Synthesizing the info from How to engage a Resumable upload to Google Drive using google-api-ruby client? and the existing multipart upload sample leads to
videos_insert_response = client.execute!(
:api_method => youtube.videos.insert,
:body_object => body,
:media => Google::APIClient::UploadIO.new(opts[:file], 'video/*'),
:parameters => {
'uploadType' => 'resumable',
:part => body.keys.join(',')
}
)
videos_insert_response.resumable_upload.send_all(client)
puts "'#{videos_insert_response.data.snippet.title}' (video id: #{videos_insert_response.data.id}) was successfully uploaded."
That worked for me.