Create and write to deployment_clusters table

Creates a table "deployment_clusters" to expand the cluster-related
deployment details from just cluster_id to include kubernetes namespaces
as well, and adds double writes to this table. In the next
release, we can then copy the remaining data over, start reading
exclusively from deployment_clusters, and add an ignore for
deployments.cluster_id

Storing the namespace used is important for accurate deploy boards,
because Environment#deployment_namespace is the namespace for the *next*
deployment, and this can change as cluster configuration changes.

app/models/clusters/cluster.rb

@@ -31,6 +31,7 @@ module Clusters
     has_many :cluster_projects, class_name: 'Clusters::Project'
     has_many :projects, through: :cluster_projects, class_name: '::Project'
     has_one :cluster_project, -> { order(id: :desc) }, class_name: 'Clusters::Project'
+    has_many :deployment_clusters
 
     has_many :cluster_groups, class_name: 'Clusters::Group'
     has_many :groups, through: :cluster_groups, class_name: '::Group'

app/models/deployment.rb

@@ -18,6 +18,8 @@ class Deployment < ApplicationRecord
   has_many :merge_requests,
     through: :deployment_merge_requests
 
+  has_one :deployment_cluster
+
   has_internal_id :iid, scope: :project, track_if: -> { !importing? }, init: ->(s) do
     Deployment.where(project: s.project).maximum(:iid) if s&.project
   end

app/models/deployment_cluster.rb

+# frozen_string_literal: true
+
+class DeploymentCluster < ApplicationRecord
+  belongs_to :deployment, optional: false
+  belongs_to :cluster, optional: false, class_name: 'Clusters::Cluster'
+end

db/migrate/20200207151640_create_deployment_clusters.rb

+# frozen_string_literal: true
+
+class CreateDeploymentClusters < ActiveRecord::Migration[6.0]
+  DOWNTIME = false
+
+  def change
+    create_table :deployment_clusters, id: false, force: :cascade do |t|
+      t.references :deployment, foreign_key: { on_delete: :cascade }, primary_key: true, type: :integer, index: false, default: nil
+      t.references :cluster, foreign_key: { on_delete: :cascade }, type: :integer, index: false, null: false
+      t.string :kubernetes_namespace, limit: 255
+
+      t.index [:cluster_id, :kubernetes_namespace], name: 'idx_deployment_clusters_on_cluster_id_and_kubernetes_namespace'
+      t.index [:cluster_id, :deployment_id], unique: true
+    end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_02_06_111847) do
+ActiveRecord::Schema.define(version: 2020_02_07_151640) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -1340,6 +1340,13 @@ ActiveRecord::Schema.define(version: 2020_02_06_111847) do
     t.index ["token_encrypted"], name: "index_deploy_tokens_on_token_encrypted", unique: true
   end
 
+  create_table "deployment_clusters", primary_key: "deployment_id", id: :integer, default: nil, force: :cascade do |t|
+    t.integer "cluster_id", null: false
+    t.string "kubernetes_namespace", limit: 255
+    t.index ["cluster_id", "deployment_id"], name: "index_deployment_clusters_on_cluster_id_and_deployment_id", unique: true
+    t.index ["cluster_id", "kubernetes_namespace"], name: "idx_deployment_clusters_on_cluster_id_and_kubernetes_namespace"
+  end
+
   create_table "deployment_merge_requests", id: false, force: :cascade do |t|
     t.integer "deployment_id", null: false
     t.integer "merge_request_id", null: false
@@ -3744,7 +3751,7 @@ ActiveRecord::Schema.define(version: 2020_02_06_111847) do
     t.string "sso_url", null: false
     t.boolean "enforced_sso", default: false, null: false
     t.boolean "enforced_group_managed_accounts", default: false, null: false
-    t.boolean "prohibited_outer_forks", default: false, null: false
+    t.boolean "prohibited_outer_forks", default: false
     t.index ["group_id"], name: "index_saml_providers_on_group_id"
   end
 
@@ -4659,6 +4666,8 @@ ActiveRecord::Schema.define(version: 2020_02_06_111847) do
   add_foreign_key "dependency_proxy_blobs", "namespaces", column: "group_id", on_delete: :cascade
   add_foreign_key "dependency_proxy_group_settings", "namespaces", column: "group_id", on_delete: :cascade
   add_foreign_key "deploy_keys_projects", "projects", name: "fk_58a901ca7e", on_delete: :cascade
+  add_foreign_key "deployment_clusters", "clusters", on_delete: :cascade
+  add_foreign_key "deployment_clusters", "deployments", on_delete: :cascade
   add_foreign_key "deployment_merge_requests", "deployments", on_delete: :cascade
   add_foreign_key "deployment_merge_requests", "merge_requests", on_delete: :cascade
   add_foreign_key "deployments", "clusters", name: "fk_289bba3222", on_delete: :nullify

lib/gitlab/ci/pipeline/seed/deployment.rb

@@ -24,8 +24,14 @@ module Gitlab
             # non-environment job.
             return unless deployment.valid? && deployment.environment.persisted?
 
-            deployment.cluster_id =
-              deployment.environment.deployment_platform&.cluster_id
+            if cluster_id = deployment.environment.deployment_platform&.cluster_id
+              # double write cluster_id until 12.9: https://gitlab.com/gitlab-org/gitlab/issues/202628
+              deployment.cluster_id = cluster_id
+              deployment.deployment_cluster = ::DeploymentCluster.new(
+                cluster_id: cluster_id,
+                kubernetes_namespace: deployment.environment.deployment_namespace
+              )
+            end
 
             # Allocate IID for deployments.
             # This operation must be outside of transactions of pipeline creations.

spec/lib/gitlab/ci/pipeline/seed/deployment_spec.rb

@@ -33,13 +33,18 @@ describe Gitlab::Ci::Pipeline::Seed::Deployment do
         expect(subject.iid).to be_present
         expect(subject.environment.name).to eq('production')
         expect(subject.cluster).to be_nil
+        expect(subject.deployment_cluster).to be_nil
       end
 
       context 'when environment has deployment platform' do
         let!(:cluster) { create(:cluster, :provided_by_gcp, projects: [project]) }
 
-        it 'returns a deployment with cluster id' do
-          expect(subject.cluster).to eq(cluster)
+        it 'sets the cluster and deployment_cluster' do
+          expect(subject.cluster).to eq(cluster) # until we stop double writing in 12.9: https://gitlab.com/gitlab-org/gitlab/issues/202628
+          expect(subject.deployment_cluster).to have_attributes(
+            cluster_id: cluster.id,
+            kubernetes_namespace: subject.environment.deployment_namespace
+          )
         end
       end
 

spec/models/clusters/cluster_spec.rb

@@ -26,6 +26,7 @@ describe Clusters::Cluster, :use_clean_rails_memory_store_caching do
   it { is_expected.to have_one(:application_runner) }
   it { is_expected.to have_many(:kubernetes_namespaces) }
   it { is_expected.to have_one(:cluster_project) }
+  it { is_expected.to have_many(:deployment_clusters) }
 
   it { is_expected.to delegate_method(:status).to(:provider) }
   it { is_expected.to delegate_method(:status_reason).to(:provider) }

spec/models/deployment_cluster_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe DeploymentCluster do
+  let(:cluster) { create(:cluster) }
+  let(:deployment) { create(:deployment) }
+  let(:kubernetes_namespace) { 'an-example-namespace' }
+
+  subject { described_class.new(deployment: deployment, cluster: cluster, kubernetes_namespace: kubernetes_namespace) }
+
+  it { is_expected.to belong_to(:deployment).required }
+  it { is_expected.to belong_to(:cluster).required }
+
+  it do
+    is_expected.to have_attributes(
+      cluster_id: cluster.id,
+      deployment_id: deployment.id,
+      kubernetes_namespace: kubernetes_namespace
+    )
+  end
+end

spec/models/deployment_spec.rb

@@ -10,6 +10,7 @@ describe Deployment do
   it { is_expected.to belong_to(:cluster).class_name('Clusters::Cluster') }
   it { is_expected.to belong_to(:user) }
   it { is_expected.to belong_to(:deployable) }
+  it { is_expected.to have_one(:deployment_cluster) }
   it { is_expected.to have_many(:deployment_merge_requests) }
   it { is_expected.to have_many(:merge_requests).through(:deployment_merge_requests) }