java web programming using cloud platform: module 10
DESCRIPTION
Java Web Programming Using Cloud Platform Training 18-22 Feb 2013 Module 10: Google App Engine and HerokuTRANSCRIPT
Module 10: Java Cloud Platform
Dr.Thanachart Numnonda
Dr.Thanisa Kruawaisayawan
www.imcinstitute.com
18-22 February 2013
2
Objectives
What is Cloud Computing?
What is Google App Engine? Google App Engine for Java Google App Engine Development cycle
Heroku Introduction
3
What is Cloud Computing?
4
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.
5
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
6
Grid to Cloud Evolution
7
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.
8
ISP to Cloud Evolution
9
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.
10
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
11
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.
12
13
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.
14
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,
15
Setting Up App in IaaS
Source:http://acloudyplace.com/2012/01/comparing-iaas-and-paas-a-developers-perspective/
16
Setting Up App in PaaS
Source:http://acloudyplace.com/2012/01/comparing-iaas-and-paas-a-developers-perspective/
17
PaaS for Java
Amazon Elastic Beanstalk CloudBees Cloud Foundry Google App Engine Heroku for Java Red Hat OpenShift
18
PaaS for Java: Comparison
19
PaaS for Java: Comparison
20
What is Google App Engine?
21
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.
22
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
23
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
24
You end up with all this
25
26
Google Datacenters at Dallas, Oregon
27
GAE Architecture
28
GAE Physical Deployment Diagram
29
Architecture : Application Server
30
Distributed web hosting platform
31
Distributed Datastore
32
Distributed memcache
33
Specialized services
34
Google Apps + your apps
35
Google App Engine for Java
36
GAE/J
Was released on April 08 with Python support. Java included on August 09
37
App Engine for Java : One Year
Source: What’s Hot in Java for App Engine Google Con 2010
38
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
39
Java Standards on GAE
40
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
41
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)
42
GAE Datastore
43
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
44
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
45
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>";
}
46
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
47
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);
48
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
49
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);
50
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", "[email protected]")
.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", "[email protected]")
.param("firstname", "Juliet");
Queue queue = QueueFactory.getDefaultQueue();
queue.add(taskOptions);
51
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>
52
Images API
Manipulation of images
Transformation of images
Changing image formats
53
GAE Development Cycle
54
GAE Development Cycle
55
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.
56
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.
57
Google Plugin for Eclipse
58
Development Environment
Development Server Application lifecycle
management Eclipse/NetBeans
plugins /
Firefox plugin (GWT)
59
Google Plugin for Eclipse
60
Development Server
http://localhost:8888
61
Development Server Admin Consolehttp://localhost:8888/_ah/admin
62
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
63
Running your app on Google
http://<version>.<appid>.appspot.com/some/path
64
Managing Applications
Administration Console
http://appengine.google.com/a/yourdomain.com Application Dashboard Multiple application versions Analyzing log files (including admin) Analyzing resource usage
65
GAE Dashboard
66
67
Heroku
Platform as a Service for professional apps developers
Forget servers Run anything See everything Trust & Managed
68
Forget Servers
Agile deployment for Ruby, Node.js, Clojure, Java, Python, and Scala.
69
70
71
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