notify PT added/removed for autoscaling

Partially implements blueprint node-centric-chain-plugin

Change-Id: I55a615f5cc768f82c5c550c5924ed3c1a16fb405

gbpservice/neutron/services/servicechain/plugins/ncp/driver_base.py

@@ -145,6 +145,32 @@ class NodeDriverBase(object):
         """
         pass
 
+    @abc.abstractmethod
+    def update_policy_target_added(self, context, policy_target):
+        """Update a deployed Service Chain Node on adding of a PT.
+
+        This method can be used for auto scaling some services whenever a
+        Policy Target is added to a relevant PTG.
+
+        :param context: NodeDriverContext instance describing the service chain
+        and the specific node to be processed by this driver.
+        :param policy_target: Dict representing a Policy Target.
+        """
+        pass
+
+    @abc.abstractmethod
+    def update_policy_target_removed(self, context, policy_target):
+        """Update a deployed Service Chain Node on removal of a PT.
+
+        This method can be used for auto scaling some services whenever a
+        Policy Target is removed from a relevant PTG.
+
+        :param context: NodeDriverContext instance describing the service chain
+        and the specific node to be processed by this driver.
+        :param policy_target: Dict representing a Policy Target.
+        """
+        pass
+
     @abc.abstractproperty
     def name(self):
         pass

gbpservice/neutron/services/servicechain/plugins/ncp/node_drivers/dummy_driver.py

@@ -48,6 +48,14 @@ class NoopNodeDriver(driver_base.NodeDriverBase):
     def update(self, context):
         pass
 
+    @log.log
+    def update_policy_target_added(self, context, policy_target):
+        pass
+
+    @log.log
+    def update_policy_target_removed(self, context, policy_target):
+        pass
+
     @property
     def name(self):
         return self._name

gbpservice/neutron/services/servicechain/plugins/ncp/plugin.py

@@ -232,6 +232,36 @@ class NodeCompositionPlugin(servicechain_db.ServiceChainDbPlugin,
                                           updated_profile)
         return updated_profile
 
+    def update_chains_pt_added(self, context, policy_target):
+        """ Auto scaling function.
+
+        Notify the correct set of node drivers that a new policy target has
+        been added to a relevant PTG.
+        """
+        self._update_chains_pt_modified(context, policy_target, 'added')
+
+    def update_chains_pt_removed(self, context, policy_target):
+        """ Auto scaling function.
+
+        Notify the correct set of node drivers that a new policy target has
+        been removed from a relevant PTG.
+        """
+        self._update_chains_pt_modified(context, policy_target, 'removed')
+
+    def _update_chains_pt_modified(self, context, policy_target, action):
+        scis = self._get_instances_from_policy_target(context, policy_target)
+
+        for sci in scis:
+            updaters = self._get_scheduled_drivers(context, sci, 'update')
+            for update in updaters.values():
+                try:
+                    getattr(update['driver'],
+                            'update_policy_target_' + action)(
+                                update['context'], policy_target)
+                except exc.NodeDriverError as ex:
+                    LOG.error(_("Node Update on policy target modification "
+                                "failed, %s"), ex.message)
+
     def _get_instance_nodes(self, context, instance):
         if not instance['servicechain_specs']:
             return []
@@ -303,4 +333,4 @@ class NodeCompositionPlugin(servicechain_db.ServiceChainDbPlugin,
             raise exc.ServiceProfileInUseByAnInstance(
                 profile_id=original['id'], instance_id=instance.id)
         self._validate_shared_update(context, original, updated,
-                                     'service_profile')
+                                     'service_profile')

gbpservice/neutron/services/servicechain/plugins/ncp/plumber_base.py

@@ -113,7 +113,8 @@ class NodePlumberBase(object):
 
         for pt in pts:
             try:
-                gbp_plugin.delete_policy_target(context, pt.policy_target_id)
+                gbp_plugin.delete_policy_target(context, pt.policy_target_id,
+                                                notify_sc=False)
             except group_policy.PolicyTargetNotFound as ex:
                 LOG.debug(ex.message)
 
@@ -134,7 +135,8 @@ class NodePlumberBase(object):
                     'name': '', 'port_id': None}
             data.update(target)
             pt = gbp_plugin.create_policy_target(context,
-                                                 {'policy_target': data})
+                                                 {'policy_target': data},
+                                                 notify_sc=False)
             model.set_service_target(part_context, pt['id'], relationship)
 
     def _sort_deployment(self, deployment):