[SAGA-RG] Suggested errata to the SD spec

[Andre Merzky]

Quoting [Steve Fisher] (Apr 15 2009):
> >
> > 1: with URL specified:
> >
> >  When you do
> >
> >    discoverer d ("glite://cern.ch");
> >    list = d.discover (...);
> >
> >  and you have 5 adaptors (made up list)
> >
> >    glite
> >    mds
> >    local
> >    unicore
> >    condor
> >
> >  then you get a valid response from the glite adaptor.  You
> >  get no errors from the other adaptors, and no time overhead
> >  to speak off.
> 
> Thanks for the concrete example. The gLite information system is based
> on the "BDII" and accepts ldap calls (ldap://...). According to
> http://globus.org/toolkit/mds/ the mds (in GT4) is WSRF based - so you
> need to talk SOAP not LDAP. You are sure to get a rude reply if you
> make an LDAP call to a WS or a SOAP call to an LDAP server. In some
> cases the adaptor could choose to ignore a URL with the wrong scheme
> (first part of the URL). gLite does not use gLite as the scheme part
> of the url but "ldap" and most services use "http" or "https" so there
> is no easy way for an adapter to recognise the validity of an info
> system URL.
>
> I hope this is clear now.

Yes, a lot clearer, thanks!  At last I think we are getting
on the same page - thanks for your patience! :-)

So, a given URL can lead to problems if more than one
adaptor feel able to handle it.  (BTW: the failing adaptors
would *not* cause an exception on API level, as long as one
adaptor succeeds.)

Removing the URL surely would solve the problem.  But, as
said, the URL is optional anyway.  What is the gain? 

Also, the glite adaptor is free to define the schema
glite://, and translate that internally to ldap://.  We do
that, for example, with gridftp, which is translated to
gsiftp.  Also, we do that for ssh:// URLs, which are
translated into local file URLS (for sshfs mounted file
systems).

I am not saying that you should not remove the URL - just
want to make sure I understand why the URL is a problem,
really.

Best, Andre.


-- 
Nothing is ever easy.