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Re: back-ldap and rewrite/remap in 2.3



Pierangelo Masarati wrote:

[reposting with subject; sorry]

Regarding ITS#3350 (and partially my previous posting), I'd like, for 2.3,
to remove DN rewrite and attribute mapping code from back-ldap, since it's
now handled by the rwm overlay, with equivalent (and improved)
functionality. The same stuff cannot yet be removed from back-meta
without changing the configuration and the functionality because in
back-meta it occurs at and after target resolution, with separate rewrite
configuration for each target, so inside the backend functonality. However, my long term plans for back-meta are to replace it with multiple
instances of back-ldap glued together by the backglue framework.


I already have a version of back-ldap with the rwm functionality backed
out; I wonder what's the best way to proceed: should I just replace the
current back-ldap code, or have it in parallel with the original one until
the overall setup (slim back-ldap + rwm) proves to have the same
functionality and reliability? I'd avoid having all the rewrite stuff
conditionally compiled in, because it's going to be very messy, since
removing the rwm functionality really makes back-ldap very very clean: a
straight use of the Operation members into the client API.


Since making back-ldap slimmer/cleaner should also make it easier to fix if any problems do crop up, I think that's best.

On the topic of backglue - does it really provide enough functionality for the purpose? There's one area it is still definitely lacking; if a subordinate database is unreachable (e.g., it's a back-ldap that isn't currently answering) we have no way to report this in the search results. The LDAP_PARTIAL_RESULTS error code would have been useful here but that was deleted from LDAPv3. The best approach (hack) I've come up with so far is for backglue to return a Reference for any subtrees that return Unavailable, and let the client deal with the problem that way.

--
 -- Howard Chu
 Chief Architect, Symas Corp.       Director, Highland Sun
 http://www.symas.com               http://highlandsun.com/hyc
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