Re: usage of pypi-uri in the pypi importer

[zimoun]

Dear,

On Sat, 17 Oct 2020 at 21:17, Malte Frank Gerdes <malte.f.gerdes@gmail.com> 
wrote:

> i noticed that the python pypi importer generates packages definitions
> which rely on the pypi-uri function declared in the python build
> system. I observed that the python build system itself doesn't use this
> function at all, so why is it defined there and not in the python
> importer, which seems to be the only piece of software using it?

Because, “pypi-uri” is used by *a lot* of Python packages – packages
using ’python-build-system’.  For example,
gnu/packages/python-science.scm:

--8<---------------cut here---------------start------------->8---
[..]
  #:use-module (guix build-system python))

(define-public python-scipy
  (package
    (name "python-scipy")
    (version "1.3.2")
    (source
     (origin
       (method url-fetch)
       (uri (pypi-uri "scipy" version))
       (sha256
        (base32 "192d8dsybvhv19igkrsafbdafx198nz7pibkjgrqjhlr66s3jfd0"))))
    (build-system python-build-system)
[..]    
--8<---------------cut here---------------end--------------->8---

In what you are proposing, if I read correctly, the
gnu/packages/python-science.scm should have to also import ’(guix import
pypi)’.



> Also: I tried to package pyinstrument-cext and noticed that the importer
> generated function isn't able to find the source package - only
> 404's. The importer uses PyPI's json API to get information about a
> given package (this includes it's url - called source-url), so is the
> pypi-uri function needed at all? the necessary information is available
> even without it. Or are there any specific reasons why things are as
> they are?

I am not sure to understand.  Using Guix 353bdae, I get:

--8<---------------cut here---------------start------------->8---
$ guix import pypi pyinstrument-cext

Starting download of /tmp/guix-file.5tmgen
>From 
>https://files.pythonhosted.org/packages/b6/95/0a391322dd7f2f97f553373659a787b7428dfe15fc2a8e01844c8768f45e/pyinstrument_cext-0.2.2.tar.gz...
 …xt-0.2.2.tar.gz  5KiB               704KiB/s 00:00 [##################] 100.0%

Starting download of /tmp/guix-file.cZDsRo
>From 
>https://files.pythonhosted.org/packages/13/2e/d548d3727aa3c5b77eb79f667e7212de1acf93087ddce5274887abbe217d/pyinstrument_cext-0.2.2-cp27-cp27m-macosx_10_6_intel.whl...
 …-cp27m-macosx_10_6_intel.whl  7KiB  679KiB/s 00:00 [##################] 100.0%
(package
  (name "python-pyinstrument-cext")
  (version "0.2.2")
  (source
    (origin
      (method url-fetch)
      (uri (pypi-uri "pyinstrument-cext" version))
      (sha256
        (base32
          "0nycf7nhx2xzba49m8208agx5xghzxkma3iim5f43h3l3pvjb7pj"))))
  (build-system python-build-system)
  (home-page
    "https://github.com/joerick/pyinstrument_cext";)
  (synopsis
    "A CPython extension supporting pyinstrument")
  (description
    "A CPython extension supporting pyinstrument")
  (license #f))
--8<---------------cut here---------------end--------------->8---


BTW, ’pypi-uri’ eases the management of all the packages coming from
PyPI.  If the URL of PyPI change or is mirrored, it is easy to switch or
add the mirror; otherwise one would have to go package by package.
Well, if I understand correctly what you mean.


All the best,
simon