Where does WSAS fit into your enterprise deployment?

Saturday, August 23, 2008

Figure1: Open source SOA product deployment

Where does WSAS fit-in in your enterprise deployment? Figure1 shows how WSAS as well as other open source SOA products from WSO2, The Open Source SOA Company, fit into a typical enterprise deployment. Of course, this is only one of the ways in which WSAS as well as other open source SOA products from WSO2 can be deployed. In fact the above deployment diagram shows how one of largest managed care organizations has deployed WSAS as well as the other SOA products.

Figure 2: Deployment of WSO2 WSAS & WSO2 ESB for High Availability

An enterprise deployment cannot afford to have any single points of failure. Even with some degree of degraded performance, the system should continue to function correctly, until such time that it can be brought back to full operating capacity. Figure2 depicts how a 2-node WSO2 ESB cluster fronts a 2-node WSO2 WSAS cluster. WSO2 WSAS is used to expose some existing business logic running on mainframes as Web services, as well as to expose some enterprise data as Data Services. WSO2 WSAS supports POJO services, whereby POJOs containing the business logic, like in this case, can be easily exposed as Web services. In fact, this is the path take by most enterprises which begin to SOA enable their systems. It is also common for some of the business logic of such systems to reside in databases in the form of stored procedures. WSO2 Data Services running within WSAS enables the exposing of data & stored procedures as services. Of course, ideally the enterprise architects have to clearly define the contracts when designing the system before any implementation is carried out, but the real-world situation is that most companies have already invested large sums of money into their software systems, and cannot afford to throw all that away and start from scratch. So the meet-in-the-middle approach is to first expose some of the existing logic as services, and then gradually refine the systems to come up with clean contracts. Newer components in the system can do it the proper way by starting by defining clean contracts. WSAS supports the contract first approach for this purpose, where the architects will write WSDLs defining the proper interfaces, and subsequent development work will be based on these WSDLs.

For more details on how WSAS as well as other open source SOA products from WSO2 can fit into your enterprise, see this case study by Asankha Perera who is the Software Architect and Product Manager of WSO2 ESB