[unct-devel] ideas

[<ok...@ya...>]

I've thought a little about this suggested feature of being able to
make a change across multiple hosts and decided how I think it would
perhaps be best achieved.

I suggested before that I think the config file modifying program
should be a separate program[1] which can be invoked from the
command-line instead. If we have this, then rsh and ssh would be plenty
good enough for connecting to a remote host to run commands. This makes
things much more simple and easy and secure. It works well for CVS. And
we don't have to reinvent half of ssh and link against SSL, PAM etc. It
is sticking to the UNIX philosophy of doing one thing only but doing it
well.

If you imagine an action such as changing a user (such as with
usermod), it would be useful to bring up on screen the user's current
details when prompting the user for new details. Also, for some of the
fields such as group membership, we would want to provide a list of all
possible groups. When making a change across multiple hosts, you would
have to contend with this information being different on different
machines. It'd make things simpler to just take the information from a
single machine (by default the local one). If applying the change on a
remote host produces an error, then we have to display the error (shell
scripts should be run with the -e (exit on error) option).

[1] as an initial rough design for this program, it could have modules
for various generic config file styles (such as .ini (e.g smb.conf),
.xml, fixed character separated lists (e.g. /etc/passwd), assignment
lists (e.g. wgetrc)). The modules would provide an abstract interface
to the config file format mapping them into an XML like structure. We
could then use something like XSLT matching syntax to specify the
changes. So for smb.conf, you might match the [global] section, select
the workgroup key and change it's value. Everything else gets copied
as-is. For programs with simple config files, we'll perhaps be able to
use sed or awk instead of the new command. Initially, it might be
better to stick to existing UNIX commands and come to this when we need
it.

To outline my ideas for the main config tool: There would be a
directory structure containing .xml files. So this directory might
contain a Networking directory which might include dns.xml routing.xml
ppp.xml bind.xml. The directory structure could be more than one level
deep. Individual directories and files here could be removed or added.
Symbolic links could be used so that for example, NFS configuration
might be under both networking and file systems. And as I suggested
before an environment variable would list directories to search for
these files.

Individual .xml files would look a bit like an HTML form but more
complex. An input field might specify a shell script which if run would
generate a list of possible values. So if you want to delete a print
queue, it could generate a list of print queues to prompt you with.
When you submit changes, it would again have a shell script to run. m4
preprocessing this shell script would make it possible to make the
script minimal and to insert the user-entered values into the script.

The distribution could contain a set of these xml files which would be
combined with information gleaned from autoconf, and processed with
XSLT to produce more platform specific xml files. If the project is
successful, applications could distribute their own xml files.

You may have already decided on this but I would suggest that
everything supports unicode from day one. Unfortunately, I don't know
much about it.

I'm not too sure that I like the program's name. I tend to prefer
natural language words (not necessarily English) to vowel-less
acronyms. Another suggestion is that the project is moved from
Sourceforge to GNU's Savannah. I'm not 100% happy with the new
Sourceforge terms. It'd give us a higher profile with the FSF and
improve chances of becoming official GNU. Being officially part of GNU
would help a lot in making the project successful (plenty of GNU
projects do better than superior alternatives).

Oliver


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