build_meta.py 9.7 KB

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  1. """A PEP 517 interface to setuptools
  2. Previously, when a user or a command line tool (let's call it a "frontend")
  3. needed to make a request of setuptools to take a certain action, for
  4. example, generating a list of installation requirements, the frontend would
  5. would call "setup.py egg_info" or "setup.py bdist_wheel" on the command line.
  6. PEP 517 defines a different method of interfacing with setuptools. Rather
  7. than calling "setup.py" directly, the frontend should:
  8. 1. Set the current directory to the directory with a setup.py file
  9. 2. Import this module into a safe python interpreter (one in which
  10. setuptools can potentially set global variables or crash hard).
  11. 3. Call one of the functions defined in PEP 517.
  12. What each function does is defined in PEP 517. However, here is a "casual"
  13. definition of the functions (this definition should not be relied on for
  14. bug reports or API stability):
  15. - `build_wheel`: build a wheel in the folder and return the basename
  16. - `get_requires_for_build_wheel`: get the `setup_requires` to build
  17. - `prepare_metadata_for_build_wheel`: get the `install_requires`
  18. - `build_sdist`: build an sdist in the folder and return the basename
  19. - `get_requires_for_build_sdist`: get the `setup_requires` to build
  20. Again, this is not a formal definition! Just a "taste" of the module.
  21. """
  22. import io
  23. import os
  24. import sys
  25. import tokenize
  26. import shutil
  27. import contextlib
  28. import setuptools
  29. import distutils
  30. from setuptools.py31compat import TemporaryDirectory
  31. from pkg_resources import parse_requirements
  32. from pkg_resources.py31compat import makedirs
  33. __all__ = ['get_requires_for_build_sdist',
  34. 'get_requires_for_build_wheel',
  35. 'prepare_metadata_for_build_wheel',
  36. 'build_wheel',
  37. 'build_sdist',
  38. '__legacy__',
  39. 'SetupRequirementsError']
  40. class SetupRequirementsError(BaseException):
  41. def __init__(self, specifiers):
  42. self.specifiers = specifiers
  43. class Distribution(setuptools.dist.Distribution):
  44. def fetch_build_eggs(self, specifiers):
  45. specifier_list = list(map(str, parse_requirements(specifiers)))
  46. raise SetupRequirementsError(specifier_list)
  47. @classmethod
  48. @contextlib.contextmanager
  49. def patch(cls):
  50. """
  51. Replace
  52. distutils.dist.Distribution with this class
  53. for the duration of this context.
  54. """
  55. orig = distutils.core.Distribution
  56. distutils.core.Distribution = cls
  57. try:
  58. yield
  59. finally:
  60. distutils.core.Distribution = orig
  61. def _to_str(s):
  62. """
  63. Convert a filename to a string (on Python 2, explicitly
  64. a byte string, not Unicode) as distutils checks for the
  65. exact type str.
  66. """
  67. if sys.version_info[0] == 2 and not isinstance(s, str):
  68. # Assume it's Unicode, as that's what the PEP says
  69. # should be provided.
  70. return s.encode(sys.getfilesystemencoding())
  71. return s
  72. def _get_immediate_subdirectories(a_dir):
  73. return [name for name in os.listdir(a_dir)
  74. if os.path.isdir(os.path.join(a_dir, name))]
  75. def _file_with_extension(directory, extension):
  76. matching = (
  77. f for f in os.listdir(directory)
  78. if f.endswith(extension)
  79. )
  80. file, = matching
  81. return file
  82. def _open_setup_script(setup_script):
  83. if not os.path.exists(setup_script):
  84. # Supply a default setup.py
  85. return io.StringIO(u"from setuptools import setup; setup()")
  86. return getattr(tokenize, 'open', open)(setup_script)
  87. class _BuildMetaBackend(object):
  88. def _fix_config(self, config_settings):
  89. config_settings = config_settings or {}
  90. config_settings.setdefault('--global-option', [])
  91. return config_settings
  92. def _get_build_requires(self, config_settings, requirements):
  93. config_settings = self._fix_config(config_settings)
  94. sys.argv = sys.argv[:1] + ['egg_info'] + \
  95. config_settings["--global-option"]
  96. try:
  97. with Distribution.patch():
  98. self.run_setup()
  99. except SetupRequirementsError as e:
  100. requirements += e.specifiers
  101. return requirements
  102. def run_setup(self, setup_script='setup.py'):
  103. # Note that we can reuse our build directory between calls
  104. # Correctness comes first, then optimization later
  105. __file__ = setup_script
  106. __name__ = '__main__'
  107. with _open_setup_script(__file__) as f:
  108. code = f.read().replace(r'\r\n', r'\n')
  109. exec(compile(code, __file__, 'exec'), locals())
  110. def get_requires_for_build_wheel(self, config_settings=None):
  111. config_settings = self._fix_config(config_settings)
  112. return self._get_build_requires(
  113. config_settings, requirements=['wheel'])
  114. def get_requires_for_build_sdist(self, config_settings=None):
  115. config_settings = self._fix_config(config_settings)
  116. return self._get_build_requires(config_settings, requirements=[])
  117. def prepare_metadata_for_build_wheel(self, metadata_directory,
  118. config_settings=None):
  119. sys.argv = sys.argv[:1] + ['dist_info', '--egg-base',
  120. _to_str(metadata_directory)]
  121. self.run_setup()
  122. dist_info_directory = metadata_directory
  123. while True:
  124. dist_infos = [f for f in os.listdir(dist_info_directory)
  125. if f.endswith('.dist-info')]
  126. if (
  127. len(dist_infos) == 0 and
  128. len(_get_immediate_subdirectories(dist_info_directory)) == 1
  129. ):
  130. dist_info_directory = os.path.join(
  131. dist_info_directory, os.listdir(dist_info_directory)[0])
  132. continue
  133. assert len(dist_infos) == 1
  134. break
  135. # PEP 517 requires that the .dist-info directory be placed in the
  136. # metadata_directory. To comply, we MUST copy the directory to the root
  137. if dist_info_directory != metadata_directory:
  138. shutil.move(
  139. os.path.join(dist_info_directory, dist_infos[0]),
  140. metadata_directory)
  141. shutil.rmtree(dist_info_directory, ignore_errors=True)
  142. return dist_infos[0]
  143. def _build_with_temp_dir(self, setup_command, result_extension,
  144. result_directory, config_settings):
  145. config_settings = self._fix_config(config_settings)
  146. result_directory = os.path.abspath(result_directory)
  147. # Build in a temporary directory, then copy to the target.
  148. makedirs(result_directory, exist_ok=True)
  149. with TemporaryDirectory(dir=result_directory) as tmp_dist_dir:
  150. sys.argv = (sys.argv[:1] + setup_command +
  151. ['--dist-dir', tmp_dist_dir] +
  152. config_settings["--global-option"])
  153. self.run_setup()
  154. result_basename = _file_with_extension(
  155. tmp_dist_dir, result_extension)
  156. result_path = os.path.join(result_directory, result_basename)
  157. if os.path.exists(result_path):
  158. # os.rename will fail overwriting on non-Unix.
  159. os.remove(result_path)
  160. os.rename(os.path.join(tmp_dist_dir, result_basename), result_path)
  161. return result_basename
  162. def build_wheel(self, wheel_directory, config_settings=None,
  163. metadata_directory=None):
  164. return self._build_with_temp_dir(['bdist_wheel'], '.whl',
  165. wheel_directory, config_settings)
  166. def build_sdist(self, sdist_directory, config_settings=None):
  167. return self._build_with_temp_dir(['sdist', '--formats', 'gztar'],
  168. '.tar.gz', sdist_directory,
  169. config_settings)
  170. class _BuildMetaLegacyBackend(_BuildMetaBackend):
  171. """Compatibility backend for setuptools
  172. This is a version of setuptools.build_meta that endeavors
  173. to maintain backwards
  174. compatibility with pre-PEP 517 modes of invocation. It
  175. exists as a temporary
  176. bridge between the old packaging mechanism and the new
  177. packaging mechanism,
  178. and will eventually be removed.
  179. """
  180. def run_setup(self, setup_script='setup.py'):
  181. # In order to maintain compatibility with scripts assuming that
  182. # the setup.py script is in a directory on the PYTHONPATH, inject
  183. # '' into sys.path. (pypa/setuptools#1642)
  184. sys_path = list(sys.path) # Save the original path
  185. script_dir = os.path.dirname(os.path.abspath(setup_script))
  186. if script_dir not in sys.path:
  187. sys.path.insert(0, script_dir)
  188. # Some setup.py scripts (e.g. in pygame and numpy) use sys.argv[0] to
  189. # get the directory of the source code. They expect it to refer to the
  190. # setup.py script.
  191. sys_argv_0 = sys.argv[0]
  192. sys.argv[0] = setup_script
  193. try:
  194. super(_BuildMetaLegacyBackend,
  195. self).run_setup(setup_script=setup_script)
  196. finally:
  197. # While PEP 517 frontends should be calling each hook in a fresh
  198. # subprocess according to the standard (and thus it should not be
  199. # strictly necessary to restore the old sys.path), we'll restore
  200. # the original path so that the path manipulation does not persist
  201. # within the hook after run_setup is called.
  202. sys.path[:] = sys_path
  203. sys.argv[0] = sys_argv_0
  204. # The primary backend
  205. _BACKEND = _BuildMetaBackend()
  206. get_requires_for_build_wheel = _BACKEND.get_requires_for_build_wheel
  207. get_requires_for_build_sdist = _BACKEND.get_requires_for_build_sdist
  208. prepare_metadata_for_build_wheel = _BACKEND.prepare_metadata_for_build_wheel
  209. build_wheel = _BACKEND.build_wheel
  210. build_sdist = _BACKEND.build_sdist
  211. # The legacy backend
  212. __legacy__ = _BuildMetaLegacyBackend()