module DownloadManager class ParallelDownloadQueue DOWNLOAD_MAX_PARALLEL = ENV.fetch('DOWNLOAD_MAX_PARALLEL') { 10 } attr_accessor :attachments, :destination, :on_error def initialize(attachments, destination) @attachments = attachments @destination = destination end def download_all hydra = Typhoeus::Hydra.new(max_concurrency: DOWNLOAD_MAX_PARALLEL) attachments.map do |attachment, path| begin download_one(attachment: attachment, path_in_download_dir: path, http_client: hydra) rescue => e on_error.call(attachment, path, e) end end hydra.run end # can't be used with typhoeus, otherwise block is closed before the request is run by hydra def download_one(attachment:, path_in_download_dir:, http_client:) attachment_path = File.join(destination, path_in_download_dir) attachment_dir = File.dirname(attachment_path) FileUtils.mkdir_p(attachment_dir) if !Dir.exist?(attachment_dir) # defensive, do not write in undefined dir if attachment.is_a?(PiecesJustificativesService::FakeAttachment) File.write(attachment_path, attachment.file.read, mode: 'wb') else request = Typhoeus::Request.new(attachment.url) request.on_body do |chunk| File.write(attachment_path, chunk, mode: 'a+b') end request.on_complete do |response| unless response.success? File.delete(attachment_path) if File.exist?(attachment_path) # -> case of retries failed, must cleanup partialy downloaded file on_error.call(attachment, path_in_download_dir, response.code) end end http_client.queue(request) end end end end