Manish Pandit, the Director of Engineering at IGN, discusses the evolution of APIs at IGN from 2006 to 2012, emphasizing the transition to Scala for improved performance and developer experience. The presentation covers the development of three versions of the API, the benefits of using Scala, including concurrency, immutability, and a robust developer community, as well as the challenges faced in learning and maintaining Scala. Future efforts include opening up APIs, continuous deployment, and simplifying technology stacks at IGN.

1. Evolving IGN’s new APIs with
Scala
Manish Pandit
Oct 4th, 2012

2. About me
Manish Pandit
Director of Engineering, IGN
@lobster1234
linkedin.com/in/mpandit

3. About IGN
We are a leading online media and services company
obsessed with gaming and entertainment.
56MM Monthly Unique Views
737MM Monthly Page Views
20MM Monthly Video Views

4. My Objective
Is:
To get you excited about building APIs in Scala
Isn't:
To incite a functional vs. imperative, or Scala vs.
____ debate

5. Agenda
• APIs at IGN
• API Evolution
• Why Scala
• API Development with Scala
• Monitoring, Maintaining, Evolving
• Performance Management

6. APIs at IGN
• Offer SOA advantages
• Isolate the back end systems from the FE
• IGN is going where the audience is, fast
– Mobile Devices, Consoles, TVs, Aggregators
• APIs are a specialized skillset
• Expand the development to outside
developers

7. APIs at IGN : Numbers
• ~5 Billion requests a month
• Average Response time of under 20ms on
cache misses
• 17 APIs between Social, OAuth, and Content
• Hardest hit APIs doing about 25K RPM at peak

8. Evolution

9. The API Evolution : V1 [2006]
• The CMS and the desktop site calling Java
Services, which wrapped Oracle DB calls
behind Hibernate.
• Caching with Memcache
– Near-far Cache Architecture to address hot spots
• Not all content types were supported
• Schema was still too complex

10. The API Evolution : V2 [2009]
• Rails based Content API, Java based Social API
– Standards around request/response
– Automated Testing
– MongoDB NoSQL storage to simplify the schema
– Solr
• Video and Blogs served by V2 API
• Games and Articles still used V1
• Mixed-infrastructure with Rails and Java
echosystem
• Performance sucked royally

11. The API Evolution : V3 [2012]
• A fresh look at the APIs and IGN’s direction
• First attempt to
– Integrate all content types
– Open up the APIs to external consumers
– Evolve the CMS, traditionally a monolithic system
– ElasticSearch
– Varnish Response Caching
• A learning opportunity for traditional Java
stack engineers

12. API Development
• MVC Model for APIs
– View, which marshals/unmarshals request and
response data
– Controller, which picks the right model to serve
the request
– Model, which has the necessary logic to talk to the
database, or other APIs to fetch data

13. Why Scala
• Performance tied to cores than processor
speed, i.e. concurrency
• Ideal for API development – (relatively) simple
to handle concurrency and immutability
• JVM based = Performance
• Re-use Java toolkits and libraries
• Concise, expressive code (1:2.5 with Java)
• Actor model makes the difficult parts easy

14. Why Scala
• Richer Collections API
• Traits enabling Mix-Ins and behavior re-use
• Statically Typed w/Type inference
• Functional
• Growing developer community
• REPL
• Culture – learning, hacking and achieving

15. The Biggest Reason
• Just makes sense

16. The Biggest Reason
• Just makes sense
– Pattern matching
– Implicit conversions
– Control abstractions for collection mapping,
filtering, iterating
– Guaranteed Singletons at the classloader level
– Almost non-existent boilerplate
….Productive, and fun!

17. Picking up Scala : Week 1
• Scala for Java Developers fast-tracked the
learning
• Syntax Familiarity
• Java without semicolons?
def total(nums: List[Int]) :Int = {
var sum:Int=0
for(num<-nums) {
sum+=num
}
sum
}

18. Picking up Scala : Week 4
• Reduce the lines of code, embrace
immutability, use the functional paradigms
built into the language
• Unmystrify the implicits magic
nums.foldLeft(0)((n,c) => n+c)

19. Picking up Scala : Today
• Focus on immutability
• Think functional – with the knowledge gained
from using the functional aspects of the
language, build control abstractions
• Keep learning and applying

20. API Components
• Scalatra (View, Controller)
• Lift-MongoRecord for MongoDB (Model)
• Casbah for MongoDB
• Play! Anorm for MySQL
• Actors for tasks like syndication
• Maven for Builds
• MongoDB for persistance

21. Other API Components
• Varnish Cache
• Elasticsearch
• Yammer Metrics (ping, healthcheck)
• Swagger (self-documenting RESTful APIs)
• 3Scale for Partner APIs
• IntelliJ IDEA and Eclipse with ScalaIDE

22. Challenges with Scala
• Learning Curve depends on the culture
• TPS Cover Sheets, vs. Hack Nights
• Scala is what you make of it

23. Awesome..?
http://scalaz.github.com/scalaz/scalaz-2.9.1-6.0.4/doc.sxr/scalaz/BKTree.scala.html

24. Challenges with Scala
• Scala is what you make of it
– Middle ground – simple is beautiful
• Tooling not as rich as Java
– Changing with Typesafe investing in ScalaIDE

25. Challenges with Scala
• Slow compilation based on the source
– How well the code matches up to the JVM
constructs
• No (binary) compatibility of dependencies for
the major releases (2.8, 2.9, 2.10(?))
• Monitoring
– No native instrumentation agents as they exist for
Java

26. API Development : Deploying
• Continuous Deployment
• Jenkins hooks to github
• Pushes artifact(s) to Nexus
• Fabric to push code to production (to be
automated)

27. API Performance Management
• As far as Scala goes, the tips are not much
different than Java
– GC Tuning
– Avoid shared state
– Parallel collections

28. API Performance Management
• For the overall APIs, the performance tuning has
many knobs to work around with
– Stateless services
– Async calls with Akka Agents
– Response level cache
• Keep an eye on the database and network
– Control the payload size
– Use reasonable defaults
– Allow field filtering
– Paginate your response

29. Monitoring and Maintenance
• Newrelic
– JVM stats, SQL trace
– Supports Scala via annotations, but not as rich as
Java
• Typesafe Console for Akka

30. Future of APIs at IGN
• Opening up the APIs
• Tests, tests, tests..
• Move towards simplifying the stack
– sbt vs. maven
– Typesafe stack

31. The IGN Tech Stack

32. Resources
• Do NOT use scaladoc as your 1st reference, at
least initially
• StackOverflow
• Twitter’s Scala School
• Online blogs and tutorials
• Book: Scala for the Impatient
• Scala Meetup Groups in your area
• Coursera course on FP by Martin Odersky

33. Questions