Components of the Run-Time Governance Environment
When you use CentraSite to govern Web services at run time, the basic components in the run-time environment are:
A policy enforcement point such as
webMethods Mediator.
webMethods Mediator is a service mediation and policy enforcement application for Web services. The Web services can be SOAP-based, REST-based or plain XML Web services.
Mediator hosts virtual services, which are proxy services that receive requests from consumers on behalf of particular Web services. Mediator can also host virtualized APIs, which are proxy APIs for Web services that have been externalized as Application Programming Interfaces (APIs).
Mediator enforces the run-time governance policies or rules that you define for your virtual services or virtualized APIs (such as security enforcement and audit-trail logging) and handles mediation measures between consumer and provider (such as message transformation and message routing).
Besides serving as an intermediary between consumer applications and native services, Mediator also collects performance statistics and event information about the traffic flowing between consumers and the native services, and reports this data to CentraSite.
Mediator is designed for use with CentraSite. The Mediator application is delivered as a package called WmMediator, which runs on webMethods Integration Server. It provides an infrastructure for the run-time governance policies or rules that you define.
Virtualized services or virtualized APIs.
You can choose to expose your Web services as virtualized services. When you create a virtualized service, you also define:
Run-time governance policies for the virtualized service.
The consumer applications that are used to allow consumers to access the virtualized service.
As an alternative to exposing your Web services as virtualized services, you can instead expose the Web services as virtualized APIs, which perform a role similar to virtualized services. When you virtualize an API, you also define:
Policy enforcement rules for the API.
API keys, which enable users to securely access the API.
You define all these components in CentraSite, and you store and manage them from CentraSite's UDDI registry/repository.
Native services, which are Web services that process requests submitted by consumers. If a native service produces a response, it returns the response to the virtualized service or virtualized API, and the virtualized service or virtualized API returns it to the consumer.
CentraSite, which serves several key roles in the run-time environment. Besides serving as the system of record for the artifacts in the SOA environment (such as virtualized services or virtualized APIs and their run-time governance policies or rules),
CentraSite provides the tools you use to define these artifacts and deploy them to
Mediator. Additionally,
CentraSite receives and logs the performance metrics and event data collected by
Mediator and provides tools for viewing this data.
Subsequent sections of the CentraSite documentation provide the information you need for designing and configuring your run-time governance environment in CentraSite. The following sub-sections provide a brief overview of those subsequent sections:
