Overview of Google App Engine features for developing web applications and rest api.

1. DEPLOYING APPLICATIONS
TO CLOUD

2. ABOUT ME
 Alexander Zamkovyi
Java Developer @ Intro Pro
Linked[in]: ua.linkedin.com/in/invaa/
e-mail: alex@zamkovyi.name

3. GOOGLE APP ENGINE
 Part of Google Cloud Platform (trusted by 4 million applications)
 Platform-as-a-Service (Java, Python, PHP, Go)
 264k websites (258k is active), according to builtwith.com
 Coca-cola, Snapchat, Ubisoft, Rovio, BestBuy, Sony Music, ...

4. REASONS TO LEARN GOOGLE APP ENGINE
 Highly scalable
 Integration
 Cost-effective
 Well documented
 It’s Google

5. CLOUD, CLOUD, CLOUD!

6. PLAN
 Google Cloud Endpoints
 Google App Engine Development Process
 Deployment and Troubleshooting
 Persistence
 Limitations

7. GOOGLE CLOUD ENDPOINTS

8. GOOGLE CLOUD ENDPOINTS

9. THE SANDBOX
 Java 7 JVM in a safe "sandboxed" environment
 Servlet 2.5 standard
 Standard WAR directory structure
 Secured "sandbox" environment isolates application for service and security
 The JVM can execute any Java bytecode that operates within the sandbox
restrictions

10. DEMO (CLOUD ENDPOINTS)
Web frontend
 Deployed: https://cloudendpointstic.appspot.com
 Sources: https://github.com/GoogleCloudPlatform

11. DEMO (CLOUD ENDPOINTS)
Android client
 Deployed:
https://play.google.com/store/apps/details?id=com.devrel.sa
mples.ttt
 Sources: https://github.com/GoogleCloudPlatform

13. DEVELOPMENT PROCESS

14. REQUIREMENTS AND PREREQUISITES
 JDK 1.7 (recommended)
 Apache Maven 3.1+
 MySQL 5+ (for local dev server)
 Google account
 Application ID
 IDE

15. GAE JAVA PROJECT STRUCTURE
 You'll add your own application Java classes
to src/main/java/...
 You'll configure your application using the
file src/main/webapp/WEB-INF/appengine.web.xml
 You'll configure your application deployment using
the file src/main/webapp/WEB-INF/web.xml

16. THE JAVA DEVELOPMENT SERVER
 jetty-6.1.x (built-in)
 The development web server simulates the App Engine Java runtime
environment and all of its services, including the datastore

17. ADMIN CONSOLE
 http://localhost:port/_ah/admin

18. DEPLOYMENT AND
TROUBLESHOOTING

19. UPLOADING APP
 mvn appengine:update

20. DEVELOPER'S CONSOLE
 https://console.developers.google.com/

21. APPCFG
 appcfg.cmd
[options]
<action>
<war-location>

22. PERSISTENCE

23. DATASTORE AND RDBMS

24. DEMO (CLOUD DATASTORE AND CLOUD SQL)
Calendar app
Features:
 JPA (Cloud SQL vs Cloud Datastores)
 Spring MVC
 jQuery
 Deployed: http://cloudcalendarservice.appspot.com/
 Sources: https://github.com/invaa/CloudCalendar

25. LIMITATIONS

26. AN APP ENGINE APPLICATION CANNOT
 write to the filesystem. Applications must use the App Engine datastore for
storing persistent data. Reading from the filesystem is allowed, and all
application files uploaded with the application are available
 respond slowly. A web request to an application must be handled within a few
seconds. Processes that take a very long time to respond are terminated to
avoid overloading the web server
 make other kinds of system calls

27. WEB.XML FEATURES NOT SUPPORTED
 App Engine supports the <load-on-startup> element for servlet declarations.
However, the load actually occurs during the first request handled by the web
server instance, not prior to it
 Some deployment descriptor elements can take a human readable display
name, description and icon for use in IDEs. App Engine doesn't use these,
and ignores them
 App Engine doesn't support JNDI environment variables (<env-entry>)
 App Engine doesn't support EJB resources (<resource-ref>)
 Notification of the destruction of servlets, servlet context, or filters is not
supported
 The <distributable> element is ignored
 Servlet scheduling with <run-at> is not supported

28. JPA FEATURES NOT SUPPORTED
 Owned many-to-many relationships
 "Join" queries. You cannot use a field of a child entity in a filter when
performing a query on the parent kind. Note that you can test the parent's
relationship field directly in a query using a key
 Aggregation queries (group by, having, sum, avg, max, min)
 Polymorphic queries. You cannot perform a query of a class to get instances
of a subclass. Each class is represented by a separate entity kind in the
datastore

29. JRE WHITE LIST

30. Q&A
ua.linkedin.com/in/invaa/
alex@zamkovyi.name