Delete remote uploads

ObjectStore uploader requires presence of associated `uploads` record
when deleting the upload file (through the carrierwave's after_commit
hook) because we keep info whether file is LOCAL or REMOTE in `upload`
object.

For this reason we can not destroy uploads as "dependent: :destroy" hook
because these would be deleted too soon. Instead we rely on
carrierwave's hook to destroy `uploads` in after_commit hook.

But in before_destroy hook we still have to delete not-mounted uploads
(which don't use carrierwave's destroy hook). This has to be done in
before_Destroy instead of after_commit because `FileUpload` requires
existence of model's object on destroy action.

This is not ideal state of things, in a next step we should investigate
how to unify model dependencies so we can use same workflow for all
uploads.

Related to #45425

app/models/appearance.rb

 class Appearance < ActiveRecord::Base
+  include WithUploads
   include CacheMarkdownField
   include AfterCommitQueue
   include ObjectStorage::BackgroundMove
@@ -14,8 +15,6 @@ class Appearance < ActiveRecord::Base
   mount_uploader :logo,         AttachmentUploader
   mount_uploader :header_logo,  AttachmentUploader
-  has_many :uploads, as: :model, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
-
   CACHE_KEY = "current_appearance:#{Gitlab::VERSION}".freeze
   after_commit :flush_redis_cache

app/models/concerns/with_uploads.rb

+# Mounted uploaders are destroyed by carrierwave's after_commit
+# hook. This hook fetches upload location (local vs remote) from
+# Upload model. So it's neccessary to make sure that during that
+# after_commit hook model's associated uploads are not deleted yet.
+# IOW we can not use denepdent => :destroy :
+# has_many :uploads, as: :model, dependent: :destroy
+#
+# And because not-mounted uploads require presence of upload's
+# object model when destroying them (FileUploader's `build_upload` method
+# references `model` on delete), we can not use after_commit hook for these
+# uploads.
+#
+# Instead FileUploads are destroyed in before_destroy hook and remaining uploads
+# are destroyed by the carrierwave's after_commit hook.
+
+module WithUploads
+  extend ActiveSupport::Concern
+
+  # Currently there is no simple way how to select only not-mounted
+  # uploads, it should be all FileUploaders so we select them by
+  # `uploader` class
+  FILE_UPLOADERS = %w(PersonalFileUploader NamespaceFileUploader FileUploader).freeze
+
+  included do
+    has_many :uploads, as: :model
+
+    before_destroy :destroy_file_uploads
+  end
+
+  # mounted uploads are deleted in carrierwave's after_commit hook,
+  # but FileUploaders which are not mounted must be deleted explicitly and
+  # it can not be done in after_commit because FileUploader requires loads
+  # associated model on destroy (which is already deleted in after_commit)
+  def destroy_file_uploads
+    self.uploads.where(uploader: FILE_UPLOADERS).destroy_all
+  end
+end

app/models/group.rb

@@ -2,6 +2,7 @@ require 'carrierwave/orm/activerecord'
 class Group < Namespace
   include Gitlab::ConfigHelper
+  include WithUploads
   include AfterCommitQueue
   include AccessRequestable
   include Avatarable
@@ -30,8 +31,6 @@ class Group < Namespace
   has_many :variables, class_name: 'Ci::GroupVariable'
   has_many :custom_attributes, class_name: 'GroupCustomAttribute'
-  has_many :uploads, as: :model, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
-
   has_many :boards
   has_many :badges, class_name: 'GroupBadge'

app/models/project.rb

@@ -4,6 +4,7 @@ class Project < ActiveRecord::Base
   include Gitlab::ConfigHelper
   include Gitlab::ShellAdapter
   include Gitlab::VisibilityLevel
+  include WithUploads
   include AccessRequestable
   include Avatarable
   include CacheMarkdownField
@@ -301,8 +302,6 @@ class Project < ActiveRecord::Base
     inclusion: { in: ->(_object) { Gitlab.config.repositories.storages.keys } }
   validates :variables, variable_duplicates: { scope: :environment_scope }
-  has_many :uploads, as: :model, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
-
   # Scopes
   scope :pending_delete, -> { where(pending_delete: true) }
   scope :without_deleted, -> { where(pending_delete: false) }

app/models/user.rb

@@ -3,6 +3,7 @@ require 'carrierwave/orm/activerecord'
 class User < ActiveRecord::Base
   extend Gitlab::ConfigHelper
+  include WithUploads
   include Gitlab::ConfigHelper
   include Gitlab::SQL::Pattern
   include AfterCommitQueue
@@ -137,7 +138,6 @@ class User < ActiveRecord::Base
   has_many :custom_attributes, class_name: 'UserCustomAttribute'
   has_many :callouts, class_name: 'UserCallout'
-  has_many :uploads, as: :model, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
   has_many :term_agreements
   belongs_to :accepted_term, class_name: 'ApplicationSetting::Term'

changelogs/unreleased/jprovazn-remote-upload-destroy.yml

+---
+title: Fix deletion of Object Store uploads
+merge_request:
+author:
+type: fixed

spec/models/appearance_spec.rb

@@ -5,7 +5,7 @@ describe Appearance do
   it { is_expected.to be_valid }
-  it { is_expected.to have_many(:uploads).dependent(:destroy) }
+  it { is_expected.to have_many(:uploads) }
   describe '.current', :use_clean_rails_memory_store_caching do
     let!(:appearance) { create(:appearance) }
@@ -41,4 +41,12 @@ describe Appearance do
       expect(new_row.valid?).to eq(false)
     end
   end
+
+  context 'with uploads' do
+    it_behaves_like 'model with mounted uploader', false do
+      let(:model_object) { create(:appearance, :with_logo) }
+      let(:upload_attribute) { :logo }
+      let(:uploader_class) { AttachmentUploader }
+    end
+  end
 end

spec/models/group_spec.rb

@@ -15,7 +15,7 @@ describe Group do
     it { is_expected.to have_many(:notification_settings).dependent(:destroy) }
     it { is_expected.to have_many(:labels).class_name('GroupLabel') }
     it { is_expected.to have_many(:variables).class_name('Ci::GroupVariable') }
-    it { is_expected.to have_many(:uploads).dependent(:destroy) }
+    it { is_expected.to have_many(:uploads) }
     it { is_expected.to have_one(:chat_team) }
     it { is_expected.to have_many(:custom_attributes).class_name('GroupCustomAttribute') }
     it { is_expected.to have_many(:badges).class_name('GroupBadge') }
@@ -691,4 +691,12 @@ describe Group do
       end
     end
   end
+
+  context 'with uploads' do
+    it_behaves_like 'model with mounted uploader', true do
+      let(:model_object) { create(:group, :with_avatar) }
+      let(:upload_attribute) { :avatar }
+      let(:uploader_class) { AttachmentUploader }
+    end
+  end
 end

spec/models/project_spec.rb

@@ -76,7 +76,7 @@ describe Project do
     it { is_expected.to have_many(:project_group_links) }
     it { is_expected.to have_many(:notification_settings).dependent(:delete_all) }
     it { is_expected.to have_many(:forks).through(:forked_project_links) }
-    it { is_expected.to have_many(:uploads).dependent(:destroy) }
+    it { is_expected.to have_many(:uploads) }
     it { is_expected.to have_many(:pipeline_schedules) }
     it { is_expected.to have_many(:members_and_requesters) }
     it { is_expected.to have_many(:clusters) }
@@ -3739,4 +3739,12 @@ describe Project do
       it { is_expected.to be_nil }
     end
   end
+
+  context 'with uploads' do
+    it_behaves_like 'model with mounted uploader', true do
+      let(:model_object) { create(:project, :with_avatar) }
+      let(:upload_attribute) { :avatar }
+      let(:uploader_class) { AttachmentUploader }
+    end
+  end
 end

spec/models/user_spec.rb

@@ -39,7 +39,7 @@ describe User do
     it { is_expected.to have_many(:builds).dependent(:nullify) }
     it { is_expected.to have_many(:pipelines).dependent(:nullify) }
     it { is_expected.to have_many(:chat_names).dependent(:destroy) }
-    it { is_expected.to have_many(:uploads).dependent(:destroy) }
+    it { is_expected.to have_many(:uploads) }
     it { is_expected.to have_many(:reported_abuse_reports).dependent(:destroy).class_name('AbuseReport') }
     it { is_expected.to have_many(:custom_attributes).class_name('UserCustomAttribute') }
@@ -2769,4 +2769,12 @@ describe User do
       expect { user.increment_failed_attempts! }.not_to change(user, :failed_attempts)
     end
   end
+
+  context 'with uploads' do
+    it_behaves_like 'model with mounted uploader', false do
+      let(:model_object) { create(:user, :with_avatar) }
+      let(:upload_attribute) { :avatar }
+      let(:uploader_class) { AttachmentUploader }
+    end
+  end
 end

spec/support/shared_examples/models/with_uploads_shared_examples.rb

+require 'spec_helper'
+
+shared_examples_for 'model with mounted uploader' do |supports_fileuploads|
+  describe '.destroy' do
+    before do
+      stub_uploads_object_storage(uploader_class)
+
+      model_object.public_send(upload_attribute).migrate!(ObjectStorage::Store::REMOTE)
+    end
+
+    it 'deletes remote uploads' do
+      expect_any_instance_of(CarrierWave::Storage::Fog::File).to receive(:delete).and_call_original
+
+      expect { model_object.destroy }.to change { Upload.count }.by(-1)
+    end
+
+    it 'deletes any FileUploader uploads which are not mounted', skip: !supports_fileuploads do
+      create(:upload, uploader: FileUploader, model: model_object)
+
+      expect { model_object.destroy }.to change { Upload.count }.by(-2)
+    end
+  end
+end