Add Openstack guidelines spec from Ansible

These may not be 100% perfect, but they are a good
starting place and we can improve them over time.

Change-Id: Ifb21554d67863b4e4e964f3e98263c3dafcb607f

docs/openstack_guidelines.rst

@@ -0,0 +1,70 @@
+.. _OpenStack_module_development:
+
+OpenStack Ansible Modules
+=========================
+
+These are a set of modules for interacting with OpenStack as either an admin
+or an end user. If the module does not begin with ``os_``, it's either deprecated
+or soon to be. This document serves as developer coding guidelines for
+modules intended to be here.
+
+.. contents::
+   :local:
+
+Naming
+------
+
+* All module names should start with ``os_``
+* Name any module that a cloud consumer would expect to use after the logical resource it manages: 
+  ``os_server`` not ``os_nova``. This naming convention acknowledges that the end user does not care 
+  which service manages the resource - that is a deployment detail. For example cloud consumers may
+  not know whether their floating IPs are managed by Nova or Neutron.
+* Name any module that a cloud admin would expect to use with the service and the resource: 
+  ``os_keystone_domain``.
+* If the module is one that a cloud admin and a cloud consumer could both use,
+  the cloud consumer rules apply.
+
+Interface
+---------
+
+* If the resource being managed has an id, it should be returned.
+* If the resource being managed has an associated object more complex than
+  an id, it should also be returned.
+
+Interoperability
+----------------
+
+* It should be assumed that the cloud consumer does not know
+  details about the deployment choices their cloud provider made. A best
+  effort should be made to present one sane interface to the Ansible user
+  regardless of deployer choices.
+* It should be assumed that a user may have more than one cloud account that
+  they wish to combine as part of a single Ansible-managed infrastructure.
+* All modules should work appropriately against all existing versions of
+  OpenStack regardless of upstream EOL status. The reason for this is that
+  the Ansible modules are for consumers of cloud APIs who are not in a
+  position to impact what version of OpenStack their cloud provider is
+  running. It is known that there are OpenStack Public Clouds running rather
+  old versions of OpenStack, but from a user point of view the Ansible
+  modules can still support these users without impacting use of more
+  modern versions.
+
+Libraries
+---------
+
+* All modules should use ``OpenStackModule`` from
+  ``ansible_collections.openstack.cloud.plugins.module_utils.openstack``
+  as their base class.
+* All modules should include ``extends_documentation_fragment: openstack``.
+* All complex cloud interaction or interoperability code should be housed in
+  the `openstacksdk <https://opendev.org/openstack/openstacksdk>`_
+  library.
+* All OpenStack API interactions should happen via the openstacksdk and not via
+  OpenStack Client libraries. The OpenStack Client libraries do no have end
+  users as a primary audience, they are for intra-server communication.
+
+Testing
+-------
+
+* Integration testing is currently done in `OpenStack's CI system
+  <https://opendev.org/openstack/ansible-collections-openstack/src/branch/master/zuul.yaml>`