h1. JRuby on Google App Engine

Google App Engine allows you to run our apps on Googles infrastructure

h2. Easy to start - easy to scale

150K developers, 50K apps

h3. BuddyPoke

Scales to over 35 mio. users

h3. Google Moderator

Moderate questions during meetings - used by the White House

h2. Infrastructure

h3. Components

You upload your application, we ship it out to multiple servers
The whole system is designed to be fault-tolerant too

h3. Languages

Java Runtime & Libraries

h3. Distributed Datastore: BigTable

Similar to CouchDB. You can't use joins on BigTable.

You get an array of hashes. Each object of the same kind can have different structures if you want.
The API is basically an object database.

h2. Datamapper

class Comment
  include DataMapper::Resource
  
  property :text, String
  belongs_to, :post
end

class Post
  include DataMapper::Resource
  
  property DataMapper::Resource
  
  property :text, String
  has n, :comments
end

Migrations are still missing. But you can do an online migration.

h2. APIs

h3. Memcache API

You are not allowed to open sockets, to start threads or write files on app engine.

h3. URL Fetch API

h3. Google Accounts API

Your users don't need Yet Another Account

h3. Other APIs

Send email
Loggin
Image Manipulation (Ruby API missing)
Cron
+ More to come (receiving e-mails, large file uploads)

h2.

h2. Questions

If I build a Jruby on Rails app and use BigTable, I am pretty much stuck with Google, right?

h2. Live demo

Nick's Sample Rails App (http://github.com/nicksieger/jruby-rack/tree/master)

Ola's Yarbl Rails App
Ola's Bumble Datastore Wrapper

h2. Reggae

http://github.com/knowtheory/reggae/tree/master

Google App Engine Hackathon - 5.30 - 8.30 @ CabooseConf