Web Services BOF

1
Web Services BOF

• This is a proposed new working group coming out
  of the Grid Computing Environments Research
  Group, as an outgrowth of their investigations of
  grid portals.
• Why Web Services ?
• Use of industry standards
• HTTP, HTTPS, XML, SOAP, WSDL, UDDI,
• Support for many languages
• Compiled and scripted
• Self describing protocols
• easier management of versioning, evolution
• Support for authentication
• Strong Industry Support
• Microsofts .NET initiative
• SUNs ONE (Open Net Environment)

2
Web Browser
Application
Authenticated connections
XML to HTML servlet
Web Service
Web Server (Portal)
Web Service
Web Service
Remote Web Server
Grid Service
Web Service
Local Backend Services (batch, file, etc.)
Storage system
Grid resources, e.g. Condor
Batch system
A three / four tier web services architecture
3
XML technologies

• Advantages
• Self describing data (contains meta data)
• Facilitates heterogenous systems
• Robust against evolution
• (no fragile versioning that distributed object
  systems encounter)
• New server generates additional tags which are
  ignored by old client
• New client detects absence of new tags knows it
  is talking to an old server (and/or supplies
  defaults)
• Capable of defining all key concepts and
  operations for both client-server and
  client-portal communications
• Technologies
• XML eXtensible Markup Language
• SOAP Simple Object Access Protocol (modern rpc
  system)
• WSDL Web Services Description Language (idl)
• UDDI Universal Description, Discovery and
  Integration

4
Proposed New Working Group Activities

• 1) Investigate application of the latest web
  technologies to grid computing XML, SOAP, WSDL,
  UDDI (Result report)
•  
• 2) Investigate options for authentication with
  web servers in the context of these
  technologies, including credential forwarding,
  proxy credential repositories, single sign-on
  (Result report)
•   
• 3) Set up a limited testbed of multiple
  sites and servers to demonstrate a small number
  of web services
•   batch system interface(s)
• data management interface(s)
• shared UDDI server (as if this were a "virtual
  organization)
• and clients
• web browser, human readable output
  (portal interactions)
• custom client with use of SOAP client
  libraries
• (Result report, working demonstration code)