Difference between revisions of "IS-Publisher"

Revision as of 21:58, 7 January 2009

In conjunction with the IS-Client and the IS-Notifier, the IS-Publisher represents the mediation layer gCube Services will rely on to interact with the Information Service as a whole.

The role of the IS-Publisher is to feed the IS with:

• GCUBEResource profiles
• services' states as of WS-ResourceProperty documents

In addition, it offers a built-in mechanism to publish the GCUBEResource profiles as local events to whoever subscribe for them.

Design

The IS-Publisher is the implementation of two interfaces (ISPublisher and ISLocaLPublisher) defined in the context of the gCore Framework to decouple gCube Services from the specific implementation of the Information Service.

Publishing a profile

In order to publish a GCUBEResource profile the IS-Publisher contacts the IS-Registry service of the publishing scope by invoking its appropriate operations. The following operation can be used to manage profiles on the IS:

• registerGCUBEResource() – which takes as input parameter a message containing a resource (gCUBEResource), an operational scope (GCUBEScope), i.e. an object representing a scope in the gCube model of VO/VREs, and a security manager (GCUBESecurityManager), i.e. the component keeping track of credentials, and returns a string containing the registered profile if the registration is successful;
• updateGCUBEResource() – which takes as input parameter a message containing a resource, an operational scope and a security manager and updates a resource previously registered in the IS.
• removeGCUBEResource() – which takes as input parameter a message containing a resource ID, a resource type, an operational scope and a security manager and removes the corresponding resource previously registered in the IS;

Publishing a service's state

Services' states are represented by a view on the stateful resources data of each service. Such a view is then defined as a WS-ResourceProperty document. The IS-Publisher takes as input the whole GCUBE stateful resource and it is able to extract from there its state and publish it. The following operations allow to publish and unpublish a state:

• registerWSResource() – which takes as input parameter a message containing a stateful resource (each stateful entity different from a gCube Resource) and optionally the registration name and the scope and register such a resource in the IS;
• removeWSResource() – which takes as input parameter a message containing a stateful resource (each stateful entity different from a gCube Resource) and optionally the registration name and the scope and removes such a resource.

The update of the state is automatically performed by the underlying framework as explained in the implementation section.

Implementation

The main functions supported from the IS-Publisher are:

• registerISNotification() – which takes as input parameter a message containing the topic producer (actually its EPR), a list of topics, an operational scope and a security manager and registers such topics in the IS-Notifier;
• registerToISResource() – which takes as input parameter a message containing the topic producer (actually its EPR), a list of topics, an operational scope and a security manager and registers such topics in the IS-Notifier;
• unregisterFromISNotification() – which takes as input parameter a message containing the topic producer (actually its EPR), a list of topics, an operational scope and a security manager and un-registers such topics from the IS-Notifier;
• unregisterISNotification() – which takes as input parameter a message containing the topic producer (actually its EPR), a list of topics, an operational scope and a security manager and un-registers such topics from the IS-Notifier;

Sample usage