Real life experience from
AppEngine & Django
Udi h Bauman
Google Developers Day Israel 08

About me
 SW architect and developer
 Expertise in BI and Semantic Web
 Using Python, Django, AppEngine & EC2 for
daily work

About my company
 We develop and automate Value Creation
Processes and by that enable enterprises to
maximize their profits.
 Our solution is Django
based & considered one
of the largest & most
complex enterprise products developed in
Django.
 Our CEO is Orr Mendelson, a top expert in
Value Creation
 We are in Beta stage in several enterprises

My experience in web applications

Great Web Technologies Pain!
 CGI
 ASP
 ColdFusion
 Servlets
 JSP
 EJB
 .Net
 Open-Source Java frameworks
 AJAX frameworks
 PHP
 Ruby
 Rails

Lesson #1
is the best
Web technology
today.

Django Example
 Web site for Visualizing time differences around
Daylight Saving Time events
− http://daylight-savings-time.info

Using Django
 Data model takes minutes to define
 Django builds the DB based on the data model
 Django generates the back-office administration
screens
 Django provided the I18N layer
 The logic written in Python is OO, simple &
succinct, so both dev & maintenance are extra
fast
 I could focus only on the logic
 I kept it simple

Is it mature enough? Does it scale?
 Dev technology is really tested when the project
passes a certain level of size & complexity
 Some technologies, optimized for rapid
development, don't scale beyond that point:
they don't allow the flexibility & power to grow in
complexity & scale, without compromising
features & simplicity
 After working for 2 years, building a very large
& complex enterprise product, I can truly say
Django is mature enough & scales extremely
well

Still have to take care of:
 Deployment
− Configuring Apache, DB, Virtual hosting, Prod &
Staging environments, &c
 Specific application requirements:
− Traffic peaks
− DB clustering & extreme scalability

Using AppEngine
 AppEngine is based on Django, & solves the 1
pain left when using it - it just takes from you all
the worries & boring work on:
− deployment
− hosting
− scalability
− DB management

Lesson #2
is awesome!

AppEngine Demo
 Alex Arshavski & me made a small Demo of
using AppEngine for a previous developers
event at Google
 It took us 2 cafe meetings
 Try application at:
− http://ppl-search.appspot.com
 Download source code:
− http://code.google.com/p/ppl-search

How come we could build it so fast?
 Because AppEngine (& Django) let's you focus
just on the business logic, & do it simply
 Because we used of components & Web-
Services, that we just needed to mash-up
 Because the documentation is extremely good,
& you can get an answer to any problem you
encounter

What's the catch?
 Experienced people always think long-term &
manage risks
 So their main concern is vendor locking – being
tied to Google for ever with their application
 It turns out Google had to make some
modifications to Django, so writing for
AppEngine, isn't like writing pure Django (which
can run anywhere)

Tip
 Always use the AppEngine Django Helper

Using the Django helper
 Let's you write regular Django application, and
adapts them to AppEngine
 Abstracts some of the Google API's
 Allows you to take your site to other
cloud/hosting services with only minor changes
 To use it:
− Create an app using the AppEngine SDK
− Replace the content of the folder created with the
content of the helper
− Rename the app in the app.yaml file

Is AppEngine production ready?
 Make sure to be familiar with the quota of the
service
− Requests are limited to 10s
− Throughput is limited
 Note that its not yet production ready, mainly in
the aspects of uptime SLA & support.
 Subscribe to the outage announecement
Google group to get notifications on Up-Time
− There's also a great monitoring dashboard of cloud
services: http://cloudstatus.com

BTW, about Amazon EC2
 The main difference is that EC2 just provides
the cloud infrastructure, but not the application
stack, so you still have the headaches of
deployment, configuration &c
 The good thing is that it's completely flexible, &
can run any technology / legacy application

Criticism on Django
 “Why I hate Django” - hilarious keynote from
DjangoCon, by Cal Henderson (Flickr's
Architect):
− http://tinyurl.com/hatedjango
 Extremely funny..

Thank you !
Udi h Bauman
http://twitter.com/dibau_naum_h
DibauNaumH@gmail.com