python -m dowsing.pep517 /path/to/repo | jq .
from dowsing.pep517 import get_metadata dist = get_metadata(Path("/path/to/repo"))
I don't want to execute arbitrary
setup.py in order to find out their basic
metadata. I don't want to use the pep517 module in a sandbox, because commonly
packages forget to list their build-time dependencies.
This project is one step better than grepping source files, but also understands
pyproject.toml (from PEP 517/518). It does pretty well run
on a sampling of pypi projects, but does fail on some notable ones (including
When it fails, a key will be
"??" and due to some quirks in list context, this
The reality of python packaging, even with recent PEPs, is that most nontrivial
python packages do moderately interesting stuff in their
- Imports (either from local code, or
- Fetching things from the Internet
- Running commands
- Making sure native libs are installed, or there's a working C compiler
- Choosing deps based on platform
From the perspective of basically running a distro, they produce messages
intended for humans, rather than actually using the mechanisms that we have in
PEP 508 (environment markers) and 518 (pyproject.toml requires). There is also
no well-specified way to request native libs, and many projects choose to fail
setup.py when libs are missing.
This project is a bridge to find several things out, about primarily setup.py but also understanding some popular PEP 517/518 builders as a one-stop-shop, about:
- doesn't actually execute, so fetches or execs can't cause it to fail [done]
- cases where we could find out the version string, but it fails to import [done]
- lets you simulate the
pep517module's output on different platforms [done]
- a lower-level api suitable for making edits to the place where the setup args are defined [done]
- to list potential imports, and guess at missing build-time deps (something
numpy.distutilsis pretty clear) [todo]
Doing this "right"
A bunch of this is papering over problems with the current reality. If you have
an existing sandbox and are ok with ~30% of projects just failing to build, you
can rely on the
pep517 module's API to actually execute the code on the
current version of python.
If you're willing to run the code and have it take longer, take a look at the
get_requires_for_* or have it generate the metadata (assuming
what you want is in there). An example is in
dowsing.pep517 api is designed to do something similar, but not
fail on missing build-time requirements.
- PEP 241, Metadata 1.0
- PEP 314, Metadata 1.1
- PEP 345, Metadata 1.2
- PEP 566, Metadata 2.1
dowsing is copyright Tim Hatch, and licensed under
the MIT license. I am providing code in this repository to you under an open
source license. This is my personal repository; the license you receive to
my code is from me and not from my employer. See the
LICENSE file for details.