Refactor GBP with the Neutron RESTful APIs

Refactor the resource mapping driver with the neutron RESTful APIs.

Change-Id: I658320e0aa6d0be51c05365841175615a297cbf3
Implements: blueprint neutron-rest-api-refactor

specs/kilo/gbp-refactor-neutron-restful-api.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+=====================================================
+Group Based Policy Refactor: Use Neutron RESTful APIs
+=====================================================
+
+Launchpad blueprint:
+https://blueprints.launchpad.net/group-based-policy/+spec/neutron-rest-api-refactor
+
+This blueprint proposes using neutron RESTful APIs in resource mapping driver.
+
+Problem description
+===================
+The current (Juno) GBP RMD interacts with neutron directly through
+neutron-plugin calls. This tight coupling prevents GBP from being
+instantiated as separate process/service.
+
+This blueprint proposes a loose coupling by moving GBP to use the neutron
+RESTful APIs. More specifically, a neutron RESTful API client wrapper will be
+implemented, and the neutron internal APIs previously used in GBP will be
+replaced by calls to this client wrapper.
+
+Proposed change
+===============
+The proposed change will:
+
+1. Add neutron v2 API module. This module will provide APIs to neutron
+resources' CRUD operation. This code will be added to:
+gbpservice/network/neutronv2
+This will be similar to how nova is doing it [2].
+2. Refactor resource mapping driver code to replace neutron neutron-plugin
+calls with the neutron v2 API calls.
+
+Alternative
+------------
+None.
+
+Data model impact
+-----------------
+Re-factoring the resource mapping driver code with the neutron RESTful APIs
+are invisible to users, therefore should not by itself require structural
+changes to the data model currently defined in the group based policy.
+
+REST API impact
+---------------
+None.
+
+Security impact
+---------------
+None.
+
+Notifications impact
+--------------------
+None.
+
+Other end user impact
+---------------------
+None.
+
+Performance Impact
+------------------
+There will be some minimal performance imapct after refactoring as RESTful
+APIs are used.
+
+Other deployer impact
+---------------------
+None.
+
+Developer impact
+----------------
+None.
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+Yapeng Wu
+
+Yi Yang
+
+Work Items
+----------
+1. Add neutron v2 API module.
+2. In RMD, replace neutron-plugin calls with neutron v2 API calls.
+
+Dependencies
+============
+Neutron Python Client (minimum version 2.3.9) and plan to move to later
+version.
+
+Testing
+=======
+1. UT for the Neutron Client Wrapper:
+Additional UT for the Neutron RESTful API wrapper will be provided.
+
+2. UT for the Resource Mapping Driver:
+In current RMD UT implementation, when a call such as "create_policy_target"[3]
+is made, the RMD UT is making neutron-plugin call. With the proposed RMD
+changes, those neutron-plugin calls will get replaced with the ClientWrapping
+class methods. To get this work in the UT environment, the ClientWraping class
+methods will be patched with neutron-plugin calls.
+
+Another type calls in current RMD UT implementation are neutron-wsgi calls (
+"new_*_request") [4]. These calls are implemented in Neutron test framework[5]
+via WSGI requests. These calls will stay as they are.
+
+3. Long Term Plan
+When GBP becomes an independent server, the neutron-wsgi calls will being
+refactored. These refactor can be handled in the spec for the independent
+server.
+
+Documentation Impact
+====================
+None
+
+References
+==========
+[1]
+http://git.openstack.org/cgit/stackforge/group-based-policy-specs/tree/specs/juno/group-based-policy-abstraction.rst
+[2] https://github.com/openstack/nova/tree/master/nova/network/neutronv2
+[3] https://github.com/stackforge/group-based-policy/blob/master/gbpservice/neutron/tests/unit/services/grouppolicy/test_resource_mapping.py#L317
+[4] https://github.com/stackforge/group-based-policy/blob/master/gbpservice/neutron/tests/unit/services/grouppolicy/test_resource_mapping.py#L339
+[5] https://github.com/openstack/neutron/blob/master/neutron/tests/unit/test_db_plugin.py#L200-L249