Migrate legacy uploads to the project location50070-legacy-attachments

Uploads coming from AttachmentUploader
need to be moved to the currently supported location
(FileUploader)

6 files changed, 485 insertions, 4 deletions

diff --git a/changelogs/unreleased/50070-legacy-attachments.yml b/changelogs/unreleased/50070-legacy-attachments.yml
new file mode 100644
index 00000000000..95917f2b5b5
--- /dev/null
+++ b/changelogs/unreleased/50070-legacy-attachments.yml
@@ -0,0 +1,5 @@
+---
+title: Migrate legacy uploads out of deprecated paths
+merge_request: 24679
+author:
+type: other
diff --git a/db/migrate/20190114184258_migrate_legacy_attachments.rb b/db/migrate/20190114184258_migrate_legacy_attachments.rb
new file mode 100644
index 00000000000..e9fb7952dc9
--- /dev/null
+++ b/db/migrate/20190114184258_migrate_legacy_attachments.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+class MigrateLegacyAttachments < ActiveRecord::Migration[5.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  DOWNTIME = false
+
+  MIGRATION = 'MigrateLegacyUploads'.freeze
+  BATCH_SIZE = 5000
+  DELAY_INTERVAL = 5.minutes.to_i
+
+  class Upload < ActiveRecord::Base
+    self.table_name = 'uploads'
+
+    include ::EachBatch
+  end
+
+  def up
+    Upload.where(uploader: 'AttachmentUploader').each_batch(of: BATCH_SIZE) do |relation, index|
+      start_id, end_id = relation.pluck('MIN(id), MAX(id)').first
+      delay = index * DELAY_INTERVAL
+
+      BackgroundMigrationWorker.perform_in(delay, MIGRATION, [start_id, end_id])
+    end
+  end
+
+  # not needed
+  def down
+  end
+end
diff --git a/doc/administration/troubleshooting/migration.md b/doc/administration/troubleshooting/migration.md
new file mode 100644
index 00000000000..4d2d268b9df
--- /dev/null
+++ b/doc/administration/troubleshooting/migration.md
@@ -0,0 +1,82 @@
+# Migrations problems
+
+## Legacy upload migration
+
+> Introduced in GitLab 12.0.
+
+  The migration takes all attachments uploaded by legacy `AttachmentUploader` and
+  migrate them to the path that current uploaders expect.
+
+Although it should not usually happen there could possibly be some attachments belonging to
+LegacyDiffNotes. These attachments can't be seen before running the migration by users and
+they should not be present in your instance.
+
+However, if you have some of them, you will need to handle them manually.
+You can find the ids of failed notes in logs as "MigrateLegacyUploads: LegacyDiffNote"
+
+1. Run a Rails console:
+
+    ```sh
+    sudo gitlab-rails console production
+    ```
+
+    or for source installs:
+
+    ```sh
+    bundle exec rails console production
+    ```
+
+ 1. Check the failed upload and find the note (you can see their ids in the logs)
+
+    ```ruby
+    upload = Upload.find(upload_id)
+    note = Note.find(note_id)
+    ```
+
+
+ 1. Check the path - it should contain `system/note/attachment`
+
+    ```ruby
+    upload.absolut_path
+    ```
+    
+ 1. Check the path in the uploader - it should differ from the upload path and should contain  `system/legacy_diff_note`
+ 
+    ```ruby
+    uploader = upload.build_uploader
+    uploader.file
+    ```
+    
+ 1. First, you need to move the file to the path that is expected from the uploader
+
+    ```ruby
+    old_path = upload.absolute_path
+    new_path = upload.absolute_path.sub('-/system/note/attachment', '-/system/legacy_diff_note')
+    new_dir = File.dirname(new_path)
+    FileUtils.mkdir_p(new_dir)
+    
+    FileUtils.mv(old_path, new_path)
+    ```
+
+ 1. You then need to move the file to the `FileUploader` and create a new `Upload` object
+ 
+    ```ruby
+    file_uploader = UploadService.new(note.project, File.read(new_path)).execute
+    ```
+ 
+ 1. And update the legacy note to contain the file.
+ 
+    ```ruby
+    new_text = "#{note.note} \n #{file_uploader.markdown_link}"
+    note.update!(
+      note: new_text
+    )
+    ```
+
+ 1. And finally, you can remove the old upload
+ 
+    ```ruby
+    upload.destroy
+    ```
+
+If you have any problems feel free to contact [GitLab Support](https://about.gitlab.com/support/).
diff --git a/lib/gitlab/background_migration/migrate_legacy_uploads.rb b/lib/gitlab/background_migration/migrate_legacy_uploads.rb
new file mode 100644
index 00000000000..af1ad930aed
--- /dev/null
+++ b/lib/gitlab/background_migration/migrate_legacy_uploads.rb
@@ -0,0 +1,128 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # This migration takes all legacy uploads (that were uploaded using AttachmentUploader)
+    # and migrate them to the new (FileUploader) location (=under projects).
+    #
+    # We have dependencies (uploaders) in this migration because extracting code would add a lot of complexity
+    # and possible errors could appear as the logic in the uploaders is not trivial.
+    #
+    # This migration will be removed in 12.4 in order to get rid of a migration that depends on
+    # the application code.
+    class MigrateLegacyUploads
+      include Database::MigrationHelpers
+      include ::Gitlab::Utils::StrongMemoize
+
+      # This class takes a legacy upload and migrates it to the correct location
+      class UploadMover
+        include Gitlab::Utils::StrongMemoize
+
+        attr_reader :upload, :project, :note
+
+        def initialize(upload)
+          @upload = upload
+          @note = Note.find_by(id: upload.model_id)
+          @project = note&.project
+        end
+
+        def execute
+          return unless upload
+
+          if !project
+            # if we don't have models associated with the upload we can not move it
+            say "MigrateLegacyUploads: Deleting upload due to model not found: #{upload.inspect}"
+            destroy_legacy_upload
+          elsif note.is_a?(LegacyDiffNote)
+            handle_legacy_note_upload
+          elsif !legacy_file_exists?
+            # if we can not find the file we just remove the upload record
+            say "MigrateLegacyUploads: Deleting upload due to file not found: #{upload.inspect}"
+            destroy_legacy_upload
+          else
+            migrate_upload
+          end
+        end
+
+        private
+
+        def migrate_upload
+          return unless copy_upload_to_project
+
+          add_upload_link_to_note_text
+          destroy_legacy_file
+          destroy_legacy_upload
+        end
+
+        # we should proceed and log whenever one upload copy fails, no matter the reasons
+        # rubocop: disable Lint/RescueException
+        def copy_upload_to_project
+          @uploader = FileUploader.copy_to(legacy_file_uploader, project)
+
+          say "MigrateLegacyUploads: Copied file #{legacy_file_uploader.file.path} -> #{@uploader.file.path}"
+          true
+        rescue Exception => e
+          say "MigrateLegacyUploads: File #{legacy_file_uploader.file.path} couldn't be copied to project uploads. Error: #{e.message}"
+          false
+        end
+        # rubocop: enable Lint/RescueException
+
+        def destroy_legacy_upload
+          note.remove_attachment = true
+          note.save
+
+          if upload.destroy
+            say "MigrateLegacyUploads: Upload #{upload.inspect} was destroyed."
+          else
+            say "MigrateLegacyUploads: Upload #{upload.inspect} destroy failed."
+          end
+        end
+
+        def destroy_legacy_file
+          legacy_file_uploader.file.delete
+        end
+
+        def add_upload_link_to_note_text
+          new_text = "#{note.note} \n #{@uploader.markdown_link}"
+          note.update!(
+            note: new_text
+          )
+        end
+
+        def legacy_file_uploader
+          strong_memoize(:legacy_file_uploader) do
+            uploader = upload.build_uploader
+            uploader.retrieve_from_store!(File.basename(upload.path))
+            uploader
+          end
+        end
+
+        def legacy_file_exists?
+          legacy_file_uploader.file.exists?
+        end
+
+        def handle_legacy_note_upload
+          note.note += "\n \n Attachment ##{upload.id} with URL \"#{note.attachment.url}\" failed to migrate \
+               for model class #{note.class}. See #{help_doc_link}."
+          note.save
+
+          say "MigrateLegacyUploads: LegacyDiffNote ##{note.id} found, can't move the file: #{upload.inspect} for upload ##{upload.id}. See #{help_doc_link}."
+        end
+
+        def say(message)
+          Rails.logger.info(message)
+        end
+
+        def help_doc_link
+          'https://docs.gitlab.com/ee/administration/troubleshooting/migrations.html#legacy-upload-migration'
+        end
+      end
+
+      def perform(start_id, end_id)
+        Upload.where(id: start_id..end_id, uploader: 'AttachmentUploader').find_each do |upload|
+          UploadMover.new(upload).execute
+        end
+      end
+    end
+  end
+end
diff --git a/spec/factories/uploads.rb b/spec/factories/uploads.rb
index 426abdc2a6c..52f6962f16b 100644
--- a/spec/factories/uploads.rb
+++ b/spec/factories/uploads.rb
@@ -54,10 +54,7 @@ FactoryBot.define do
     end
 
     trait :attachment_upload do
-      transient do
-        mount_point :attachment
-      end
-
+      mount_point :attachment
       model { build(:note) }
       uploader "AttachmentUploader"
     end
diff --git a/spec/lib/gitlab/background_migration/migrate_legacy_uploads_spec.rb b/spec/lib/gitlab/background_migration/migrate_legacy_uploads_spec.rb
new file mode 100644
index 00000000000..802c8fb8c97
--- /dev/null
+++ b/spec/lib/gitlab/background_migration/migrate_legacy_uploads_spec.rb
@@ -0,0 +1,237 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+describe Gitlab::BackgroundMigration::MigrateLegacyUploads, :migration, schema: 20190103140724 do
+  let(:test_dir) { FileUploader.options['storage_path'] }
+
+  # rubocop: disable RSpec/FactoriesInMigrationSpecs
+  let!(:namespace) { create(:namespace) }
+  let!(:project) { create(:project, :legacy_storage, namespace: namespace) }
+  let!(:issue) { create(:issue, project: project) }
+
+  let!(:note1) { create(:note, note: 'some note text awesome', project: project, noteable: issue) }
+  let!(:note2) { create(:note, note: 'some note', project: project, noteable: issue) }
+
+  let!(:hashed_project) { create(:project, namespace: namespace) }
+  let!(:issue_hashed_project) { create(:issue, project: hashed_project) }
+  let!(:note_hashed_project) { create(:note, note: 'some note', project: hashed_project, attachment: 'text.pdf', noteable: issue_hashed_project) }
+
+  let!(:standard_upload) do
+    create(:upload,
+      path: "secretabcde/image.png",
+      model_id: create(:project).id, model_type: 'Project', uploader: 'FileUploader')
+  end
+
+  def create_remote_upload(model, filename)
+    create(:upload, :attachment_upload,
+           path: "note/attachment/#{model.id}/#{filename}", secret: nil,
+           store: ObjectStorage::Store::REMOTE, model: model)
+  end
+
+  def create_upload(model, filename, with_file = true)
+    params = {
+      path: "uploads/-/system/note/attachment/#{model.id}/#{filename}",
+      model: model,
+      store: ObjectStorage::Store::LOCAL
+    }
+
+    upload = if with_file
+               create(:upload, :with_file, :attachment_upload, params)
+             else
+               create(:upload, :attachment_upload, params)
+             end
+
+    model.update(attachment: upload.build_uploader)
+    model.attachment.upload
+  end
+
+  let(:start_id) { 1 }
+  let(:end_id) { 10000 }
+
+  def new_upload_legacy
+    Upload.find_by(model_id: project.id, model_type: 'Project')
+  end
+
+  def new_upload_hashed
+    Upload.find_by(model_id: hashed_project.id, model_type: 'Project')
+  end
+
+  shared_examples 'migrates files correctly' do
+    before do
+      described_class.new.perform(start_id, end_id)
+    end
+
+    it 'removes all the legacy upload records' do
+      expect(Upload.where(uploader: 'AttachmentUploader')).to be_empty
+
+      expect(standard_upload.reload).to eq(standard_upload)
+    end
+
+    it 'creates new upload records correctly' do
+      expect(new_upload_legacy.secret).not_to be_nil
+      expect(new_upload_legacy.path).to end_with("#{new_upload_legacy.secret}/image.png")
+      expect(new_upload_legacy.model_id).to eq(project.id)
+      expect(new_upload_legacy.model_type).to eq('Project')
+      expect(new_upload_legacy.uploader).to eq('FileUploader')
+
+      expect(new_upload_hashed.secret).not_to be_nil
+      expect(new_upload_hashed.path).to end_with("#{new_upload_hashed.secret}/text.pdf")
+      expect(new_upload_hashed.model_id).to eq(hashed_project.id)
+      expect(new_upload_hashed.model_type).to eq('Project')
+      expect(new_upload_hashed.uploader).to eq('FileUploader')
+    end
+
+    it 'updates the legacy upload notes so that they include the file references in the markdown' do
+      expected_path = File.join('/uploads', new_upload_legacy.secret, 'image.png')
+      expected_markdown = "some note text awesome \n ![image](#{expected_path})"
+      expect(note1.reload.note).to eq(expected_markdown)
+
+      expected_path = File.join('/uploads', new_upload_hashed.secret, 'text.pdf')
+      expected_markdown = "some note \n [text.pdf](#{expected_path})"
+      expect(note_hashed_project.reload.note).to eq(expected_markdown)
+    end
+
+    it 'removed the attachments from the note model' do
+      expect(note1.reload.attachment.file).to be_nil
+      expect(note2.reload.attachment.file).to be_nil
+      expect(note_hashed_project.reload.attachment.file).to be_nil
+    end
+  end
+
+  context 'when legacy uploads are stored in local storage' do
+    let!(:legacy_upload1) { create_upload(note1, 'image.png') }
+    let!(:legacy_upload_not_found) { create_upload(note2, 'image.png', false) }
+    let!(:legacy_upload_hashed) { create_upload(note_hashed_project, 'text.pdf', with_file: true) }
+
+    shared_examples 'removes legacy local files' do
+      it 'removes all the legacy upload records' do
+        expect(File.exist?(legacy_upload1.absolute_path)).to be_truthy
+        expect(File.exist?(legacy_upload_hashed.absolute_path)).to be_truthy
+
+        described_class.new.perform(start_id, end_id)
+
+        expect(File.exist?(legacy_upload1.absolute_path)).to be_falsey
+        expect(File.exist?(legacy_upload_hashed.absolute_path)).to be_falsey
+      end
+    end
+
+    context 'when object storage is disabled for FileUploader' do
+      it_behaves_like 'migrates files correctly'
+      it_behaves_like 'removes legacy local files'
+
+      it 'moves legacy uploads to the correct location' do
+        described_class.new.perform(start_id, end_id)
+
+        expected_path1 = File.join(test_dir, 'uploads', namespace.path, project.path, new_upload_legacy.secret, 'image.png')
+        expected_path2 = File.join(test_dir, 'uploads', hashed_project.disk_path, new_upload_hashed.secret, 'text.pdf')
+
+        expect(File.exist?(expected_path1)).to be_truthy
+        expect(File.exist?(expected_path2)).to be_truthy
+      end
+
+      context 'when the upload move fails' do
+        it 'does not remove old uploads' do
+          expect(FileUploader).to receive(:copy_to).twice.and_raise('failed')
+
+          described_class.new.perform(start_id, end_id)
+
+          expect(legacy_upload1.reload).to eq(legacy_upload1)
+          expect(legacy_upload_hashed.reload).to eq(legacy_upload_hashed)
+          expect(standard_upload.reload).to eq(standard_upload)
+        end
+      end
+    end
+
+    context 'when object storage is enabled for FileUploader' do
+      before do
+        stub_uploads_object_storage(FileUploader)
+      end
+
+      it_behaves_like 'migrates files correctly'
+      it_behaves_like 'removes legacy local files'
+
+      # The process of migrating to object storage is a manual one,
+      # so it would go against expectations to automatically migrate these files
+      # to object storage during this migration.
+      # After this migration, these files should be able to successfully migrate to object storage.
+      it 'stores files locally' do
+        described_class.new.perform(start_id, end_id)
+
+        expected_path1 = File.join(test_dir, 'uploads', namespace.path, project.path, new_upload_legacy.secret, 'image.png')
+        expected_path2 = File.join(test_dir, 'uploads', hashed_project.disk_path, new_upload_hashed.secret, 'text.pdf')
+
+        expect(File.exist?(expected_path1)).to be_truthy
+        expect(File.exist?(expected_path2)).to be_truthy
+      end
+    end
+
+    context 'with legacy_diff_note upload' do
+      let!(:merge_request) { create(:merge_request, source_project: project) }
+      let!(:legacy_diff_note) { create(:legacy_diff_note_on_merge_request, note: 'some note', project: project, noteable: merge_request) }
+      let!(:legacy_upload_diff_note) do
+        create(:upload, :with_file, :attachment_upload,
+               path: "uploads/-/system/note/attachment/#{legacy_diff_note.id}/some_legacy.pdf", model: legacy_diff_note)
+      end
+
+      before do
+        described_class.new.perform(start_id, end_id)
+      end
+
+      it 'does not remove legacy diff note file' do
+        expect(File.exist?(legacy_upload_diff_note.absolute_path)).to be_truthy
+      end
+
+      it 'removes all the legacy upload records except for the one with legacy_diff_note' do
+        expect(Upload.where(uploader: 'AttachmentUploader')).to eq([legacy_upload_diff_note])
+      end
+
+      it 'adds link to the troubleshooting documentation to the note' do
+        help_doc_link = 'https://docs.gitlab.com/ee/administration/troubleshooting/migrations.html#legacy-upload-migration'
+
+        expect(legacy_diff_note.reload.note).to include(help_doc_link)
+      end
+    end
+  end
+
+  context 'when legacy uploads are stored in object storage' do
+    let!(:legacy_upload1) { create_remote_upload(note1, 'image.png') }
+    let!(:legacy_upload_not_found) { create_remote_upload(note2, 'non-existing.pdf') }
+    let!(:legacy_upload_hashed) { create_remote_upload(note_hashed_project, 'text.pdf') }
+    let(:remote_files) do
+      [
+        { key: "#{legacy_upload1.path}" },
+        { key: "#{legacy_upload_hashed.path}" }
+      ]
+    end
+    let(:connection) { ::Fog::Storage.new(FileUploader.object_store_credentials) }
+    let(:bucket) { connection.directories.create(key: 'uploads') }
+
+    def create_remote_files
+      remote_files.each { |file| bucket.files.create(file) }
+    end
+
+    before do
+      stub_uploads_object_storage(FileUploader)
+      create_remote_files
+    end
+
+    it_behaves_like 'migrates files correctly'
+
+    it 'moves legacy uploads to the correct remote location' do
+      described_class.new.perform(start_id, end_id)
+
+      connection = ::Fog::Storage.new(FileUploader.object_store_credentials)
+      expect(connection.get_object('uploads', new_upload_legacy.path)[:status]).to eq(200)
+      expect(connection.get_object('uploads', new_upload_hashed.path)[:status]).to eq(200)
+    end
+
+    it 'removes all the legacy upload records' do
+      described_class.new.perform(start_id, end_id)
+
+      remote_files.each do |remote_file|
+        expect(bucket.files.get(remote_file[:key])).to be_nil
+      end
+    end
+  end
+  # rubocop: enable RSpec/FactoriesInMigrationSpecs
+end