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Re: [grouper-dev] Re: [grouper-users] Dynamics groups in grouper

Chronological Thread 
  • From: Kathryn Huxtable <>
  • To:
  • Cc: Tom Barton <>, "GW Brown, Information Systems and Computing" <>,
  • Subject: Re: [grouper-dev] Re: [grouper-users] Dynamics groups in grouper
  • Date: Fri, 22 Feb 2008 13:47:50 -0600

This is why I'm more database-centric and less LDAP-centric. I prefer to
master everything in a database and use LDAP only as a receptacle for
application queries.

At KU we provision a relational database with our IdMS data, including
the Grouper groups. We provision LDAP from that.

It's not so difficult to make triggers on tables create actions that
result in memberships changing, not that we've done that. KU uses the
loader approach, but who knows what the future will bring. Last I heard
they were looking at Sun Identity Manager.


On Fri, 2008-02-22 at 09:55 +0100, Arnaud Deman wrote:
> Tom Barton a écrit :
> > Arnaud Deman wrote:
> >>> How many dynamic groups are you likely to need? Do they have to be
> >>> fully enumerated i.e. will you be expecting to list these
> >>> memberships or just test whether someone is a member?
> > >
> >> A lot ! ;) We don't know currently exactly how many but it is
> >> possible that we have to manage several thoushands (say between 3000
> >> and 5000). And of course we would like to enumerate them ! We can't
> >> do that with the PAGS groups and it was also one of our motivation to
> >> extends Grouper for this purpose.
> >
> > This is where dynamic and static groups mix about as well as oil and
> > water. You can't know that a subject is not a member of a dynamic
> > group until you evaluate the dynamic group membership filter on that
> > subject. So, to enumerate a subject's memberships will require that
> > all dynamic group filters are evaluated. If you have 5000 of those,
> > they'll all need to be evaluated every time you need to enumerate
> > memberships.
> >
> > This type of issue is what led us early on to maintain "flattened"
> > group membership information in grouper, ie, compute the indirect
> > membership effects of subgroups and composite groups as they are
> > created. That enables us to quickly enumerate memberships on demand. I
> > suspect that only a "pre-computed" approach to dynamic group
> > membership can scale to more than a handful of dynamic groups.
> >
> > Something must update the attributes in the LDAP directory (or many
> > LDAP directories?) that appear in the filters defining your dynamic
> > groups. Can this LDAP updating process be used to trigger updating of
> > the flattened membership of dynamically-defined groups?
> >
> > Tom
> Hello,
> Effectively, this problem is more harder than I thought and I realize
> that my approach may be naive...
> Actually our problem is to determine which attributes have been modified
> and ideally to trigger an update when it occures.
> I may be wrong (I hope I am wrong), but I don't think this is possible
> in a standard LDAP configuration.
> Nevertheless, with another colleague, we still try to find a solution,
> and there is perhaps a possibility. We have to consider it more but it
> would be based on this points :
> i) I can determine if the subject has changed or not,(most of the time
> he won't ), even if I can't determine directly which attributes have
> been modified.
> ii) I know wich attributes are involved in the dynimics groups definitions.
> iii) I Know the old (dynamics) memberships of the subject, in the
> attribute isMemberOf.
> We are looking if we are able to do what we want with this elements.
> If we can't, we will have to use the loader approach. I answered to fast
> to the advice of Gary, and eventually, a loader like the one descibed by
> Kathryn may be our solution.
> Regards,
> Arnaud.

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