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Hi all,<br>
<br>
On 24/05/2011 09:59, Estanislao Gonzalez wrote:
<blockquote cite="mid:4DDB6554.3040800@dkrz.de" type="cite">
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Hi,<br>
<br>
just to be more precise: indeed I think security and CIM data
(meta-data from experiments and so on) should be kept away from
the catalogs.<br>
<br>
</blockquote>
<br>
I also agree that access policy should be decoupled from the
publication step and that CIM metadata should be kept away from the
catalogs. CIM instances are exposed through atom feed and services ;
that's enough. I agree it's not fairly easy to match files and
associated CIM instances but everything is available to do this
mapping.<br>
<br>
<blockquote cite="mid:4DDB6554.3040800@dkrz.de" type="cite"> Still,
Luca's idea of merging QC level info with the files itself might
be a valid idea. The difference is that QC is pretty much like a
"semantic" checksum for a file. AFAIK you cannot "downgrade" the
QC without altering the file, i.e. if the file is QC L2 and while
performing QC L3 checks an error is found, the file will either be
QC L3 approved (the modeler defines the "oddity" as "expected") or
it doesn't, which implies a "QC L2 passed; QC L3 failed" flag or
the retraction (and maybe re-publication) of it altogether.<br>
<br>
Well, that's at least why I think the QC flag is a little
different and it's *closely* related to the file. The only
difference with the checksum is IMHO that it takes more time to be
determined (as well as require other files for it's computation)
and thus it's performed in an out-of-band fashion.<br>
<br>
We need that QC flag somewhere... and it's far more important than
the rest of the CIM meta-data (getting back to Gavin's point about
CIM issues and differentiating it to this QC flag: yes, you can
still get to the file and download it without CIM data... but
without the QC flag you'll have no clue if you *really* want to
rely on this data).<br>
</blockquote>
<br>
Generally speaking I don't think QC flag is far more important than
the rest of the CIM meta-data. At least climate modellers and
climate scientists will be able to perform their own QC. If
something is wrong with a file (bad units, bad variable (example :
precipitation claiming it's a temperature),... , or others
discrepancy far more difficult to detect) they will most likely
detect it and gave feedback to the appropriate modelling groups.
This direct feedback is very important to the whole process. CIM
metadata will put some more light over those data and will help
scientists to decide up to which point they can rely on a dataset
for a particular purpose.<br>
<br>
Regarding WG2, WG3, and commercial use of this data the QC flag will
be something important. But one must keep in mind that producing
information from a multi model - multi experiment project like CMIP5
is a challenging and extremely difficult task. One need an
incredible amount of information to perform the right decision. The
QC flag won't be able to summarise that with a "use this data : yes
or no"<br>
<br>
<br>
<blockquote cite="mid:4DDB6554.3040800@dkrz.de" type="cite"> To be
honest I can't understand why people download this data if they
*know* it might get corrected. Would you start writing a paper on
something that might be altogether wrong?... I suspect they don't
realize this.<br>
</blockquote>
<br>
The group CMIP5 research know that ; it's 100% part of the job. The
process they will follow:<br>
<br>
- download variables & experiments they are interested in<br>
- perform a first home made analysis on those files<br>
- it's very likely they will catch a lot of things the QC tools
won't<br>
- give feedbacks to the modelling groups that produced a dataset
they found "strange"<br>
- modelling groups will analyse the situation and will decide to
update or delete or keep the files unchanged<br>
- perform a more detailled analysis (catching may be a few more
errors)<br>
- give feedbacks to the modelling groups that produced a dataset
they found "strange"<br>
- modelling groups will analyse the situation and will decide to
update or delete or keep the files unchanged<br>
- start to write their paper<br>
- will do a second round to check if data has been updated (new
version, erased version)<br>
- download files that has been updated<br>
- discard files that has been deleted on esg<br>
- rerun their analysis procedure<br>
- update figures and conclusion of the analysis<br>
- will publish a paper that will include proper datasets<br>
- this paper will clearly mention a strange dataset. <br>
<br>
This process has already started.<br>
<br>
So as a modelling group you will pay extra attention to the
feedbacks your receive (you don't want thousands of paper saying
your data are strange). And you want to be sure that analyst will
use the latest version of your files, or won't use it if you decided
to erase it from ESG.<br>
<br>
That worked like a charm for CMIP3. We want it better for CMIP5.<br>
<br>
Regards.<br>
Sébastien<br>
<br>
<blockquote cite="mid:4DDB6554.3040800@dkrz.de" type="cite"> Anyway,
my 2c...<br>
<br>
Thanks,<br>
Estani<br>
<br>
Am 24.05.2011 03:06, schrieb Gavin M. Bell:
<blockquote cite="mid:4DDB0479.2040904@llnl.gov" type="cite">
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Hi Luca, <br>
<br>
I think that the separation of concerns trumps the apparent
"simplicity". Though it is apparently easy to republish (I am
not sure I fully agree with that, at least not from the
anecdotal information I hear from folks)... it is unnecessary to
publish if we keep concerns separated.<br>
<br>
As Estani said, the publisher publishes and does basic
mechanical sanity checks on data. That should be the full
extent of its operation. As far as what is easy... one could
'easily' set up an index over the CIM info and "join" on
datasetid. This also provides loose coupling. If the CIM
system has issues, that just means that when you look at your
search results you won't see CIM info, but you will still see
the dataset and be able to fetch and manipulate it and
everything else. Also if the CIM changes it doesn't affect the
pubblisher or publishing in any way. Catalogs should be viewed
as "files" in the system... they essentially are logical files
(containing pointers to physical files).<br>
<br>
I am still not convinced by your arguments that fusing and
coupling these two semantically different aspects of the system
so tightly is the right long term architectural solution. It
may be good now, but it not as flexible later. We should leave
open the avenue for other meta-metadata to be imbued onto our
system ex-post-facto without much ado.<br>
<br>
my $0.02<br>
<br>
On 5/23/11 2:08 AM, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:stephen.pascoe@stfc.ac.uk">stephen.pascoe@stfc.ac.uk</a>
wrote:
<blockquote
cite="mid:4C353E6E4A08AE4792B350DAA392B521196329@EXCHMBX01.fed.cclrc.ac.uk"
type="cite">
<pre wrap="">I'm with Estani on this. Authorisation decisions are best decoupled from the application where possible. Phil is on leave today but I'm sure he'd say the same thing and give much more detailed reasoning.
I think the catalogue already mixes slightly too much information together: location-independent file metadata and location-specific service information. If we add access control it becomes too tightly coupled.
Stephen.
---
Stephen Pascoe +44 (0)1235 445980
Centre of Environmental Data Archival
STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK
-----Original Message-----
From: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:go-essp-tech-bounces@ucar.edu">go-essp-tech-bounces@ucar.edu</a> [<a moz-do-not-send="true" class="moz-txt-link-freetext" href="mailto:go-essp-tech-bounces@ucar.edu">mailto:go-essp-tech-bounces@ucar.edu</a>] On Behalf Of Estanislao Gonzalez
Sent: 21 May 2011 09:30
To: Cinquini, Luca (3880)
Cc: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:go-essp-tech@ucar.edu">go-essp-tech@ucar.edu</a>
Subject: Re: [Go-essp-tech] resolution on securing opendap aggregations via ESGF
Hi,
In my opinion we shouldn't encode the access restriction in the catalog
for these reasons:
1) Changing the access would involved re-publishing the files. (this
will be done for instance when QC L2 is reached CMIP5 Research -> CMIP5
Commercial). And think about what would happen if we want to change the
access restriction in a couple of years... we should publish everything
again, and that would involve quite some effort to understand the
procedure again...
2) I'm not sure of this, but I fear TDS security cannot handle multiple
roles. Right now you can publish to as many roles as required, and read
and write access is kept separately. This would involve extending the
TDS capabilities.
3) There could be potential inconsistencies if the authorization service
is detached from datanode (like with the gateway right now) and the
publisher alters the role but forgets to cascade the changes to the
authorizing service (which would proceed according to the last harvested
info)
4) And last but not least, I'm not sure we want to mix administration
with publication. The publisher should only care about making data
available, the administrator should organize this and be responsible for
the security.
So basically I don't agree :-) Although I do think, if required, we
could change "esg-user" for "esgf-controlled" if it's more intuitive.
My 2c anyways,
Estani
Am 20.05.2011 19:17, schrieb Cinquini, Luca (3880):
</pre>
<blockquote type="cite">
<pre wrap="">Hi,
a few points again on the issue of securing opendap aggregations served by the TDS with ESGF filters:
o There's a new release of the ESGF security filters (esg-orp 1.1.2) that maps the TDS request URI to the dataset ID, and should solve this problem. You can experiment with the JPL test TDS server:
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://test-datanode.jpl.nasa.gov/thredds/catalog.html">http://test-datanode.jpl.nasa.gov/thredds/catalog.html</a>
where the AIRS dataset (and aggregations) is secured, the MLS is not.
o Now the data node authorization filter will correctly identify the aggregation as secured, and call the configured authorization service. Currently, the p2p Node authorization service can be configured to allow authorization based on URL matching, so it will work. The gateway authorization service will have to implement its own logic to establish authorization.
o Finally, I am wondering if we shouldn't change the way we encode authorization in thredds catalogs. Right now, we use restrictAccess="esg-user" for ALL collections, but should we consider about encoding the proper required access control attribute instead, for example restrictAccess="CMIP5 Research" ? Something to think about - there are prons and cons about this - it's all a question on wether the access control belongs in the catalog (and can be harvested for searching...) or not.
thanks, Luca
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</pre>
</blockquote>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Gavin M. Bell
--
"Never mistake a clear view for a short distance."
-Paul Saffo
</pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Estanislao Gonzalez
Max-Planck-Institut für Meteorologie (MPI-M)
Deutsches Klimarechenzentrum (DKRZ) - German Climate Computing Centre
Room 108 - Bundesstrasse 45a, D-20146 Hamburg, Germany
Phone: +49 (40) 46 00 94-126
E-Mail: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:gonzalez@dkrz.de">gonzalez@dkrz.de</a> </pre>
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<br>
<pre class="moz-signature" cols="72">--
Sébastien Denvil
IPSL, Pôle de modélisation du climat
UPMC, Case 101, 4 place Jussieu,
75252 Paris Cedex 5
Tour 45-55 2ème étage Bureau 209
Tel: 33 1 44 27 21 10
Fax: 33 1 44 27 39 02
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