eric6/DebugClients/Python/MultiprocessingExtension.py

# -*- coding: utf-8 -*-

# Copyright (c) 2020 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a function to patch multiprocessing.Process to support
debugging of the process.
"""

import sys
import traceback

_debugClient = None
_originalProcess = None
_originalBootstrap = None


# TODO: add support for start method 'forkserver'
# TODO: add support for start method 'spawn'
def patchMultiprocessing(module, debugClient):
    """
    Function to patch the multiprocessing module.
    
    @param module reference to the imported module to be patched
    @type module
    @param debugClient reference to the debug client object
    @type DebugClient
    """     # __IGNORE_WARNING_D234__
    global _debugClient, _originalProcess, _originalBootstrap
    
    _debugClient = debugClient
    
    if sys.version_info >= (3, 4):
        _originalProcess = module.process.BaseProcess
    else:
        _originalProcess = module.Process
    _originalBootstrap = _originalProcess._bootstrap
    
    class ProcessWrapper(_originalProcess):
        """
        Wrapper class for multiprocessing.Process.
        """
        def _bootstrap(self, *args, **kwargs):
            """
            Wrapper around _bootstrap to start debugger.
            
            @param args function arguments
            @type list
            @param kwargs keyword only arguments
            @type dict
            @return exit code of the process
            @rtype int
            """
            if (
                _debugClient.debugging and
                _debugClient.multiprocessSupport
            ):
                try:
                    (wd, host, port, exceptions, tracePython, redirect,
                     noencoding) = _debugClient.startOptions[:7]
                    _debugClient.startDebugger(
                        sys.argv[0], host=host, port=port,
                        exceptions=exceptions, tracePython=tracePython,
                        redirect=redirect, passive=False,
                        multiprocessSupport=True
                    )
                except Exception:
                    print("Exception during multiprocessing bootstrap init:")
                    # __IGNORE_WARNING_M801__
                    traceback.print_exc(file=sys.stdout)
                    sys.stdout.flush()
                    raise
            
            return _originalBootstrap(self, *args, **kwargs)
    
    if sys.version_info >= (3, 4):
        _originalProcess._bootstrap = ProcessWrapper._bootstrap
    else:
        module.Process = ProcessWrapper