Re: [geclipse-dev] Re: LFC registration - Was: Re: Strange SE after Grid

[Ariel Garcia <garcia@xxxxxxxxxx>]

Hi Mateusz,

> There is no warranty that this will work everywhere, but for SEs I
> tested it's ok.
>
> Hopefully this will work.

nope... hoping is almost always not enough!

0 - you can ask :-)
1 - you can check the sources for lcg-cr and the like
2 - you can ask ;-)

> There was some hardcoded URI in the sources. I forgot that I had left it
>  there. Problem is that I don't know how to get reliable data from the
> BDII. Currently I create such a URI for the replica:
>   srm://<HOST>:<PORT>/dpm/<HOST2>/home/<VO_NAME>/generated/<TODAY>
> where <HOST> and <PORT> are from BDII,
> <VO_NAME> is know because of token used during connection to the LFC Server
> <HOST2> is just a substring of <HOST> (ex. se.reef.man.poznan.pl ->
> reef.man.poznan.pl, iwrse.fzk.de -> fzk.de) [so, it's a domain]
> <TODAY> - today's date

uhuhuh....
that will fail sooner or later, rather sooner than later probably... that path 
can be changed at will in the yaim config file for a DPM SE for instance!!


- 1st problem: choose a SE host where to upload the file. The BDII provides 
all the SEs available for the VO so we have the info. To decide which one to 
use there are 3 possibilities:
	1.a - use a random/first one (most users would prefer a more "reliable"
                 algorithm to decide where their data is and make sure it
                 ends up in a reliable SE)
	1.b - have a setting in the VO for the user to select his default SE
                 (very unflexible... we cannot "force" a default SE to be
                 defined for each VO, oherwise we clash with the VO import
                 feature, but we could combine this method with another one)
	1.c - ask the user each time (this one alone can be cumbersome for real
                 day use...)

- 2nd problem: once the SE was choosen, get the right place to upload. 
	* The BDII publishes the base path under GlueSAPath or GlueSARoot
           (so no need to guess the 
                    "/dpm/<HOST2>/home/<VO_NAME>/"  piece)
	* the "generated" part is fine, you use the %Y-%m-%d format right?
	* in any case, please look for  the 
               generate_surls (gfal_internal gfal, char *errbuf, int errbufsz)
           method in the gfal.c file of the GFAL lib:                
http://glite.cvs.cern.ch:8180/cgi-bin/glite.cgi/org.glite.data.gfal/src/gfal.c?revision=1.106&view=markup
           and try to follow a similar/compatible approach.

For 1  i rather favor a combined solution, in which the user gets asked for 
the SE (like when doing job submission you are asked for the WMS) if there is 
no default SE defined in the VO, and the default one used otherwise.

Cheers, Ariel