"""A PEP 517 interface to setuptools
Previously, when a user or a command line tool (let's call it a "frontend")
needed to make a request of setuptools to take a certain action, for
example, generating a list of installation requirements, the frontend would
would call "setup.py egg_info" or "setup.py bdist_wheel" on the command line.
PEP 517 defines a different method of interfacing with setuptools. Rather
than calling "setup.py" directly, the frontend should:
1. Set the current directory to the directory with a setup.py file
2. Import this module into a safe python interpreter (one in which
setuptools can potentially set global variables or crash hard).
3. Call one of the functions defined in PEP 517.
What each function does is defined in PEP 517. However, here is a "casual"
definition of the functions (this definition should not be relied on for
bug reports or API stability):
- `build_wheel`: build a wheel in the folder and return the basename
- `get_requires_for_build_wheel`: get the `setup_requires` to build
- `prepare_metadata_for_build_wheel`: get the `install_requires`
- `build_sdist`: build an sdist in the folder and return the basename
- `get_requires_for_build_sdist`: get the `setup_requires` to build
Again, this is not a formal definition! Just a "taste" of the module.
"""
import io
import os
import sys
import tokenize
import shutil
import contextlib
import setuptools
import distutils
from setuptools.py31compat import TemporaryDirectory
from pkg_resources import parse_requirements
from pkg_resources.py31compat import makedirs
__all__ = ['get_requires_for_build_sdist',
'get_requires_for_build_wheel',
'prepare_metadata_for_build_wheel',
'build_wheel',
'build_sdist',
'__legacy__',
'SetupRequirementsError']
class SetupRequirementsError(BaseException):
def __init__(self, specifiers):
self.specifiers = specifiers
class Distribution(setuptools.dist.Distribution):
def fetch_build_eggs(self, specifiers):
specifier_list = list(map(str, parse_requirements(specifiers)))
raise SetupRequirementsError(specifier_list)
@classmethod
@contextlib.contextmanager
def patch(cls):
"""
Replace
distutils.dist.Distribution with this class
for the duration of this context.
"""
orig = distutils.core.Distribution
distutils.core.Distribution = cls
try:
yield
finally:
distutils.core.Distribution = orig
def _to_str(s):
"""
Convert a filename to a string (on Python 2, explicitly
a byte string, not Unicode) as distutils checks for the
exact type str.
"""
if sys.version_info[0] == 2 and not isinstance(s, str):
# Assume it's Unicode, as that's what the PEP says
# should be provided.
return s.encode(sys.getfilesystemencoding())
return s
def _get_immediate_subdirectories(a_dir):
return [name for name in os.listdir(a_dir)
if os.path.isdir(os.path.join(a_dir, name))]
def _file_with_extension(directory, extension):
matching = (
f for f in os.listdir(directory)
if f.endswith(extension)
)
file, = matching
return file
def _open_setup_script(setup_script):
if not os.path.exists(setup_script):
# Supply a default setup.py
return io.StringIO(u"from setuptools import setup; setup()")
return getattr(tokenize, 'open', open)(setup_script)
class _BuildMetaBackend(object):
def _fix_config(self, config_settings):
config_settings = config_settings or {}
config_settings.setdefault('--global-option', [])
return config_settings
def _get_build_requires(self, config_settings, requirements):
config_settings = self._fix_config(config_settings)
sys.argv = sys.argv[:1] + ['egg_info'] + \
config_settings["--global-option"]
try:
with Distribution.patch():
self.run_setup()
except SetupRequirementsError as e:
requirements += e.specifiers
return requirements
def run_setup(self, setup_script='setup.py'):
# Note that we can reuse our build directory between calls
# Correctness comes first, then optimization later
__file__ = setup_script
__name__ = '__main__'
with _open_setup_script(__file__) as f:
code = f.read().replace(r'\r\n', r'\n')
exec(compile(code, __file__, 'exec'), locals())
def get_requires_for_build_wheel(self, config_settings=None):
config_settings = self._fix_config(config_settings)
return self._get_build_requires(config_settings, requirements=['wheel'])
def get_requires_for_build_sdist(self, config_settings=None):
config_settings = self._fix_config(config_settings)
return self._get_build_requires(config_settings, requirements=[])
def prepare_metadata_for_build_wheel(self, metadata_directory,
config_settings=None):
sys.argv = sys.argv[:1] + ['dist_info', '--egg-base',
_to_str(metadata_directory)]
self.run_setup()
dist_info_directory = metadata_directory
while True:
dist_infos = [f for f in os.listdir(dist_info_directory)
if f.endswith('.dist-info')]
if (len(dist_infos) == 0 and
len(_get_immediate_subdirectories(dist_info_directory)) == 1):
dist_info_directory = os.path.join(
dist_info_directory, os.listdir(dist_info_directory)[0])
continue
assert len(dist_infos) == 1
break
# PEP 517 requires that the .dist-info directory be placed in the
# metadata_directory. To comply, we MUST copy the directory to the root
if dist_info_directory != metadata_directory:
shutil.move(
os.path.join(dist_info_directory, dist_infos[0]),
metadata_directory)
shutil.rmtree(dist_info_directory, ignore_errors=True)
return dist_infos[0]
def _build_with_temp_dir(self, setup_command, result_extension,
result_directory, config_settings):
config_settings = self._fix_config(config_settings)
result_directory = os.path.abspath(result_directory)
# Build in a temporary directory, then copy to the target.
makedirs(result_directory, exist_ok=True)
with TemporaryDirectory(dir=result_directory) as tmp_dist_dir:
sys.argv = (sys.argv[:1] + setup_command +
['--dist-dir', tmp_dist_dir] +
config_settings["--global-option"])
self.run_setup()
result_basename = _file_with_extension(tmp_dist_dir, result_extension)
result_path = os.path.join(result_directory, result_basename)
if os.path.exists(result_path):
# os.rename will fail overwriting on non-Unix.
os.remove(result_path)
os.rename(os.path.join(tmp_dist_dir, result_basename), result_path)
return result_basename
def build_wheel(self, wheel_directory, config_settings=None,
metadata_directory=None):
return self._build_with_temp_dir(['bdist_wheel'], '.whl',
wheel_directory, config_settings)
def build_sdist(self, sdist_directory, config_settings=None):
return self._build_with_temp_dir(['sdist', '--formats', 'gztar'],
'.tar.gz', sdist_directory,
config_settings)
class _BuildMetaLegacyBackend(_BuildMetaBackend):
"""Compatibility backend for setuptools
This is a version of setuptools.build_meta that endeavors to maintain backwards
compatibility with pre-PEP 517 modes of invocation. It exists as a temporary
bridge between the old packaging mechanism and the new packaging mechanism,
and will eventually be removed.
"""
def run_setup(self, setup_script='setup.py'):
# In order to maintain compatibility with scripts assuming that
# the setup.py script is in a directory on the PYTHONPATH, inject
# '' into sys.path. (pypa/setuptools#1642)
sys_path = list(sys.path) # Save the original path
script_dir = os.path.dirname(os.path.abspath(setup_script))
if script_dir not in sys.path:
sys.path.insert(0, script_dir)
try:
super(_BuildMetaLegacyBackend,
self).run_setup(setup_script=setup_script)
finally:
# While PEP 517 frontends should be calling each hook in a fresh
# subprocess according to the standard (and thus it should not be
# strictly necessary to restore the old sys.path), we'll restore
# the original path so that the path manipulation does not persist
# within the hook after run_setup is called.
sys.path[:] = sys_path
# The primary backend
_BACKEND = _BuildMetaBackend()
get_requires_for_build_wheel = _BACKEND.get_requires_for_build_wheel
get_requires_for_build_sdist = _BACKEND.get_requires_for_build_sdist
prepare_metadata_for_build_wheel = _BACKEND.prepare_metadata_for_build_wheel
build_wheel = _BACKEND.build_wheel
build_sdist = _BACKEND.build_sdist
# The legacy backend
__legacy__ = _BuildMetaLegacyBackend()
