Building your next business with Google technologies Google App Engine & Google Web Toolkit

Part One - Introduction Hosting on Google Google App Engine Developing amazing web applications the easy way Google Web Toolkit

Some homework Set up your Java App Engine environment Google Plugin for Eclipse App Engine SDK

Hosting on Google

Some App Engine Partners

Managing Everything is Hard

DIY Hosting means hidden costs Idle capacity Software patches & upgrades License fees Lots of maintenance Traffic & utilization forecasting Upgrades

Google App Engine

Easy to build Easy to manage Easy to scale

Google App Engine “We wear pagers so you don’t have to”

Google App Engine

Appservers: What do they do?

Many applications Many concurrent requests Smaller app footprint + fast requests = more apps

Enforce Isolation Keeps apps safe from each other

Enforce statelessness Allows for scheduling flexibility

Service API requests

App Server

1. Checks for cached instance If it exists, no initialization

2. Execute request 3. Cache the instance System is designed to maximize caching

Slow first request, faster subsequent requests Optimistically cache data in your instances!

Web-based Admin Console

Web-based Admin Console

API Requests App Server

1. 2. 3. 4. 5.

App issues API call App Server accepts App Server blocks runtime App Server issues call Returns the response Use APIs to do things you don't want to do in your runtime, such as...

Basic Services Memcache

Mail

Images

Datastore

URL Fetch

XMPP

Cron

Blobstore

User Service

Specialized Services XMPP API - Send & Receive Channel API - Browser Push Fast Image Serving Matcher API Mapper Library Task Queue OpenID / OAuth

App Master

App Servers Serve dynamic requests Where your code runs App Master Schedules applications Informs Front Ends

App Engine Requests

Routed to the nearest Google datacenter Travels over Google's network to App Engine Frontends Same infrastructure other Google products use Lots of advantages for free

Request For Dynamic Content Routing at the Frontend

Front Ends route dynamic requests to App Servers

Request for Static Content Static Content Servers

Google Static Content Serving Built on shared Google Infrastructure Static files are physically separate from code files Specialized infrastructure App runtimes don't serve static content

Always free to get started - Example quotas 6.5 CPU hrs/day 1 GB storage 657K URL Fetch calls / day 2,000 recipients emailed / day 1 GB/day bandwidth 1,000,000 tasks enqueued 46,000,000 XMPP messages/day 26

Language runtimes

Extended Language support through JVM Java Scala JRuby (Ruby) Mirah Groovy Quercus (PHP) Rhino (JavaScript) Jython (Python) Clojure (Lisp)

Mirah: Making Java feel dynamic

Type inference Ruby syntax Blocks Closures Metaprogramming

Still statically compiles to fast bytecode with no runtime dependencies.

import javax.swing.* frame = JFrame.new "Welcome to Mirah" frame.setSize 300, 300 frame.setVisible true button = JButton.new "Press me" frame.add button frame.show button.addActionListener do |event| button.setText "Mirah Rocks!" end

Mirah

Works with App Engine, Android, and GWT. Still experimental, but getting closer to version 1.0

www.mirah.org

What’s new? Always On Large API Calls Channel API Mapper API Multitenant Apps with Namespace API High Performance Image Serving OpenId/Oauth integration High Replication Database Increased quotas Can pause Task Queues And other stuff.. See: http://googleappengine.blogspot. com/

App Engine Roadmap http://code.google.com/appengine/docs/roadmap.html

Background servers

Improved monitoring/alerting

SSL for your domain Hosted SQL

Datastore dump and restore facility

Mapping operations across datasets

Google App Engine for Business Same scalable cloud hosting platform. Designed for the enterprise.

Enterprise application management

Centralized domain console Enterprise reliability and support 99.9% Service Level Agreement Premium Developer Support Hosted SQL Managed relational SQL database in the cloud SSL on your domain Including "naked" domain support Secure by default Integrated Single Sign On (SSO) Pricing that makes sense Pay only for what you use

Google App Engine for Business

Google Web Toolkit Helping you create amazing web applications

Agenda Introduction Why in Java? Feature tour Developer productivity Compiler magic Need for speed Q&A

Mission statement "GWT's mission is to radically improve the web experience for users by enabling developers to use existing Java tools to build no-compromise AJAX for any modern browser."

Focus Productivity for developers Language, IDEs, tools, libraries People, ecosystem

Performance for your users 'Perfect' caching Whole program optimization Better than practical hand written code

Optimizing the entire development cycle Write

Debug

Optimize

Run

Core Java APIs

JVM Debugging

GWT Compiler

Desktop

Widgets

Development Mode

Image Bundle (Sprites)

Mobile

CSS Magic

Online/Offline

End User Performance

Gadgets

A real browser Libraries

Java IDEs

Developer Productivity

GWT Browser-Proofs Your JavaScript Code...

IE

Firefox

Safari Chrome

Opera

So what can you build with Google Web Toolkit?

GWT App Gallery http://gwtgallery.appspot.com/

Google products

Why in Java?

Can you find the bug?

Hint: JavaScript is a dynamic language

Catch errors at compile time

Java is a static language

Feature tour

More than just a compiler Development Mode

History just works

Pre-built widgets, e.g. Rich Text Area

RTL, I18N, L10N, A11Y

Simple, Powerful RPCs interface SpellService extends RemoteService { /** * Checks spelling and suggests * alternatives. * @param the word to check * @return the list of alternatives */ String[] suggest(String word); }

Widget Libraries GWT (http://code.google.com/webtoolkit/) Incubator (http://code.google.com/p/google-web-toolkit-incubator/) Smart GWT (http://code.google.com/p/smartgwt/) GWT-Ext (http://code.google.com/p/gwt-ext/) Vaadin (IT Mill Toolkit) (http://vaadin.com/) GWT mosaic (http://code.google.com/p/gwt-mosaic/) Ext GWT (http://extjs.com/products/gxt/) Advanced GWT Components (http://advanced-gwt.sourceforge.net/)

Developer productivity

GWT 2.0 operating modes Development Mode All about productivity Java + JavaScript In a real browser

Production Mode All about performance Compiled, pure JavaScript/CSS/HTML

Development Mode

Web Server

Code Server

Java Virtual Machine Duke, the Java mascot Copyright © Sun Microsystems Inc., all rights reserved.

Google Plugin for Eclipse

The end of the preaching

Fast is better than slow > Minimize bandwidth l Can you use gzip encoding? l Is your CSS compiled/minimized? > Limit your HTTP-requests l Do your user agent support multipart? l Can you leverage spriting? (minimize that whitespace!)

Conclusion >Know your audience. >Target devices based on your target market. >Render your content intelligently: leverage existing libraries to know their capabilities.

Part Two - Going Deeper Programming in App Engine Build simple app using key App Engine components Q&A Competition

Java Environment Apps run in the Java 6 virtual machine (JVM) App Engine SDK supports Java 5 and higher Uses the Java servlet standard for web apps Heavy use of common Java standards where possible JDO/JPA for Datastore JavaMail for Email Service java.net for URL Fetch Service JVM instance for each app is sandboxed for security No threads, local file system access or arbitrary network connections Seamless development in Eclipse via Google Eclipse Plugin Development server runs locally and simulates Datastore, services and sandbox restrictions

Python Environment Support for Python 2.5 or higher App interacts with the App Engine web server via the Common Gateway Interface (CGI) protocol Support for any WSGI-capable web application framework such as Django and and CherryPy Python interpreter runs in a sandbox for security No threads, local file system access, modules with C code or arbitrary network connections Tools for testing, uploading application files, managing Datastore indexes, downloading log data, etc. Development server runs locally and simulates Datastore, services and sandbox restrictions

Let's get our hands dirty Customer requirement Build a sample guest book application in Python (or Java) Expectations You have completed the Code Lab environment setup after you registered. Instructions here (http://goo.gl/cph4) Follow along the codelab here (http://goo.gl/SWEE)

Case Study: Guest Book App

Demo (goo.gl/tBAw)

Before you start, think about... Programming Language What runtime environment to use? (Python, or, Java) Logging in and logging out How to authenticate users? (Users Service) Storing data How to persist and query data? (Datastore) Look and feel How to design a dynamic UI? (Templates)

Functional requirements Set up your app Java: web.xml & appengine-web.xml Python: app.yaml Authentication: Application can log user in and log user out Application has different behaviour depending on whether a user is logged in or not Logged-out (anonymous) users can post shoutouts and see shoutouts of other anonymous users Logged-in (authenticated) users can post shoutouts and see their own shoutouts Datastore: Store shoutouts in a database

Java: Hello World (http://goo.gl/tBbu)

Java: Authentication

Java : Datastore

Java: Saving a Shoutout

Java: Retrieving Shoutouts

Python: Hello World (http://goo.gl/SWEE)

Python: Authentication

Python: Datastore

Python: Saving a Shoutout

Python: Retrieving Shoutouts greetings = db.GqlQuery("SELECT * FROM Greeting ORDER BY date DESC LIMIT 10") greetings = Greeting.gql("ORDER BY date DESC LIMIT 10") greetings = Greeting.gql("WHERE author = :1 ORDER BY date DESC", users.get_current_user()) greetings = Greeting.gql("WHERE author = :author ORDER BY date DESC", author=users.get_current_user())

Look and feel Separate application logic and appearance Should be easy to update without changing application logic The Java way JSP The Python way Django templates

Python: Templating with Django guestbook.html

Java: Templating with JSP guestbook.jsp

Java: Serving Static Files

Python: Serving Static Files

Uploading to AppEngine Go to appengine.google.com Create an application ID Change your local application ID to match that on appengine.google.com Click the 'Deploy' button to upload it to the Google App Engine cloud View your application at .appspot.com

Useful App Engine Resources App Engine development in Java - http://goo.gl/hCBC App Engine development in Python - http://goo.gl/yhv5

Q&A

Case Study: StockWatcher App

Demo

Come see us at the Code Clinic Using Google App Engine and Web Toolkit from Eclipse

Appendix

Using Google App Engine + Web Toolkit With Eclipse using the Eclipse plugin

Homework Deploy to App Engine

Channel API Asynchronous Server

Client Communication

Channel-based Bi-directional

Server Send messages via ChannelService object Receive messages in a web hook

Client JavaScript library Receive server messages in a callback

Built on Gmail chat client (Google Talk)

Channel API - Server Interface /** * ChannelService allows you to manage two-way connections * with clients. */ public interface ChannelService { /** * Creates a channel associated with the provided applicationKey */ String createChannel(String applicationKey); /** * Sends a ChannelMessage to the client. */ void sendMessage(ChannelMessage message); /** * Parse the incoming message in request. This method * should only be called within a channel webhook. */ ChannelMessage parseMessage(HttpServletRequest request); }

Channel API - Client (JavaScript) // Create a new channel var channel = new wnd.goog.appengine.Channel(channelId); // Setup communications with the server var socket = channel.open(); socket.onopen = function(event) { // socket is now fully functional }; socket.onmessage = function(event) { // handle string msg (event.data) }; // Hello, server. How are you? socket.send(msg);

Dance Dance Robot

Mapper API Part 1 of the MapReduce story Batch processing at scale Sample Use Cases Report Generation Data export Schema Migration

Built on Task Queues Rate configurable

Mapper API - OSS Project Open source software - Apache 2 license http://mapreduce.appspot.com Patches welcome :)

Entirely user-space Just include it in your project!

Python & Java versions Features Automatic sharding Automatic rate limiting /mapreduce/status Counters Batching datastore operations

Presentations soon on: bit.ly/gksa

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