Viewing file:  wrappers.py (13.11 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
import threading
from contextlib import contextmanager
import os
from os.path import abspath, join as pjoin
import shutil
from subprocess import check_call, check_output, STDOUT
import sys
from tempfile import mkdtemp
from . import compat
from .in_process import _in_proc_script_path
__all__ = [
'BackendUnavailable',
'BackendInvalid',
'HookMissing',
'UnsupportedOperation',
'default_subprocess_runner',
'quiet_subprocess_runner',
'Pep517HookCaller',
]
@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 _supported_features(self):
"""Return the list of optional features supported by the backend."""
return self._call_hook('_supported_features', {})
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_editable(self, config_settings=None):
"""Identify packages required for building an editable 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_editable', {
'config_settings': config_settings
})
def prepare_metadata_for_build_editable(
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 an editable
wheel, and the dist-info extracted from that (unless _allow_fallback is
False).
"""
return self._call_hook('prepare_metadata_for_build_editable', {
'metadata_directory': abspath(metadata_directory),
'config_settings': config_settings,
'_allow_fallback': _allow_fallback,
})
def build_editable(
self, wheel_directory, config_settings=None,
metadata_directory=None):
"""Build an editable wheel from this project.
Returns the name of the newly created file.
In general, this will call the 'build_editable' hook in the backend.
However, if that was previously called by
'prepare_metadata_for_build_editable', 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_editable', {
'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(data.get('missing_hook_name') or 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)
|