copy_cap_recipe.rb

namespace :copy do
  
  # Allows for the copy of asset directories from remote environments into the
  # corresponding system directory. The download is maintained in your /tmp
  # directory, so that subsequent executions will not fetch from the remote
  # server unless forced to.
  #
  # This is extremely useful for developing/debugging migrations, where you'd
  # like to focus on just a few assets, and need to re-run the migration many
  # times.
  #
  # asset_path may be to any depth in order to reduce the amount of content
  # which is retrieved. For instance, I regularly use this:
  #
  #    cap production copy:assets -Sasset_path=/public/avatars/000/000/004/4
  #
  desc 'Copy remote assets to local application'
  task :assets, :roles => :app, :except => {:no_release => true} do
    asset_path = fetch(:asset_path, nil)
    raise "Please specify '-Sasset_path=public/avatars'" if asset_path.nil?
    
    compressed_file_name = asset_path.gsub(/\//, '_') + '.tar.bz2'
    compressed_file_path = "/tmp/#{compressed_file_name}"
    
    if File.exists?(compressed_file_path) && fetch(:force, false) == false
      logger.debug "Assets exist '#{compressed_file_path}'. Force download with '-Sforce=true'."
    else
      remote_asset_path = File.join(current_path, asset_path)
      logger.debug "Copying remote assets '#{remote_asset_path}' to '#{File.join(FileUtils.pwd, asset_path)}'"
      
      asset_path_exists = capture "if [ -d #{remote_asset_path} ]; then echo 'true'; else echo 'false'; fi"
      raise "Assets do not exist on #{environment} at #{remote_asset_path}" unless asset_path_exists
      
      run "tar -C #{current_path} -cjf #{compressed_file_path} #{asset_path}"
      get compressed_file_path, compressed_file_path
      run "rm #{compressed_file_path}"
    end
    
    system "tar -xjf #{compressed_file_path}"
    logger.debug "Assets extracted in #{FileUtils.pwd}"
  end
  
end