Create a droplet in the kpack stager

- Previously for kpack apps, the droplet was created when the build
controller would send a patch request to CAPI after a successful OCI
Image build. We wanted to create the droplet when the Image CR is
created so that the Image CR would have a droplet guid label that could
be used by the image controller to know which droplet to update after a
stack update.
- Removed droplet creation from the BuildUpdate action
- Non-kpack lifecycle app staging workflows should not have been changed or
impacted by this change.

[172542372]

Co-authored-by: Piyali Banerjee <pbanerjee@pivotal.io>
Co-authored-by: Nat Bennett <nbennett@pivotal.io>

Author: piyalibanerjee

app/actions/build_update.rb

@@ -15,7 +15,7 @@ def update(build, message)
         if message.state == VCAP::CloudController::BuildModel::FAILED_STATE
           build.fail_to_stage!('StagerError', message.error)
         elsif message.state == VCAP::CloudController::BuildModel::STAGED_STATE
-          droplet = VCAP::CloudController::DropletCreate.new.create_docker_droplet(build)
+          droplet = build.droplet
           droplet.lock!
           droplet.docker_receipt_image = message.lifecycle.dig(:data, :image)
           droplet.process_types = message.lifecycle.dig(:data, :processTypes)

lib/cloud_controller/kpack/stager.rb

@@ -6,6 +6,7 @@ class Stager
     }.freeze
     APP_GUID_LABEL_KEY = 'cloudfoundry.org/app_guid'.freeze
     BUILD_GUID_LABEL_KEY = 'cloudfoundry.org/build_guid'.freeze
+    DROPLET_GUID_LABEL_KEY = 'cloudfoundry.org/droplet_guid'.freeze
     STAGING_SOURCE_LABEL_KEY = 'cloudfoundry.org/source_type'.freeze
 
     def initialize(builder_namespace:, registry_service_account_name:, registry_tag_base:)
@@ -64,8 +65,9 @@ def image_resource(staging_details, builder_spec)
           name: staging_details.package.app.guid,
           namespace: builder_namespace,
           labels: {
-            APP_GUID_LABEL_KEY.to_sym => staging_details.package.app.guid,
-            BUILD_GUID_LABEL_KEY.to_sym => staging_details.staging_guid,
+            APP_GUID_LABEL_KEY.to_sym =>  staging_details.package.app.guid,
+            BUILD_GUID_LABEL_KEY.to_sym =>  staging_details.staging_guid,
+            DROPLET_GUID_LABEL_KEY.to_sym => create_droplet_and_get_guid(staging_details),
             STAGING_SOURCE_LABEL_KEY.to_sym => 'STG'
           },
           annotations: {
@@ -154,5 +156,11 @@ def client
     def blobstore_url_generator
       ::CloudController::DependencyLocator.instance.blobstore_url_generator
     end
+
+    def create_droplet_and_get_guid(staging_details)
+      build = VCAP::CloudController::BuildModel.find(guid: staging_details.staging_guid)
+      droplet = VCAP::CloudController::DropletCreate.new.create_docker_droplet(build)
+      droplet.guid
+    end
   end
 end

spec/request/builds_spec.rb

@@ -583,7 +583,9 @@
       end
 
       context 'updating state' do
-        let(:build_model) { VCAP::CloudController::BuildModel.make(package: package_model, state: VCAP::CloudController::BuildModel::STAGING_STATE) }
+        let(:build_model) { VCAP::CloudController::BuildModel.make(:kpack, package: package_model,
+          state: VCAP::CloudController::BuildModel::STAGING_STATE)
+        }
         let(:request) do
           {
             state: 'STAGED',

spec/support/fakes/blueprints.rb

@@ -78,9 +78,10 @@ module VCAP::CloudController
   BuildModel.blueprint(:kpack) do
     guid     { Sham.guid }
     state    { VCAP::CloudController::DropletModel::STAGING_STATE }
-    app { AppModel.make }
+    app { AppModel.make(droplet_guid: guid) }
     kpack_lifecycle_data { KpackLifecycleDataModel.make(build: object.save) }
     package { PackageModel.make(app: app) }
+    droplet { DropletModel.make(:docker, build: object.save) }
   end
 
   BuildModel.blueprint(:buildpack) do

spec/unit/actions/build_update_spec.rb

@@ -133,6 +133,7 @@ module VCAP::CloudController
 
       context 'when updating state' do
         let(:build) { BuildModel.make(:kpack) }
+
         context 'when a build was successfully completed' do
           let(:body) do
             {
@@ -154,6 +155,7 @@ module VCAP::CloudController
             build_update.update(build, message)
 
             expect(build.state).to eq('STAGED')
+            expect(build.droplet.state).to eq('STAGED')
             expect(build.droplet.docker_receipt_image).to eq('some-fake-image:tag')
             expect(build.droplet.process_types).to eq({ 'foo' => 'foo start', 'bar' => 'bar start' })
           end

spec/unit/lib/cloud_controller/kpack/stager_spec.rb

@@ -63,7 +63,6 @@ module Kpack
     before do
       allow(CloudController::DependencyLocator.instance).to receive(:k8s_api_client).and_return(client)
       allow(CloudController::DependencyLocator.instance).to receive(:blobstore_url_generator).and_return(blobstore_url_generator)
-
       allow(client).to receive(:get_image).and_return(nil)
       allow(client).to receive(:get_custom_builder).and_return(default_builder_obj)
     end
@@ -87,8 +86,11 @@ module Kpack
       let(:package) do
         VCAP::CloudController::PackageModel.make(app: VCAP::CloudController::AppModel.make(:kpack))
       end
-      let(:build) { VCAP::CloudController::BuildModel.make(:kpack) }
-
+      let!(:build) { VCAP::CloudController::BuildModel.make(:kpack) }
+      let!(:droplet) { VCAP::CloudController::DropletModel.make(:docker, app: package.app) }
+      before do
+        allow_any_instance_of(VCAP::CloudController::DropletCreate).to receive(:create_docker_droplet).with(build).and_return(droplet)
+      end
       it 'checks if the image exists' do
         allow(client).to receive(:create_image)
         expect(client).to receive(:get_image).with(package.app.guid, 'namespace').and_return(nil)
@@ -103,6 +105,7 @@ module Kpack
             name: package.app.guid,
             namespace: 'namespace',
             labels: {
+              Stager::DROPLET_GUID_LABEL_KEY => droplet.guid,
               Stager::APP_GUID_LABEL_KEY => package.app.guid,
               Stager::BUILD_GUID_LABEL_KEY => build.guid,
               Stager::STAGING_SOURCE_LABEL_KEY => 'STG',