VOStore as WS-Resource

Hi,

following up the discussion of ownership of data-items in VOStores, here's an alternative approach: make the store an ephemeral resource in the style established by WS-RF.

Justification: most users will borrow storage supplied by resource providers and access it via VOStores. We need an interface for managing the loan of the storage (quotas, remaining length of lease etc.) WS-RF is an interface for managing leases of resources.

Mechanism: "a VOStore" becomes a dynamic resource. An agent creates one on a VOStore server by calling some operation that follows the resource-factory pattern. (This method is outside the scope of the current VOStore interface.) Agents address such a dynamic store using the normal WS-RF mechanism: a SOAP header. All the data-items written to the store are owned by the creator of the store. The space used in the store can be cleared up using the WS-RF interface; if the storage is leased for a certain time, then it can be set to clear itself up. Users could create more than one dynamic store on the same VOStore server; they could create a dynamic store for each project or for each job.

Advantages: we get the management interface without having to invent and debate it in IVOA. We get to implement the management interface using WS-RF toolkits if we choose (this is transparent to the clients, so the use of toolkits can vary from store to store). Users of VOStore get to manage data-items in multiple, dynamic stores without going through VOSpace. We may be able to get WS-RF management tools from the grid community.

Disadvantages: the implementor of the store has to implement WS-RF or to use a WS-RF toolkit. Clients of the store have to supply the WS-RF header.

NB: the WS-RF thing doesn't change the operation signatures of VOStore. We could use a client for a fixed VOStore on a dynamic VOStore by adding a handler (e.g. the Axis or JAX-RPC kind) that adds the WS-RF SOAP header.

Cheers,
Guy

Guy Rixon 				        gtr-at-ast.cam.ac.uk
Institute of Astronomy   	                Tel: +44-1223-337542
Madingley Road, Cambridge, UK, CB3 0HA		Fax: +44-1223-337523