Businesses looking to build more agile architectures that enable them to discover and reuse their IT assets in...
new ways can take a page from NASA's playbook.
Long before acronyms like SOA, SOAP and UDDI were part of the vernacular, the earth science community, under the auspices of the NASA, began building an SOA for the Earth Observing System Clearinghouse (ECHO), which allows scientists to access, search and share earth science meta data. Now NASA has rolled out an extended services registry for ECHO, based on a UDDI registry from Systinet Corp., Burlington, Mass., which allows third parties to publish and access data.
ECHO, initiated in 1998, was built from the get-go, utilizing XML and Web service technologies. The ECHO system acts as middleware between data partners and client partners; client partners develop software to access the information.
Initially, ECHO was a registry of earth science data where providers of that data could publish and register their holdings. "We always intended to [offer] the same capability for those organizations and people willing to offer up services in the earth science realm," said Keith Wichmann, principal systems engineer for ECHO at government contractor Global Science & Technology Inc. (GST), Greenbelt, Md., which implemented the system along with subcontractor Blueprint Technologies Inc., Vienna, Va. "We needed a mechanism for exposing those services. UDDI looked like it was going to be the best choice. And it had to be integrated with our data registry."
The new extended service registry "is geared to allowing third parties to publish their Web service capabilities and to associate those services with the data on which they can act, as represented in ECHO's data registry," said Robin Pfister, lead information management system engineer, for the Earth Science Data and Information System Project.
The concept behind ECHO is that of a "marketplace," said Mark Nestler, program manager for GST. "There's a wealth of data out there already. The challenge is to discover it and find new ways to use it."
According to Pfister, the driver behind ECHO, and for its service orientation, is that scientists want more control over resources.
"ECHO is meeting a need driven by a change in the way the earth science community needs to access data in order to do their research and applications," she said. Fundamentally, this change is that the scientists want more control over resources that they contribute, and they want more direct access to resources that other scientists contribute. If we view these resources -- data, data transformation services, etc. -- as services, then a service-oriented architecture naturally fits the needs of the community."
Flexibility is also important, said Jeanne O'Kelley, president and CEO of Blueprint. "When you're working with users from around the world, it means people have their own ways of doing things. Giving them that flexibility has been real important in the design."
ECHO was developed with a layered architecture, which would allow it to adapt to new standards and changes, Wichmann said. He said the team also agreed that "the best way of interacting with the system was that all participants would send XML messages to the system and the system would respond, and we built a mechanism to do that. Then SOAP came along and we extended to SOAP."
The ECHO environment comprises an Oracle 9i back-end database from Oracle Corp., and the plan is to move to Oracle 10g. The WebLogic application server from BEA Systems Inc. hosts most of the core business logic. Apache Axis and Tomcat are also utilized. The Systinet UDDI server is used to expose the service registry through the industry standard UDDI protocol. And developers use Eclipse and a variety of other tools.
Wichmann said the team is in the process of upgrading ECHO to be compliant with the Web Services Interoperability (WS-I) Basic Profile. In version 8 of the system (the current version is 6), he said, "ECHO itself will be available as a Web service."
"While ECHO has had a SOAP view of the system since the standardization of SOAP, ECHO's use of that needed to be beefed up to meet the spirit of the Web service basic profile so that our end users -- developers -- could leverage industry tools to build on ECHO's capabilities," Pfister said. "These capabilities will also be registered in the service registry."
According to David Butler, Systinet vice president of marketing, "We're now starting to see SOA and Web services standards being put to use in fairly large projects. This is a large-scale discovery project, and one more example that the stack of SOAP/WSDL/UDDI is becoming the preferred way of supporting and governing those services."