Getting started

Here’s how to get rolling:

  1. Install the gems

    $ sudo gem install google-appengine

  2. Assign an app identifier

    Simply create an application at appspot.com,
    we'll refer to that as my-app in this document.

  3. Generate your rails app

    $ rails my-app; cd my-app;

  4. Generate a rackup file

    In the same folder, save this as config.ru.

    require 'appengine-rack'
AppEngine::Rack.configure_app(
  :application => 'my-app',
  :version => 1 )

%w{R db/ doc/ log/ script/ test/ tmp/}.each do |x|
  AppEngine::Rack.app.resource_files.exclude "/#{x}**"
end
ENV['RAILS_ENV'] = AppEngine::Rack.environment
require 'config/environment'

run ActionController::Dispatcher.new

  5. Check gem sources for datamapper

    $ gem sources

    Only when missing, add it like this...
    $ sudo gem source -a http://gems.datamapper.org

  6. Install gems into your app

    $ appcfg.rb gem install rails \
  dm-appengine rails_datamapper

  7. Generate a model

    $ ./script/generate dm_model book \
  title:string summary:text image_url:string \
  available:boolean pages:integer \
  -f --skip-timestamps --skip-migration

  8. Modify the Rails Initializer

    Add the following to your config/environment.rb.

    # Set DataMapper to use dm-appengine adapter
require 'dm-core'
DataMapper.setup(:default, "appengine://auto")

# Set Logger from appengine-apis, all environments
require 'appengine-apis/logger'
config.logger = AppEngine::Logger.new

# Skip frameworks you're not going to use.
config.frameworks -= [ :active_record ]

  9. Run your app locally

    $ dev_appserver.rb .

  10. Open up the console

    $ appcfg.rb run -S irb
> require 'config/environment'

  11. Deploy to App Engine

    $ appcfg.rb update .