uniqueness of overlays for a database

["Pierangelo Masarati" <ando@sys-net.it>]

I'm facing the opportunity to consider whether an instance of an overlay
should eb unique or not for a given database.  Currently, we can load how
many instances of an overlay on the stack of a database.  It is the
administrator's duty to make sure the same overlay is not loaded multiple
times.  However, for some reason, specific databases may need an overlay
whenever some feature is requested.  A clean solution would be to move the
configuration directive from the database to the overlay; for some reason,
currently there are a couple backends (ldap, relay) that directly
instantiate the "rwm" overlay when some configuration directive is
present.  I was thinking about adding some flag argument to
overlay_config, to specify whether that overlay must be unique or not,
and, in case, if multiple instantiation should be treated as an error or
be ignored.  This is not a priority, because back-relay can live without
it (it's clearly specified in the man page how the rwm overlay should or
should not be used), while in back-ldap this would be required only to
allow existing configurations to use the new back-ldap + rwm without
changes.

See http://www.openldap.org/lists/openldap-bugs/200411/msg00049.html and
follow-ons for details.

Comments?

p.

-- 
Pierangelo Masarati
mailto:pierangelo.masarati@sys-net.it


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