Update PagesDomains data model for serverless domains

- Add `usage` enum to distinguish between serverless and pages domains
- Replace unique index on `domain` with unique index on
  `[domain, wildcard]` so that the wildcard and non-wildcard variants of
  a domain can coexist
- Rename `domain_type` to `scope` to be more semantic

app/models/pages_domain.rb

@@ -6,7 +6,8 @@ class PagesDomain < ApplicationRecord
   SSL_RENEWAL_THRESHOLD = 30.days.freeze
 
   enum certificate_source: { user_provided: 0, gitlab_provided: 1 }, _prefix: :certificate
-  enum domain_type: { instance: 0, group: 1, project: 2 }, _prefix: :domain_type
+  enum scope: { instance: 0, group: 1, project: 2 }, _prefix: :scope
+  enum usage: { pages: 0, serverless: 1 }, _prefix: :usage
 
   belongs_to :project
   has_many :acme_orders, class_name: "PagesDomainAcmeOrder"
@@ -26,8 +27,9 @@ class PagesDomain < ApplicationRecord
   validate :validate_intermediates, if: ->(domain) { domain.certificate.present? && domain.certificate_changed? }
 
   default_value_for(:auto_ssl_enabled, allow_nil: false) { ::Gitlab::LetsEncrypt.enabled? }
-  default_value_for :domain_type, allow_nil: false, value: :project
+  default_value_for :scope, allow_nil: false, value: :project
   default_value_for :wildcard, allow_nil: false, value: false
+  default_value_for :usage, allow_nil: false, value: :pages
 
   attr_encrypted :key,
     mode: :per_attribute_iv_and_salt,
@@ -220,7 +222,7 @@ class PagesDomain < ApplicationRecord
 
   # rubocop: disable CodeReuse/ServiceClass
   def update_daemon
-    return if domain_type_instance?
+    return if usage_serverless?
 
     ::Projects::UpdatePagesConfigurationService.new(project).execute
   end

changelogs/unreleased/ali-add-type-to-pages-domains.yml

+---
+title: Update PagesDomains data model for serverless domains
+merge_request: 23943
+author:
+type: changed

db/migrate/20200128184209_add_usage_to_pages_domains.rb

+# frozen_string_literal: true
+
+class AddUsageToPagesDomains < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  PAGES_USAGE = 0
+
+  disable_ddl_transaction!
+
+  def up
+    add_column_with_default :pages_domains, :usage, :integer, limit: 2, default: PAGES_USAGE, allow_null: false # rubocop:disable Migration/AddColumnWithDefault
+  end
+
+  def down
+    remove_column :pages_domains, :usage
+  end
+end

db/migrate/20200129034515_update_indexes_of_pages_domains_add_usage_domain_wildcard_remove_domain.rb

+# frozen_string_literal: true
+
+class UpdateIndexesOfPagesDomainsAddUsageDomainWildcardRemoveDomain < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :pages_domains, :usage
+    add_concurrent_index :pages_domains, [:domain, :wildcard], unique: true
+    remove_concurrent_index :pages_domains, :domain
+  end
+
+  def down
+    remove_concurrent_index :pages_domains, :usage
+    remove_concurrent_index :pages_domains, [:domain, :wildcard]
+    add_concurrent_index :pages_domains, :domain, unique: true
+  end
+end

db/migrate/20200129035446_rename_pages_domains_domain_type_to_scope.rb

+# frozen_string_literal: true
+
+class RenamePagesDomainsDomainTypeToScope < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    rename_column_concurrently :pages_domains, :domain_type, :scope
+  end
+
+  def down
+    undo_rename_column_concurrently :pages_domains, :domain_type, :scope
+  end
+end

db/post_migrate/20200129035708_cleanup_rename_pages_domains_domain_type_to_scope.rb

+# frozen_string_literal: true
+
+class CleanupRenamePagesDomainsDomainTypeToScope < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    cleanup_concurrent_column_rename :pages_domains, :domain_type, :scope
+  end
+
+  def down
+    undo_cleanup_concurrent_column_rename :pages_domains, :domain_type, :scope
+  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_01_27_090233) do
+ActiveRecord::Schema.define(version: 2020_01_29_035708) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -3018,13 +3018,15 @@ ActiveRecord::Schema.define(version: 2020_01_27_090233) do
     t.datetime_with_timezone "certificate_valid_not_after"
     t.integer "certificate_source", limit: 2, default: 0, null: false
     t.boolean "wildcard", default: false, null: false
-    t.integer "domain_type", limit: 2, default: 2, null: false
+    t.integer "usage", limit: 2, default: 0, null: false
+    t.integer "scope", limit: 2, default: 2, null: false
     t.index ["certificate_source", "certificate_valid_not_after"], name: "index_pages_domains_need_auto_ssl_renewal", where: "(auto_ssl_enabled = true)"
-    t.index ["domain"], name: "index_pages_domains_on_domain", unique: true
-    t.index ["domain_type"], name: "index_pages_domains_on_domain_type"
+    t.index ["domain", "wildcard"], name: "index_pages_domains_on_domain_and_wildcard", unique: true
     t.index ["project_id", "enabled_until"], name: "index_pages_domains_on_project_id_and_enabled_until"
     t.index ["project_id"], name: "index_pages_domains_on_project_id"
     t.index ["remove_at"], name: "index_pages_domains_on_remove_at"
+    t.index ["scope"], name: "index_pages_domains_on_scope"
+    t.index ["usage"], name: "index_pages_domains_on_usage"
     t.index ["verified_at", "enabled_until"], name: "index_pages_domains_on_verified_at_and_enabled_until"
     t.index ["verified_at"], name: "index_pages_domains_on_verified_at"
     t.index ["wildcard"], name: "index_pages_domains_on_wildcard"

spec/factories/pages_domains.rb

@@ -377,7 +377,8 @@ x6zG6WoibsbsJMj70nwseUnPTBQNDP+j61RJjC/r
 
     trait :instance_serverless do
       wildcard { true }
-      domain_type { :instance }
+      scope { :instance }
+      usage { :serverless }
     end
   end
 end

spec/models/pages_domain_spec.rb

@@ -180,8 +180,12 @@ describe PagesDomain do
       expect(subject.wildcard).to eq(false)
     end
 
-    it 'defaults domain_type to project' do
-      expect(subject.domain_type).to eq('project')
+    it 'defaults scope to project' do
+      expect(subject.scope).to eq('project')
+    end
+
+    it 'defaults usage to pages' do
+      expect(subject.usage).to eq('pages')
     end
   end
 
@@ -315,11 +319,11 @@ describe PagesDomain do
   end
 
   describe '#update_daemon' do
-    context 'when domain_type is instance' do
-      it 'does nothing' do
+    context 'when usage is serverless' do
+      it 'does not call the UpdatePagesConfigurationService' do
         expect(Projects::UpdatePagesConfigurationService).not_to receive(:new)
 
-        create(:pages_domain, domain_type: :instance)
+        create(:pages_domain, usage: :serverless)
       end
     end