This document discusses how Yahoo! uses Node.js and the Mojito framework to build scalable web applications. It highlights benefits like code reuse through shared npm dependencies, dynamic configuration, and improved performance compared to Apache/PHP. Mojito apps declare dependencies in a package.json file and npm automatically installs them. Yahoo! also uses an internal private npm registry for testing and immutable package publishing. Overall, the document argues that Mojito allows Yahoo! engineers to build and maintain applications using only JavaScript, avoiding context switches between languages.

1. Yahoo! scale Node.js
@Fabian_Frank
<fabian@pagefault.de>
The Yahoo! Axis Team
http://axis.yahoo.com

2. Challenges
• Being able to share code (across
applications)
• Dynamic configuration, per environment
• Stability and performance

3. Code re-use
• Different applications (teams), same
problems
• Potential side effects, e.g. through
unexpected updates

4. npm
• Package manager for Node.js packages
• resolves dependencies automatically
• hosts packages in a central registry

5. Mojito and npm
• Every Mojito application can specify its
dependencies in package.json
• Mojito probes node_modules/, when
loading Mojito resources
http://developer.yahoo.com/cocktails/mojito/docs/topics/mojito_npm.html

6. Mojito resource
• YUI Module
• Mojito add-on
• Mojit (views, a controller, models)

7. npm dependencies
"dependencies": {
"mojito": "=0.3.26",
"mojito-shaker": "~0.7.5",
"yui": ">=3.5.1"
}
$ npm shrinkwrap
http://npmjs.org/doc/shrinkwrap.html

8. Internal npm
• Only the build system can publish packages
• Packages are published only after unit and
functional tests passed
• immutable packages

9. Dynamic configuration
• Change application behavior without
redeployment
• JSON is a common way to express
configuration in JavaScript applications
• YQL Storage holds JSON
http://developer.yahoo.com/yql/guide/yql-cloud-chapter.html

10. Configuration through YQL
http://developer.yahoo.com/yql/console/

11. Node.js 0.6
• transparent change for Mojito users
• important fixes and improvements in HTTP
and DNS

12. YUI 3.5
• officially supports Node.js
• removed jsdom dependency
• Y.io uses request as transport layer
http://yuilibrary.com/yui/docs/yui/nodejs.html https://github.com/mikeal/request

13. Node.js 0.8

14. Performance
http://www.slideshare.net/FabianFrankDe/nodejs-performance-case-study

15. Performance
• Mojito&Manhattan compared to
Apache&PHP
• CPU bound
• found that Manhattan can serve twice the
amount of requests at half the latency

16. Performance

17. Stability
• Yahoo! Axis is served using Mojito and
Manhattan
• Hundreds of requests per second
• Static HTML and CSS, dynamic pages,
API entry points
• Monitoring

18. Building and Maintenance
• Need to know only one language and
framework, no context switches.
• Allows to postpone design decisions
• Easier to revert design decisions
• Easier deployment and resource allocation
http://developer.yahoo.com/blogs/ydn/posts/2011/11/yahoo-announces-cocktails-%E2%80%93-shaken-not-stirred/

19. Conclusion
• Mojito works for our computers
• Mojito works for us, as engineers

20. Thank you!
• Fabio Hirata, @fabiohh
• Caridy Patiño, @caridy
• Eugene Kashida, @ekashida
• Fabian Frank, @Fabian_Frank