55752c87a2
The loading of modules from wheels wasn't properly separated from the rest of Python yet. Now `load_wheel()` properly cleans up after itself, making it impossible for other code to do `import the_module_from_the_wheel`.
152 lines
4.8 KiB
Python
152 lines
4.8 KiB
Python
# SPDX-License-Identifier: GPL-3.0-or-later
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"""External dependencies loader."""
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import contextlib
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import importlib
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from pathlib import Path
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import sys
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import logging
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from types import ModuleType
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from typing import Iterator
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_my_dir = Path(__file__).parent
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_log = logging.getLogger(__name__)
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def load_wheel(module_name: str, fname_prefix: str = "") -> ModuleType:
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"""Loads a wheel from 'fname_prefix*.whl', unless the named module can be imported.
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This allows us to use system-installed packages before falling back to the shipped wheels.
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This is useful for development, less so for deployment.
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If `fname_prefix` is the empty string, it will use the module name.
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"""
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if not fname_prefix:
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fname_prefix = _fname_prefix_from_module_name(module_name)
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try:
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module = importlib.import_module(module_name)
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except ImportError as ex:
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_log.debug("Unable to import %s directly, will try wheel: %s", module_name, ex)
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else:
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_log.debug(
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"Was able to load %s from %s, no need to load wheel %s",
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module_name,
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module.__file__,
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fname_prefix,
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)
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assert isinstance(module, ModuleType)
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return module
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wheel = _wheel_filename(fname_prefix)
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# Load the module from the wheel file. Keep a backup of sys.path so that it
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# can be restored later. This should ensure that future import statements
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# cannot find this wheel file, increasing the separation of dependencies of
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# this add-on from other add-ons.
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with _sys_path_mod_backup(wheel):
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try:
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module = importlib.import_module(module_name)
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except ImportError as ex:
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raise ImportError(
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"Unable to load %r from %s: %s" % (module_name, wheel, ex)
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) from None
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_log.debug("Loaded %s from %s", module_name, module.__file__)
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assert isinstance(module, ModuleType)
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return module
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def load_wheel_global(module_name: str, fname_prefix: str = "") -> ModuleType:
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"""Loads a wheel from 'fname_prefix*.whl', unless the named module can be imported.
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This allows us to use system-installed packages before falling back to the shipped wheels.
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This is useful for development, less so for deployment.
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If `fname_prefix` is the empty string, it will use the first package from `module_name`.
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In other words, `module_name="pkg.subpkg"` will result in `fname_prefix="pkg"`.
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"""
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if not fname_prefix:
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fname_prefix = _fname_prefix_from_module_name(module_name)
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try:
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module = importlib.import_module(module_name)
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except ImportError as ex:
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_log.debug("Unable to import %s directly, will try wheel: %s", module_name, ex)
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else:
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_log.debug(
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"Was able to load %s from %s, no need to load wheel %s",
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module_name,
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module.__file__,
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fname_prefix,
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)
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return module
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wheel = _wheel_filename(fname_prefix)
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wheel_filepath = str(wheel)
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if wheel_filepath not in sys.path:
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sys.path.insert(0, wheel_filepath)
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try:
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module = importlib.import_module(module_name)
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except ImportError as ex:
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raise ImportError(
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"Unable to load %r from %s: %s" % (module_name, wheel, ex)
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) from None
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_log.debug("Globally loaded %s from %s", module_name, module.__file__)
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return module
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@contextlib.contextmanager
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def _sys_path_mod_backup(wheel_file: Path) -> Iterator[None]:
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"""Temporarily inserts a wheel onto sys.path.
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When the context exits, it restores sys.path and sys.modules, so that
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anything that was imported within the context remains unimportable by other
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modules.
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"""
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old_syspath = sys.path[:]
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old_sysmod = sys.modules.copy()
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try:
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sys.path.insert(0, str(wheel_file))
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yield
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finally:
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# Restore without assigning a new list instance. That way references
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# held by other code will stay valid.
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sys.path[:] = old_syspath
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sys.modules.clear()
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sys.modules.update(old_sysmod)
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def _wheel_filename(fname_prefix: str) -> Path:
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path_pattern = "%s*.whl" % fname_prefix
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wheels: list[Path] = list(_my_dir.glob(path_pattern))
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if not wheels:
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raise RuntimeError("Unable to find wheel at %r" % path_pattern)
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# If there are multiple wheels that match, load the last-modified one.
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# Alphabetical sorting isn't going to cut it since BAT 1.10 was released.
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def modtime(filepath: Path) -> float:
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return filepath.stat().st_mtime
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wheels.sort(key=modtime)
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return wheels[-1]
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def _fname_prefix_from_module_name(module_name: str) -> str:
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return module_name.split(".", 1)[0]
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if __name__ == "__main__":
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logging.basicConfig(level=logging.DEBUG)
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wheel = _wheel_filename("python_dateutil")
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print(f"Wheel: {wheel}")
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module = load_wheel("dateutil", "python_dateutil")
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print(f"module: {module}")
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