Content prepared for delivering session in Python Pune meetup

1. Akshay Mathur
@akshaymathu

2. Ground Rules
• Disturb Everyone
– Not by phone rings
– Not by local talks
– By more information
and questions
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3. Let’s Know Each Other
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Do you code?
OS?
Language?
Used GAE?
Why are you attending?
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4. Akshay Mathur
• Founding Team Member of
– ShopSocially (Enabling “social” for retailers)
– AirTight Neworks (Global leader of WIPS)
• 15+ years in IT industry
– Currently Principal Architect at ShopSocially
– Mostly worked with Startups
• From Conceptualization to Stabilization
• At different functions i.e. development, testing, release
• With multiple technologies
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5. What shall we learn
• Why GAE (Google App Engine)?
• General advantages of
– IaaS (Infrastructure as a Service)
– PaaS (Platform as a Service)
• Using GAE SDK
– Available Services from Google
• Filling the Gap
– Including third party libraries
– Creating MVC structure
• Available boilerplate code for quick start
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6. Why GAE
• Application PaaS maintained by Google
– Same platform that powers Google Applications
• Familiar technologies
– Python, PHP, Java, Go
• Readymade additional services
– Storage, Email, Chat, Task queue etc.
• No (or very low) initial cost
– Free quotas
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7. @akshaymathu
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8. IaaS
• Move your local/data center servers to cloud
– Don’t worry about hardware
– Scale up/down as needed
• Simplified logistics for IT admins
• Pay only for used infrastructure
• Custom hardware is not available
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9. PaaS: Advantages
• Move your application environment on cloud
– Focus only on your application
– Don’t worry for upgrades
– Easy to scale
– Easy to administer
• Get all benefits of IaaS
• Control in developers’ hand
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10. @akshaymathu
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11. PaaS: Limitations
• No control over machines
– No access to file system
– No ssh
• No native software installation
– Use only the provided software
– Upgrade with the provider
• Limitation on usage of network stack
– No sniffing of traffic
– Limited use of ports
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12. Getting Started
Hello world!

13. Why Python
• Because we love it 
• GAE says:
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14. Getting Started
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Install Python 
Download and install GAE SDK
Configure app.yaml
Write code
Test locally as GAE app
Deploy
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15. Runtime configuration: app.yaml
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16. Code: main.py
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17. Deploy
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18. @akshaymathu
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19. Gearing up for Bigger App
Creating the basic Structure

20. Included Libraries
Webapp2, Django, Ssl, PIL, Pycrypto,
Setuptools, Webob, Yaml, MySQLdb
Endpoints: Libraries for building APIs in an App Engine application.
Jinja2: A modern and designer friendly templating language for Python.
Lxml: A Pythonic binding for the C libraries libxml2 and libxslt.
Markupsafe: A XML/HTML/XHTML markup safe string for Python.
Matplotlib: A 2D plotting library which produces publication-quality figures.
Numpy: A general-purpose library for array-processing.
Protorpc: A framework for implementing HTTP-based remote procedure call (RPC)
services.
PyAMF: A library that provides (AMF) Action Message Format functionality.
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21. Available Services
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22. Data Storage
• Datastore
– A schemaless object datastore providing robust, scalable storage
for your web application, a rich data modeling API, and a SQLlike query language called GQL.
• Blobstore
– Allows your application to serve large data objects, such as
video or image files, that are too large for storage in the
Datastore service.
• Memcache
– A distributed, in-memory data cache that can be used to greatly
improve application performance.
• Logs
– Provides programmatic access to application and request logs
from within your application.
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23. Communications
• Channel
– Creates a persistent connection between your application and
Google servers, so you can send messages to JavaScript clients
in real time without "polling."
• Mail
– Sends email messages on behalf of administrators and users
with Google Accounts, and receives mail at various addresses.
• URL Fetch
– Uses Google's networking infrastructure to efficiently issue
HTTP and HTTPS requests to URLs on the web.
• XMPP
– Enables an application to send and receive chat messages to
and from any XMPP-compatible chat messaging service.
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24. Process Management
• Task Queue
– Allows applications to perform work outside of a
user request, and organize that work into small,
discrete units, called "tasks," to be executed later.
• Scheduled Tasks
– Allows applications to configure regularly
scheduled tasks that operate at defined times or
regular intervals.
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25. Computation
• Backends
– Instances of your application that are exempt from
request deadlines and have access to more
memory and CPU resources.
• Images
– Manipulates, combines, and enhances images,
converts images between formats, and queries
image metadata such as height and frequency of
colors.
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26. App configuration and management
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App Identity
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Capabilities
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Makes it easy to compartmentalize your data to serve many client organizations from a single instance of
your application.
Traffic Splitting
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Lets external applications transparently access App Engine services. For example, you can use Remote API to
access a production datastore from an app running on your local machine.
Multitenancy
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Allows applications to be served via both HTTPS and HTTP via a custom domain instead of an appspot.com
address.
Remote
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Provides detection of outages and scheduled maintenance for specific APIs and services, so that your
application may bypass them or inform your users.
SSL for Custom Domains
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Gives code access to the application identity; provides framework to assert this identity over OAuth.
Allows you to roll out features for your app slowly over a period of time, and do A/B Testing. Traffic Splitting
works by splitting incoming requests to different versions of your app.
Users
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Allows applications to sign in users with Google Accounts or OpenID, and address these users with unique
identifiers.
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27. Third-party Services
• SendGrid (Email)
– Use SendGrid's library to send emails from your
app and you can see statistics on opens, clicks,
unsubscribes, spam reports and more.
• Twilio (SMS/Voice)
– Enables your application to make and receive
phone calls, send and receive text messages, and
make VoIP calls from any phone, tablet, or
browser.
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28. Preview Features
• Google Cloud Endpoints
– Enables automatic generation of APIs, making it easier to create a web
backend for web clients and mobile clients such as Android or Apple's iOS.
• Google Cloud SQL
– A fully-managed web service that allows you to create, configure, and use
relational databases that live in Google's cloud.
• Google Cloud Storage Client Library
– Lets your application read files from and write files to buckets in Google Cloud
Storage, with with internal error handling and retry logic.
• Modules
– Lets developers factor large applications into logical components that can
share stateful services and communicate in a secure fashion.
• Sockets
– Enables support for outbound sockets using the language-specific, built-in
libraries.
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29. Experimental Features
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MapReduce
– An optimized adaptation of the MapReduce computing model for efficient distributed
computing over large data sets.
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OAuth
– Using Google Accounts and the OAuth API, any App Engine application can be an OAuth
consumer.
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OpenID
– An open technology used for authenticating users across various web services.
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PageSpeed
– A family of tools that automatically optimizes the performance of your application.
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Task Queue REST API
– Enables the use of an App Engine task queue over REST.
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Task Queue Tagging
– Leases up to a specified number of tasks with the same tag from the queue for a
specified period of time.
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30. Search
• Search
– Allows your application to perform Google-like
searches over structured data such as: plain text,
HTML, atom, numbers, dates, and geographic
locations.
• Prospective Search
– A querying service that allows your application to
match search queries against real-time data
streams.
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31. Filling the Gap
• Including other libraries
– Place them within your app
– Only pure Python libs can be used
• Creating MVC structure
– Create your own directory structure
– Adjust path for supporting it
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32. MVC Structure
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33. New Code: main.py
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34. Global Configuration: config.py
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35. Route List
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36. Controller
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37. Base Controller
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38. Third Party Libs
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39. Static Files
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40. @akshaymathu
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41. Dive Deeper
Get the app working

42. Scheduled Tasks: cron.yaml
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43. Datastore
• NoSQL database is available in free quota
– SQL database (Google Cloud SQL) is also available
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44. Data Manipulation
• Functions
– .get_by_id()
– .all()
– .put()
– db.delete()
• GQL
– .gql()
• People.gql("where email_addr = :1 and passwd
= :2", username, get_password_hash(passwd))
– gql_query()
• gql_query(”select * from people where
email_addr = :1 and passwd = :2", username,
get_password_hash(passwd))
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45. Task Queue
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46. Sending Emails
• Gmail is available as mail service by default
– Sendgrid can also be used
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47. Using Others’ Web API
• Urlfetch can be used for accessing external
web urls
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48. Sockets
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Only for paid apps
Works exactly same as standard socket library
Inbound sockets are not allowed
Outbound sockets can be used with
restrictions
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49. Google’s Login
from google.appengine.api import users
user = users.get_current_user()
if user:
user.nickname()
users.create_logout_url('/')))
else:
users.create_login_url('/'))
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50. Working with Images
• Images can be stored in database in blob fields
• Available transforms
– Resize, Crop
– Rotate, Flip horizontal /vertical
– Enhance (Im feeling lucky)
• Formats Conversions
– from: JPEG, PNG, WEBP, GIF, BMP, TIFF and ICO
– to: JPEG, WEBP and PNG
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51. Image Manipulation
from google.appengine.api import images
img = images.Image(blob_key=blob_key)
img.resize(width=80, height=100)
img.im_feeling_lucky()
thumbnail = img.execute_transforms(
output_encoding=images.JPEG)
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52. Caching
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53. @akshaymathu
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54. Available Code on GitHub
• Implementation of login system
– mathurakshay/gae-social-login
• https://github.com/mathurakshay/gae-social-
• Just the MVC structure
– droot/gae-boilerplate
• https://github.com/droot/gae-boilerplate
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55. Summary
• GAE is good readymade platform
– For trying out things
– For your side project
• Many services are readily available
• Starts with no (or very low) upfront cost
• Think thrice before you start big business on
GAE
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56. Thanks
@akshaymathu
@akshaymathu
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