Subject: Re: [bug#39547] [PATCH] website: Provide JSON sources list used by Software Heritage.

From: zimoun <[email-masked]>
Date: Fri, 14 Feb 2020 10:04:01 +0100

Hi Ludo,

Thank you for the review.

On Fri, 14 Feb 2020 at 09:40, Ludovic Courtès <[email-masked]> wrote:
> zimoun <[email-masked]> skribis:

> > Format discussed here <https://forge.softwareheritage.org/D2025#51269>.
> >
> > * website/apps/packages/builder.scm (sources-json-builder): New procedure.
>
> [...]
>
> > +(define (sources-json-builder)
> > +  "Return a JSON page listing all the sources."
>
> Please add a reference to
> <https://forge.softwareheritage.org/D2025#51269> here.

ok

> > +  (define (origin->json origin)
> > +    (define method
> > +      (origin-method origin))
> > +
> > +    (define uri                         ;represented as string
> > +      (origin-uri origin))
> > +
> > +    (define (mirror->url uri)
> > +      (uri->string (car (maybe-expand-mirrors uri %mirrors))))
> > +
> > +    (define (resolve urls)
> > +      (let* ((url (car urls))
> > +             (uri (string->uri url))
> > +             (rest (cdr urls)))
> > +        (case (uri-scheme uri)
> > +          ((mirror) (mirror->url uri))
> > +          ((http) url)
> > +          ((https) url)
> > +          (else
> > +           (if (null? rest)
> > +               url
> > +               (resolve rest))))))
> > +
> > +    `((type . ,(cond ((eq? url-fetch method) 'url)
> > +                     ((eq? git-fetch method) 'git)
> > +                     ((eq? svn-fetch method) 'svn)
> > +                     (else                   #nil)))
> > +      ,@(cond ((eq? url-fetch method)
> > +               `(("url" . ,(match uri
> > +                               ((? string? url) (mirror->url (string->uri url)))
> > +                               ((urls ...) (resolve urls))))))
> > +              ((eq? git-fetch method)
> > +               `(("git_url" . ,(git-reference-url uri))))
> > +              ((eq? svn-fetch method)
> > +               `(("svn_url" . ,(svn-reference-url uri))))
> > +              (else '()))
> > +      ,@(if (eq? method git-fetch)
> > +            `(("git_ref" . ,(git-reference-commit uri)))
> > +            '())
> > +      ,@(if (eq? method svn-fetch)
> > +            `(("svn_revision" . ,(svn-reference-revision
> > +                                  uri)))
> > +            '())))
>
> Could you, in a first patch, move ‘origin->json’ out of
> ‘packages-json-builder’, and in a second patch, add mirror-expansion
> feature?

Yes, I will try but I am a bit lost. There is:
 - packages-json-builder that I did not modified
 - sources-json-builder which the "adaptation" of the former to output
to the sources.json format.

Well, do you want a refactor of 'origin->json' shared by the 2
"{sources,packages}-json-builder"?

> For mirror:// expansion, I think you can just write something like:
>
>   (define uris
>     (append-map (cut maybe-expand-mirrors <> %mirrors)
>                 (match url
>                   ((_ ...) (map string->uri url))
>                   (_       (list (string->uri url))))))
>
> and then pick the first element of the list.

Yes, it is better. :-)

> In parallel, I’d recommend suggesting a format change or addition that
> would allow us to provide all the URLs.  :-)

Ok :-)

> With those changes in place, I think we’ll be ready to go!

Working on updating the package Julia, I have seen that some patches
are 'origin' and live for example upstream
(https://blablab/project.git/patches/fancy-name.patch) and the current
patch will not list them. Therefore, if upstream disappears and/or
change in-place the patches, Guix would not be able to re-build in the
future (time-machine).

I am trying to implement a recursive exporter.
Well, I will try to make that the v2 contains your suggestions and all
the patches.

Cheers,
simon