Why is the Repository and Registry the heart of the SOA based business?
By Julia Doll, SAP NetWeaver Product Management – SOA middleware
SOA is a new promising technology based on services. In a SOA landscape, there are three participants: a service provider, a service consumer and a registry. The central point of a SOA is a directory where the endpoints of services, which are connected to the provider implementations, are published its generated services and the consumer can find the services that provide the needed functionality. This directory is called a Service Registry. It contains the descriptions of all the services and acts as the “yellow pages” of services.
SAP NetWeaver SOA Middleware provides a Services Registry, which is based on UDDI v.3, which is an open standard defined by OASIS. It determines guidelines about what kind of search and publish functionalities a registry should provide. Moreover, it enables interoperability of registries from different providers. UDDI stores the services’ metadata, endpoints and categories. It refers to its WSDL file (standard description of the service). In addition to the UDDI standards, SAP offers a classification service and a keyword search service, which enriches the search. On the whole, the registry offers the following search algorithms:
- Search on the name
- Search on a keyword (enabled by keyword search service)
- Browsing by category (enabled by classification service)
Besides the registry, SAP NetWeaver SOA Middleware offers a repository where all services are stored. It has a modeling environment, which ensures certain governance rules at design time. For example, the repository objects have to be derived from the global data types standard and the services need to fit into the process component model that is defined by SAP and others in the Enterprise Software industry. It stores all the services and patterns of a business. One big advantage of the SAP repository in comparison to its competitors is that SAP delivers also the backend services based on their delivered products.
Repository and registry together enable the reusability of services. Together they build not only the heart of a SOA but also of a business itself:
In every step of the SOA lifecycle, the registry/repository will be accessed as a central point. In the beginning of the lifecycle, the business analysts figure out what kind of services the company needs and publish the prepared services into the registry/repository. The missing services are then modeled and built afterwards. This is done by another group of employees in the organization. Now applications can be built by composing the services. This can be done with the consumption tool called SAP NetWeaver Composition Environment 7.1, which directly accesses the registry from its development environment. Business analysts manage and optimize the repository by analyzing the service portfolio in order to optimize usage and lower TCO, which result in a higher ROI.
In the SDN SAP provides a test registry for customers to figure out it’s publish and search functionality. SAP also provides a detailed Service documentation of all offered SAP services supported by a powerful search engine under the name “Es workplace”. http://www.sdn.sap.com/irj/sdn/esworkplace