doing "regenerative" packages (ark 1)

Nothing new here, but... I ended up noodling a little w/
what you might call "regenerative" packages -- I would
*KILL* for a good name... -- and was pleased that it
worked.

First: a r-ve package is one where you routinely change the
"source" and need to deploy/reveal it over and over again.
Automount maps, export lists, /etc/sudoers, /etc/hosts, and
so on.  Your systems change, you change the "system source"
that records things, and you need to re-splat all the files
that depend on those facts.

In my case, I was doing automount maps and /etc/exports
files.  (I happen to generate these from "dchunks" xml
files, but it doesn't matter.)

Here's how I want these things to work:

* I want to regenerate all these files every night, but
  *not* put them into production [reveal].  Simple reason:
  these are the kinds of files that, if messed up (across
  every host), leave you with a very dead/hobbling system.

* The sidai stuff has a "diffing deploy" -- it goes right up
  to "deploy" on every host and then diffs that against the
  previously-revealed version.

* I want to look at those diffs before anything dangerous
  happens.

  If I'm happy with what I see, do the reveal.

Even w/ ARK 1, we have enough machinery to do this! (Albeit
clunkily)  Here's my playing-around script to do
diffing-deploy of automount maps and /etc/exports:

#! /bin/sh
HOSTS='--hosts=slimy,slinger,slicker' # or --hosts=. ?
VERBOSE='' # --verbose

for pkg in		\
    automount-maps	\
    etc-exports		\
    ; do

    # remove the offending ark-state info:
    arkpkg reveal --use-deps=min --invalidate-node=$pkg--CURRENT-configure --invalidate-match-pattern=. $HOSTS $pkg--CURRENT | xargs /bin/rm -f

    # only re-do back up to 'deploy' (really a "diffing deploy", usually):
    arkpkg deploy $HOSTS --use-deps=min $VERBOSE $pkg--CURRENT

    # if happy with what you see, you could finish the job with:
    # arkpkg reveal $HOSTS --use-deps=min $VERBOSE $pkg--CURRENT
done

All I have to do is add more "regenerative packages of
interest" to the list, and I've got it.  Hooray!

(I'll say more if anybody cares.)

Will