Fixes: Stale Service chain entries seen in Schema Introspect

Deleting a VN should check for service chain references
and delete the service chain as well if the service chain
does not have VN references.

Change-Id: I8040032459821fa8dc3a555ff59d4278698b50a8
ClosesBug: 1545475

src/config/schema-transformer/config_db.py

@@ -358,6 +358,41 @@ def check_multi_policy_service_chain_status(self):
                     sc, other_si_name, multi_policy_enabled)
     # end check_multi_policy_service_chain_status
 
+    def delete_inactive_service_chains(self, old_scs, new_scs=None):
+
+        # Delete the service chains that are no longer active
+        for remote_vn_name in old_scs:
+            # Get the Remote VNs in this VN's service chain and 
+            # get a list of the remote service chains in the remote
+            # VNs which has this VNs name.
+            remote_vn = VirtualNetworkST.get(remote_vn_name)
+            if remote_vn is None:
+                remote_service_chain_list = []
+            else:
+                remote_service_chain_list = remote_vn.service_chains.get(self.name)
+
+            # Get a list of this VN's service chains which has a
+            # remote VN name as one of its service endpoints.
+            # Case 1: If the Service Chain is present in the updated
+            #         SC list (if any), then dont do anythnig.
+            # Case 2: If the SC is not present in the updated SC
+            #         list (if any), but present in the remote VN
+            #         SC list, then invalidate it and mark it for
+            #         deletion.
+            # Case 3: If the SC is not present in the updated SC
+            #         list (if any) and not in the remote VN SC list,
+            #         then delete it permanentely since there is no
+            #         VNs that are referring to this SC.
+            service_chain_list = old_scs[remote_vn_name]
+            for service_chain in service_chain_list or []:
+                if new_scs and\
+                   service_chain in (new_scs.get(remote_vn_name) or []):
+                    continue
+                if service_chain in (remote_service_chain_list or []):
+                    service_chain.destroy()
+                else:
+                    service_chain.delete()
+
     def delete_obj(self):
         for policy_name in self.network_policys:
             policy = NetworkPolicyST.get(policy_name)
@@ -366,9 +401,7 @@ def delete_obj(self):
             policy.virtual_networks.discard(self.name)
 
         self.update_multiple_refs('virtual_machine_interface', {})
-        for service_chain_list in self.service_chains.values():
-            for service_chain in service_chain_list:
-                service_chain.destroy()
+        self.delete_inactive_service_chains(self.service_chains)
         for ri_name in self.routing_instances:
             RoutingInstanceST.delete(ri_name)
         if self.acl:
@@ -1324,22 +1357,7 @@ def evaluate(self):
             # end for service_chain
         # end for remote_vn_name
 
-        # Delete the service chains that are no longer active
-        for remote_vn_name in old_service_chains:
-            remote_vn = VirtualNetworkST.get(remote_vn_name)
-            if remote_vn is None:
-                continue
-            remote_service_chain_list = remote_vn.service_chains.get(self.name)
-            service_chain_list = old_service_chains[remote_vn_name]
-            for service_chain in service_chain_list or []:
-                if service_chain in (self.service_chains.get(remote_vn_name)
-                                     or []):
-                    continue
-                if service_chain in (remote_service_chain_list or []):
-                    service_chain.destroy()
-                else:
-                    service_chain.delete()
-        # for remote_vn_name
+        self.delete_inactive_service_chains(old_service_chains, self.service_chains)
 
         self.update_route_table()
         self.update_pnf_presence()

src/config/schema-transformer/test/test_service.py

@@ -107,6 +107,12 @@ def check_v6_service_chain_info(self, fq_name, expected):
             raise Exception('Ipv6 service chain info not found for %s' % fq_name)
         self.assertEqual(sci, expected)
 
+    @retries(5)
+    def check_service_chain_is_deleted(self, sc_uuid):
+        for sc in to_bgp.ServiceChain.values():
+            if sc_uuid == sc.name:
+                raise Exception('Service chain %s not deleted' % sc_uuid)
+
     @retries(5)
     def check_analyzer_ip(self, vmi_fq_name):
         vmi = self._vnc_lib.virtual_machine_interface_read(vmi_fq_name)
@@ -928,6 +934,42 @@ def test_service_policy_no_vm(self):
         self.check_ri_is_deleted(fq_name=self.get_ri_name(vn2_obj))
     # end test_service_policy_no_vm
 
+    def test_service_policy_delete_vns_deletes_scs(self):
+        # Test to check deleting VNs without deleting the
+        # policy associated, deletes the service chain.
+
+        # create  vn1
+        vn1_name = self.id() + 'vn1'
+        vn1_obj = self.create_virtual_network(vn1_name, '10.0.0.0/24')
+
+        # create vn2
+        vn2_name = self.id() + 'vn2'
+        vn2_obj = self.create_virtual_network(vn2_name, '20.0.0.0/24')
+
+        service_name = self.id() + 's1'
+        np = self.create_network_policy(vn1_obj, vn2_obj)
+        seq = SequenceType(1, 1)
+        vnp = VirtualNetworkPolicyType(seq)
+
+        vn1_obj.set_network_policy(np, vnp)
+        vn2_obj.set_network_policy(np, vnp)
+        self._vnc_lib.virtual_network_update(vn1_obj)
+        self._vnc_lib.virtual_network_update(vn2_obj)
+
+        np.network_policy_entries.policy_rule[0].action_list.apply_service = ["default-domain:default-project:"+service_name]
+        np.set_network_policy_entries(np.network_policy_entries)
+        self._vnc_lib.network_policy_update(np)
+        sc = self.wait_to_get_sc()
+        sc_ri_name = 'service-'+sc+'-default-domain_default-project_' + service_name
+
+        self._vnc_lib.virtual_network_delete(fq_name=vn1_obj.get_fq_name())
+        self._vnc_lib.virtual_network_delete(fq_name=vn2_obj.get_fq_name())
+
+        self.check_service_chain_is_deleted(sc_uuid=sc)
+        self.check_vn_is_deleted(uuid=vn1_obj.uuid)
+        self.check_vn_is_deleted(uuid=vn2_obj.uuid)
+    # end test_service_policy_delete_vns_deletes_scs
+
     def test_multi_service_in_policy(self):
         # create  vn1
         vn1_name = self.id() + 'vn1'