Pecan: Define plugin crud methods in base class

Refactors the current pecan code to use predefined methods to get
the plugin methods the controllers will call.  This also adds in
parent resource information to build those method names, but parent
support will not be complete until a follow up patch.

Change-Id: I4e0e6ef96364991a9393bc5fba495e37dade68a1
Closes-Bug: #1596754

neutron/api/v2/base.py

@@ -101,7 +101,7 @@ class Controller(object):
                 LOG.info(_LI("Allow sorting is enabled because native "
                              "pagination requires native sorting"))
                 self._allow_sorting = True
-
+        self.parent = parent
         if parent:
             self._parent_id_name = '%s_id' % parent['member_name']
             parent_part = '_%s' % parent['member_name']

neutron/pecan_wsgi/controllers/resource.py

@@ -36,11 +36,10 @@ class ItemController(utils.NeutronPecanController):
         return self.get(*args, **kwargs)
 
     def get(self, *args, **kwargs):
-        getter = getattr(self.plugin, 'get_%s' % self.resource)
         neutron_context = request.context['neutron_context']
         fields = request.context['query_params'].get('fields')
-        return {self.resource: getter(neutron_context, self.item,
-                                      fields=fields)}
+        return {self.resource: self.plugin_shower(neutron_context, self.item,
+                                                  fields=fields)}
 
     @utils.when(index, method='HEAD')
     @utils.when(index, method='POST')
@@ -53,19 +52,18 @@ class ItemController(utils.NeutronPecanController):
         neutron_context = request.context['neutron_context']
         resources = request.context['resources']
         # TODO(kevinbenton): bulk?
-        updater = getattr(self.plugin, 'update_%s' % self.resource)
         # Bulk update is not supported, 'resources' always contains a single
         # elemenet
         data = {self.resource: resources[0]}
-        return {self.resource: updater(neutron_context, self.item, data)}
+        return {self.resource: self.plugin_updater(neutron_context,
+                                                   self.item, data)}
 
     @utils.when(index, method='DELETE')
     def delete(self):
         # TODO(kevinbenton): setting code could be in a decorator
         pecan.response.status = 204
         neutron_context = request.context['neutron_context']
-        deleter = getattr(self.plugin, 'delete_%s' % self.resource)
-        return deleter(neutron_context, self.item)
+        return self.plugin_deleter(neutron_context, self.item)
 
     @utils.expose()
     def _lookup(self, collection, *remainder):
@@ -100,9 +98,9 @@ class CollectionsController(utils.NeutronPecanController):
     def get(self, *args, **kwargs):
         # NOTE(blogan): query_params is set in the QueryParametersHook
         query_params = request.context['query_params']
-        lister = getattr(self.plugin, 'get_%s' % self.collection)
         neutron_context = request.context['neutron_context']
-        return {self.collection: lister(neutron_context, **query_params)}
+        return {self.collection: self.plugin_lister(neutron_context,
+                **query_params)}
 
     @utils.when(index, method='HEAD')
     @utils.when(index, method='PATCH')
@@ -121,13 +119,12 @@ class CollectionsController(utils.NeutronPecanController):
     def create(self, resources):
         if len(resources) > 1:
             # Bulk!
-            method = 'create_%s_bulk' % self.resource
+            creator = self.plugin_bulk_creator
             key = self.collection
             data = {key: [{self.resource: res} for res in resources]}
         else:
-            method = 'create_%s' % self.resource
+            creator = self.plugin_creator
             key = self.resource
             data = {key: resources[0]}
-        creator = getattr(self.plugin, method)
         neutron_context = request.context['neutron_context']
         return {key: creator(neutron_context, data)}

neutron/pecan_wsgi/controllers/utils.py

@@ -90,8 +90,15 @@ def when(index, *args, **kwargs):
 
 class NeutronPecanController(object):
 
+    LIST = 'list'
+    SHOW = 'show'
+    CREATE = 'create'
+    UPDATE = 'update'
+    DELETE = 'delete'
+
     def __init__(self, collection, resource, plugin=None, resource_info=None,
-                 allow_pagination=None, allow_sorting=None):
+                 allow_pagination=None, allow_sorting=None,
+                 parent_resource=None):
         # Ensure dashes are always replaced with underscores
         self.collection = collection and collection.replace('-', '_')
         self.resource = resource and resource.replace('-', '_')
@@ -117,6 +124,17 @@ class NeutronPecanController(object):
             self.plugin)
         self.primary_key = self._get_primary_key()
 
+        parent_resource = '_%s' % parent_resource if parent_resource else ''
+        self._parent_id_name = ('%s_id' % parent_resource
+                                if parent_resource else None)
+        self._plugin_handlers = {
+            self.LIST: 'get%s_%s' % (parent_resource, self.collection),
+            self.SHOW: 'get%s_%s' % (parent_resource, self.resource)
+        }
+        for action in [self.CREATE, self.UPDATE, self.DELETE]:
+            self._plugin_handlers[action] = '%s%s_%s' % (
+                action, parent_resource, self.resource)
+
     def build_field_list(self, request_fields):
         added_fields = []
         combined_fields = []
@@ -148,6 +166,31 @@ class NeutronPecanController(object):
                 return key
         return default_primary_key
 
+    @property
+    def plugin_lister(self):
+        return getattr(self.plugin, self._plugin_handlers[self.LIST])
+
+    @property
+    def plugin_shower(self):
+        return getattr(self.plugin, self._plugin_handlers[self.SHOW])
+
+    @property
+    def plugin_creator(self):
+        return getattr(self.plugin, self._plugin_handlers[self.CREATE])
+
+    @property
+    def plugin_bulk_creator(self):
+        return getattr(self.plugin,
+                       '%s_bulk' % self._plugin_handlers[self.CREATE])
+
+    @property
+    def plugin_deleter(self):
+        return getattr(self.plugin, self._plugin_handlers[self.DELETE])
+
+    @property
+    def plugin_updater(self):
+        return getattr(self.plugin, self._plugin_handlers[self.UPDATE])
+
 
 class ShimRequest(object):
 

neutron/pecan_wsgi/startup.py

@@ -70,8 +70,17 @@ def initialize_all():
             resource = legacy_controller.resource
             plugin = legacy_controller.plugin
             attr_info = legacy_controller.attr_info
+            # Retrieving the parent resource.  It is expected the format of
+            # the parent resource to be:
+            # {'collection_name': 'name-of-collection',
+            #  'member_name': 'name-of-resource'}
+            # collection_name does not appear to be used in the legacy code
+            # inside the controller logic, so we can assume we do not need it.
+            parent = legacy_controller.parent or {}
+            parent_resource = parent.get('member_name')
             new_controller = res_ctrl.CollectionsController(
-                collection, resource, resource_info=attr_info)
+                collection, resource, resource_info=attr_info,
+                parent_resource=parent_resource)
             manager.NeutronManager.set_plugin_for_resource(resource, plugin)
             if path_prefix:
                 manager.NeutronManager.add_resource_for_path_prefix(