reps/docs/.tox/docs/bin/pip install -rrequirements.txt (see /Users/ckd/git-reps/docs/.tox/docs/log/docs-1.log)', 1)
ERROR:   docs-linkcheck: could not install deps [-rrequirements.txt]; v = InvocationError('/Users/ckd/git-reps/docs/.tox/docs-linkcheck/bin/pip install -rrequirements.txt (see /Users/ckd/git-reps/docs/.tox/docs-linkcheck/log/docs-linkcheck-1.log)', 1)

It usually means you ran tox and not tox -edocs, which will result in running jobs inside submodules which aren’t supported by the environment defined by the requirements.txt file in the documentation tox setup. Just run tox -edocs and it should be fine.

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 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 -edocs

Builds on Read the Docs

It appears as though the Read the Docs builds don’t 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, this patch: https://git.opendaylight.org/gerrit/41679

Finally fixed the fact that our builds for failing because they were taking too long by removing directories of generated javadoc that were present from previous runs.

Project Documentation Requirements

Submitting Documentation Outlines (M3)

  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 direction 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 you need provide based on the features your project will have and which ones will be user-facing.

    • The kinds of required documentation can be found below in the Requirements for projects section.
    • Note that you might need to create multiple different 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 a 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 aren’t set in stone, but do help. If you think there’s a better name, use it and we’ll 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 isn’t 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’s helpful if you also post a +0 reply to the gerrit saying what patch set you just submitted and what you fixed in the patch set.
    • The documentation team will also be creating (or asking projects to create) small groups of 2-4 projects that will peer review each other’s documentation. Patches which have seen a few cycles of peer review will be prioritized for review and merge by the documentation team.

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 that this is intended to be who is 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.

Boron Project Documentation Requirements

Kinds of Documentation

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

  • User/Operator: for people looking to use the feature w/o writing code
    • Should include an overview of the project/feature
    • Should include description of availbe configuration options and what they do
  • Developer: for people looking to use the feature in code w/o modifying it
    • Should include API documentation, e.g., enunciate for REST, Javadoc for Java, ??? for RESTCONF/models
  • Contributor: for people looking to extend or modify the feature’s source code
  • Installation: for people looking for instructions to install the feature after they have downloaded the ODL release
    • 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
      • We’d also like them to note if the options should be checkboxes (i.e., they can each be turned on/off independently) or a drop down (i.e., 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 do the following

  • 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
      • This can be provided as a single .rst file or multiple .rst files if the features fall into different groups
      • This should start with ~300 word overview of the project and include references to any automatically-generated API documentation as well as more general developer information (see Kinds of Documentation).
    • User/Operator documentation for every every user-facing feature (if any)
      • ‘’Note: This should be per-feature, not per-project. User’s shouldn’t have to know which project a feature came from.’‘
      • Intimately related features, e.g., l2switch-switch, l2switch-switch-rest, and l2switch-switch-ui, can be documented as one noting the differences
      • This 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 Kinds of Documentation above.
    • Release Notes (both on the wiki and reStructuredText) as part of the release review.
  • This documentation will be contributed to the docs repo (or possibly imported from the project’s own repo with tooling that is under development)
    • Projects MAY be ENCOURGAGED to instead provide this from their own repository if the tooling is developed
    • Projects choosing to meet the requirement 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
    • Note that the documentation team will also be creating (or asking projects to create) small groups of 2-4 projects that will peer review each other’s documentation. Patches which have seen a few cycles of peer review will be prioritized for review and merge by the documentation team.

Timeline for Deliverables from Projects

  • M3: Documentation Started
    • Identified the kinds of documentation that will be provided and for what features
      • Release Notes are not required until release reviews at RC2
    • Created the appropriate .rst files in the docs repository (or their own repository if the tooling is available)
    • Have an outline for the expected documentation in those .rst files including the relevant (sub)sections and a sentence or two explaining what will go there
      • Obviusly, providing actual documentation in the (sub)sections is encouraged and meets this requirement
    • Milestone readout should include
      1. the list of kinds of documentation
      2. the list of corresponding .rst files and their location, e.g., repo and path
      3. the list of commits creating those .rst files
      4. the current word counts of those .rst files
  • M4: Documentation Continues
    • The readout at M4 should include the word counts of all .rst files with links to commits
    • The goal is to have draft documentation complete so that the documentation group can comment on it.
  • M5: 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 as .rst pushed to integration (or locally in the project’s repository if the tooling is developed)