Gem Bundle, then make a gems.jar

README.rdoc

Gems with Java extensions on App Engine¶ ↑

While creating the gems.jar, we simply divert any jar files directly to WEB-INF/lib

=> Packaging gems
Installing fast_xs.jar
Installing hpricot_scan.jar

As long as we don’t have name collisions, the extension jar files work from WEB-INF/lib

. 9262117 ... appengine-api-1.0-sdk-1.3.0.jar
.  583552 ... appengine-api-labs-1.3.0.jar
. 8986963 ... appengine-jruby-0.0.7.pre.jar
.   13465 ... fast_xs.jar
. 5926408 ... gems.jar
.   55431 ... hpricot_scan.jar
.  152043 ... jruby-rack-0.9.6.jar

This required the most recent build of appengine-tools 0.0.8.pre

sudo gem uninstall appengine-tools
sudo gem install appengine-tools --pre

gem_bundler.rb

require 'zip/zipfilesystem'
require 'rubygems/command_manager'
require 'appengine-tools/bundler'

module AppEngine
  module Admin
    TARGET_VERSION = '1.8'
    TARGET_ENGINE = 'jruby'
    GEM_PLATFORM = Gem::Platform.new("universal-java-#{TARGET_VERSION}")

    class GemBundler

      # . . .

      def gem_bundle(args)
        return unless args.include?('--update') || gems_out_of_date
        Gem.platforms = [Gem::Platform::RUBY, GEM_PLATFORM]
        Gem.configuration = Gem::ConfigFile.new(args.unshift('bundle'))
        ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : nil
        # Override RUBY_ENGINE (we bundle from MRI for JRuby)
        Object.const_set('RUBY_ENGINE', TARGET_ENGINE)
        puts "=> Bundling gems"
        begin
          Dir.chdir(@root) do
            Gem::CommandManager.instance.run(Gem.configuration.args)
          end
        rescue Gem::SystemExitException => e
          exit e.exit_code unless e.exit_code == 0
        end
        # Restore RUBY_ENGINE (limit the scope of this hack)
        Object.const_set('RUBY_ENGINE', ruby_engine) unless ruby_engine.nil?
        bundler_dir = "#{app.gems_dir}/bundler_gems"
        target_pair = "#{TARGET_ENGINE}/#{TARGET_VERSION}"
        gem_patch = "require 'bundler_gems/#{target_pair}/environment'"
        File.open("#{bundler_dir}/environment.rb",'w') {|f| f << gem_patch }
        FileUtils.rm app.gems_jar, :force => true # blow away the old jar
        puts "=> Packaging gems"
        gem_files = Dir["#{bundler_dir}/#{target_pair}/dirs/**/**"] +
                    Dir["#{bundler_dir}/#{target_pair}/gems/**/**"] +
                    Dir["#{bundler_dir}/#{target_pair}/environment.rb"] +
                    Dir["#{bundler_dir}/environment.rb"]
        Zip::ZipFile.open(app.gems_jar, 'w') do |jar|
          gem_files.reject {|f| f == app.gems_jar}.each do |file|
            if file[-4..-1].eql? '.jar'
              puts "Installing #{File.basename(file)}"
              FileUtils.cp file, app.webinf_lib
            else
              jar.add(file.sub("#{app.gems_dir}/",''), file)
            end
          end
        end
      end

      # . . .

    end
  end
end

Gemfile .rb

# Critical default settings:
disable_system_gems
disable_rubygems
bundle_path '.gems/bundler_gems'

# List gems to bundle here:
gem 'rails_dm_datastore'
gem 'rails', "2.3.5"
gem 'i18n'
gem 'tzinfo'
gem 'builder'

gem 'hpricot', '0.8.2'
gem 'mechanize', '0.8.5'