Re: (ITS#6531) Modify updateref to generate referrals on the backend

[masarati@aero.polimi.it]

> Full_Name: Ryan Steele
> Version: 2.4.18
> OS: Ubuntu Server
> URL: ftp://ftp.openldap.org/incoming/
> Submission from: (NULL) (207.106.239.81)
>
>
> Per conversation on the #openldap IRC channel on Freenode with Howard Chu,
> it
> has been deemed appropriate to modify the behavior of updateref to answer
> referrals on the backend.  This would allow one to use updateref to
> automatically chase referrals for individual backends, instead of it being
> all
> or nothing.  Here is the tail end of the channel conversation:
>
>
> <hyc> when you configure an updateref on a backend, that referral is only
> generated in the frontend so putting the overlay on the database, misses
> it...
>
> <rgsteele> Well, I am intending to set an updateref on that backend
>
> <hyc> then you have a problem
>
> <rgsteele> Hm, so you can't do automatic referrals on individual backends
> then?
>
> <rgsteele> That was my original question, or at least the intent of it.
>
> <hyc> not using updateref, no
>
> <rgsteele> Does your response imply there's another way?
>
> <hyc> probably we should fix updateref to be generated at the backend
> level
>
> <rgsteele> That would be good - I'd be happy to write tests or something
> to help
> with that.
>
> <hyc> the "other way" is the normal referral mechanism - using referral
> entries
> inside a database
>
> <hyc> but like I said, updateref is a relic, we've carried it forward
> without
> really adapting it
>
> <hyc> probably should file an ITS about this
>
> <rgsteele> Interesting, I wasn't aware of that method. I'll have to do
> some
> research on that - thanks! Also, is there anything I can do to help get
> the
> process of fixing updateref to generate referrals on the backend?
>
> <rgsteele> I can file the ITS if you like?
>
> <hyc> go ahead

It is correct that referrals are generated by the frontend, but the
frontend uses information contained in the updateref of each database. 
The slapo-chain needs to be global, in order to intercept those referrals.

Although redesigning referral generation in slapd could streamline things,
I don't quite see what issues can't be addressed using a global instance
of slapo-chain.  You can configure referral chasing differently for
different domains using the chain-uri directive.  I favor fixing only
what's actually broken.

p.