setting class based on file change

[Luke A. Kanies]

I am currently using rsync to pull files down, with ISconf as the
framework for deciding what gets pulled down.

I'm hoping to change that transport to cfengine, but to do so, I need to
be able to uncouple copying the file from triggering an action based on
the file changing.

I know that it's very easy to set cfengine up to copy a file, and to
perform an action if that file is changed.  The problem then is that you
have now coupled those actions.  That isn't always a problem, but in my
case, I'm copying an entire directory of files, and any of those files
might have a different action associated with them.

For instance, I'm not currently (although I might soon) maintaining all of
my config files individually; instead, I maintain a central copy of
sshd_config and syslogd.conf.  When I update those files in the central
location, they get automatically copied down using rsync.

The problem is, those files are part of a larger fileset.  Both of those
files are maintained on a per-platform basis with a bunch of other files.
So, my copy statement would look like this:

control:
  fileserver = ( myserver.mydomain.com )
  filesource = ( /var/filesets )
  platform = ( ExecResult(/some/program) )
  domain = ( ExecResult(domainname) )

copy:
  ${filesource}/${platform}/     dest=/
                                 type=checksum
                                 server=${fileserver}

And this would copy, say, both my syslogd.conf and sshd_config files down,
but then I want cfengine to restart syslogd if syslogd.conf changes, and
restart sshd if sshd_config changes.

I can't think of a way to do this without specifying that each of those
files gets copied independently, which makes my configs more verbose than
they need to be, or without creating an external module which maintains an
external list of files to check and checksums associated with them, which
is definitely duplication of information (and thus bad).

Is there a way to decouple these actions?  I'm hoping not to rely on these
methods eventually, but if I can't provide this kind of decoupling to
start, it's going to make my migration significantly more difficult.

This seems to be a bit of a general problem in cfengine; most operations
are relatively tightly coupled, and changing one thing requires changing a
bunch of other stuff.

Thanks,
Luke

-- 
Man is the only animal that can remain on friendly terms with the
victims he intends to eat until he eats them.
                -- Samuel Butler (1835-1902)