Documentation

This is a brief style guide for Zuul documentation.

ReStructuredText Conventions

Code Blocks

When showing a YAML example, use the .. code-block:: yaml directive so that the sample appears as a code block with the correct syntax highlighting.

Literal Values

Filenames and literal values (such as when we instruct a user to type a specific string into a configuration file) should use the RST ``literal`` syntax.

YAML supports boolean values expressed with or without an initial capital letter. In examples and documentation, use true and false in lowercase type because the resulting YAML is easier for users to type and read.

Terminology

Zuul employs some specialized terminology. To help users become acquainted with it, we employ a glossary. Observe the following:

Specialized terms should have entries in the glossary.
If the term is being defined in the text, don’t link to the glossary (that would be redundant), but do emphasize it with *italics* the first time it appears in that definition. Subsequent uses within the same subsection should be in regular type.
If it’s being used (but not defined) in the text, link the first usage within a subsection to the glossary using the :term: role, but subsequent uses should be in regular type.
Be cognizant of how readers may jump to link targets within the text, so be liberal in considering that once you cross a link target, you may be in a new “subsection” for the above guideline.

Zuul Sphinx Directives

The following extra Sphinx directives are available in the zuul domain. The zuul domain is configured as the default domain, so the zuul: prefix may be omitted.

zuul:attr::

This should be used when documenting Zuul configuration attributes. Zuul configuration is heavily hierarchical, and this directive facilitates documenting these by emphasising the hierarchy as appropriate. It will annotate each configuration attribute with a nice header with its own unique hyperlink target. It displays the entire hierarchy of the attribute, but emphasises the last portion (i.e., the field being documented).

To use the hierarchical features, simply nest with indentation in the normal RST manner.

It supports the required and default options and will annotate the header appropriately. Example:

.. attr:: foo

   Some text about ``foo``.

   .. attr:: bar
      :required:
      :default: 42

      Text about ``foo.bar``.

foo

Some text about foo.

foo.bar (required) Default: 42: Text about foo.bar.

zuul:value::

Similar to zuul:attr, but used when documenting a literal value of an attribute.

.. attr:: foo

   Some text about foo.  It supports the following values:

   .. value:: bar

      One of the supported values for ``foo`` is ``bar``.

   .. value:: baz

      Another supported values for ``foo`` is ``baz``.

foo

Some text about foo. It supports the following values:

bar: One of the supported values for foo is bar.

baz: Another supported values for foo is baz.

zuul:var::

Also similar to zuul:attr, but used when documenting an Ansible variable which is available to a job’s playbook. In these cases, it’s often necessary to indicate the variable may be an element of a list or dictionary, so this directive supports a type option. It also supports the hidden option so that complex data structure definitions may continue across sections. To use this, set the hidden option on a zuul:var:: directive with the root of the data structure as the name. Example:

.. var:: foo

   Foo is a dictionary with the following keys:

   .. var:: items
      :type: list

      Items is a list of dictionaries with the following keys:

      .. var:: bar

         Text about bar

Section Boundary

.. var:: foo
   :hidden:

   .. var:: baz

      Text about baz

foo

Foo is a dictionary with the following keys:

foo.items Type: list

Items is a list of dictionaries with the following keys:

foo.items[].bar: Text about bar

Section Boundary

foo.baz: Text about baz

Zuul Sphinx Roles

The following extra Sphinx roles are available. Use these within the text when referring to attributes, values, and variables defined with the directives above. Use these roles for the first appearance of an object within a subsection, but use the ``literal`` role in subsequent uses.

:zuul:attr:

This creates a reference to the named attribute. Provide the fully qualified name (e.g., :attr:`pipeline.manager`)

:zuul:value:

This creates a reference to the named value. Provide the fully qualified name (e.g., :attr:`pipeline.manager.dependent`)

:zuul:var:

This creates a reference to the named variable. Provide the fully qualified name (e.g., :var:`zuul.executor.name`)