Example of how to upload app previews from an ordered structure the apple app store by using Fatland and Spaceship

Fastfile

# This file contains the fastlane.tools configuration
# You can find the documentation at https://docs.fastlane.tools
#
# For a list of all available actions, check out
#
#     https://docs.fastlane.tools/actions
#
# For a list of all available plugins, check out
#
#     https://docs.fastlane.tools/plugins/available-plugins
#

# Uncomment the line if you want fastlane to automatically update itself
# update_fastlane

default_platform(:ios)

platform :ios do

  lane :upload_video do
    fastlane_require 'spaceship'

    Spaceship::ConnectAPI.login()
    app = Spaceship::ConnectAPI::App.find("com.example.my-app")
    app_version = app.get_edit_app_store_version(platform:Spaceship::ConnectAPI::Platform::IOS)
    localizations = app_version.get_app_store_version_localizations

    # iterate all locales for this app
    localizations.each do |localization|
      puts "Locale: #{localization.locale}"

      preview_sets = localization.get_app_preview_sets
      preview_sets.each do |preview_set|
        puts "\t#{preview_set.preview_type} #{preview_set.app_previews.size}"
      end

      # iterate all preview types for this locale
      Spaceship::ConnectAPI::AppPreviewSet::PreviewType::ALL.each do |preview_type|
        UI.message("Process preview type #{preview_type}")

        # find the preview set for this type
        preview_set = preview_sets.find do |set|
          set.preview_type == preview_type
        end

        # create preview set if it does not exist yet
        if preview_set.nil?
          UI.message("Skipping #{preview_type}; not create first in app store")
          next
          #preview_set = localization.create_app_preview_set(attributes: {
          #  previewType: preview_type
          #})
        end

        # delete all existing previews
        if !preview_set.app_previews.empty? && UI.confirm("Delete existing previews?")
          preview_set.app_previews.each do |app_preview|
            UI.message("Deleting #{app_preview.id}")
            app_preview.delete!
            UI.message("Deleted #{app_preview.id}")
          end
        end

        # upload all previews for this localization and type
        if UI.confirm("Upload new previews?")
          video_dir = "app_previews/#{localization.locale}/#{preview_type}/"
          if !Dir.exists?(video_dir)
            UI.message("Video directory #{video_dir} does not exist; skipping")
            next
          end

          Dir.foreach(video_dir) do |filename|
            next if filename == '.' or filename == '..'
            path = File.absolute_path("#{video_dir}#{filename}")
            UI.message("Upload video #{path}")
            preview_set.upload_preview(path: path, wait_for_processing: false)
          end # for foreach
        end # if upload previews
      end # foreach all preview types
    end # foreach localizations
  end # lane
end # platform do