Document for available HOT custom constraints

[Joanna H. Huang]

The HOT custom constraints on parameters are very useful for verifying user inputs while creating a stack. For instance, the following parameter definition will only allow valid value of instance flavor known to Nova:

  flavor:
    type: string
    label: Instance Flavor
    default: m1.medium
    description: The flavor to use
    constraints:
      - custom_constraint: nova.flavor
        description: Instance Flavor must be a flavor known to Nova

However, it is lacking of document to describe the currently available custom constraints implemented in various Heat resource plugins. I checked Heat Engine source code and found the following custom constraints:

  cinder.volume
  cinder.vtype
  cinder.snapshot
  glance.image
  keystone.domain
  neutron.network
  neutron.router
  neutron.port
  neutron.subnet
  nova.flavor
  nova.keypair
  nova.server
  sahara.image
  trove.flavor

It would be good to have some document collecting information about all available custom constraints for HOT parameters.

[Pavlo Shchelokovskyy (pshchelo)]

Joanna, you do not have to check the source code of the engine. Since all custom constraints are implemented as stevedore plugins, this section of setup.cfg [1] gives you the full list of constraints available in the main code tree. Other resource / client plugins (like those in contrib) might add additional constraints.

[1] https://github.com/openstack/heat/blob/master/setup.cfg#L60-L74

[Steve Baker (steve-stevebaker)]

This could be automatically generated by sphinx, like our resource types

http://git.openstack.org/cgit/openstack/heat/tree/doc/source/ext/resources.py

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/225295

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/225295
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=6b837a85ff2f2ebcbf02e2a457586d5a6625d1c7
Submitter: Jenkins
Branch: master

commit 6b837a85ff2f2ebcbf02e2a457586d5a6625d1c7
Author: Mark Vanderwiel <email address hidden>
Date: Fri Sep 18 14:57:47 2015 -0500

    Add table of custom constraints to hot spec

    Added a generic sphinx extension to allow text from a file to
    be pulled into the documentation in simple table format.
    It allows flexibility to be used for other types of
    list of heat configuration data in the future.

    Change-Id: I96c936df3bc42c385e73a8dc76c0f9a29e17ea3f
    Closes-Bug: #1453718