Re: "guix pack -f docker" does too much work

["Ludovic Courtès" <ludo@gnu.org>]

Hi,

Ricardo Wurmus <rekado@elephly.net> skribis:

> a few months ago "guix pack -f docker" was modified to produce layers.
> This is great!  Unfortunately, "guix pack" itself still produces one big
> tarball containing all these layers.  There is no sharing of previously
> built layers, because they are all hidden inside the pack.

Right.

> I think it would be great if "guix pack -f docker" could avoid building
> all these identical layers again and again.  Perhaps it would be
> possible to have a single derivation for each layer?  This way we
> wouldn't have to recreate the same layer archives every time.

That sounds nice in terms of saving CPU time.  It’s less nice in terms
of disk usage: a single ‘guix pack -f docker’ run would populate the
store with roughly twice the size of the closure.

I think each solution (single derivation vs. one derivation per layer)
makes a different tradeoff.  I don’t have a strong feeling about which
one is better.

WDYT?

Ludo’.