SkyeCORE - Rev Up Your OSGi Services!

SkyeCORE

Rev Up Your OSGi Services!

What is SkyeCORE?

• A distributed applications platform.

• Automates the discovery and publishing of services.

• Built on top of the Eclipse Platform.

• Fully supports and exposes OSGi (Equinox).

Demo Presentation

• Hello World Service Example

• Demonstrates the dynamic discovery and invocation of a remote service.

• Entire example source code available: http://www.skyecore.net/downloads/Hello

World Example.zip.

P2P Network Model

• Based on JXTA.

• SkyeCORE Instance ≈ Peer

• Peers identified via UUID.

• Publish/Discover Advertisements.

• Support for Peer Groups (Scoped and Secure Environments).

Discovery

• LAN: Multicasting is used.

• WAN: Controlled propagated search via Rendezvous Peers.

LAN 1

Peer A

Netw

ork Boun

dary

LAN 2

Peer B

RDV 1 RDV

2

Peer C

Peer D

Security

• Encrypted data transfer.

• Peer Credentials: Used in the authentication of peers and access control.

• Support for digests and signatures on messages to ensure integrity.

• Works with firewalls and NAT devices.

• May require a Relay Peer to relay messages for peers behind Firewall/NAT.

Firewalls and NAT

Relay Z

Peer A Peer

B

Firewall

Service Interfaces

• Developed as Java interfaces.

• Provide a contractual API for service implementations.

• Declared through Service Interfaces extension point.

Services

• Developed as Java objects.

• Implement 1 or more service interfaces.

• Abide by a lifecycle (init, destroy).

• Declared through Services extension point.

Service Sessions

• Used to identify a peer across service requests.

• Store/persist peer information using any type of Java object.

• Access session ID, creation and last accessed time.

How’s It Work?

• Proxies (local and remote) generated from service interfaces.

• Service Registration (Local):– Generation of local proxy– Local proxy registered in OSGi

service registry.– Service Advertisement published.

How’s It Work? (continued)

• Service Discovery (Remote):– Service Advertisement discovered.– Generation of remote proxy– Remote proxy registered in OSGi

service registry.

How’s It Work? (continued)

• Remote Method Invocation:– Establish connection via bi-directional pipe.

– Create and send Service Request (service name, method, serialized args) over pipe.

– Process request (Service Engine); perform invocation through reflection.

– Create and send Service Response (return value/exception) over pipe.

How’s It Work? (continued)

• What happens when a service becomes unavailable?

• Remote proxy is unregistered if:– Connection fails– Service Unavailable Exception– Service Advertisement indicates

unavailable status.

How’s It Work? (continued)

Tracking Services

• Accomplished via OSGi Service Tracker.

• Specify 1 or more service interfaces to track with optional filtering.

• Added, modified, and removed notifications.

Events

• Supports notification of several events:– Discoveries– Published– Searches– Service Interface and Service

Registrations.

• Register listeners in OSGi Service Registry (“Whiteboard” Pattern)

Creating an App

• Based on Eclipse plug-in model.

• Deploy as plug-ins or features.

• System bootstrap allows for complete application control and launching of a custom UI.

Console

• Provides a text-based command UI.

• Core commands used to list services, interfaces, discoveries, etc.

• Extended with custom commands via Commands extension point.

Road Map

• SkyeCORE 2.0 slated for October 2009 release.– Streaming capability.– Enhanced security.– Subscriber model (propagation of

custom events).– SIE (SkyeCORE Interface

Environment) graphical UI based on Eclipse workbench.

– User desired features!

Distributed OSGi

• RFC 119

• Built around the OSGi service model.

• Distribution software and Discovery service components.

• Interoperability with other technologies.

• Enable a service to be remote via setting of property.

Resources

• SkyeCORE - http://www.skyecore.net Developer’s Guide, API JavaDocs, Downloads, Hello World Example Source, SDK, Forum, Feedback

• JXTA - https://jxta.dev.java.net

• OSGi 4.2 Early Draft: http://www.osgi.org/download/osgi-4.2-early-draft.pdf

Thank You!

Wayne Williams

[email protected]