java web programming using cloud platform: module 10

Module 10: Java Cloud Platform

Dr.Thanachart Numnonda

Dr.Thanisa Kruawaisayawan

www.imcinstitute.com

18-22 February 2013

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Objectives

What is Cloud Computing?

What is Google App Engine? Google App Engine for Java Google App Engine Development cycle

Heroku Introduction

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What is Cloud Computing?

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Cloud Computing : Definition (Wikipedia)

Cloud Computing is Internet-based computing, whereby shared resources, software, and information are provided to computers and other devices on demand, like the electricity grid.

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Cloud Computing Characteristics

Massive, abstracted infrastructure Dynamic allocation, scaling, movement of

applications Pay per use No long-term commitments OS, application architecture independent No hardware or software to install

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Grid to Cloud Evolution

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Web 2.0 & Cloud Computing

Web 2.0 concentrates on the private user and clouds are decscendents of data centers which services the enterprise.

Web 2.0 promotes SaaS. Web 2.0 needs massive scaling technologies. User centric Web 2.0 companies (Twitter,

Slideshare) are relying on Cloud Services.

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ISP to Cloud Evolution

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Software as a Service (SaaS)

SaaS is at the highest layer and features a complete application offered as a service, on-demand,

via multitenancy — meaning a single instance of the software runs on the provider’s infrastructure and serves multiple client organizations.

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Platform as a Service (PaaS)

The middle layer, or PaaS, is the encapsulation of a development environment abstraction and the packaging of a payload of services

PaaS offerings can provide for every phase of software development and testing, or they can be specialized around a particular area, such as content management

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Infrastructure as a Service (IaaS)

IaaS is at the lowest layer and is a means of delivering basic storage and compute capabilities as standardized services over the network.

Servers, storage systems, switches,routers, and other systems are pooled (through virtualization technology, for example) to handle specific types of workloads — from batch processing to server/storage augmentation during peak loads.

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Deployment Model

Public Cloud: provider refers to the cloud platform that targets any types of customers.

Private Cloud: infrastructure that’s hosted internally, targeting specific customers or sometimes exclusively within an organization.

Hybrid Cloud: the combination of public and private clouds, or sometimes on-premise services.

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IaaS & PaaS: Developer's Perspectives

IaaS normally provides up to O/S level as your choice; for example Amazon Web Services (AWS) offers several types of Operating Systems such as Windows Server, Linux SUSE, and Linux Red Hat. Developer need to install own middleware, database, etc.

PaaS, given that the database server, VM, and web server VM are readily provisioned,

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Setting Up App in IaaS

Source:http://acloudyplace.com/2012/01/comparing-iaas-and-paas-a-developers-perspective/

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Setting Up App in PaaS

Source:http://acloudyplace.com/2012/01/comparing-iaas-and-paas-a-developers-perspective/

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PaaS for Java

Amazon Elastic Beanstalk CloudBees Cloud Foundry Google App Engine Heroku for Java Red Hat OpenShift

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PaaS for Java: Comparison

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PaaS for Java: Comparison

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What is Google App Engine?

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Google App Engine : Definition (Wikipedia)

It is a platform for hosting web applications in Google-managed data centers. It is cloud computing technology which virtualizes applications across multiple servers and data centers.

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Google App Engine

Running your web application in Google infrastructure

Support different runtime environments Java (JRE 6 with limitation, Servlet 2.5, JDO,

JPA) Python (2.5.2) Apps run in sandbox. Automatic scaling and load balancing No server restart, no network issues

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Hosting Java web apps traditionally

Not so popular except enterprise High rates as compared to PHP hosting Shared Tomcat instance among users Restrictions on any time deployments due to

shared server Dedicated hosts works fine but they are costly

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You end up with all this

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Google Datacenters at Dallas, Oregon

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GAE Architecture

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GAE Physical Deployment Diagram

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Architecture : Application Server

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Distributed web hosting platform

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Distributed Datastore

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Distributed memcache

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Specialized services

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Google Apps + your apps

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Google App Engine for Java

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GAE/J

Was released on April 08 with Python support. Java included on August 09

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App Engine for Java : One Year

Source: What’s Hot in Java for App Engine Google Con 2010

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GAE Java Runtime Environment

Java 6 VM Servlet 2.5 Container HTTP Session support (need to enable explicitly) JDO/JPA for Datastore API JSR 107 for Memcache API javax.mail for Mail API javax.net.URLConnection for URLFetch API

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Java Standards on GAE

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Services by App Engine

Memcache API – high performance in-memory key-value cache

Datastore – database storage and operations URLFetch – invoking external URLs Mail – sending mail from your application Task Queues – for invoking background processes Images – for image manipulation Cron Jobs – scheduled tasks on defined time User Accounts – using Google accounts for

authentication

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Limitations

Programming Model : Application runs in sandbox and can not– Write to file system

– Make arbitrary network connections

– Use multiple threads/processes

– Perform long-lasting processing

– Permissions

– Know about other instances/applications Quotas (Requests, In/Out bandwidth, CPU time,

API calls)

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GAE Datastore

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GAE Datastore

Storing data and manipulation Based on Bigtable Bigtable is proprietary and hidden from the app

developers Not a relational database (No SQL) GQL (Google Query Language) to query Stores data as entities Distribution, replication, load balancing behind

the scene Need to use JDO/JPA

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User Service : Google Accounts

Google Accounts are encouraged as the preferred authentication mechanism for App Engine– It assumes that all users have a Google Account

– Google authentication for private domains isn’t available yet

Access to Google account data -> email, id The Development Server simulates Google

Accounts Access constraints based on roles

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User API : Example

import com.google.appengine.api.users.*;

UserService userService = UserServiceFactory.getUserService();

User user = userService.getCurrentUser();

String navBar;

if (user == null) {

navBar = "<p>Welcome! <a href=\"" + userService.createLoginURL("/") +"\">Sign in or register</a> to customize.</p>";

} else {

navBar = "<p>Welcome, " + user.getEmail() + "! You can <a href=\"" +userService.createLogoutURL("/") +"\">sign out</a>.</p>";

}

import com.google.appengine.api.users.*;

UserService userService = UserServiceFactory.getUserService();

User user = userService.getCurrentUser();

String navBar;

if (user == null) {

navBar = "<p>Welcome! <a href=\"" + userService.createLoginURL("/") +"\">Sign in or register</a> to customize.</p>";

} else {

navBar = "<p>Welcome, " + user.getEmail() + "! You can <a href=\"" +userService.createLogoutURL("/") +"\">sign out</a>.</p>";

}

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URLFetch API

import java.net.*;

import java.io.*;

URL url = new URL("htp://...");

InputStream inp = new InputStreamReader(url.openStream());

BufferedReader reader = new BufferedReader(inp);

String line;

while ((line = reader.readLine()) != null) {

//do something

}

reader.close();

import java.net.*;

import java.io.*;

URL url = new URL("htp://...");

InputStream inp = new InputStreamReader(url.openStream());

BufferedReader reader = new BufferedReader(inp);

String line;

while ((line = reader.readLine()) != null) {

//do something

}

reader.close();

Invoking external URLs from your application over HTTP and HTTPs

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Mail API Send emails on the behalf of app administrator to

the Google account use. You can not receive emails

import javax.mail.*;

Session session = Session.getDefaultInstance(new Properties(), null);

InternetAddress admins = new InternetAddress("admins");

Message msg = new MimeMessage(session);

msg.setFrom(admins);

msg.addRecipient(Message.RecipientType.TO, admins);

msg.setSubject("subject");

msg.setText("text");

Transport.send(msg);

import javax.mail.*;

Session session = Session.getDefaultInstance(new Properties(), null);

InternetAddress admins = new InternetAddress("admins");

Message msg = new MimeMessage(session);

msg.setFrom(admins);

msg.addRecipient(Message.RecipientType.TO, admins);

msg.setSubject("subject");

msg.setText("text");

Transport.send(msg);

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Memcache Service

Distributed in memory cache, better than DataStore

Key-value pair mapping Configurable expiration time but Unreliable might be vanished at any time Supported Interfaces :

– JACHE (JSR 107: JCACHE – Java Temporary Caching API)

– The Low-Level Memcache API

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Memcache API : Example

import static java.util.Collections.emptyMap;

import javax.cache.*;

CacheFactory cacheFactory = CacheManager.getInstance().getCacheFactory();

Cache cache = cacheFactory.createCache(emptyMap());

cache.put(key, value);

cache.get(key);

import static java.util.Collections.emptyMap;

import javax.cache.*;

CacheFactory cacheFactory = CacheManager.getInstance().getCacheFactory();

Cache cache = cacheFactory.createCache(emptyMap());

cache.put(key, value);

cache.get(key);

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Task Queues API Perform background processes by inserting tasks into

queues. Instructions need to be mention in file queue.xml, in

the WEB-INF/ dir

import com.google.appengine.api.labs.taskqueue.Queue;

import com.google.appengine.api.labs.taskqueue.QueueFactory;

import com.google.appengine.api.labs.taskqueue.TaskOptions;

// ...

TaskOptions taskOptions =

TaskOptions.Builder.url("/send_invitation_task")

.param("address", "juliet@example.com")

.param("firstname", "Juliet");

Queue queue = QueueFactory.getDefaultQueue();

queue.add(taskOptions);

import com.google.appengine.api.labs.taskqueue.Queue;

import com.google.appengine.api.labs.taskqueue.QueueFactory;

import com.google.appengine.api.labs.taskqueue.TaskOptions;

// ...

TaskOptions taskOptions =

TaskOptions.Builder.url("/send_invitation_task")

.param("address", "juliet@example.com")

.param("firstname", "Juliet");

Queue queue = QueueFactory.getDefaultQueue();

queue.add(taskOptions);

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Cron Jobs Up to 20 scheduled tasks per app Cron jobs (scheduled tasks) supported in cron.xml

in WEB-INF dir Schedule instructions contain Englis-like format

<?xml version="1.0" encoding="UTF-8"?>

<cronentries>

<cron>

<url>/listbooks</url>

<description>Repopulate the cache every day at

5am</description>

<schedule>every day 05:00</schedule>

</cron>

</cronentries>

<?xml version="1.0" encoding="UTF-8"?>

<cronentries>

<cron>

<url>/listbooks</url>

<description>Repopulate the cache every day at

5am</description>

<schedule>every day 05:00</schedule>

</cron>

</cronentries>

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Images API

Manipulation of images

Transformation of images

Changing image formats

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GAE Development Cycle

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GAE Development Cycle

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Getting Started

The application owner must have a Google Account to get the tools regardless of language.

Use Java 6 for development. Eclipse and Netbeans have official plugins. Both SDKs ship with a Development Web Server

that runs locally and provides a sandbox almost identical to the real run-time.

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Software Development Kit

App Engine SDK

– Includes web server (Jetty)– Emulates all the GAE services

SDK includes an upload tool to deploy app to GAE

Command line tools included.

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Google Plugin for Eclipse

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Development Environment

Development Server Application lifecycle

management Eclipse/NetBeans

plugins /

Firefox plugin (GWT)

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Google Plugin for Eclipse

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Development Server

http://localhost:8888

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Development Server Admin Consolehttp://localhost:8888/_ah/admin

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Deployment Environment

Application is deployed as .war which contains. Deployment is integrated in IDE Deploy multiple version of the application at the

same time Your app lives at

– <app_id>.appspot.com or– Custom domain with Google Apps

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Running your app on Google

http://<version>.<appid>.appspot.com/some/path

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Managing Applications

Administration Console

http://appengine.google.com/a/yourdomain.com Application Dashboard Multiple application versions Analyzing log files (including admin) Analyzing resource usage

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GAE Dashboard

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Heroku

Platform as a Service for professional apps developers

Forget servers Run anything See everything Trust & Managed

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Forget Servers

Agile deployment for Ruby, Node.js, Clojure, Java, Python, and Scala.

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Resources

Google App Engine at a glance, Stefan Christoph Developing Java Based Web Applications in Google App Engine, Tahir Akram, Dec. 2009 Google App Engine, Patrick Chanezon, Mar 2010

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Thank you

thanachart@imcinstitute.com

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www.imcinstitute.com