Use FastDestroy for deleting uploads

It gathers list of file paths to delete before destroying
the parent object. Then after the parent_object is destroyed
these paths are scheduled for deletion asynchronously.

Carrierwave needed associated model for deleting upload file.
To avoid this requirement, simple Fog/File layer is used directly
for file deletion, this allows us to use just a simple list of paths.

18 files changed, 322 insertions, 22 deletions

diff --git a/app/models/concerns/fast_destroy_all.rb b/app/models/concerns/fast_destroy_all.rb
index 2bfa7da6c1c..89aa6347fbe 100644
--- a/app/models/concerns/fast_destroy_all.rb
+++ b/app/models/concerns/fast_destroy_all.rb
@@ -70,6 +70,7 @@ module FastDestroyAll
 
   module Helpers
     extend ActiveSupport::Concern
+    include AfterCommitQueue
 
     class_methods do
       ##
diff --git a/app/models/concerns/with_uploads.rb b/app/models/concerns/with_uploads.rb
index 2bdef2a40e4..50a9b19299a 100644
--- a/app/models/concerns/with_uploads.rb
+++ b/app/models/concerns/with_uploads.rb
@@ -17,6 +17,7 @@
 
 module WithUploads
   extend ActiveSupport::Concern
+  include FastDestroyAll::Helpers
 
   # Currently there is no simple way how to select only not-mounted
   # uploads, it should be all FileUploaders so we select them by
@@ -25,18 +26,9 @@ module WithUploads
 
   included do
     has_many :uploads, as: :model
+    has_many :file_uploads, -> { where(uploader: FILE_UPLOADERS) }, class_name: 'Upload', as: :model, dependent: :delete_all # rubocop:disable Cop/ActiveRecordDependent
 
-    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).find_each do |upload|
-      upload.destroy
-    end
+    use_fast_destroy :file_uploads
   end
 
   def retrieve_upload(_identifier, paths)
diff --git a/app/models/upload.rb b/app/models/upload.rb
index e01e9c6a4f0..20860f14b83 100644
--- a/app/models/upload.rb
+++ b/app/models/upload.rb
@@ -25,6 +25,25 @@ class Upload < ActiveRecord::Base
     Digest::SHA256.file(path).hexdigest
   end
 
+  class << self
+    ##
+    # FastDestroyAll concerns
+    def begin_fast_destroy
+      {
+        Uploads::Local => Uploads::Local.new.keys(with_files_stored_locally),
+        Uploads::Fog => Uploads::Fog.new.keys(with_files_stored_remotely)
+      }
+    end
+
+    ##
+    # FastDestroyAll concerns
+    def finalize_fast_destroy(keys)
+      keys.each do |store_class, paths|
+        store_class.new.delete_keys_async(paths)
+      end
+    end
+  end
+
   def absolute_path
     raise ObjectStorage::RemoteStoreError, "Remote object has no absolute path." unless local?
     return path unless relative_path?
diff --git a/app/models/uploads/base.rb b/app/models/uploads/base.rb
new file mode 100644
index 00000000000..f9814159958
--- /dev/null
+++ b/app/models/uploads/base.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Uploads
+  class Base
+    BATCH_SIZE = 100
+
+    attr_reader :logger
+
+    def initialize(logger: nil)
+      @logger ||= Rails.logger
+    end
+
+    def delete_keys_async(keys_to_delete)
+      keys_to_delete.each_slice(BATCH_SIZE) do |batch|
+        DeleteStoredFilesWorker.perform_async(self.class, batch)
+      end
+    end
+  end
+end
diff --git a/app/models/uploads/fog.rb b/app/models/uploads/fog.rb
new file mode 100644
index 00000000000..b44e273e9ab
--- /dev/null
+++ b/app/models/uploads/fog.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module Uploads
+  class Fog < Base
+    include ::Gitlab::Utils::StrongMemoize
+
+    def available?
+      object_store.enabled
+    end
+
+    def keys(relation)
+      return [] unless available?
+
+      relation.pluck(:path)
+    end
+
+    def delete_keys(keys)
+      keys.each do |key|
+        connection.delete_object(bucket_name, key)
+      end
+    end
+
+    private
+
+    def object_store
+      Gitlab.config.uploads.object_store
+    end
+
+    def bucket_name
+      return unless available?
+
+      object_store.remote_directory
+    end
+
+    def connection
+      return unless available?
+
+      strong_memoize(:connection) do
+        ::Fog::Storage.new(object_store.connection.to_hash.deep_symbolize_keys)
+      end
+    end
+  end
+end
diff --git a/app/models/uploads/local.rb b/app/models/uploads/local.rb
new file mode 100644
index 00000000000..ffbf840a9d2
--- /dev/null
+++ b/app/models/uploads/local.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module Uploads
+  class Local < Base
+    def keys(relation)
+      relation.includes(:model).find_each.map {|u| u.absolute_path }
+    end
+
+    def delete_keys(keys)
+      keys.each do |path|
+        delete_file(path)
+      end
+    end
+
+    private
+
+    def delete_file(path)
+      unless exists?(path)
+        logger.warn("File '#{path}' doesn't exist, skipping")
+        return
+      end
+
+      unless in_uploads?(path)
+        message = "Path '#{path}' is not in uploads dir, skipping"
+        logger.warn(message)
+        Gitlab::Sentry.track_exception(RuntimeError.new(message), extra: { uploads_dir: storage_dir })
+        return
+      end
+
+      FileUtils.rm(path)
+      delete_dir!(File.dirname(path))
+    end
+
+    def exists?(path)
+      path.present? && File.exist?(path)
+    end
+
+    def in_uploads?(path)
+      path.start_with?(storage_dir)
+    end
+
+    def delete_dir!(path)
+      Dir.rmdir(path)
+    rescue Errno::ENOENT
+      # Ignore: path does not exist
+    rescue Errno::ENOTDIR
+      # Ignore: path is not a dir
+    rescue Errno::ENOTEMPTY, Errno::EEXIST
+      # Ignore: dir is not empty
+    end
+
+    def storage_dir
+      @storage_dir ||= File.realpath(Gitlab.config.uploads.storage_path)
+    end
+  end
+end
diff --git a/app/workers/all_queues.yml b/app/workers/all_queues.yml
index 2c55806a286..d9fd395c5ec 100644
--- a/app/workers/all_queues.yml
+++ b/app/workers/all_queues.yml
@@ -134,3 +134,4 @@
 - delete_diff_files
 - detect_repository_languages
 - repository_cleanup
+- delete_stored_files
diff --git a/app/workers/delete_stored_files_worker.rb b/app/workers/delete_stored_files_worker.rb
new file mode 100644
index 00000000000..ff7931849d8
--- /dev/null
+++ b/app/workers/delete_stored_files_worker.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class DeleteStoredFilesWorker
+  include ApplicationWorker
+
+  def perform(class_name, keys)
+    klass = begin
+      class_name.constantize
+    rescue NameError
+      nil
+    end
+
+    unless klass
+      message = "Unknown class '#{class_name}'"
+      logger.error(message)
+      Gitlab::Sentry.track_exception(RuntimeError.new(message))
+      return
+    end
+
+    klass.new(logger: logger).delete_keys(keys)
+  end
+end
diff --git a/changelogs/unreleased/fast-upload-delete.yml b/changelogs/unreleased/fast-upload-delete.yml
new file mode 100644
index 00000000000..c4a85624aa0
--- /dev/null
+++ b/changelogs/unreleased/fast-upload-delete.yml
@@ -0,0 +1,5 @@
+---
+title: Delete file uploads asynchronously when deleting a project or other resources.
+merge_request: 20977
+author:
+type: added
diff --git a/config/sidekiq_queues.yml b/config/sidekiq_queues.yml
index d8002815bac..4782a223561 100644
--- a/config/sidekiq_queues.yml
+++ b/config/sidekiq_queues.yml
@@ -82,3 +82,4 @@
   - [detect_repository_languages, 1]
   - [auto_devops, 2]
   - [repository_cleanup, 1]
+  - [delete_stored_files, 1]
diff --git a/spec/lib/gitlab/import_export/all_models.yml b/spec/lib/gitlab/import_export/all_models.yml
index 7df129da95a..bae5b21c26f 100644
--- a/spec/lib/gitlab/import_export/all_models.yml
+++ b/spec/lib/gitlab/import_export/all_models.yml
@@ -287,6 +287,7 @@ project:
 - statistics
 - container_repositories
 - uploads
+- file_uploads
 - import_state
 - members_and_requesters
 - build_trace_section_names
diff --git a/spec/models/appearance_spec.rb b/spec/models/appearance_spec.rb
index 77b07cf1ac9..35415030154 100644
--- a/spec/models/appearance_spec.rb
+++ b/spec/models/appearance_spec.rb
@@ -20,7 +20,7 @@ describe Appearance do
   end
 
   context 'with uploads' do
-    it_behaves_like 'model with mounted uploader', false do
+    it_behaves_like 'model with uploads', false do
       let(:model_object) { create(:appearance, :with_logo) }
       let(:upload_attribute) { :logo }
       let(:uploader_class) { AttachmentUploader }
diff --git a/spec/models/group_spec.rb b/spec/models/group_spec.rb
index 87aa5a46c21..e63881242f6 100644
--- a/spec/models/group_spec.rb
+++ b/spec/models/group_spec.rb
@@ -739,7 +739,7 @@ describe Group do
   end
 
   context 'with uploads' do
-    it_behaves_like 'model with mounted uploader', true do
+    it_behaves_like 'model with uploads', true do
       let(:model_object) { create(:group, :with_avatar) }
       let(:upload_attribute) { :avatar }
       let(:uploader_class) { AttachmentUploader }
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 50920d9d1fc..93c83fd21fd 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -3898,7 +3898,7 @@ describe Project do
   end
 
   context 'with uploads' do
-    it_behaves_like 'model with mounted uploader', true do
+    it_behaves_like 'model with uploads', true do
       let(:model_object) { create(:project, :with_avatar) }
       let(:upload_attribute) { :avatar }
       let(:uploader_class) { AttachmentUploader }
diff --git a/spec/models/uploads/fog_spec.rb b/spec/models/uploads/fog_spec.rb
new file mode 100644
index 00000000000..4a44cf5ab0f
--- /dev/null
+++ b/spec/models/uploads/fog_spec.rb
@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Uploads::Fog do
+  let(:data_store) { described_class.new }
+
+  before do
+    stub_uploads_object_storage(FileUploader)
+  end
+
+  describe '#available?' do
+    subject { data_store.available? }
+
+    context 'when object storage is enabled' do
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when object storage is disabled' do
+      before do
+        stub_uploads_object_storage(FileUploader, enabled: false)
+      end
+
+      it { is_expected.to be_falsy }
+    end
+  end
+
+  context 'model with uploads' do
+    let(:project) { create(:project) }
+    let(:relation) { project.uploads }
+
+    describe '#keys' do
+      let!(:uploads) { create_list(:upload, 2, :object_storage, uploader: FileUploader, model: project) }
+      subject { data_store.keys(relation) }
+
+      it 'returns keys' do
+        is_expected.to match_array(relation.pluck(:path))
+      end
+    end
+
+    describe '#delete_keys' do
+      let(:keys) { data_store.keys(relation) }
+      let!(:uploads) { create_list(:upload, 2, :with_file, :issuable_upload, model: project) }
+      subject { data_store.delete_keys(keys) }
+
+      before do
+        uploads.each { |upload| upload.build_uploader.migrate!(2) }
+      end
+
+      it 'deletes multiple data' do
+        paths = relation.pluck(:path)
+
+        ::Fog::Storage.new(FileUploader.object_store_credentials).tap do |connection|
+          paths.each do |path|
+            expect(connection.get_object('uploads', path)[:body]).not_to be_nil
+          end
+        end
+
+        subject
+
+        ::Fog::Storage.new(FileUploader.object_store_credentials).tap do |connection|
+          paths.each do |path|
+            expect { connection.get_object('uploads', path)[:body] }.to raise_error(Excon::Error::NotFound)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/models/uploads/local_spec.rb b/spec/models/uploads/local_spec.rb
new file mode 100644
index 00000000000..3468399f370
--- /dev/null
+++ b/spec/models/uploads/local_spec.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Uploads::Local do
+  let(:data_store) { described_class.new }
+
+  before do
+    stub_uploads_object_storage(FileUploader)
+  end
+
+  context 'model with uploads' do
+    let(:project) { create(:project) }
+    let(:relation) { project.uploads }
+
+    describe '#keys' do
+      let!(:uploads) { create_list(:upload, 2, uploader: FileUploader, model: project) }
+      subject { data_store.keys(relation) }
+
+      it 'returns keys' do
+        is_expected.to match_array(relation.map(&:absolute_path))
+      end
+    end
+
+    describe '#delete_keys' do
+      let(:keys) { data_store.keys(relation) }
+      let!(:uploads) { create_list(:upload, 2, :with_file, :issuable_upload, model: project) }
+      subject { data_store.delete_keys(keys) }
+
+      it 'deletes multiple data' do
+        paths = relation.map(&:absolute_path)
+
+        paths.each do |path|
+          expect(File.exist?(path)).to be_truthy
+        end
+
+        subject
+
+        paths.each do |path|
+          expect(File.exist?(path)).to be_falsey
+        end
+      end
+    end
+  end
+end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 6cb27246f06..ff075e65c76 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -3231,7 +3231,7 @@ describe User do
   end
 
   context 'with uploads' do
-    it_behaves_like 'model with mounted uploader', false do
+    it_behaves_like 'model with uploads', false do
       let(:model_object) { create(:user, :with_avatar) }
       let(:upload_attribute) { :avatar }
       let(:uploader_class) { AttachmentUploader }
diff --git a/spec/support/shared_examples/models/with_uploads_shared_examples.rb b/spec/support/shared_examples/models/with_uploads_shared_examples.rb
index 47ad0c6345d..43033a2d256 100644
--- a/spec/support/shared_examples/models/with_uploads_shared_examples.rb
+++ b/spec/support/shared_examples/models/with_uploads_shared_examples.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-shared_examples_for 'model with mounted uploader' do |supports_fileuploads|
+shared_examples_for 'model with uploads' do |supports_fileuploads|
   describe '.destroy' do
     before do
       stub_uploads_object_storage(uploader_class)
@@ -8,16 +8,42 @@ shared_examples_for 'model with mounted uploader' do |supports_fileuploads|
       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
+    context 'with mounted uploader' do
+      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)
+        expect { model_object.destroy }.to change { Upload.count }.by(-1)
+      end
     end
 
-    it 'deletes any FileUploader uploads which are not mounted', skip: !supports_fileuploads do
-      create(:upload, uploader: FileUploader, model: model_object)
+    context 'with not mounted uploads', :sidekiq, skip: !supports_fileuploads do
+      context 'with local files' do
+        let!(:uploads) { create_list(:upload, 2, uploader: FileUploader, model: model_object) }
 
-      expect { model_object.destroy }.to change { Upload.count }.by(-2)
+        it 'deletes any FileUploader uploads which are not mounted' do
+          expect { model_object.destroy }.to change { Upload.count }.by(-3)
+        end
+
+        it 'deletes local files' do
+          expect_any_instance_of(Uploads::Local).to receive(:delete_keys).with(uploads.map(&:absolute_path))
+
+          model_object.destroy
+        end
+      end
+
+      context 'with remote files' do
+        let!(:uploads) { create_list(:upload, 2, :object_storage, uploader: FileUploader, model: model_object) }
+
+        it 'deletes any FileUploader uploads which are not mounted' do
+          expect { model_object.destroy }.to change { Upload.count }.by(-3)
+        end
+
+        it 'deletes remote files' do
+          expect_any_instance_of(Uploads::Fog).to receive(:delete_keys).with(uploads.map(&:path))
+
+          model_object.destroy
+        end
+      end
     end
   end
 end