Guix extension to display derivation (and rewrite fixed-output)

Guix extension to display derivation (and rewrite fixed-output)

[Simon Tournier]

Hi,

As an Emacs user, exploring Derivation (the .drv files) is easy since
there is an Emacs mode.  However, I have been annoyed with some pipe
through ’sed’ and friends.

Therefore, I wrote a very simple Guix extension [1] that outputs
derivation content using recutils format.

--8<---------------cut here---------------start------------->8---
$ guix drv-show $(guix build hello -d)
name: /gnu/store/qr00sgbh3vwwqswmgjjymg6wkys9r4i2-hello-2.12.1.drv
outputs:
+ /gnu/store/6fbh8phmp3izay6c0dpggpxhcjn4xlm5-hello-2.12.1   [out]
inputs:
+ /gnu/store/3ds56xg6njpw6hnp2w4xpx4psw5mka5q-glibc-2.35.drv                [out]
+ /gnu/store/3zh2qpi897s2x229s93iakji86b08a20-hello-2.12.1.drv              [out]
+ /gnu/store/5bqhdbbl71r9r936w6w8zzqlk41md3wx-glibc-2.35.drv                [out]
+ /gnu/store/67nh3fzviy3q4s8ar8cg0dzhyzgwrwdd-module-import-compiled.drv    [out]
+ /gnu/store/7fsz44vifdc0ws0amnpwnmig3ra6hb53-gcc-11.3.0.drv                [lib]
+ /gnu/store/fchdaawcrxb35llbl7fj7lcsq5asmk4b-guile-2.0.14.drv              [out]
+ /gnu/store/ky030dkfkfr3l8xgdbv45j6bs87988lx-gcc-11.3.0.drv                [lib]
+ /gnu/store/n9kblf5cx4lphrydjr90sp3zfvcdr1pb-glibc-utf8-locales-2.35.drv   [out]
system: x86_64-linux
builder:
+ /gnu/store/4p1l5bdxxbyyqc3wh0d07jv9rp1pdcy7-guile-2.0.14/bin/guile
+ --no-auto-compile
+ -L /gnu/store/a6acf6dds8s9fw7dp5div03rwik0x4x2-module-import
+ -C /gnu/store/yk897hj2p5mdx6hw47s90n8x9pn6s36c-module-import-compiled
+ /gnu/store/fiy8arwqm8vwaqs4h8b361kbmjmd1yra-hello-2.12.1-builder
environment:
+ allowSubstitutes: 0
+ guix properties: ((type . graft) (graft (count . 2)))
+ out: /gnu/store/6fbh8phmp3izay6c0dpggpxhcjn4xlm5-hello-2.12.1
+ preferLocalBuild: 1
--8<---------------cut here---------------end--------------->8---

Do you think it would be useful to package it?  Or maybe to include it
as another subcommand (or part of some subcommand)?

Let me know. :-)

My motivation to do it now is this story:

    https://simon.tournier.info/posts/2024-04-11-rewrite-drv.html


Cheers,
simon

1: https://gitlab.com/zimoun/guix-drv

Re: Guix extension to display derivation (and rewrite fixed-output)

[Leo Famulari]

On Fri, Apr 12, 2024 at 08:28:11PM +0200, Simon Tournier wrote:
> Therefore, I wrote a very simple Guix extension [1] that outputs
> derivation content using recutils format.

Amazing! That's so useful.

> Do you think it would be useful to package it?  Or maybe to include it
> as another subcommand (or part of some subcommand)?

I'd love for this to be built in to Guix. I'm often struggling to read
derivations while debugging or analysing something.

Adding plumbing subcommand 'derivation'?

[Simon Tournier]

Hi Leo,

On ven., 12 avril 2024 at 20:04, Leo Famulari <leo@famulari.name> wrote:

>> Do you think it would be useful to package it?  Or maybe to include it
>> as another subcommand (or part of some subcommand)?
>
> I'd love for this to be built in to Guix. I'm often struggling to read
> derivations while debugging or analysing something.

So I propose to add the plumbing command ’derivation’.  Any objection?

Cheers,
simon

Re: Adding plumbing subcommand 'derivation'?

[Leo Famulari]

On Sat, Apr 13, 2024 at 12:32:45PM +0200, Simon Tournier wrote:
> So I propose to add the plumbing command ’derivation’.  Any objection?

Sounds good to me, but give it a couple days for everyone else to ponder
the bike shed ;)

Re: Adding plumbing subcommand 'derivation'?

[Ricardo Wurmus]

Hi Simon,

> So I propose to add the plumbing command ’derivation’.  Any objection?

I think it's useful to have.  To avoid proliferation of sub-commands, do
you think we could put this under "inspect", a generic sub-command for
all sorts of as yet to be invented introspection tools?

-- 
Ricardo

Re: Adding plumbing subcommand 'derivation'?

[Christina O'Donnell]

Hi,

In the interest of throwing ideas out there, and with the caveat that 
this is rather uninformed:

I think having  a derivation sub-command makes the most sense to me. E.g.

`guix derivation show` for `guix drv-show`
`guix derivation update` for `guix drv-drv` (or 'refresh' or 'fix')

I have also been thinking that it'd potentially be useful to have 
something like:

`guix derivation edit /gnu/store/...-xyz.drv`

Which then produces a temp directory that you may edit with whatever 
tools you like, then on command checks for changed files, recompute 
hashes recursively, and puts the modified derivations and back into the 
store. I think this would be mainly be useful as a debugging tool or for 
changes that no longer build, for cases where the new `guix derivation 
update` wouldn't work.

On the tangential subject of plumbing commands, I've also started to 
write a `guix store` command that simply exposes functions in (guix 
store) as a command line interface as a way of learning the internals of 
Guix.

This would have sub-commands like:

`guix store get-references`
`guix store get-referrers`
`guix store info` - dumps the `path-info`
`guix store put xyz` - puts xyz into the store as a fixed derivation 
binary blob.

I say this as a way of clarifying the design of `guix derivation`, not 
as extra stuff that needs go in at the same time. Most of these commands 
might be deemed unnecessary.

Alternatively, as you say, Ricardo:

`guix inspect get-references`
`guix inspect get referrers`
`guix inspect path-info`
`guix inspect show-derivation`

However, in that case, another home would need to be found for drv-drv 
at minimum since I wouldn't expect 'inspect' to modify anything.

Kind regards,

Christina

On 18/04/2024 09:40, Ricardo Wurmus wrote:
> Hi Simon,
>
>> So I propose to add the plumbing command ’derivation’.  Any objection?
> I think it's useful to have.  To avoid proliferation of sub-commands, do
> you think we could put this under "inspect", a generic sub-command for
> all sorts of as yet to be invented introspection tools?
>

Re: Adding plumbing subcommand 'derivation'?

[Christina O'Donnell]

Correction:

On 18/04/2024 13:57, Christina O'Donnell wrote:
> [...]
>
> `guix store get-references`
> `guix store get-referrers`
> `guix store info` - dumps the `path-info`
> `guix store put xyz` - puts xyz into the store as a fixed derivation 
> binary blob.
>
> [...]
I've just checked and get-references and get-referrers are available as:

`guix gc --references`
`guix gc --referrers`

Kind regards,
Christina

Re: Adding plumbing subcommand 'derivation'?

[Ludovic Courtès]

Hi,

Simon Tournier <zimon.toutoune@gmail.com> skribis:

> On ven., 12 avril 2024 at 20:04, Leo Famulari <leo@famulari.name> wrote:
>
>>> Do you think it would be useful to package it?  Or maybe to include it
>>> as another subcommand (or part of some subcommand)?
>>
>> I'd love for this to be built in to Guix. I'm often struggling to read
>> derivations while debugging or analysing something.
>
> So I propose to add the plumbing command ’derivation’.  Any objection?

We should see how that fits into the set of tools we already have, in
particular the (guix derivations) interface and the REPL meta-commands.

My gut feeling, with a Schemer bias, is that we’d rather enrich the
Scheme API and/or REPL than add more commands (this is not Nix :-)).

But I don’t know, maybe we can have both?

Ludo’.

Re: Adding plumbing subcommand 'derivation'?

[Simon Tournier]

Hi,

On ven., 19 avril 2024 at 16:02, Ludovic Courtès <ludo@gnu.org> wrote:

> We should see how that fits into the set of tools we already have, in
> particular the (guix derivations) interface and the REPL meta-commands.
>
> My gut feeling, with a Schemer bias, is that we’d rather enrich the
> Scheme API and/or REPL than add more commands (this is not Nix :-)).
>
> But I don’t know, maybe we can have both?

Yes, I think that’s orthogonal and a good idea.

Maybe a new plumbing generic subcommand, as “guix inspect” or “guix
store”, where showing the fields of a derivation would be a
sub-subcommand.  For instance, diffing two derivations from the
command-line seems helpful when  debugging – I often do that with Emacs
exploiting buffer facilities. :-)

In addition, it could be helpful to improve the readability for the
pretty-printer.  Other said, somehow redesign this:

--8<---------------cut here---------------start------------->8---
(set-record-type-printer! <derivation>
                          (lambda (drv port)
                            (format port "#<derivation ~a => ~a ~a>"
                                    (derivation-file-name drv)
                                    (string-join
                                     (map (match-lambda
                                           ((_ . output)
                                            (derivation-output-path output)))
                                          (derivation-outputs drv)))
                                    (number->string (object-address drv) 16))))
--8<---------------cut here---------------end--------------->8---

It looks like a plan. ;-)

Cheers,
simon