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

[Michal Atlas]

Hi,
> > Also seems that Nix's way only quickly imports the changed layers? And
> > Guix's always imports the whole thing, at least I think?
> What do you mean by “imports the whole thing”?

I'm not sure what exactly happens, so correct me if I'm wrong, however 
if I time the different approaches, I think that how Guix creates a 
single-layered image, then if anything changes the entire image gets 
re-imported into docker. Though with the layered approach, if only one 
or two paths change, then those get imported, (and even though there's 
still some baseline that compression takes up) docker importing just the 
changed paths is a very noticeable speedup.

On that note, I know that guix pack goes through %compressors in order, 
however zstd is an insane improvement over gzip when working with 
containers, would it perhaps be possible to default to it, or would that 
break far too many workflows, or is there another reason? Perhaps during 
changing how guix pack works would be a good time to make both breaking 
changes at once?

Thanks, Michal.