Google App Engine
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Transcript of Google App Engine
David PageThe OTOBAS Group Pty Ltd
19 April 2008BarCamp Canberra
OverviewWhat is the Google App Engine?FeaturesLimitationsWhere is it going?
What is Google App Engine?Trial beta announced on April 7Web application development environmentBased on Python scripting languageIncludes a data store (non-relational)Google hosts the application
Can use default domain or use your ownBasic is free, Fee based structure yet to be
announcedhttp://code.google.com/appengine/
FeaturesDynamic web serving, with full support for
common web technologiesPersistent storage with queries, sorting and
transactionsAutomatic scaling and load balancingAPIs for authenticating users and sending
email using Google AccountsA fully featured local development
environment that simulates Google App Engine on your computer
The Data StoreDistributed data storage serviceFeatures a query engine and supports
transactions including optimistic locking and rollback
The distributed datas tore grows with the dataThe data store is not like a traditional relational
database:Data objects, or "entities," have a kind and a set
of properties. Queries can retrieve entities of a given kind
filtered and sorted by the values of the properties.
Other FeaturesAccount administration done via Google
accountsAPIs can access other web resourcesEnvironment is sandboxed, but scaling is
automaticThe SDK provides a complete runtime
environment
LimitationsAn application can only access other
computers on the Internet through the provided URL fetch and email services and APIs.
Other computers can only connect to the application by making HTTP (or HTTPS) requests on the standard ports.
An application cannot write to the file system. An app can read files, but only files uploaded
with the application code. The app must use the App Engine data store
for all data that persists between requests.
LimitationsApplication code only runs in response to a web
request Must return response data within a few seconds. A request handler cannot spawn a sub-process
or execute code after the response has been sent.
A query can only return 1,000 resultsFree environment limits:
500mb data store5 million page views per month
Where is it Going?Google is stalking on-line computing:
Search engineGoogle mailTabbed home page with widgetsGoogle office applicationsGoogle Apps
Web pages Collaboration (document sharing, intranet, chat etc) Calendar Documents
Google App Engine
Where is it Going?Implications:
Explosion of small on-line web applications = more users
Modularised approach = mash-upsOpportunity to move small business from PC to webGreatly reduced cost of deploymentCheaper to move to online tradingAffordable scaling of application
Where next?Move to cheap web enabled devices/mobile devicesBroaden base and apply search ability to everythingMore eyeballs = more advertising revenue