Sharing scripts across slack roles

[Steve Atwell]

When writing slack roles, I find that my preinstall scripts and
postinstall scripts often need to do the same sorts of things in
different slack roles. E.g., make modifications to /etc/rc.conf on BSD.
I'd like to have libraries of shell functions that I can share among my
slack roles so that I can stop maintaining so many duplicates of the
same code.

Does anyone have any suggestions for how to do this? I'm not able to
think of any elegant solutions to this problem. Symlinks in the scripts
directory won't work because rsync will just copy them as symlinks. I
could put together some scripts that automatically copy libraries into
slack roles' scripts dirs, but that's kind of gross. Or I could
*shudder* use hard links, but that's even grosser and not trivial to do
with a svn-backed slack repository. I thought about just putting the
libs in a slack role, but without dependencies between roles, how do I
ensure that the libraries get installed first? I also thought about
just calling slack from within the role's preinstall, but really you'd
probably want to call slack recursively using the same path to slack and
with the same options, especially the -s option. (Make has similar
issues with recursion, and it deals with it by having users run
"$(MAKE)" instead of "make" because the former propagates options to the
recursive make. I suppose slack could set a SLACKCMD environment
variable that could deal with this.)

Another option would be to modify slack to support a shared library
directory that always gets rsynced over along with roles that are
fetched. We could add a lib/ directory alongside the etc/ and roles/
directories at the base of the slack repository, and always rsync it.
The downside to this is that in larger installations with many admins
using slack, the lib directory could easily get unweildy. Maybe have a
requires file in the scripts directory that lists what files are needed
from lib? Of course, at that point, we might as well just implement
slack role dependencies.

Thoughts, anyone?

--
Steve Atwell <sat...@disjoint.net>

[Alan Sundell]

Why not a package with executable scripts that anyone can use (not
just slack)? Seems more UNIXy. These days, I think we can spare a
fork(), and none of the other advantages of functions seem major.

I've wanted something like that for a while. Maybe it's time to get
the ball rolling. We can make a "slack-utils" package in the repo. Do
you have some scripts to seed it with?

--Alan

[Steve Atwell]

Sure, whether they're shell functions or scripts doesn't particularly
matter.

On the one hand, I think the idea of having pre-packaged utilities to do
everything I want would be nice. But taking a pragmatic point of view,
there will always be some OS or distribution or weird site-specific
behavior that slack-utils doesn't support. So when I discover that
there's some new little thing that I want to do, all I have to do is
write a patch, get the maintainer to accept it, wait for a new release
to be cut, build a new package, and get the new package installed on all
my machines. That's a pretty heavyweight solution to avoiding
duplication of eight lines of shell script across three slack roles,
don't you think?

I still think that allowing the individual slack repository maintainers
to easily drop in their own libraries (or library executables or
whatever) with minimal fuss is the way to go.

Maybe we could combine your idea and my idea. We could have a shared
script area in the slack repository, and then we can put together a
slack-stdlib with common general-purpose functions that admins can
install into their repository.

--
Steve Atwell <sat...@disjoint.net>

[David Lowry]

I have a whole set of add-on scripts I wrote that have some shared
functionality. I'd be glad to share them. Maybe they would help give
some ideas.

What would be the best way of getting them to the group? Upload to the
site? Attachments? They aren't that big.

David

[mbostwick]

I'm doing a brand new slack installation for 70+ machines and 15+
roles. If anyone has any scripts that they want to share I'd be
really happy to check them out. The files section on google groups
might be a good place to upload them.

http://groups.google.com/group/slack-users/files

Thanks!

-Matt

[David Lowry]

I uploaded a tar file to the URL Matt mentioned. I'm not sure if
anything there will help anybody, but hopefully it will help fuel some
ideas for slack development.

http://groups.google.com/group/slack-users/web/slack-addons.tar.gz

Like I said in the README, there's almost no docs anywhere. Right now
I won't be able to do a lot of work on things like docs and cleanup,
but I should be able to answer any questions you might have about how
I did things.

David