Do we need charm "snippets"?

James Westby james.westby at
Wed Nov 23 04:00:47 UTC 2011

On Tue, 22 Nov 2011 13:49:41 -0800, Clint Byrum <clint at> wrote:
> I think the best way to get this done is to add a bit of "Should" policy
> that states that code should not be copied from one charm to another,
> but instead should be added to charm-helper and removed from both charms.

I see this as somewhat similar to maintainer scripts in packaging
(e.g.,) which has shown that

  nothing < documentation of patterns < copied snippets < shared helper
    library < built in

It's pretty easy to start moving up this chain and getting some
benefit. In fact it's the path that patterns/snippets take if they
remain useful and get adopted.

So +1 on doing something here, and +1 for doing it incrementally as
Clint suggests.

Also, keep an eye out for where something should move up a level, as
if the mass at one leve grows too large there will start to be problems
(e.g. having too many copied snippets can lead to it being hard to
change something in core juju as it would break too many charms.)



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