Add label_selector support to route policies list

- RoutePoliciesListMessage now inherits from MetadataListMessage,
  which auto-registers :label_selector and wires
  LabelSelectorRequirementValidator
- build_dataset in RoutePoliciesController delegates to
  LabelSelectorQueryGenerator when a selector is requested

Author: rkoster

app/controllers/v3/route_policies_controller.rb

@@ -7,6 +7,7 @@
 require 'decorators/include_route_policy_route_decorator'
 require 'actions/route_policy_create'
 require 'repositories/route_policy_event_repository'
+require 'fetchers/label_selector_query_generator'
 
 class RoutePoliciesController < ApplicationController
   def index
@@ -169,6 +170,15 @@ def build_dataset(message)
 
     dataset = dataset.where(source_guid: message.source_guids) if message.requested?(:source_guids)
 
+    if message.requested?(:label_selector)
+      dataset = VCAP::CloudController::LabelSelectorQueryGenerator.add_selector_queries(
+        label_klass: VCAP::CloudController::RoutePolicyLabelModel,
+        resource_dataset: dataset,
+        requirements: message.requirements,
+        resource_klass: VCAP::CloudController::RoutePolicy
+      )
+    end
+
     dataset
   end
 end

app/messages/route_policies_list_message.rb

@@ -1,7 +1,7 @@
-require 'messages/list_message'
+require 'messages/metadata_list_message'
 
 module VCAP::CloudController
-  class RoutePoliciesListMessage < ListMessage
+  class RoutePoliciesListMessage < MetadataListMessage
     register_allowed_keys %i[
       guids
       route_guids

spec/request/route_policies_spec.rb

@@ -583,6 +583,28 @@ def expected_rule_json(rule)
       end
     end
 
+    describe 'filtering by label_selector' do
+      let(:another_route) { VCAP::CloudController::Route.make(space: space, domain: mtls_domain) }
+      let!(:labelled_policy) do
+        policy = VCAP::CloudController::RoutePolicy.create(source: 'cf:any', route_id: mtls_route.id)
+        VCAP::CloudController::RoutePolicyLabelModel.create(resource_guid: policy.guid, key_name: 'env', value: 'prod')
+        policy
+      end
+      let!(:unlabelled_policy) do
+        VCAP::CloudController::RoutePolicy.create(source: 'cf:any', route_id: another_route.id)
+      end
+
+      it 'returns only policies matching the label selector' do
+        get '/v3/route_policies?label_selector=env=prod', nil, admin_header
+
+        expect(last_response.status).to eq(200)
+        parsed = Oj.load(last_response.body)
+        guids = parsed['resources'].pluck('guid')
+        expect(guids).to include(labelled_policy.guid)
+        expect(guids).not_to include(unlabelled_policy.guid)
+      end
+    end
+
     context 'with include=source' do
       let!(:frontend_app) { VCAP::CloudController::AppModel.make(space: space, name: 'frontend-app') }
       let!(:other_space) { VCAP::CloudController::Space.make(organization: org, name: 'other-space') }

spec/unit/messages/route_policies_list_message_spec.rb

@@ -125,6 +125,19 @@ module VCAP::CloudController
         end
       end
 
+      describe 'label_selector' do
+        it 'accepts a label_selector param' do
+          message = RoutePoliciesListMessage.from_params({ 'label_selector' => 'env=prod' })
+          expect(message).to be_valid
+          expect(message).to be_requested(:label_selector)
+        end
+
+        it 'rejects an invalid label_selector' do
+          message = RoutePoliciesListMessage.from_params({ 'label_selector' => '%%invalid' })
+          expect(message).not_to be_valid
+        end
+      end
+
       describe 'validations' do
         it 'validates space_guids is an array' do
           message = RoutePoliciesListMessage.from_params space_guids: 'not array'