1 files changed, 202 insertions, 0 deletions
diff --git a/app/workers/object_storage/migrate_uploads_worker.rb b/app/workers/object_storage/migrate_uploads_worker.rb
new file mode 100644
index 00000000000..01ed123e6c8
--- /dev/null
+++ b/app/workers/object_storage/migrate_uploads_worker.rb
@@ -0,0 +1,202 @@
+# frozen_string_literal: true
+# rubocop:disable Metrics/LineLength
+# rubocop:disable Style/Documentation
+
+module ObjectStorage
+  class MigrateUploadsWorker
+    include ApplicationWorker
+    include ObjectStorageQueue
+
+    SanityCheckError = Class.new(StandardError)
+
+    class Upload < ActiveRecord::Base
+      # Upper limit for foreground checksum processing
+      CHECKSUM_THRESHOLD = 100.megabytes
+
+      belongs_to :model, polymorphic: true # rubocop:disable Cop/PolymorphicAssociations
+
+      validates :size, presence: true
+      validates :path, presence: true
+      validates :model, presence: true
+      validates :uploader, presence: true
+
+      before_save  :calculate_checksum!, if: :foreground_checksummable?
+      after_commit :schedule_checksum,   if: :checksummable?
+
+      scope :stored_locally, -> { where(store: [nil, ObjectStorage::Store::LOCAL]) }
+      scope :stored_remotely, -> { where(store: ObjectStorage::Store::REMOTE) }
+
+      def self.hexdigest(path)
+        Digest::SHA256.file(path).hexdigest
+      end
+
+      def absolute_path
+        raise ObjectStorage::RemoteStoreError, "Remote object has no absolute path." unless local?
+        return path unless relative_path?
+
+        uploader_class.absolute_path(self)
+      end
+
+      def calculate_checksum!
+        self.checksum = nil
+        return unless checksummable?
+
+        self.checksum = self.class.hexdigest(absolute_path)
+      end
+
+      def build_uploader(mounted_as = nil)
+        uploader_class.new(model, mounted_as).tap do |uploader|
+          uploader.upload = self
+          uploader.retrieve_from_store!(identifier)
+        end
+      end
+
+      def exist?
+        File.exist?(absolute_path)
+      end
+
+      def local?
+        return true if store.nil?
+
+        store == ObjectStorage::Store::LOCAL
+      end
+
+      private
+
+      def checksummable?
+        checksum.nil? && local? && exist?
+      end
+
+      def foreground_checksummable?
+        checksummable? && size <= CHECKSUM_THRESHOLD
+      end
+
+      def schedule_checksum
+        UploadChecksumWorker.perform_async(id)
+      end
+
+      def relative_path?
+        !path.start_with?('/')
+      end
+
+      def identifier
+        File.basename(path)
+      end
+
+      def uploader_class
+        Object.const_get(uploader)
+      end
+    end
+
+    class MigrationResult
+      attr_reader :upload
+      attr_accessor :error
+
+      def initialize(upload, error = nil)
+        @upload, @error = upload, error
+      end
+
+      def success?
+        error.nil?
+      end
+
+      def to_s
+        success? ? "Migration successful." : "Error while migrating #{upload.id}: #{error.message}"
+      end
+    end
+
+    module Report
+      class MigrationFailures < StandardError
+        attr_reader :errors
+
+        def initialize(errors)
+          @errors = errors
+        end
+
+        def message
+          errors.map(&:message).join("\n")
+        end
+      end
+
+      def report!(results)
+        success, failures = results.partition(&:success?)
+
+        Rails.logger.info header(success, failures)
+        Rails.logger.warn failures(failures)
+
+        raise MigrationFailures.new(failures.map(&:error)) if failures.any?
+      end
+
+      def header(success, failures)
+        "Migrated #{success.count}/#{success.count + failures.count} files."
+      end
+
+      def failures(failures)
+        failures.map { |f| "\t#{f}" }.join('\n')
+      end
+    end
+
+    include Report
+
+    def self.enqueue!(uploads, mounted_as, to_store)
+      sanity_check!(uploads, mounted_as)
+
+      perform_async(uploads.ids, mounted_as, to_store)
+    end
+
+    # We need to be sure all the uploads are for the same uploader and model type
+    # and that the mount point exists if provided.
+    #
+    def self.sanity_check!(uploads, mounted_as)
+      upload = uploads.first
+
+      uploader_class = upload.uploader.constantize
+      model_class = uploads.first.model_type.constantize
+
+      uploader_types = uploads.map(&:uploader).uniq
+      model_types = uploads.map(&:model_type).uniq
+      model_has_mount = mounted_as.nil? || model_class.uploaders[mounted_as] == uploader_class
+
+      raise(SanityCheckError, "Multiple uploaders found: #{uploader_types}") unless uploader_types.count == 1
+      raise(SanityCheckError, "Multiple model types found: #{model_types}") unless model_types.count == 1
+      raise(SanityCheckError, "Mount point #{mounted_as} not found in #{model_class}.") unless model_has_mount
+    end
+
+    def perform(ids, mounted_as, to_store)
+      @mounted_as = mounted_as&.to_sym
+      @to_store = to_store
+
+      uploads = Upload.preload(:model).where(id: ids)
+
+      sanity_check!(uploads)
+      results = migrate(uploads)
+
+      report!(results)
+    rescue SanityCheckError => e
+      # do not retry: the job is insane
+      Rails.logger.warn "#{self.class}: Sanity check error (#{e.message})"
+    end
+
+    def sanity_check!(uploads)
+      self.class.sanity_check!(uploads, @mounted_as)
+    end
+
+    def build_uploaders(uploads)
+      uploads.map { |upload| upload.build_uploader(@mounted_as) }
+    end
+
+    def migrate(uploads)
+      build_uploaders(uploads).map(&method(:process_uploader))
+    end
+
+    def process_uploader(uploader)
+      MigrationResult.new(uploader.upload).tap do |result|
+        begin
+          uploader.migrate!(@to_store)
+        rescue => e
+          result.error = e
+        end
+      end
+    end
+  end
+end