Allow droplet image to be updated.

- Allow droplet image to be updated if droplet has a docker lifecycle
and if the droplet has already been staged. This lays the groundwork for
the image controller to be able to patch a droplet with a rebased image reference.

[#172542372]
Co-authored-by: Piyali Banerjee <pbanerjee@pivotal.io>
Co-authored-by: Nat Bennett <nbennett@pivotal.io>

Author: piyalibanerjee

app/actions/droplet_update.rb

@@ -1,11 +1,19 @@
 module VCAP::CloudController
   class DropletUpdate
-    class Error < ::StandardError
-    end
+    class Error < ::StandardError; end
+    class InvalidDroplet < StandardError; end
 
     def update(droplet, message)
       droplet.db.transaction do
         droplet.lock!
+
+        if message.requested?(:image)
+          raise InvalidDroplet.new('Droplet image cannot be updated during staging') if droplet.staging?
+          raise InvalidDroplet.new('Images can only be updated for docker droplets') unless droplet.docker?
+
+          droplet.docker_receipt_image = message.image
+        end
+
         LabelsUpdate.update(droplet, message.labels, DropletLabelModel)
         AnnotationsUpdate.update(droplet, message.annotations, DropletAnnotationModel)
         droplet.save

app/messages/droplet_update_message.rb

@@ -2,8 +2,9 @@
 
 module VCAP::CloudController
   class DropletUpdateMessage < MetadataBaseMessage
-    register_allowed_keys []
+    register_allowed_keys [:image]
 
+    validates :image, string: true, allow_nil: true
     validates_with NoAdditionalKeysValidator
   end
 end

spec/request/droplets_spec.rb

@@ -1463,5 +1463,39 @@
         }
       )
     end
+
+    context 'when updating the image (on a docker droplet)' do
+      let(:app_model) { VCAP::CloudController::AppModel.make(:docker, space_guid: space.guid, name: 'my-docker-app') }
+      let(:package_model) { VCAP::CloudController::PackageModel.make(app_guid: app_model.guid) }
+      let(:rebased_image_reference) { 'rebased-image-reference' }
+      let!(:og_docker_droplet) do
+        VCAP::CloudController::DropletModel.make(
+          :kpack,
+          state: VCAP::CloudController::DropletModel::STAGED_STATE,
+          app_guid: app_model.guid,
+          package_guid: package_model.guid,
+          droplet_hash: 'shalalala',
+          sha256_checksum: 'droplet-checksum-sha256',
+        )
+      end
+      before do
+        og_docker_droplet.update(docker_receipt_image: 'some-image-reference')
+      end
+      let(:update_request) do
+        {
+          image: rebased_image_reference
+        }
+      end
+      it 'updates the image' do
+        patch "/v3/droplets/#{og_docker_droplet.guid}", update_request.to_json, developer_headers
+        expect(last_response.status).to eq(200), last_response.body
+
+        og_docker_droplet.reload
+        parsed_response = MultiJson.load(last_response.body)
+        expect(parsed_response['image']).to eq(
+          rebased_image_reference
+        )
+      end
+    end
   end
 end

spec/support/fakes/blueprints.rb

@@ -129,6 +129,8 @@ module VCAP::CloudController
     guid { Sham.guid }
     droplet_hash { nil }
     sha256_checksum { nil }
+    docker_receipt_image { nil }
+    app { AppModel.make(:kpack, droplet_guid: guid) }
     state { VCAP::CloudController::DropletModel::STAGED_STATE }
     buildpack_lifecycle_data { nil.tap { |_| object.save } }
   end

spec/unit/actions/droplet_update_spec.rb

@@ -10,49 +10,102 @@ module VCAP::CloudController
     subject(:droplet_update) { DropletUpdate.new }
 
     describe '#update' do
-      let!(:droplet) { DropletModel.make }
-
-      let!(:label) do
-        VCAP::CloudController::DropletLabelModel.make(
-          key_prefix: 'indiana.edu',
-          key_name: 'state',
-          value: 'Indiana',
-          resource_guid: droplet.guid
-        )
-      end
+      context 'buildpack droplet update' do
+        let!(:droplet) { DropletModel.make }
+        let!(:label) do
+          VCAP::CloudController::DropletLabelModel.make(
+            key_prefix: 'indiana.edu',
+            key_name: 'state',
+            value: 'Indiana',
+            resource_guid: droplet.guid
+          )
+        end
 
-      let!(:annotation) do
-        VCAP::CloudController::DropletAnnotationModel.make(
-          key: 'University',
-          value: 'Toronto',
-          resource_guid: droplet.guid
-        )
-      end
+        let!(:annotation) do
+          VCAP::CloudController::DropletAnnotationModel.make(
+            key: 'University',
+            value: 'Toronto',
+            resource_guid: droplet.guid
+          )
+        end
 
-      let(:message) do
-        VCAP::CloudController::DropletUpdateMessage.new({
-          metadata: {
-            labels: {
-              freaky: 'wednesday',
-              'indiana.edu/state' => nil,
-            },
-            annotations: {
-              reason: 'add some more annotations',
+        let(:message) do
+          VCAP::CloudController::DropletUpdateMessage.new({
+            metadata: {
+              labels: {
+                freaky: 'wednesday',
+                'indiana.edu/state' => nil,
+              },
+              annotations: {
+                reason: 'add some more annotations',
+              },
             },
-          },
-        })
-      end
+          })
+        end
+
+        it 'update the droplet record' do
+          expect(message).to be_valid
+          updated_droplet = droplet_update.update(droplet, message)
 
-      it 'update the droplet record' do
-        expect(message).to be_valid
-        updated_droplet = droplet_update.update(droplet, message)
+          expect(updated_droplet.labels.first.key_name).to eq 'freaky'
+          expect(updated_droplet.labels.first.value).to eq 'wednesday'
+          expect(updated_droplet.labels.size).to eq 1
+          expect(updated_droplet.annotations.size).to eq(2)
+          expect(Hash[updated_droplet.annotations.map { |a| [a.key, a.value] }]).
+            to eq({ 'University' => 'Toronto', 'reason' => 'add some more annotations' })
+        end
+        context 'trying to update a buildpack droplet image' do
+          let(:message) do
+            VCAP::CloudController::DropletUpdateMessage.new({
+              image: 'some-image-reference',
+              metadata: {
+                labels: {
+                  freaky: 'wednesday',
+                  'indiana.edu/state' => nil,
+                },
+                annotations: {
+                  reason: 'add some more annotations',
+                },
+              },
+            })
+          end
+          it 'returns an error saying that a buildpack droplet image cannot be updated' do
+            expect(message).to be_valid
+            expect { droplet_update.update(droplet, message)
+            }.to raise_error(DropletUpdate::InvalidDroplet, 'Images can only be updated for docker droplets')
+          end
+        end
+      end
+      context 'docker droplet update' do
+        let!(:docker_droplet) do
+          VCAP::CloudController::DropletModel.make(:kpack)
+        end
 
-        expect(updated_droplet.labels.first.key_name).to eq 'freaky'
-        expect(updated_droplet.labels.first.value).to eq 'wednesday'
-        expect(updated_droplet.labels.size).to eq 1
-        expect(updated_droplet.annotations.size).to eq(2)
-        expect(Hash[updated_droplet.annotations.map { |a| [a.key, a.value] }]).
-          to eq({ 'University' => 'Toronto', 'reason' => 'add some more annotations' })
+        let(:message) do
+          VCAP::CloudController::DropletUpdateMessage.new({
+            image: 'new-image-reference'
+          })
+        end
+        context 'the image of a staged docker droplet is requested to be updated' do
+          before do
+            docker_droplet.update(docker_receipt_image: 'some-image-reference')
+          end
+          it 'updates the droplet record with new image reference' do
+            expect(message).to be_valid
+            updated_droplet = droplet_update.update(docker_droplet, message)
+            expect(updated_droplet.docker_receipt_image).to eq 'new-image-reference'
+          end
+        end
+        context 'the image of a staging docker droplet is requested to be updated' do
+          before do
+            docker_droplet.update(state: VCAP::CloudController::DropletModel::STAGING_STATE)
+          end
+          it 'returns an error saying that a droplet update cannot occur during staging' do
+            expect(message).to be_valid
+            expect { droplet_update.update(docker_droplet, message)
+            }.to raise_error(DropletUpdate::InvalidDroplet, 'Droplet image cannot be updated during staging')
+          end
+        end
       end
     end
   end

spec/unit/messages/droplet_update_message_spec.rb

@@ -5,6 +5,7 @@ module VCAP::CloudController
   RSpec.describe DropletUpdateMessage do
     let(:body) do
       {
+        'image' => 'some-image-reference',
         'metadata' => {
           'labels' => {
             'potatoes' => 'taterTots'
@@ -17,6 +18,7 @@ module VCAP::CloudController
       it 'can parse labels and annotations' do
         params =
           {
+            "image": 'new-image-reference',
             "metadata": {
               "labels": {
                 "potato": 'mashed'
@@ -30,6 +32,7 @@ module VCAP::CloudController
         expect(message).to be_valid
         expect(message.labels).to include("potato": 'mashed')
         expect(message.annotations).to include("eating": 'potatoes')
+        expect(message.image).to eq('new-image-reference')
       end
 
       it 'validates both bad labels and bad annotations' do
@@ -43,6 +46,15 @@ module VCAP::CloudController
         expect(message).not_to be_valid
         expect(message.errors_on(:metadata)).to match_array(["'annotations' is not an object", "'labels' is not an object"])
       end
+
+      it 'validates bad image references' do
+        params = {
+          "image": { 'blah': 34234 }
+        }
+        message = DropletUpdateMessage.new(params)
+        expect(message).not_to be_valid
+        expect(message.errors_on(:image)).to match_array(['must be a string'])
+      end
     end
   end
 end