[glue-wg] Enumerations for DPM and related InterfaceNames was: Re: New Endpoint and Service types

[stephen.burke at stfc.ac.uk]

Florido Paganelli [mailto:florido.paganelli at hep.lu.se] said:
> the group would like to have an organization name. It has beed decided
> that if there is no organization name, then one can fallback to the
> group reserver organization name, that can be used for orphan 
> projects.
> 
> therefore we suggest:
> 
>   org.ogf.glue.dpm
> 
> What do people think about this?

As I've said before, the ServiceType is only going to be useful if there is a need to identify a set of services which is bigger than a single implementation and smaller than the universe of all Services (or all Storage Services in this case). It may be that there is no such need, in which case we may as well use a ServiceType based on the implementation name (we have to publish something, it's a mandatory attribute).

In any case, there's a meeting of the storage providers organised by Maria to discuss this kind of thing in a couple of weeks (https://indico.cern.ch/event/311528/), so we should wait to see what comes out of that.

> > - "org.webdav" and "org.xrootd" to InterfaceName
> 
> This I completely fail to understand.
> 
> webdav and xrootd are protocol names. Why would they be 
> interfacenames?
> An interface name is an "identification of the Interface" as GDF.147
> says. org. is not an organization.

I don't understand your point. InterfaceNames are often protocol names, although they may be more restricted to indicate a specialised use, for example the BDII uses LDAP as a protocol but the InterfaceNames are bdii_site and bdii_top (which aren't especially well-formed but have been in use for a long time). In general, if an Interface is specific to a particular product or project then we would prefer the Name qualified by a DNS-style prefix to avoid name clashes (not because the name has any significance).

For standard well-known protocols like say http there is no need for any prefix as there's no likelihood of a clash. Arguably xroot is not such a general standard, but we long ago agreed on "xroot" as the name, it's been in use for many years and I think there's little chance of a clash.

As we already discussed, webdav is a different case. It's certainly a standard, but it remains undecided whether we regard it as an interface in its own right or as a subset of http (and/or https?).

> now, we have dCache publishing:
>    xroot
> as interface name, which I think is as bad as the above.

Since that is what we specified, dcache is correct.

> This needs severe sanitization.

No. For established names that have been in use for a long time I think changing them would be a very bad idea, it gains nothing and would be disruptive for a long time. Past experience with trying to rename things is that it's nearly impossible to remove all traces of the old name, so I would say that it should only be considered where there's an overriding reason. (Also note that the GOC DB has decided not to bring its names in line for the same reason.)

> My suggestion for these two InterfaceNames would be:
> 
>   org.ogf.glue.dpm.webdav
>   org.ogf.glue.dpm.xrootd

No, that would be crazy - these are *standard* protocols, they are not in any way specific to DPM, so they need to have universal names.

> How they can be used in discovery I already said in several emails.
> InterfaceName should NOT be used to indentify the protocol or the
> cababilities. For that there is existing attributes.

This is nonsense - InterfaceName is precisely the agreed attribute to identify the protocol.

Stephen
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