(ITS#4261) [enhancement] Factor replication code out of slapd

[ando@sys-net.it]

Full_Name: Pierangelo Masarati
Version: HEAD
OS: irrelevant
URL: http://www.sys-net.it/~ando/Download/slurpover-2005-12-15.1.patch.bz2
Submission from: (NULL) (81.72.89.40)
Submitted by: ando


This patch, for HEAD as of December 15th, 2005, factors replication code out of
slapd.  It's actually composed of two parts, which are tightly coupled and thus
it's submitted as just one.

It provides two overlays:

"slurprov" takes care of logging modifications to the replog, and of those
config statements that are actually used by slurpd: replica-{args,pid}file,
replica, replicationinterval.  It should be instantiated inside any master
database.

"consumer" is a generic consumer interface.  It handles generic consumer issues,
like rejecting non-replication modifications (unless set up as so-called
"multimaster") and, for syncrepl, it accounts for the configuration.

Both overlays support back-config.

Current issues:
- some existing overlays that are replog-aware are not handled yet.  As such,
slapo-refint(5) and slapo-ppolicy(5) cannot be compiled along with
slapo-slurprov(5);
- the overlays need to be explicitly instantiated; the rest of the configuration
is fully compatible with the current.  It would be nice to have them
automatically instantiated when the appropriate replication statements occur in
slapd.conf(5), I don't think it's going to be a big deal;
- slapo-consumer(5) must be global; thus, a single slapo-consumer(5) takes care
of all consumer database in the DSA.  As a consequence, the related
configuration is held in subordinate entries of the global overlay rather than
inside (or subordinate to) the related database.  This makes configuration via
back-config little intuitive
- slapo-consumer(5) doesn't yet support run-time configuration via back-config;
only EMIT is available.

The patch is provided for initial discussion, development and testing.  I plan
to commit it when it's a bit more mature, i.e. when the above issues are closed.
 Note though that (at least on my laptop ;) it passes all tests, and
significantly all replication-related ones.

p.

PS: no space left on device on ftp.openldap.org; I've placed it on my website.