processify for Python 3

LICENSE

MIT License

Copyright (c) [year] [fullname]

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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SOFTWARE.

processify.py

"""
https://gist.github.com/schlamar/2311116
with Python 3 adaptations and some code formatting.
"""

import os
import sys
import traceback
from functools import wraps
from multiprocessing import Process, Queue


def processify(func):
    """
    Decorator to run a function as a process.
    Be sure that every argument and the return value
    is *pickable*.
    The created process is joined, so the code does not
    run in parallel.
    """

    def process_func(q, *args, **kwargs):
        try:
            ret = func(*args, **kwargs)
        except Exception:
            ex_type, ex_value, tb = sys.exc_info()
            error = ex_type, ex_value, ''.join(traceback.format_tb(tb))
            ret = None
        else:
            error = None

        q.put((ret, error))

    # register original function with different name
    # in sys.modules so it is pickable
    process_func.__name__ = func.__name__ + 'processify_func'
    setattr(sys.modules[__name__], process_func.__name__, process_func)

    @wraps(func)
    def wrapper(*args, **kwargs):
        q = Queue()
        p = Process(target=process_func, args=(q,) + args, kwargs=kwargs)
        p.start()
        ret, error = q.get()
        p.join()

        if error:
            ex_type, ex_value, tb_str = error
            message = '%s (in subprocess)\n%s' % (str(ex_value), tb_str)
            raise ex_type(message)

        return ret

    return wrapper


@processify
def test_function():
    return os.getpid()


@processify
def test_deadlock():
    return range(30000)


@processify
def test_exception():
    raise RuntimeError('xyz')


def test():
    print(os.getpid())
    print(test_function())
    print(len(test_deadlock()))
    test_exception()


if __name__ == '__main__':
    test()

Hi @Chiron1991 would you mind to add a MIT license to this snippet ?

Hi @Chiron1991 would you mind to add a MIT license to this snippet ?

Not at all, here you go.

Thank you 🎆