Update cluster applications API to support serverless domains

- Serialize available domains and currently associated domain when
  presenting Knative
- When Knative is updated, create an association to the newly
  selected domain

app/models/clusters/applications/knative.rb

@@ -41,6 +41,8 @@ module Clusters
 
       scope :for_cluster, -> (cluster) { where(cluster: cluster) }
 
+      has_one :pages_domain, through: :serverless_domain_cluster
+
       def chart
         'knative/knative'
       end
@@ -49,6 +51,14 @@ module Clusters
         { "domain" => hostname }.to_yaml
       end
 
+      def available_domains
+        PagesDomain.instance_serverless
+      end
+
+      def find_available_domain(pages_domain_id)
+        available_domains.find_by(id: pages_domain_id)
+      end
+
       def allowed_to_uninstall?
         !pre_installed?
       end

app/serializers/cluster_application_entity.rb

@@ -13,4 +13,6 @@ class ClusterApplicationEntity < Grape::Entity
   expose :modsecurity_enabled, if: -> (e, _) { e.respond_to?(:modsecurity_enabled) }
   expose :update_available?, as: :update_available, if: -> (e, _) { e.respond_to?(:update_available?) }
   expose :can_uninstall?, as: :can_uninstall
+  expose :available_domains, using: Serverless::DomainEntity, if: -> (e, _) { e.respond_to?(:available_domains) }
+  expose :pages_domain, using: Serverless::DomainEntity, if: -> (e, _) { e.respond_to?(:pages_domain) }
 end

app/serializers/serverless/domain_entity.rb

+# frozen_string_literal: true
+
+module Serverless
+  class DomainEntity < Grape::Entity
+    expose :id
+    expose :domain
+  end
+end

app/services/clusters/applications/base_service.rb

@@ -35,6 +35,12 @@ module Clusters
             application.oauth_application = create_oauth_application(application, request)
           end
 
+          if application.instance_of?(Knative)
+            Serverless::AssociateDomainService
+              .new(application, pages_domain_id: params[:pages_domain_id], creator: current_user)
+              .execute
+          end
+
           worker = worker_class(application)
 
           application.make_scheduled!

app/services/serverless/associate_domain_service.rb

+# frozen_string_literal: true
+
+module Serverless
+  class AssociateDomainService
+    PLACEHOLDER_HOSTNAME = 'example.com'.freeze
+
+    def initialize(knative, pages_domain_id:, creator:)
+      @knative = knative
+      @pages_domain_id = pages_domain_id
+      @creator = creator
+    end
+
+    def execute
+      return if unchanged?
+
+      knative.hostname ||= PLACEHOLDER_HOSTNAME
+
+      knative.pages_domain = knative.find_available_domain(pages_domain_id)
+      knative.serverless_domain_cluster.update(creator: creator) if knative.pages_domain
+
+      ClusterConfigureIstioWorker.perform_async(knative.cluster_id)
+    end
+
+    private
+
+    attr_reader :knative, :pages_domain_id, :creator
+
+    def unchanged?
+      knative.pages_domain&.id == pages_domain_id
+    end
+  end
+end

spec/fixtures/api/schemas/cluster_status.json

@@ -39,9 +39,15 @@
         "stack": { "type": ["string", "null"] },
         "modsecurity_enabled": { "type": ["boolean", "null"] },
         "update_available": { "type": ["boolean", "null"] },
-        "can_uninstall": { "type": "boolean" }
+        "can_uninstall": { "type": "boolean" },
+        "available_domains": {
+          "type": "array",
+          "items": { "$ref": "#/definitions/domain" }
+        },
+        "pages_domain": { "type": [ { "$ref": "#/definitions/domain" }, "null"] }
       },
       "required" : [ "name", "status" ]
-    }
+    },
+    "domain": { "id": "integer", "domain": "string" }
   }
 }

spec/models/clusters/applications/knative_spec.rb

@@ -196,4 +196,34 @@ describe Clusters::Applications::Knative do
   describe 'validations' do
     it { is_expected.to validate_presence_of(:hostname) }
   end
+
+  describe '#available_domains' do
+    let!(:domain) { create(:pages_domain, :instance_serverless) }
+
+    it 'returns all instance serverless domains' do
+      expect(PagesDomain).to receive(:instance_serverless).and_call_original
+
+      domains = subject.available_domains
+
+      expect(domains.length).to eq(1)
+      expect(domains).to include(domain)
+    end
+  end
+
+  describe '#find_available_domain' do
+    let!(:domain) { create(:pages_domain, :instance_serverless) }
+
+    it 'returns the domain scoped to available domains' do
+      expect(subject).to receive(:available_domains).and_call_original
+      expect(subject.find_available_domain(domain.id)).to eq(domain)
+    end
+  end
+
+  describe '#pages_domain' do
+    let!(:sdc) { create(:serverless_domain_cluster, knative: knative) }
+
+    it 'returns the the associated pages domain' do
+      expect(knative.reload.pages_domain).to eq(sdc.pages_domain)
+    end
+  end
 end

spec/serializers/cluster_application_entity_spec.rb

@@ -59,5 +59,23 @@ describe ClusterApplicationEntity do
         expect(subject[:external_ip]).to eq('111.222.111.222')
       end
     end
+
+    context 'for knative application' do
+      let(:pages_domain) { create(:pages_domain, :instance_serverless) }
+      let(:application) { build(:clusters_applications_knative, :installed) }
+
+      before do
+        create(:serverless_domain_cluster, knative: application, pages_domain: pages_domain)
+      end
+
+      it 'includes available domains' do
+        expect(subject[:available_domains].length).to eq(1)
+        expect(subject[:available_domains].first).to eq(id: pages_domain.id, domain: pages_domain.domain)
+      end
+
+      it 'includes pages_domain' do
+        expect(subject[:pages_domain]).to eq(id: pages_domain.id, domain: pages_domain.domain)
+      end
+    end
   end
 end

spec/serializers/serverless/domain_entity_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Serverless::DomainEntity do
+  describe '#as_json' do
+    let(:domain) { create(:pages_domain, :instance_serverless) }
+
+    subject { described_class.new(domain).as_json }
+
+    it 'has an id' do
+      expect(subject[:id]).to eq(domain.id)
+    end
+
+    it 'has a domain' do
+      expect(subject[:domain]).to eq(domain.domain)
+    end
+  end
+end

spec/services/clusters/applications/create_service_spec.rb

@@ -137,10 +137,14 @@ describe Clusters::Applications::CreateService do
         let(:params) do
           {
             application: 'knative',
-            hostname: 'example.com'
+            hostname: 'example.com',
+            pages_domain_id: domain.id
           }
         end
 
+        let(:domain) { create(:pages_domain, :instance_serverless) }
+        let(:associate_domain_service) { double('AssociateDomainService') }
+
         before do
           expect_any_instance_of(Clusters::Applications::Knative)
             .to receive(:make_scheduled!)
@@ -158,6 +162,20 @@ describe Clusters::Applications::CreateService do
         it 'sets the hostname' do
           expect(subject.hostname).to eq('example.com')
         end
+
+        it 'executes AssociateDomainService' do
+          expect(Serverless::AssociateDomainService).to receive(:new) do |knative, args|
+            expect(knative).to be_a(Clusters::Applications::Knative)
+            expect(args[:pages_domain_id]).to eq(params[:pages_domain_id])
+            expect(args[:creator]).to eq(user)
+
+            associate_domain_service
+          end
+
+          expect(associate_domain_service).to receive(:execute)
+
+          subject
+        end
       end
 
       context 'elastic stack application' do

spec/services/clusters/applications/update_service_spec.rb

@@ -7,8 +7,9 @@ describe Clusters::Applications::UpdateService do
 
   let(:cluster) { create(:cluster, :project, :provided_by_gcp) }
   let(:user) { create(:user) }
-  let(:params) { { application: 'knative', hostname: 'udpate.example.com' } }
+  let(:params) { { application: 'knative', hostname: 'update.example.com', pages_domain_id: domain.id } }
   let(:service) { described_class.new(cluster, user, params) }
+  let(:domain) { create(:pages_domain, :instance_serverless) }
 
   subject { service.execute(test_request) }
 
@@ -51,6 +52,24 @@ describe Clusters::Applications::UpdateService do
 
           subject
         end
+
+        context 'knative application' do
+          let(:associate_domain_service) { double('AssociateDomainService') }
+
+          it 'executes AssociateDomainService' do
+            expect(Serverless::AssociateDomainService).to receive(:new) do |knative, args|
+              expect(knative.id).to eq(application.id)
+              expect(args[:pages_domain_id]).to eq(params[:pages_domain_id])
+              expect(args[:creator]).to eq(user)
+
+              associate_domain_service
+            end
+
+            expect(associate_domain_service).to receive(:execute)
+
+            subject
+          end
+        end
       end
 
       context 'application is not schedulable' do

spec/services/serverless/associate_domain_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Serverless::AssociateDomainService do
+  subject { described_class.new(knative, pages_domain_id: pages_domain_id, creator: creator) }
+
+  let(:sdc) { create(:serverless_domain_cluster, pages_domain: create(:pages_domain, :instance_serverless)) }
+  let(:knative) { sdc.knative }
+  let(:creator) { sdc.creator }
+  let(:pages_domain_id) { sdc.pages_domain_id }
+
+  context 'when the domain is unchanged' do
+    let(:creator) { create(:user) }
+
+    it 'does not schedule a ClusterConfigureIstioWorker' do
+      expect(ClusterConfigureIstioWorker).not_to receive(:perform_async)
+
+      subject.execute
+    end
+
+    it 'does not update creator' do
+      expect { subject.execute }.not_to change { sdc.reload.creator }
+    end
+  end
+
+  context 'when domain is changed to nil' do
+    let(:pages_domain_id) { nil }
+    let(:creator) { create(:user) }
+
+    it 'removes the association between knative and the domain' do
+      expect { subject.execute }.to change { knative.reload.pages_domain }.from(sdc.pages_domain).to(nil)
+    end
+
+    it 'does not attempt to update creator' do
+      expect { subject.execute }.not_to raise_error
+    end
+
+    it 'schedules a ClusterConfigureIstioWorker for the cluster' do
+      expect(ClusterConfigureIstioWorker).to receive(:perform_async).with(knative.cluster_id)
+
+      subject.execute
+    end
+  end
+
+  context 'when a new domain is associated' do
+    let(:pages_domain_id) { create(:pages_domain, :instance_serverless).id }
+    let(:creator) { create(:user) }
+
+    it 'creates an association with the domain' do
+      expect { subject.execute }.to change { knative.pages_domain.id }.from(sdc.pages_domain.id).to(pages_domain_id)
+    end
+
+    it 'schedules a ClusterConfigureIstioWorker for the cluster' do
+      expect(ClusterConfigureIstioWorker).to receive(:perform_async).with(knative.cluster_id)
+
+      subject.execute
+    end
+
+    it 'updates creator' do
+      expect { subject.execute }.to change { sdc.reload.creator }.from(sdc.creator).to(creator)
+    end
+  end
+
+  context 'when knative is not authorized to use the pages domain' do
+    let(:pages_domain_id) { create(:pages_domain).id }
+
+    before do
+      expect(knative).to receive(:available_domains).and_return(PagesDomain.none)
+    end
+
+    it 'sets pages_domain_id to nil' do
+      expect { subject.execute }.to change { knative.reload.pages_domain }.from(sdc.pages_domain).to(nil)
+    end
+  end
+
+  context 'when knative hostname is nil' do
+    let(:knative) { build(:clusters_applications_knative, hostname: nil) }
+
+    it 'sets hostname to a placeholder value' do
+      expect { subject.execute }.to change { knative.hostname }.to('example.com')
+    end
+  end
+
+  context 'when knative hostname exists' do
+    let(:knative) { build(:clusters_applications_knative, hostname: 'hostname.com') }
+
+    it 'does not change hostname' do
+      expect { subject.execute }.not_to change { knative.hostname }
+    end
+  end
+end