Add unique foreign keys to Geo registries

We need to prevent duplicates for the registries

ee/changelogs/unreleased/296928-geo-add-unique-constraint-to-registry-foreign-keys.yml

+---
+title: 'Geo: Add unique constraints to container repository and terraform state registries'
+merge_request: 54841
+author:
+type: fixed

ee/db/geo/post_migrate/20210217020154_add_unique_index_on_container_repository_registry.rb

+# frozen_string_literal: true
+
+class AddUniqueIndexOnContainerRepositoryRegistry < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  OLD_INDEX_NAME = 'index_container_repository_registry_on_repository_id'
+  NEW_INDEX_NAME = 'index_container_repository_registry_repository_id_unique'
+
+  disable_ddl_transaction!
+
+  def up
+    # Removing duplicated records that would prevent creating an unique index.
+    execute <<-SQL
+      DELETE FROM container_repository_registry
+      USING (
+        SELECT container_repository_id, MIN(id) as min_id
+        FROM container_repository_registry
+        GROUP BY container_repository_id
+        HAVING COUNT(id) > 1
+      ) as container_repository_registry_duplicates
+      WHERE container_repository_registry_duplicates.container_repository_id = container_repository_registry.container_repository_id
+      AND container_repository_registry_duplicates.min_id <> container_repository_registry.id
+    SQL
+
+    add_concurrent_index(:container_repository_registry,
+                         :container_repository_id,
+                         unique: true,
+                         name: NEW_INDEX_NAME)
+
+    remove_concurrent_index_by_name :container_repository_registry, OLD_INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index(:container_repository_registry,
+                         :container_repository_id,
+                         name: OLD_INDEX_NAME)
+
+    remove_concurrent_index_by_name :container_repository_registry, NEW_INDEX_NAME
+  end
+end

ee/db/geo/post_migrate/20210217020156_add_unique_index_on_terraform_state_version_registry.rb

+# frozen_string_literal: true
+
+class AddUniqueIndexOnTerraformStateVersionRegistry < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  OLD_INDEX_NAME = 'index_tf_state_versions_registry_on_tf_state_versions_id'
+  NEW_INDEX_NAME = 'index_tf_state_versions_registry_tf_state_versions_id_unique'
+
+  disable_ddl_transaction!
+
+  def up
+    # Removing duplicated records that would prevent creating an unique index.
+    execute <<-SQL
+      DELETE FROM terraform_state_version_registry
+      USING (
+        SELECT terraform_state_version_id, MIN(id) as min_id
+        FROM terraform_state_version_registry
+        GROUP BY terraform_state_version_id
+        HAVING COUNT(id) > 1
+      ) as terraform_state_version_registry_duplicates
+      WHERE terraform_state_version_registry_duplicates.terraform_state_version_id = terraform_state_version_registry.terraform_state_version_id
+      AND terraform_state_version_registry_duplicates.min_id <> terraform_state_version_registry.id
+    SQL
+
+    add_concurrent_index(:terraform_state_version_registry,
+                         :terraform_state_version_id,
+                         unique: true,
+                         name: NEW_INDEX_NAME)
+
+    remove_concurrent_index_by_name :terraform_state_version_registry, OLD_INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index(:terraform_state_version_registry,
+                         :terraform_state_version_id,
+                         name: OLD_INDEX_NAME)
+
+    remove_concurrent_index_by_name :terraform_state_version_registry, NEW_INDEX_NAME
+  end
+end

ee/db/geo/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2021_02_08_175408) do
+ActiveRecord::Schema.define(version: 2021_02_17_020156) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -23,7 +23,7 @@ ActiveRecord::Schema.define(version: 2021_02_08_175408) do
     t.datetime "retry_at"
     t.datetime "last_synced_at"
     t.datetime "created_at", null: false
-    t.index ["container_repository_id"], name: "index_container_repository_registry_on_repository_id"
+    t.index ["container_repository_id"], name: "index_container_repository_registry_repository_id_unique", unique: true
     t.index ["retry_at"], name: "index_container_repository_registry_on_retry_at"
     t.index ["state"], name: "index_container_repository_registry_on_state"
   end
@@ -217,7 +217,7 @@ ActiveRecord::Schema.define(version: 2021_02_08_175408) do
     t.text "last_sync_failure"
     t.index ["retry_at"], name: "index_terraform_state_version_registry_on_retry_at"
     t.index ["state"], name: "index_terraform_state_version_registry_on_state"
-    t.index ["terraform_state_version_id"], name: "index_tf_state_versions_registry_on_tf_state_versions_id"
+    t.index ["terraform_state_version_id"], name: "index_tf_state_versions_registry_tf_state_versions_id_unique", unique: true
   end
 
 end

ee/spec/factories/geo/container_repository_registry.rb

@@ -24,5 +24,9 @@ FactoryBot.define do
       last_synced_at { 1.day.ago }
       retry_count { 0 }
     end
+
+    trait :with_repository_id do
+      sequence(:container_repository_id)
+    end
   end
 end

ee/spec/models/geo/container_repository_registry_spec.rb

@@ -6,7 +6,7 @@ RSpec.describe Geo::ContainerRepositoryRegistry, :geo do
   include ::EE::GeoHelpers
 
   it_behaves_like 'a BulkInsertSafe model', Geo::ContainerRepositoryRegistry do
-    let(:valid_items_for_bulk_insertion) { build_list(:container_repository_registry, 10, container_repository: create(:container_repository), created_at: Time.zone.now) }
+    let(:valid_items_for_bulk_insertion) { build_list(:container_repository_registry, 10, :with_repository_id, created_at: Time.zone.now) }
     let(:invalid_items_for_bulk_insertion) { [] } # class does not have any validations defined
   end