Hi Adrian,
You cannot use a metalink as a destination, but you can use
a metalink as a source for a remote destination ;-)
Cheers,
Michal
________________________________________
From: Adrian Sevcenco
Sent: 01 April 2019 15:02
To: Michal Kamil Simon; [log in to unmask]
Subject: Re: xrootd python :: CopyProcess - stop the queue if a job succeed
On 4/1/19 3:20 PM, Michal Kamil Simon wrote:
> Hi Adrian,
>
> The name attribute specifies the destination file name
> (or a relative path to the file as in the example), however keep
> in mind that the destination might be remote.
hmmm, i thought that metalink files are only for download
> To give you an example:
>
> / xrdcp input.meta4 root://hostname//path/dir/
>
> and say the name attribute is /subdir/file.txt/
>
> the effective destination will be:
> /root://hostname//path/dir/subdir/file.txt/
>
> however if you overwrite the destination file name in /xrdcp/ command
> line, e.g.:
>
> xrdcp input.meta4 /root://hostname//path/dir/file.txt/
>
> the name attribute will be ignored.
>
> Hope this makes it more clear :-)
yeah, i just ignored the fact that it can be used with remote destinations
well, thanks for info :)
looking forward for the fix :)
Thanks a lot!
Adrian
>
> Cheers,
> Michal
> ________________________________________
> From: Adrian Sevcenco
> Sent: 01 April 2019 13:22
> To: Michal Kamil Simon; [log in to unmask]
> Subject: Re: xrootd python :: CopyProcess - stop the queue if a job succeed
>
> On 4/1/19 1:10 PM, Michal Kamil Simon wrote:
> > Hi Adrian,
> Hi!
>
> > Thanks for providing an example metalink, indeed
> > it seems there is a problem with parsing a metalink
> > that contains urls with alice tokens. I'll provide a fix for
> > that.
> Thanks a lot!!
>
> > Regarding the destination, you are suppose to specify
> > possible sources in the metalink, but it must not contain
> > the destination, which has to be specified as for any other
> > copy job.
> well, https://tools.ietf.org/html/rfc5854#section-4.1.2.1
> metalink:file elements MUST have a "name" attribute, which contains
> the local file name to which the downloaded file will be written.
>
> This is why i said that destination should not be required...
> but of course is not hard for me to take care to use the same destination
> file as it is written in the meta4 file
>
> Thanks a lot!
> Adrian
>
>
> >
> > Cheers,
> > Michal
> > ________________________________________
> > From: Adrian Sevcenco
> > Sent: 31 March 2019 00:09
> > To: Michal Kamil Simon; [log in to unmask]
> > Subject: Re: xrootd python :: CopyProcess - stop the queue if a job succeed
> >
> > On 3/28/19 5:31 PM, Michal Kamil Simon wrote:
> >> Hi Adrian,
> > Hi Michal!
> >
> >> If (for now) you simply want to download a file having different
> >> replicas (with
> >> different names, etc.) a metalink is what you need. Have a look at:
> > cool! it is perfect for my need
> >
> >> https://en.wikipedia.org/wiki/Metalink#Example_Metalink_4.0_.meta4_file
> >>
> >> you can create a metalink containing different URLs and assign priorities
> >> to them. You could e.g. generate the metalink from python and then use a
> >> local metalink as source in the CopyProcess.
> >>
> >> Once we release 4.9.1 you will be also able to do a multi-source download
> >> using a metalink.
> >>
> >> However, this wont work for uploads.
> > of course!
> >
> > I made one for testing,
> > https://sev.spacescience.ro/adrian/meta/alice_cern.ch_user_a_asevcenc_testfile.meta4
> >
> > but it seems that there are problems :
> > 1. the url part is not parsed properly
> >
> > 2. the usage require a destination (but that is required and included in
> > the metalink) - so maybe if the source is meta4 the destination is taken
> > from the meta file and no longer required in cli?
> >
> > I am sure that there is a problem with the url parsing because the same
> > url works for a normal add_job copy request
> >
> > Additional question for when it will be working :
> > for the python part - add_Job, will take as source this .meta4 file?
> >
> > Thank you!!
> > Adrian
> >
> >>
> >> Cheers,
> >> Michal
> >> ________________________________________
> >> From: Adrian Sevcenco
> >> Sent: 28 March 2019 16:03
> >> To: Michal Kamil Simon; [log in to unmask]
> >> Subject: Re: xrootd python :: CopyProcess - stop the queue if a job succeed
> >>
> >> On 3/28/19 4:35 PM, Michal Kamil Simon wrote:
> >> > Hi Adrian,
> >> Hi!
> >>
> >> > My impression (correct me if I'm wrong) is that you are trying to do
> >> a multi-source transfer,
> >> > right?
> >> well, that would have been the optimal result, but at this moment i was
> >> just trying
> >> to download a file while trying all replicas
> >>
> >> > If so, you need to specify in the CopyProcess the sourceLimit, and as
> >> a source you need
> >> > to specify a metalink containing all the replicas, or a manager (in
> >> this case the client will
> >> > figure out what the replicas are by itself by using locate).
> >> my case is a little special ... the same file have multiple replicas
> >> that have _different_ physical names
> >> and authz envelopes ...
> >> as a client i have all required info.. i know for my logical file name
> >> /alice/cern.ch/user/a/asevcenc/testfile
> >> that the actual links are :
> >> root://eosalice.cern.ch:1094//06/17419/a7f1c690-4e49-11e9-8a64-0242266c4d21?_LONG_STRING_OF_OPTIONS_
> >> and
> >> root://ipngridxrd0.in2p3.fr:1094//06/17419/a7f1c690-4e49-11e9-8a64-0242266c4d21?_LONG_STRING_OF_OPTIONS_
> >>
> >> how can i create/what is the format of a metalink?
> >> can i somehow put toghether the remote links from above?
> >>
> >> would the same mechanism work for upload?
> >>
> >> > I just pushed a patch for the client that is enabling multi-source
> >> download in python bindings
> >> > (63e9604) and will port it for 4.9.1.
> >> great! thanks a lot!!!
> >>
> >> Adrian
> >>
> >>
> >> >
> >> > Cheers,
> >> > Michal
> >> > ________________________________________
> >> > From: [log in to unmask] [[log in to unmask]] on
> >> behalf of Adrian Sevcenco [[log in to unmask]]
> >> > Sent: 28 March 2019 14:22
> >> > To: [log in to unmask]
> >> > Subject: xrootd python :: CopyProcess - stop the queue if a job succeed
> >> >
> >> > Hi! In my use case (ALICE), to download a file, i get all replicas
> >> > and i add them as copy jobs to a CopyProcess ..
> >> > I would like to stop the CopyProcess when a job is succesful ..
> >> > Is there a way to do this?
> >> > Maybe in MyCopyProgressHandler.end() to check if results['status'] have
> >> > a "status: 0" and cancel all CopyProcess?
> >> > Is there a way to stop a CopyProcess? or other way to take into
> >> account the posibility
> >> > of multiple replicas?
> >> >
> >> > Thank you!
> >> > Adrian
> >> >
> >> >
> >> > ########################################################################
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> >> >
> >
> >
>
>
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