OSGi DevCon 2012 Although modularity concepts from OSGi might not map cleanly to programming languages other than Java, the ideas around OSGi Micro Services might be universally applicable. In this talk we will examine the JavaScript-based Micro Service implementation used at the core of the Eclipse Orion project. After several iterations and more than a couple of failed attempts to improve on OSGi, our implementation is now essentially aligned with OSGi Micro Services. We will discuss lessons learned and show how our implementation can be used stand-alone in arbitrary web pages as well as in Node.js

1. JavaScript Micro Services
Simon Kaegi
27 March 2012

2. What are Micro Services?
• OSGi minus the modularity

3. … about software development in a browser

4. Orion and OSGi Modularity
• e4 – OSGi style modularity in JavaScript
{ "Bundle-SymbolicName":"sample.jsbundle",
"Bundle-Version":"1.0",
"Bundle-ScriptPath":"script.js",
"Import-Package":"a.resource;version=[1.0.0,2.0.0)",
"Export-Package":"sample.resource;version=1.0.0",
"Require-Bundle:"some.other.bundle“
}
• AMD – RequireJS
define(["dojo", "orion/serviceregistry", "dojo/DeferredList"],
function(dojo, mServiceregistry){… return exports});

6. Orion Plugins
• Orion applications are NOT made up of plugins
• Orion pages are designed to be 'extended' with plugins
• Orion plugins are 'separate' HTML pages hosted in non-visible IFrames
• Can be cross origin and communicate using HTML5 postMessage which is
ASYNC
• Plugins are isolated and secure against direct modification of the hosting
page

7. 7
Web Application
Front-endWeb Client
Web Application
Front-endWeb Server
Web Application
Front-endPluginWeb Application
Front-endPluginWeb Application
Front-endPlugin
Web Application
Front-endWeb Client
Web Application
Front-endWeb Server
Web Application
Front-endProxied Service
Web Application
Front-endProxied Service
Java Web Application / OSGi Proxy Server / Portal

8. Web Application
Front-endWeb Client
Web Application
Front-endWeb Server
Orion way / Client-side Extension
Web Application
Front-endPlugin
Web Application
Front-endWeb Server
Web Application
Front-endPlugin
Web Application
Front-endWeb Server

9. Eclipse IDE Extensibility

10. Orion Extensibility
registerService(INTERFACE_NAME, IMPLEMENTATION, PROPERTIES)
In-page
Plugin

11. Comparing OSGi and Orion Service APIs
• Orion provides a nearly complete implementation of the Service API from
OSGi BundleContext
• ServiceReference, ServiceRegistration, …
• service listeners, event types
• Use Strings instead of java.lang.class when referencing Service interfaces
• All Service calls return a “promise” – needed to abstract asynchronous
service implementations
• No ServiceTracker currently
• originally built into getService but this was a mistake

13. What’s next
• Declarative Services
• wire.js – extends Asynchronous Module Definition
define([“wire!aService", “wire!anotherService],
function(aService, anotherService){…});
• Configuration Admin and Metatype Services
• Permission Policy and Admin

14. 14
http://eclipse.org/orion/