Why don't we have "Guix channels"?

Why don't we have "Guix channels"?

[Chris Marusich]

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Hi,

Nix has a feature called "channels".  To quote the docs, "a channel is a
Nix mechanism for distributing Nix expressions and associated binaries"
[1].  It sounds like this includes the nix tools like "nix-build", but
I'm not sure.  In any case, it's clearly similar to "guix pull", but at
first blush channels seems more featureful and more useful.  Here are
some features:

* A user can "subscribe" [2] to multiple channels ("stable", "unstable",
  etc.).

* "Correctness: The channel is only updated to a new revision of
  NixOS/Nixpkgs if it passes certain tests" [3].

* "Efficiency: The channel is only updated after all Hydra builds in
  that revision have finished, *and* all binaries have been mirrored"
  [3].

* "In principle, you can do rollbacks on the channels profile ("nix-env
  -p /nix/var/nix/profiles/per-user/root/channels --rollback") if you
  don't like the result of a 'nix-channel --update'" [3].

These all sound like features which would be nice to have in Guix, so I
wonder: why doesn't Guix have "channels", too?

For more information about Nix channels, see here (Eelco's thesis [4]
includes more technical details - search it for the word "channel"):

[1] https://nixos.org/nixos/manual/#sec-upgrading
[2] https://nixos.org/nix/manual/#sec-channels
[3] https://nixos.org/wiki/Install/remove_software#nix-channels
[4] http://nixos.org/%7Eeelco/pubs/phd-thesis.pdf

-- 
Chris

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Re: Why don't we have "Guix channels"?

[Chris Marusich]

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Apologies for the self-reply, but I wanted to point out that it seems
"channels" were actually mentioned here as a possible future direction
for "guix pull":

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22629

Still, I'm curious to hear what others think about it.

-- 
Chris

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Re: Why don't we have "Guix channels"?

[Pjotr Prins]

On Thu, Dec 08, 2016 at 11:35:39PM -0800, Chris Marusich wrote:
> Apologies for the self-reply, but I wanted to point out that it seems
> "channels" were actually mentioned here as a possible future direction
> for "guix pull":
> 
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22629
> 
> Still, I'm curious to hear what others think about it.

Guix channels is high on our list of priorities. So far, no one has
found time to work on it properly.

Pj.

Re: Why don't we have "Guix channels"?

[Ludovic Courtès]

Pjotr Prins <pjotr.public12@thebird.nl> skribis:

> On Thu, Dec 08, 2016 at 11:35:39PM -0800, Chris Marusich wrote:
>> Apologies for the self-reply, but I wanted to point out that it seems
>> "channels" were actually mentioned here as a possible future direction
>> for "guix pull":
>> 
>> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22629
>> 
>> Still, I'm curious to hear what others think about it.
>
> Guix channels is high on our list of priorities. So far, no one has
> found time to work on it properly.

Indeed.

We need to work on the next “guix pull” once 0.12 is out, and “channels”
are one of the things.

Guix is different from Nix{,pkgs} here in that there’s no “Guixpkgs”:
everything works together, and we upgrade everything in lockstep.  That
way we make sure packages rely on features that the (guix …) modules
support.

Ludo’.