import threading from contextlib import contextmanager import os from os.path import dirname, abspath, join as pjoin import shutil from subprocess import check_call, check_output, STDOUT import sys from tempfile import mkdtemp from . import compat __all__ = [ 'BackendUnavailable', 'BackendInvalid', 'HookMissing', 'UnsupportedOperation', 'default_subprocess_runner', 'quiet_subprocess_runner', 'Pep517HookCaller', ] try: import importlib.resources as resources def _in_proc_script_path(): return resources.path(__package__, '_in_process.py') except ImportError: @contextmanager def _in_proc_script_path(): yield pjoin(dirname(abspath(__file__)), '_in_process.py') @contextmanager def tempdir(): td = mkdtemp() try: yield td finally: shutil.rmtree(td) class BackendUnavailable(Exception): """Will be raised if the backend cannot be imported in the hook process.""" def __init__(self, traceback): self.traceback = traceback class BackendInvalid(Exception): """Will be raised if the backend is invalid.""" def __init__(self, backend_name, backend_path, message): self.backend_name = backend_name self.backend_path = backend_path self.message = message class HookMissing(Exception): """Will be raised on missing hooks.""" def __init__(self, hook_name): super(HookMissing, self).__init__(hook_name) self.hook_name = hook_name class UnsupportedOperation(Exception): """May be raised by build_sdist if the backend indicates that it can't.""" def __init__(self, traceback): self.traceback = traceback def default_subprocess_runner(cmd, cwd=None, extra_environ=None): """The default method of calling the wrapper subprocess.""" env = os.environ.copy() if extra_environ: env.update(extra_environ) check_call(cmd, cwd=cwd, env=env) def quiet_subprocess_runner(cmd, cwd=None, extra_environ=None): """A method of calling the wrapper subprocess while suppressing output.""" env = os.environ.copy() if extra_environ: env.update(extra_environ) check_output(cmd, cwd=cwd, env=env, stderr=STDOUT) def norm_and_check(source_tree, requested): """Normalise and check a backend path. Ensure that the requested backend path is specified as a relative path, and resolves to a location under the given source tree. Return an absolute version of the requested path. """ if os.path.isabs(requested): raise ValueError("paths must be relative") abs_source = os.path.abspath(source_tree) abs_requested = os.path.normpath(os.path.join(abs_source, requested)) # We have to use commonprefix for Python 2.7 compatibility. So we # normalise case to avoid problems because commonprefix is a character # based comparison :-( norm_source = os.path.normcase(abs_source) norm_requested = os.path.normcase(abs_requested) if os.path.commonprefix([norm_source, norm_requested]) != norm_source: raise ValueError("paths must be inside source tree") return abs_requested class Pep517HookCaller(object): """A wrapper around a source directory to be built with a PEP 517 backend. :param source_dir: The path to the source directory, containing pyproject.toml. :param build_backend: The build backend spec, as per PEP 517, from pyproject.toml. :param backend_path: The backend path, as per PEP 517, from pyproject.toml. :param runner: A callable that invokes the wrapper subprocess. :param python_executable: The Python executable used to invoke the backend The 'runner', if provided, must expect the following: - cmd: a list of strings representing the command and arguments to execute, as would be passed to e.g. 'subprocess.check_call'. - cwd: a string representing the working directory that must be used for the subprocess. Corresponds to the provided source_dir. - extra_environ: a dict mapping environment variable names to values which must be set for the subprocess execution. """ def __init__( self, source_dir, build_backend, backend_path=None, runner=None, python_executable=None, ): if runner is None: runner = default_subprocess_runner self.source_dir = abspath(source_dir) self.build_backend = build_backend if backend_path: backend_path = [ norm_and_check(self.source_dir, p) for p in backend_path ] self.backend_path = backend_path self._subprocess_runner = runner if not python_executable: python_executable = sys.executable self.python_executable = python_executable @contextmanager def subprocess_runner(self, runner): """A context manager for temporarily overriding the default subprocess runner. """ prev = self._subprocess_runner self._subprocess_runner = runner try: yield finally: self._subprocess_runner = prev def get_requires_for_build_wheel(self, config_settings=None): """Identify packages required for building a wheel Returns a list of dependency specifications, e.g.:: ["wheel >= 0.25", "setuptools"] This does not include requirements specified in pyproject.toml. It returns the result of calling the equivalently named hook in a subprocess. """ return self._call_hook('get_requires_for_build_wheel', { 'config_settings': config_settings }) def prepare_metadata_for_build_wheel( self, metadata_directory, config_settings=None, _allow_fallback=True): """Prepare a ``*.dist-info`` folder with metadata for this project. Returns the name of the newly created folder. If the build backend defines a hook with this name, it will be called in a subprocess. If not, the backend will be asked to build a wheel, and the dist-info extracted from that (unless _allow_fallback is False). """ return self._call_hook('prepare_metadata_for_build_wheel', { 'metadata_directory': abspath(metadata_directory), 'config_settings': config_settings, '_allow_fallback': _allow_fallback, }) def build_wheel( self, wheel_directory, config_settings=None, metadata_directory=None): """Build a wheel from this project. Returns the name of the newly created file. In general, this will call the 'build_wheel' hook in the backend. However, if that was previously called by 'prepare_metadata_for_build_wheel', and the same metadata_directory is used, the previously built wheel will be copied to wheel_directory. """ if metadata_directory is not None: metadata_directory = abspath(metadata_directory) return self._call_hook('build_wheel', { 'wheel_directory': abspath(wheel_directory), 'config_settings': config_settings, 'metadata_directory': metadata_directory, }) def get_requires_for_build_sdist(self, config_settings=None): """Identify packages required for building a wheel Returns a list of dependency specifications, e.g.:: ["setuptools >= 26"] This does not include requirements specified in pyproject.toml. It returns the result of calling the equivalently named hook in a subprocess. """ return self._call_hook('get_requires_for_build_sdist', { 'config_settings': config_settings }) def build_sdist(self, sdist_directory, config_settings=None): """Build an sdist from this project. Returns the name of the newly created file. This calls the 'build_sdist' backend hook in a subprocess. """ return self._call_hook('build_sdist', { 'sdist_directory': abspath(sdist_directory), 'config_settings': config_settings, }) def _call_hook(self, hook_name, kwargs): # On Python 2, pytoml returns Unicode values (which is correct) but the # environment passed to check_call needs to contain string values. We # convert here by encoding using ASCII (the backend can only contain # letters, digits and _, . and : characters, and will be used as a # Python identifier, so non-ASCII content is wrong on Python 2 in # any case). # For backend_path, we use sys.getfilesystemencoding. if sys.version_info[0] == 2: build_backend = self.build_backend.encode('ASCII') else: build_backend = self.build_backend extra_environ = {'PEP517_BUILD_BACKEND': build_backend} if self.backend_path: backend_path = os.pathsep.join(self.backend_path) if sys.version_info[0] == 2: backend_path = backend_path.encode(sys.getfilesystemencoding()) extra_environ['PEP517_BACKEND_PATH'] = backend_path with tempdir() as td: hook_input = {'kwargs': kwargs} compat.write_json(hook_input, pjoin(td, 'input.json'), indent=2) # Run the hook in a subprocess with _in_proc_script_path() as script: python = self.python_executable self._subprocess_runner( [python, abspath(str(script)), hook_name, td], cwd=self.source_dir, extra_environ=extra_environ ) data = compat.read_json(pjoin(td, 'output.json')) if data.get('unsupported'): raise UnsupportedOperation(data.get('traceback', '')) if data.get('no_backend'): raise BackendUnavailable(data.get('traceback', '')) if data.get('backend_invalid'): raise BackendInvalid( backend_name=self.build_backend, backend_path=self.backend_path, message=data.get('backend_error', '') ) if data.get('hook_missing'): raise HookMissing(hook_name) return data['return_val'] class LoggerWrapper(threading.Thread): """ Read messages from a pipe and redirect them to a logger (see python's logging module). """ def __init__(self, logger, level): threading.Thread.__init__(self) self.daemon = True self.logger = logger self.level = level # create the pipe and reader self.fd_read, self.fd_write = os.pipe() self.reader = os.fdopen(self.fd_read) self.start() def fileno(self): return self.fd_write @staticmethod def remove_newline(msg): return msg[:-1] if msg.endswith(os.linesep) else msg def run(self): for line in self.reader: self._write(self.remove_newline(line)) def _write(self, message): self.logger.log(self.level, message)