exif_data.rb

class ExifData
  require 'celluloid'

  def initialize(file)
    raise 'Expects Upload!' unless file.is_a?(Upload)
    @upload = file
  end

  def process!
    # this is fictitional
    @exif_data ||= ActiveExif::new(@upload.read).process.to_hash
  end
end

magick_data.rb

class MagickData
  require 'celluloid'

  def initialize(file)
    raise 'Expects Upload!' unless file.is_a?(Upload)
    @upload = file
  end

  def process!
    # this is fictitional
    @exif_data ||= ActiveMagick::new(@upload.read).process.to_hash
  end
end

upload.rb

class Upload
  def initialize(file)
    @file = File.open(file)
  end

  def read
    @image ||= @file.read
  end
end

usage.rb

upload = Upload.new('/tmp/file.jpg')

# WILL NOT block
exif_data   = ExifData.new(upload).future   :process!
magick_data = MagickData.new(upload).future :process!


# WILL block
data = exif_data.value + magick_data.value