class Bundler::Deployment

def self.define_task(context, task_method = :task, opts = {})
  if defined?(Capistrano) && context.is_a?(Capistrano::Configuration)
    context_name = "capistrano"
    role_default = "{:except => {:no_release => true}}"
    error_type = ::Capistrano::CommandError
  else
    context_name = "vlad"
    role_default = "[:app]"
    error_type = ::Rake::CommandFailedError
  end
  roles = context.fetch(:bundle_roles, false)
  opts[:roles] = roles if roles
  context.send :namespace, :bundle do
    send :desc, <<-DESC
      Install the current Bundler environment. By default, gems will be \
      installed to the shared/bundle path. Gems in the development and \
      test group will not be installed. The install command is executed \
      with the --deployment and --quiet flags. If the bundle cmd cannot \
      be found then you can override the bundle_cmd variable to specifiy \
      which one it should use.
      You can override any of these defaults by setting the variables shown below.
      N.B. bundle_roles must be defined before you require 'bundler/#{context_name}' \
      in your deploy.rb file.
        set :bundle_gemfile,  "Gemfile"
        set :bundle_dir,      File.join(fetch(:shared_path), 'bundle')
        set :bundle_flags,    "--deployment --quiet"
        set :bundle_without,  [:development, :test]
        set :bundle_cmd,      "bundle" # e.g. "/opt/ruby/bin/bundle"
        set :bundle_roles,    #{role_default} # e.g. [:app, :batch]
    DESC
    send task_method, :install, opts do
      bundle_cmd     = context.fetch(:bundle_cmd, "bundle")
      bundle_flags   = context.fetch(:bundle_flags, "--deployment --quiet")
      bundle_dir     = context.fetch(:bundle_dir, File.join(context.fetch(:shared_path), 'bundle'))
      bundle_gemfile = context.fetch(:bundle_gemfile, "Gemfile")
      bundle_without = [*context.fetch(:bundle_without, [:development, :test])].compact
      current_release = context.fetch(:current_release)
      if current_release.to_s.empty?
        raise error_type.new("Cannot detect current release path - make sure you have deployed at least once.")
      end
      args = ["--gemfile #{File.join(current_release, bundle_gemfile)}"]
      args << "--path #{bundle_dir}" unless bundle_dir.to_s.empty?
      args << bundle_flags.to_s
      args << "--without #{bundle_without.join(" ")}" unless bundle_without.empty?
      run "cd #{current_release} && #{bundle_cmd} install #{args.join(' ')}"
    end
  end
end