101 lines
3.9 KiB
Python
101 lines
3.9 KiB
Python
"""
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Helpers pulled mostly verbatim from ``multiprocessing.spawn``
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to aid with "fixing up" the ``__main__`` module in subprocesses.
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These helpers are needed for any spawing backend that doesn't already handle this.
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For example when using ``trio_run_in_process`` it is needed but obviously not when
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we're already using ``multiprocessing``.
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"""
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import os
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import sys
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import platform
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import types
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import runpy
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from typing import Dict
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ORIGINAL_DIR = os.path.abspath(os.getcwd())
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def _mp_figure_out_main() -> Dict[str, str]:
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"""Taken from ``multiprocessing.spawn.get_preparation_data()``.
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Retrieve parent actor `__main__` module data.
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"""
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d = {}
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# Figure out whether to initialise main in the subprocess as a module
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# or through direct execution (or to leave it alone entirely)
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main_module = sys.modules['__main__']
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main_mod_name = getattr(main_module.__spec__, "name", None)
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if main_mod_name is not None:
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d['init_main_from_name'] = main_mod_name
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# elif sys.platform != 'win32' or (not WINEXE and not WINSERVICE):
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elif platform.system() != 'Windows':
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main_path = getattr(main_module, '__file__', None)
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if main_path is not None:
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if (
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not os.path.isabs(main_path) and (
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ORIGINAL_DIR is not None)
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):
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# process.ORIGINAL_DIR is not None):
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# main_path = os.path.join(process.ORIGINAL_DIR, main_path)
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main_path = os.path.join(ORIGINAL_DIR, main_path)
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d['init_main_from_path'] = os.path.normpath(main_path)
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return d
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# Multiprocessing module helpers to fix up the main module in
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# spawned subprocesses
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def _fixup_main_from_name(mod_name: str) -> None:
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# __main__.py files for packages, directories, zip archives, etc, run
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# their "main only" code unconditionally, so we don't even try to
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# populate anything in __main__, nor do we make any changes to
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# __main__ attributes
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current_main = sys.modules['__main__']
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if mod_name == "__main__" or mod_name.endswith(".__main__"):
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return
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# If this process was forked, __main__ may already be populated
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if getattr(current_main.__spec__, "name", None) == mod_name:
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return
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# Otherwise, __main__ may contain some non-main code where we need to
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# support unpickling it properly. We rerun it as __mp_main__ and make
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# the normal __main__ an alias to that
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# old_main_modules.append(current_main)
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main_module = types.ModuleType("__mp_main__")
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main_content = runpy.run_module(mod_name,
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run_name="__mp_main__",
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alter_sys=True) # type: ignore
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main_module.__dict__.update(main_content)
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sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
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def _fixup_main_from_path(main_path: str) -> None:
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# If this process was forked, __main__ may already be populated
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current_main = sys.modules['__main__']
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# Unfortunately, the main ipython launch script historically had no
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# "if __name__ == '__main__'" guard, so we work around that
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# by treating it like a __main__.py file
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# See https://github.com/ipython/ipython/issues/4698
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main_name = os.path.splitext(os.path.basename(main_path))[0]
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if main_name == 'ipython':
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return
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# Otherwise, if __file__ already has the setting we expect,
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# there's nothing more to do
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if getattr(current_main, '__file__', None) == main_path:
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return
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# If the parent process has sent a path through rather than a module
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# name we assume it is an executable script that may contain
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# non-main code that needs to be executed
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# old_main_modules.append(current_main)
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main_module = types.ModuleType("__mp_main__")
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main_content = runpy.run_path(main_path,
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run_name="__mp_main__") # type: ignore
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main_module.__dict__.update(main_content)
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sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
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