Re: ‘guix publish’ now compresses archives

[Tomáš Čech]

On Tue, Jul 19, 2016 at 03:15:38PM +0200, Ludovic Courtès wrote:
> Hello Tomáš,
>
> Tomáš Čech <address@hidden> skribis:
>
> > As I am happy to see enthusiasm about Guix, I don't think that current
> > archive format is usable for distribution of binary packages of
> > whatever origin. Problem is that we have package definition as part of
> > package manager GIT snapshot or local files but this information is
> > not distributed along with the package archive.
>
> I’m not sure what you mean.  The “substitute” mechanism is meant as a
> cache.  Guix locally compiles the package recipe to a low-level
> representation of the build process (a derivation), and then, it can
> *optionally* ask substitute servers whether they have the result
> corresponding to that derivation.
>
> A derivation is self-contained and unambiguous.  I can do:
>
> --8<---------------cut here---------------start------------->8---
> $ guix build -d sed
> /gnu/store/whkb4d5sq2326m54zpdz6hhmi37jy6j4-sed-4.2.2.drv
> $ cat $(guix build -d sed) | cut -d ']' -f 1
> Derive([("out","/gnu/store/4ls9kdy1w6ichvmbrl5wn98lxmznbkd6-sed-4.2.2","","")
> $ wget -O /tmp/sed-binary.nar.bz2 
> https://mirror.hydra.gnu.org/nar/4ls9kdy1w6ichvmbrl5wn98lxmznbkd6-sed-4.2.2
> --2016-07-19 15:09:02--  
> https://mirror.hydra.gnu.org/nar/4ls9kdy1w6ichvmbrl5wn98lxmznbkd6-sed-4.2.2
> Ni solvigas mirror.hydra.gnu.org (mirror.hydra.gnu.org)... 131.159.14.26, 
> 2001:4ca0:2001:10:225:90ff:fedb:c720
> Konektado al mirror.hydra.gnu.org (mirror.hydra.gnu.org)|131.159.14.26|:443... 
> konektita.
> HTTP peto sendita, ni atendas respondon... 200 OK
> Grando: nespecifita [application/x-nix-archive]
> Ni konservas al: '/tmp/sed-binary.nar.bz2'
>
> /tmp/sed-binary.nar     [ <=>                ] 145.07K  --.-KB/s    in 0.07s
>
> 2016-07-19 15:09:02 (2.04 MB/s) - '/tmp/sed-binary.nar.bz2' konservita [148549]
> --8<---------------cut here---------------end--------------->8---
>
> … and now I have the binary corresponds to that sed-4.2.2.drv, or so
> claims mirror.hydra.gnu.org.  (This URL scheme is what ‘guix publish’
> implements.)
>
> Thus, mirror.hydra.gnu.org does not need to know about the (package …)
> form, the Git revision of Guix, whether the recipe was local or not,
> etc.
>
> Of course I have to trust mirror.hydra.gnu.org to genuinely serve
> binaries resulting corresponding to the derivations.  To express this
> trust, I register its archive signing key, as explained at
> <https://www.gnu.org/software/guix/manual/html_node/Substitutes.html>.
>
> Does that clarify things, or am I misunderstanding?

Thanks for lenghty mail, but I'm sorry, no, I mean something
different. Let's try example situation instead.

Imagine situation where person A is running some distribution with
Guix package manager on top and has some set of his personal packages
containing additional patches which are not part of Guix GIT.

He'd like to share the package with person B, running different
distribution with Guix package manager at different revision on top,
with different set of personal packages and alterations.

I'd like to provide them a way, how to pass from person A to person B
some binary archive in a way that he could understand (and verify)
what he received. If it requries out-of-tree package definitions of
person A, patches, etc, bundle it together.

IOW, prepare Guix for being package manager for packages which are not
defined in Guix GIT.

Is that better understood?

Thanks,

S_W

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