Download - Rapidly Developing FarmVille
Rapidly Developing FarmVilleHow we built and scaled a
#1 Facebook game in 5 weeks
Amitt MahajanLead Developer – FarmVille
March 9, 2010
FarmVille
6 developers (PHP/Flash)2 artists3 producers/designers
5 week development cycle
FarmVille
18K users/day after 24 hrs1M users/day after 4 days
At Launch
110M+ Installs 31M Players/Day
Today
My Goals
• Reduce the amount of time it takes you to develop your games
• Give you a blueprint for how to reliably scale your games to millions without your servers falling over
What slows down developers?
• Other developers• Design / Art• Production (Copy)• Lack of knowledge
Increasing Developer Efficiency• All developers know both
• Design DOESN’T rule all• Developers co-own features with designers
Flash (Client)PHP (Server)
Data Driven Design
• Shoot for a content pipeline that doesn’t need a developer
• Data driven can be as easy as a designer-editable XML file
No dev needed!
String Tables
• A string table is an external file that holds strings for the app
• Best practice to prepare for localization• Developers are not blocked by production• Allows quick response to Facebook TOS
changes
Abstracted Network Layer
Goal Feature developers get client/server communication and serialization for free
AMF Protocol (RPC)
Flash PHP
Network Layer
Validation Checks
Action Batching
Networked Actions
Feature A Feature B
Network Layer
Validation Checks
Result Batching
Feature A Service
Feature B Service
Action Dispatcher
Client
Network Layer Batching
• No need to do the work twice• Reduced server load in FarmVille by 50%!
Plow
Plant
Plow
PlantPlow
Only One Request
ServeronPlow()
onPlow()
onPlant()…
Network Layer Validation
• Solves problem of unfiltered input• Ensures data is received by server in-order it
was sent
Social Network Wrapper
• Single place to perform Facebook API calls• Working with a highly dynamic API can be
difficult• Abstracting FB calls makes them easier to
integrate• Allows for cross-platform games
Continuous Deployment
• Build latest version of source-repo• Deploy to test “auto app” on Facebook to
surface production issues early
Continuous Deployment
FarmVille QA Process
QuickSmoke
Full TestPass
Auto app Staging Production
FarmVille Traffic Growth
1 Million DAUsevery week for 20 weeks
source: developeranalytics.com
Scalable Server Architecture
• We had no choice but to scale on the cloud• Every part of the server architecture scales
horizontally• No single points of failure• Take the DB out of the equation
Memcache Pool
Auto-scaling web array (PHP)
Web Server #1 Web Server #M
User Data & Updates
…
DataReads
Lazy Writes
DB Layer
Round Robin DNS
Load Balancer #1 Load Balancer #N
…
… DB-#KSlave
DB-#1Slave
DB-#KMaster
DB-#1Master
…
Web Server #1 Web Server #M
…
…
All you need to implement is…
…everything else is off-the-shelf components!
Reducing Load-times
• Users want responsive pages• Show something immediately
• Player’s won’t wait for your app to load• Stream non-critical content
Avoid Remote Calls• Remote server calls are slow and unreliable
• Aim for no remote calls during load• Embed data into Javascript
Iframe
Inline-JS here
Flash ClientEmbed
Caching Slow Calls
• Build in Facebook API caching within the social network wrapper
• Write a DB wrapper to generate and cache SQL
FarmVille Page Profiler
Goal Catch and eliminate all un-cached Facebook and DB calls
Fault Tolerance
• Servers do go down randomly• Build redundancy on all levels of server
architecture• Facebook is a dependency also
• Aim for DB-less & Facebook-less modes• “Defcon”-style error management
Runtime Config
• How do we progressively keep the game running?• Create all features with kill-switches• Create a web dashboard to allow non-
technical folks to help out
Is it still running?
• Notify your team when things break using server monitoring (Nagios/Munin)
• What to watch• Server load/traffic graphs• Memcache evictions
Stats Tracking
• How do we know what users are seeing?• Have the client send back statistics
• Number of errors• Load-times
• Take a metrics driven approach to error handling
Before Launching
• Get confidence that your stuff actually works• Perform load testing
• Social games are a marathon not a sprint• Sleep before launching!
Questions?
Thank You!