Improve backend structure of data

app/controllers/projects/clusters/applications_controller.rb

+class Projects::Clusters::ApplicationsController < Projects::ApplicationController
+  before_action :cluster
+  before_action :application_class, only: [:create]
+  before_action :authorize_read_cluster!
+  before_action :authorize_create_cluster!, only: [:create]
+
+  def new
+  end
+
+  def create
+    return render_404 if application
+
+    new_application = application_class.create(cluster: cluster)
+
+    respond_to do |format|
+      format.json do
+        if new_application.persisted?
+          head :ok
+        else
+          head :bad_request
+        end
+      end
+    end
+  end
+
+  private
+
+  def cluster
+    @cluster ||= project.clusters.find_by(cluster_id: params[:cluster_id]).present(current_user: current_user)
+  end
+
+  def application_class
+    Clusters::Cluster::Applications.find(params[:application])
+  end
+
+  def application
+    application_class.find_by(cluster: cluster)
+  end
+end

app/models/clusters/kubernetes/helm_app.rb → app/models/clusters/applications/helm.rb

 module Clusters
-  module Kubernetes
-    class HelmApp < ActiveRecord::Base
+  module Applications
+    class Helm < ActiveRecord::Base
+      self.table_name = 'clusters_applications_helm'
+
       NAME = 'helm'.freeze
 
       include ::Clusters::Concerns::AppStatus
-      belongs_to :kubernetes_service, class_name: 'KubernetesService', foreign_key: :service_id
 
-      default_value_for :version, Gitlab::Clusters::Helm::HELM_VERSION
+      belongs_to :cluser, class_name: 'Clusters::Cluster', foreign_key: :cluster_id
 
-      alias_method :cluster, :kubernetes_service
+      default_value_for :version, Gitlab::Clusters::Helm::HELM_VERSION
 
       def name
         NAME

app/models/clusters/cluster.rb

@@ -4,6 +4,10 @@ module Clusters
 
     self.table_name = 'clusters'
 
+    APPLICATIONS = {
+      Clusters::Applications::Helm::NAME => Clusters::Applications::Helm
+    }
+
     belongs_to :user
 
     has_many :cluster_projects, class_name: 'Clusters::Project'
@@ -15,13 +19,14 @@ module Clusters
     # We have to ":destroy" it today to ensure that we clean also the Kubernetes Integration
     has_one :platform_kubernetes, class_name: 'Clusters::Platforms::Kubernetes', autosave: true, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
 
+    has_one :application_helm, class_name: 'Clusters::Applications::Helm'
+
     accepts_nested_attributes_for :provider_gcp, update_only: true
     accepts_nested_attributes_for :platform_kubernetes, update_only: true
 
     validates :name, cluster_name: true
     validate :restrict_modification, on: :update
 
-    delegate :status, to: :provider, allow_nil: true
     delegate :status_reason, to: :provider, allow_nil: true
     delegate :status_name, to: :provider, allow_nil: true
     delegate :on_creation?, to: :provider, allow_nil: true
@@ -38,6 +43,14 @@ module Clusters
     scope :enabled, -> { where(enabled: true) }
     scope :disabled, -> { where(enabled: false) }
 
+    def status_name
+      if provider
+        provider.status_name
+      else
+        :created
+      end
+    end
+
     def provider
       return provider_gcp if gcp?
     end
@@ -53,6 +66,10 @@ module Clusters
     end
     alias_method :project, :first_project
 
+    def kubeclient
+      platform_kubernetes.kubeclient if kubernetes?
+    end
+
     private
 
     def restrict_modification

app/models/clusters/kubernetes.rb

-module Clusters
-  module Kubernetes
-    def self.table_name_prefix
-      'clusters_kubernetes_'
-    end
-
-    def self.app(app_name)
-      case app_name
-      when HelmApp::NAME
-        HelmApp
-      else
-        raise ArgumentError, "Unknown app #{app_name}"
-      end
-    end
-  end
-end

app/models/clusters/platforms/kubernetes.rb

@@ -60,6 +60,10 @@ module Clusters
         self.class.namespace_for_project(project) if project
       end
 
+      def kubeclient
+        @kubeclient ||= kubernetes_service.kubeclient if manages_kubernetes_service?
+      end
+
       private
 
       def enforce_namespace_to_lower_case

app/models/project.rb

@@ -189,6 +189,7 @@ class Project < ActiveRecord::Base
 
   has_one :cluster_project, class_name: 'Clusters::Project'
   has_one :cluster, through: :cluster_project, class_name: 'Clusters::Cluster'
+  has_many :clusters, through: :cluster_project, class_name: 'Clusters::Cluster'
 
   # Container repositories need to remove data from the container registry,
   # which is not managed by the DB. Hence we're still using dependent: :destroy

app/models/project_services/kubernetes_service.rb

@@ -3,8 +3,6 @@ class KubernetesService < DeploymentService
   include Gitlab::Kubernetes
   include ReactiveCaching
 
-  has_one :helm_app, class_name: 'Clusters::Kubernetes::HelmApp', foreign_key: :service_id
-
   self.reactive_cache_key = ->(service) { [service.class.model_name.singular, service.project_id] }
 
   # Namespace defaults to the project path, but can be overridden in case that
@@ -138,8 +136,8 @@ class KubernetesService < DeploymentService
     { pods: read_pods }
   end
 
-  def helm
-    Gitlab::Clusters::Helm.new(build_kubeclient!)
+  def kubeclient
+    @kubeclient ||= build_kubeclient!
   end
 
   TEMPLATE_PLACEHOLDER = 'Kubernetes namespace'.freeze

app/presenters/clusters/cluster_presenter.rb

@@ -5,5 +5,11 @@ module Clusters
     def gke_cluster_url
       "https://console.cloud.google.com/kubernetes/clusters/details/#{provider.zone}/#{name}" if gcp?
     end
+
+    def applications
+      Clusters::Cluster::APPLICATIONS.map do |key, value|
+        value.find_by(cluster_id: id)
+      end.compact
+    end
   end
 end

app/serializers/cluster_app_entity.rb

+class ClusterAppEntity < Grape::Entity
+  expose :name
+  expose :status_name, as: :status
+  expose :status_reason
+end

app/serializers/cluster_entity.rb

@@ -3,16 +3,5 @@ class ClusterEntity < Grape::Entity
 
   expose :status_name, as: :status
   expose :status_reason
-  expose :applications do |cluster, options|
-    if cluster.created?
-      {
-        helm: { status: 'installed' },
-        ingress: { status: 'error', status_reason: 'Missing namespace' },
-        runner: { status: 'installing' },
-        prometheus: { status: 'installable' }
-      }
-    else
-      {}
-    end
-  end
+  expose :applications, using: ClusterAppEntity
 end

app/services/clusters/base_helm_service.rb

@@ -8,10 +8,16 @@ module Clusters
 
     protected
 
-    def helm
-      return @helm if defined?(@helm)
+    def cluster
+      app.cluster
+    end
+
+    def kubeclient
+      cluster.kubeclient
+    end
 
-      @helm = @app.cluster.helm
+    def helm_api
+      @helm ||= Gitlab::Clusters::Helm.new(kubeclient)
     end
   end
 end

app/services/clusters/fetch_app_installation_status_service.rb

@@ -3,8 +3,8 @@ module Clusters
     def execute
       return unless app.installing?
 
-      phase = helm.installation_status(app)
-      log = helm.installation_log(app) if phase == 'Failed'
+      phase = helm_api.installation_status(app)
+      log = helm_api.installation_log(app) if phase == 'Failed'
       yield(phase, log) if block_given?
     rescue KubeException => ke
       app.make_errored!("Kubernetes error: #{ke.message}") unless app.errored?

app/services/clusters/finalize_app_installation_service.rb

 module Clusters
   class FinalizeAppInstallationService < BaseHelmService
     def execute
-      helm.delete_installation_pod!(app)
+      helm_api.delete_installation_pod!(app)
 
       app.make_errored!('Installation aborted') if aborted?
     end

app/services/clusters/install_app_service.rb

@@ -4,14 +4,14 @@ module Clusters
       return unless app.scheduled?
 
       begin
-        helm.install(app)
+        helm_api.install(app)
+
         if app.make_installing
           ClusterWaitForAppInstallationWorker.perform_in(
             ClusterWaitForAppInstallationWorker::INITIAL_INTERVAL, app.name, app.id)
         else
           app.make_errored!("Failed to update app record; #{app.errors}")
         end
-
       rescue KubeException => ke
         app.make_errored!("Kubernetes error: #{ke.message}")
       rescue StandardError => e

app/workers/concerns/cluster_app.rb

@@ -3,8 +3,9 @@ module ClusterApp
 
   included do
     def find_app(app_name, id)
-      app = Clusters::Kubernetes.app(app_name).find(id)
-      yield(app) if block_given?
+      Clusters::Applications.const_get(app_name.classify).find(id).try do |app|
+        yield(app) if block_given?
+      end
     end
   end
 end

config/routes/project.rb

@@ -190,6 +190,10 @@ constraints(ProjectUrlConstrainer.new) do
 
         member do
           get :status, format: :json
+
+          scope '*application' do
+            resource :applications, only: [:create]
+          end
         end
       end
 

db/migrate/20171031100710_create_clusters_kubernetes_helm_apps.rb

 class CreateClustersKubernetesHelmApps < ActiveRecord::Migration
   def change
-    create_table :clusters_kubernetes_helm_apps do |t|
-      t.integer :status, null: false
+    create_table :clusters_applications_helm do |t|
+      t.references :cluster, null: false, unique: true, foreign_key: { on_delete: :cascade }
 
       t.datetime_with_timezone :created_at, null: false
       t.datetime_with_timezone :updated_at, null: false
-
-      t.references :service, index: true, null: false, foreign_key: { on_delete: :cascade }
+      
+      t.integer :status, null: false
       t.string :version, null: false
       t.text :status_reason
     end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20171017145932) do
+ActiveRecord::Schema.define(version: 20171031100710) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -464,9 +464,7 @@ ActiveRecord::Schema.define(version: 20171017145932) do
 
   create_table "cluster_platforms_kubernetes", force: :cascade do |t|
     t.integer "cluster_id", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.text "api_url"
+    t.string "api_url"
     t.text "ca_cert"
     t.string "namespace"
     t.string "username"
@@ -474,6 +472,8 @@ ActiveRecord::Schema.define(version: 20171017145932) do
     t.string "encrypted_password_iv"
     t.text "encrypted_token"
     t.string "encrypted_token_iv"
+    t.datetime_with_timezone "created_at", null: false
+    t.datetime_with_timezone "updated_at", null: false
   end
 
   add_index "cluster_platforms_kubernetes", ["cluster_id"], name: "index_cluster_platforms_kubernetes_on_cluster_id", unique: true, using: :btree
@@ -491,33 +491,39 @@ ActiveRecord::Schema.define(version: 20171017145932) do
   create_table "cluster_providers_gcp", force: :cascade do |t|
     t.integer "cluster_id", null: false
     t.integer "status"
-    t.integer "num_nodes", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
     t.text "status_reason"
     t.string "gcp_project_id", null: false
     t.string "zone", null: false
+    t.integer "num_nodes", null: false
     t.string "machine_type"
     t.string "operation_id"
     t.string "endpoint"
     t.text "encrypted_access_token"
     t.string "encrypted_access_token_iv"
+    t.datetime_with_timezone "created_at", null: false
+    t.datetime_with_timezone "updated_at", null: false
   end
 
   add_index "cluster_providers_gcp", ["cluster_id"], name: "index_cluster_providers_gcp_on_cluster_id", unique: true, using: :btree
 
   create_table "clusters", force: :cascade do |t|
-    t.integer "user_id", null: false
-    t.integer "provider_type"
-    t.integer "platform_type"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
+    t.integer "user_id"
     t.boolean "enabled", default: true
     t.string "name", null: false
+    t.integer "provider_type"
+    t.integer "platform_type"
+    t.datetime_with_timezone "created_at", null: false
+    t.datetime_with_timezone "updated_at", null: false
   end
 
-  add_index "clusters", ["enabled"], name: "index_clusters_on_enabled", using: :btree
-  add_index "clusters", ["user_id"], name: "index_clusters_on_user_id", using: :btree
+  create_table "clusters_applications_helm", force: :cascade do |t|
+    t.integer "cluster_id", null: false
+    t.datetime_with_timezone "created_at", null: false
+    t.datetime_with_timezone "updated_at", null: false
+    t.integer "status", null: false
+    t.string "version", null: false
+    t.text "status_reason"
+  end
 
   create_table "container_repositories", force: :cascade do |t|
     t.integer "project_id", null: false
@@ -1872,6 +1878,7 @@ ActiveRecord::Schema.define(version: 20171017145932) do
   add_foreign_key "cluster_projects", "projects", on_delete: :cascade
   add_foreign_key "cluster_providers_gcp", "clusters", on_delete: :cascade
   add_foreign_key "clusters", "users", on_delete: :nullify
+  add_foreign_key "clusters_applications_helm", "clusters", on_delete: :cascade
   add_foreign_key "container_repositories", "projects"
   add_foreign_key "deploy_keys_projects", "projects", name: "fk_58a901ca7e", on_delete: :cascade
   add_foreign_key "deployments", "projects", name: "fk_b9a3851b82", on_delete: :cascade

spec/models/clusters/kubernetes/helm_app_spec.rb

 require 'rails_helper'
 require_relative '../kubernetes_spec'
 
-RSpec.describe Clusters::Kubernetes::HelmApp, type: :model do
+RSpec.describe Clusters::Applications::Helm, type: :model do
   it_behaves_like 'a registered kubernetes app'
 
   it { is_expected.to belong_to(:kubernetes_service) }

spec/models/clusters/kubernetes_spec.rb

-require 'rails_helper'
-
-RSpec.shared_examples 'a registered kubernetes app' do
-  let(:name) { described_class::NAME }
-
-  it 'can be retrieved with Clusters::Kubernetes.app' do
-    expect(Clusters::Kubernetes.app(name)).to eq(described_class)
-  end
-end

spec/models/project_services/kubernetes_service_spec.rb

@@ -9,7 +9,6 @@ describe KubernetesService, :use_clean_rails_memory_store_caching do
 
   describe 'Associations' do
     it { is_expected.to belong_to :project }
-    it { is_expected.to have_one(:helm_app) }
   end
 
   describe 'Validations' do