[glue-wg] Problem with LDAP binding inherited foreign-keys

[stephen.burke at stfc.ac.uk]

glue-wg-bounces at ogf.org [mailto:glue-wg-bounces at ogf.org] On
> Behalf Of Paul Millar said:
> While writing the dCache GLUE2 info-provider, I came across a problem
> with the current GLUE2 LDAP binding.

Yes, we saw the same thing with the computing service. I think I'd describe it as a feature rather than a problem - it's a logical outcome of the way we defined the LDAP binding and it does no particular harm other than increasing the data volume a bit, but it is a little odd.

> In GLUE v2.0, the Share object has a required (i.e., multiplicity of
> '1')
> association with a Service.  This is represented in the LDAP Schema as
> a
> required attribute in the GLUE2Share class: the
> GLUE2ShareServiceForeignKey attribute.

Except that it actually seems to be defined as optional - I think that was an attempt to deal with this problem, but to my mind it's the wrong solution, I think the basic relations should be mandatory.

> I've talked to Laurence about this problem and our preferred solution
> is to
> delete GLUE2StorageShareStorageServiceForeignKey and have all a
> StorageShare
> publish their association with StorageService using a
> GLUE2ShareServiceForeignKey.

If we only publish one ForeignKey attribute I agree that it should be that one, e.g. I think you should be able to navigate from any kind of Share to any kind of Service by using the same attribute.

> Does this make sense?  Are people in favour of this approach?

Broadly yes - although I would suggest making the specialised attributes (GLUE2StorageShareStorageServiceForeignKey etc) optional rather than deleting them completely, in case we subsequently find a reason to use them.

  Also we have a transitional problem - right now publishers have to publish those keys because it's a mandatory attribute, so if we delete the attribute we have to upgrade the schema and all publishers ~ simultaneously which is next to impossible even for something which is still only being tested. If we change it to being optional then everything will be happy with publishers that include them, and they can be retired later.

Stephen

PS What happens in the XML rendering?

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