Web Services Provisioning

Service lifecycle management can be most simply described as Web services provisioning and versioning. The important concept to note is that change is now decoupled from the development cycle. Change can now occur more quickly and in a more personalized way to the consumers of the Web services.

Provisioning is useful when you wish to present a Web service in a customized way for a particular group of users. Even in the case of services built only for internal consumption, there will be varying consumers across the organizational departments with different interface requirements. Some examples of the provisioning capabilities of SOAPstation include:

• Enabling the use of an external WSDL to access your service – For example, you and your business partner may each have your own order entry service. SOAPstation can be used to quickly map or transform from one WSDL to another without development changes on either side.
• Combining multiple WSDLs into one – Many customers have product information in multiple systems and wish to make the provider of this information transparent to the service consumer when they access it. In this scenario, each back-end system would expose a WSDL that could be combined into a single WSDL by SOAPstation using its compound service wizard.
• Removing specific operations from an exposed WSDL – An inventory management service for example, has many uses and many types of consumers. Internally, groups may wish to see all operations provided by the service. Externally, partners would only need a subset of these operations (e.g. just inventory, not costs). SOAPstation allows you to easily remove certain operations and expose just those that any given consumer is allowed to see.
• Creating personalized policies for each set of consumers – Varying business users of services will have varying security requirements. Rather than reconfiguring firewalls or rewriting security services within the application, SOAPstation can apply new security policies to the service to uniquely meet their needs. This is done quickly, without interrupting services or forcing other consumers to adapt to these changes.
• Tricking of inbound users – Using the same WSDL, new Access Points can be set up so that inbound users can be tracked. While it is possible to achieve similar tracking capabilities through parsing and auditing XML content there is a higher performance penalty for doing so. Additionally, setting up a new Access Point in SOAPstation enables some of the scenarios outlined above, such as creating and enforcing SLAs or personal security policies.

Provisioning Services to Meet Specific Consumer Needs

Web services represent standard interfaces to business logic. When any service is created, it specifies the set of operations, data types and message formats to be exchanged between a provider of a service and its consumers. For example, an order entry service may have an operation that allows the consumer to enter multiple line item orders. This operation may be called m_enterorder.

The m_enterorder operation then specifies what data elements are required, the data type for each element, and how to structure the request document. It then specifies what the requester of the document should expect as a reply. All of this is accomplished through the publishing of a WSDL file associated with this service.

However, it is likely that a service consumer may already have a standard interface to other systems, typically via a pre-defined XML document. In many cases, these consumers have the business power to demand adherence to their standard, not the one the provider has defined. For example, large customers often force smaller suppliers to conform to their standards or parent companies require conformance from recently acquired subsidiaries. Beyond that, two applications that have been service enabled may define data elements differently altogether. Clearly, provisioning services to match the needs of specific consumers is another cost driver in Web services projects.

As one company, General Products, rolls out its services, they prepare to make the Enter Order service available to their largest reseller. This reseller accounts for over 30 percent of General Products’ domestic volume, and therefore holds a great deal of power over them. As part of the latest round of negotiations, the reseller stipulated that General Products must accept the reseller’s XML documents for all order-related transactions. These documents vary significantly from those defined in General Products Web services definitions.

How to Incorporate the Reseller's XML?

General Products is now contractually bound to support these documents within their Web services project, and must figure out how to do so without scrapping all the work they have invested in their currently deployed services. Once again, project costs increase incrementally. This is where Web services versioning comes in.

For More Information

Find out more about Web services provisioning: download the free webinar, SOA Governance: Where the Rubber Meets the Runtime