ironic/doc/source/dev/webapi.rst
Devananda van der Veen d0e49e1b41 Documentation update
This patch contains several changes to the documentation which
were brought about by, initially, removing the webapi/v1 page and
replacing it with a link to the /api-ref/ page.

As I did that, I saw that our front page (index.html) needed to
be updated as well, and decided that the front page needed to
actually be completely rerwitten -- while preserving all the links.

Some of the TOC links from the front page were malformed because
subpages included more than one H1 heading, so I had to make small
changes in the api-audit-support and code-contribution-guide and
dev-quickstart pages, in order for the front page to render properly.

As I corrected the headings on dev-quickstart, I realized the page
was not comprehensively organized, and so decided to reorganize the
sections and make it easier to navigate.

Here is a bullet-point summary of this change:
* Major changes to content and organization of index page
* Moved the version history from webapi/v1 to dev/webapi-version-history
* Added API conceptual guide at dev/webapi
* Replaced webapi/v1 with a link to dev/webapi, in case anyone
  bookmarked it
* Removed doc references to webapi/v1
* Merged the pages dev/contributing and dev/code-contribution-guide
* Removed duplicate H1 headers in deploy/api-audit-support
* Reorganized and renamed section headers in dev/dev-quickstart,
  and made some substantive corrections and changes as well
* Updated wording at the top of the index and deploy/user-guide pages.

Change-Id: Ib418e1d4fdfab4f0e15560270f39922e33df3f12
2016-08-23 12:49:04 -07:00

77 lines
2.8 KiB
ReStructuredText

=========================
REST API Conceptual Guide
=========================
Versioning
==========
The ironic REST API supports two types of versioning:
- "major versions", which have dedicated urls.
- "microversions", which can be requested through the use of the
``X-OpenStack-Ironic-API-Version`` header.
There is only one major version supported currently, "v1". As such, most URLs
in this documentation are written with the "/v1/" prefix.
Starting with the Kilo release, ironic supports microversions. In this context,
a version is defined as a string of 2 integers separated by a dot: **X.Y**.
Here ``X`` is a major version, always equal to ``1``, and ``Y`` is
a minor version. Server minor version is increased every time the API behavior
is changed (note `Exceptions from Versioning`_).
.. note::
`Nova versioning documentation`_ has a nice guide for developers on when to
bump an API version.
The server indicates its minimum and maximum supported API versions in the
``X-OpenStack-Ironic-API-Minimum-Version`` and
``X-OpenStack-Ironic-API-Maximum-Version`` headers respectively, returned
with every response. Client may request a specific API version by providing
``X-OpenStack-Ironic-API-Version`` header with request.
The requested microversion determines both the allowable requests and the
response format for all requests. A resource may be represented differently
based on the requested microversion.
If no version is requested by the client, the minimum supported version will be
assumed. In this way, a client is only exposed to those API features that are
supported in the requested (explicitly or implicitly) API version (again note
`Exceptions from Versioning`_, they are not covered by this rule).
We recommend clients that require a stable API to always request a specific
version of API that they have been tested against.
.. note::
A special value ``latest`` can be requested instead a numerical
microversion, which always requests the newest supported API version from
the server.
.. _Nova versioning documentation: http://docs.openstack.org/developer/nova/api_microversion_dev.html#when-do-i-need-a-new-microversion
REST API Versions History
-------------------------
.. toctree::
:maxdepth: 1
API Version History <dev/webapi-version-history>
Exceptions from Versioning
--------------------------
The following API-visible things are not covered by the API versioning:
* Current node state is always exposed as it is, even if not supported by the
requested API version, with exception of ``available`` state, which is
returned in version 1.1 as ``None`` (in Python) or ``null`` (in JSON).
* Data within free-form JSON attributes: ``properties``, ``driver_info``,
``instance_info``, ``driver_internal_info`` fields on a node object;
``extra`` fields on all objects.
* Addition of new drivers.
* All vendor passthru methods.