[gfs-wg] RNS Resolver clarifications

[Peter Gardfjäll]

Hello everybody,

I've been thinking about implementing the RNS Resolver port type defined
in the RNS specification (if there already exists a reference
implementation, please let me know). However, it appears to me as if the
specification contains a few "gaps".

In particular, the {delete,update}EndpointReference, and the
updateLogicalReference operations all require the RNS Resolver to be able
to compare EPRs for equality. For instance, on a deleteEndpointReference
invokation the Resolver must find all logical references containing
the particular EPR and remove its mapping from them.

According to the WS-Addressing specification, it "provides no concept of
endpoint identity and therefore does not provide any mechanism to
determine equality or inequality of EPRs". A similar point is also made in
the RNS specification (page 25) which states that "... a single
EPR or LogicalResolver cannot be deleted or updated, since they are not
identified by any corresponding handle or name." Still, the RNS Resolver
port type is supposed to provide support for that kind of behavior.

Does this mean that the RNS Resolver specification leaves the EPR equality
decision to the implementation?

I would also like some other clarifications:

* Several RNS Resolver operations are said to "throw exceptions" when
  they for some reason fail. Exactly what fault messages are they
  supposed to return?

* Another ambiguity: what are the deleteEndpointReference semantics in
  case of failure? What if the deletion is successfull in, say, nine of
  ten mappings, but fail on the tenth? Should deletion be atomic, or
  should the fault message somehow indicate what mappings failed?

Regards,
Peter