The document provides an overview of Google App Engine, a platform that allows developers to build and host web applications without having to manage servers. It discusses the challenges of building scalable web applications, describes App Engine's features such as automatic scaling and integrated services, and covers how to develop, test, and deploy applications locally and on App Engine. It also reviews App Engine's programming languages, data storage, quotas, and billing model.

1. Google App Engine
Day of Cloud
October 16, 2009
Monday, October 19, 2009 1

2. About Me
Don Schwarz
schwardo@google.com
Software Engineer
Google
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3. Overview
• Problems with scalable web applications
• What is Google App Engine?
• Let’s Play a Game
• How much does it cost?
• Q/A
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4. Challenges of Building Web Apps
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5. Easy to start. Easy to scale.
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6. It’s all included!
Hardware
Connectivity
Operating System
Web Server
Language Runtimes
Software Services
Fault-tolerance
Load balancing
SSL Support
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7. Key Features
• No need to install or maintain your own stack
• We do the scaling for you
• Use Google’s scalable services
• We charge only for actual usage
– Always free to get started
• Built-in application management console
• Tool integration (IDE plugins, etc.)
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8. Architecture
Incoming Requests
App Engine App Engine App Engine
Load Balancer Front End Front End Front End
AppServer AppServer AppServer
Other Google
AppServer Infrastructure
API Layer - Bigtable
- Google Accounts
- Memcache
App App App
- Image manipulation
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9. Software Services
Service Google Infrastructure
Authentication Google Accounts
Datastore Bigtable
Caching Custom memcache implementation
E-mail Gmail gateway
URLFetch Caching HTTP proxy
XMPP Google Talk infrastructure
Images Picasa Web Photo Infrastructure
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10. Web Hooks
• Receiving XMPP
• Receiving Email
• Scheduled Tasks (cron)
• Task Queue (offline processing)
• Google Wave Robots
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11. Restrictions
• No threads
• No direct network connections
• ... but URLFetch & SDC
• No direct file system writes
• ... but Datastore and Memcache
• No subprocesses or native code
• “Safe” subset of runtime environment
• 30 seconds per request, 10MB limit
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12. Java
• Java 6 VM (with Hotspot)
• Full Servlet 2.5 Container
• HTTP Session support
• JSP support
• Services integrate with common Java Standards
• JDO/JPA for Datastore API
• JSR 107 for Memcache API
• javax.mail for Mail API
• java.net.URLConnection for URLFetch API
• IDE integration: Eclipse, IntelliJ, NetBeans
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13. Python
• Python 2.5.2
• CGI environment, provided by WSGI module
• Web frameworks
• webapp - Minimal built-in framework, based on WebOb
• Django 0.96 is built-in, can deploy 1.0 or 1.1
• App Engine Launcher (Mac & Windows)
• Easy access to edit, test, and deploy applications
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14. Datastore
• Datastore is:
• Transactional
• Natively Partitioned
• Hierarchical
• Schema-less
• Based on Bigtable
• Datastore is not:
• A relational database
• A SQL engine
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15. Interesting Datastore Modeling
• Ancestor
• Multi-value properties
• Variable properties
• Heterogenous property types
Kind Person Kind Person
Entity Group /Person:Ethel Entity Group /Person:Ethel
/Person:Ethel/ Key /Person:Ethel
Key
Person:Jane Age Int64: 30
Age Double: 3.5
Hobbies String: Tennis
Key:/Turtle:Sam
Pets
Key:/Dog:Ernie 15
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16. Datastore Transactions
• Transactions apply to a single Entity Group
• Global transactions are feasible
• get(), put(), delete() are transactional
• Ancestor queries are transactional
/Person:Ethel
Transaction /Person:Ethel/Person:Jane
/Person:Max
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17. Testing Locally
• “Development AppServer”
• Emulates production environment
• Enforces many of the same restrictions
• Local implementation of software services
• Disk-based datastore
• In-memory LRU memcache implementation
• Simple URLFetch implementation
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18. Deploying to the Cloud
• Application is available at:
• yourapp.appspot.com, or
• a custom domain
• Command-line and IDE-based tools
• Admin Console
• Dashboards, Data Viewer
• Request and diagnostic logs
• Billing
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19. Code Walkthrough
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20. http://java-demo.appspot.com
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21. Quotas and Billing
Resource Provided Free Additional Cost
CPU 6.5 hours/day $0.10/hour
Bandwidth In 1GByte/day $0.10/GByte
Bandwidth Out 1GByte/day $0.12/GByte
Stored Data 1 GB $0.005/GB-day
2000/day to users $0.0001/email
Emails sent
50000/day to admins
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22. Quotas and Billing: Estimates
• Will always be free to get started
• ~5 million pageviews/month free
• Pay only for what you use
• 10-20 million pageviews/month for
$20-30/month
• Payment via Google Checkout
• X-AppEngine-Estimated-CPM-US-Dollars
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23. Questions?
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24. Resources
• Speaker
• Don Schwarz (schwardo@google.com)
• Google App Engine
• http://code.google.com/appengine
• Google Group
• http://groups.google.com/group/google-appengine
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25. Backup Slides
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26. Does it scale?
http://whitehouse.gov/openforquestions 26
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27. Secure Data Connector
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28. Demo - Login
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29. Demo - Question
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30. Demo - Question Result
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31. Demo - Scoreboard
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