[Catalog-sig] V4 Pre-PEP: transition to release-file hosting on PYPI
richard at python.org
Mon Mar 18 20:02:35 CET 2013
Some suggested edits; I'm otherwise quite happy with the current draft.
On 15 March 2013 02:29, holger krekel <holger at merlinux.eu> wrote:
> History and motivations for external hosting
Could we please have a reference to the Package Index "API"* here?
> Today, most packages released on PyPI host their release files on
> PyPI, but a small percentage (XXX need updated data) rely on
> external hosting.
The above should probably be re-worded since "rely" is loaded and we
don't necessarily know the motivation for projects using external
links. The important numbers though are:
projects with any external only links: 2581
projects with only external only links: 1332
total projects: 29117
Whether the projects with links that also have hosted files (ie. the
1249 project difference between those numbers) *rely* on us retaining
the external links facility is unknown.
> Hosting modes
> The foundation of the first transition phase is the introduction of
> three "modes" of PyPI hosting for a package, affecting which links are
> generated for the ``simple/`` index. These modes are implemented
> without requiring changes to installation tools via changes to the
> algorithm for generating the machine-readable ``simple/`` index.
> The modes are:
> - ``pypi-scrape-crawl``: no change from the current situation of
> generating machine-readable links for installation tools, as
> outlined in the history_.
> - ``pypi-scrape``: for a package in this mode, links to be added to
> the ``simple/`` index are still scraped from package
> metadata. However, the "Home-page" and "Download-url" links are
> given ``rel=ext-homepage`` and ``rel=ext-download`` attributes
> instead of ``rel=homepage`` and ``rel=download``. The effect of this
> (with no change in installation tools necessary) is that these links
> will not be followed and scraped for further candidate links by present-day
> installation tools: only installable files directly hosted from PYPI or
> linked directly from PyPI metadata will be considered for installation.
> Installation tools MAY evolve to offer an option to use the new
> rel-attribution to crawl external pages but MUST NOT default to it.
I'd just like to confirm that the rel="download" / rel="ext-download"
switch will not affect the installability of distribution downloads
linked directly by download_url.
> - ``pypi-explicit``: for a package in this mode, only links to release
> files uploaded to PyPI, and external links to release files
> explicitly nominated by the package owner (via a new interface
> exposed by PyPI) will be added to the ``simple/`` index.
The bracketed bit there needs to be emphasised (ie. not just a
bracketed afterthought) as it changes the current packaging user
experience considerably for those who wish to remain externally
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