[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

processing order, preprocessing, etc.

From: Luke A. Kanies
Subject: processing order, preprocessing, etc.
Date: Sun, 22 Dec 2002 01:09:04 -0600 (CST)


I'm trying to understand how cfengine works, and how I might use it, and
I'm having trouble understanding how it processes its config files.  Is
this documented well anywhere?

For instance, what's the affect of having multiple control sections in the
same file?  Is it equivalent to a single control section?  Are all of the
control sections processed, and then the other sections, or is it all just
done linearly?  Is everything prepocessed, and then executed, such that
the last variable assignment or class definition is what matters, or can
variable assignment and then reassignment in a config make a difference?

What about if I import configs?  I know that the parent file is parsed
entirely before the child is, but are the children all parsed in the
specified order every time?  What if I have a "shellcommands" section in
the parent, and a control section in each child which sets a variable that
the parent "shellcommands" section uses and then lists "shellcommands" in 
the actionsequence; will shellcommands be run for each child file, with
that file's variable setting, or just once with the last setting, or for
each child but with the last setting?

Is there documentation I can read that describes this without me having to
test every case?

If I have a control section that looks like the following:

        actionsequence = ( shellcommands )
        variable = ( true )

and a "shellcommands" section which uses that variable:

        "/bin/echo $(variable) > /tmp/testing"

What happens if I later reassign that variable?  (Can I only assign
variables in control sections or modules?)  Will the shellcommands section
be run again?  From initial testing, it looks like I have to redefine the
shellcommands section, even though I haven't changed it.  That implies
that the config is parsed once and variables are interpolated in that
step, rather than the section being compiled with the reference to the
variable intact.  Is this so?

Anyway, if anyone has pointers on this whole process, and maybe where it's
documented, that would be great.


SELF-EVIDENT, adj.  Evident to one's self and to nobody else.
                -- Ambrose Bierce

reply via email to

[Prev in Thread] Current Thread [Next in Thread]