How do I run some python code in another process?

Question

I want to start, from Python, some other Python code, preferably a function, but in another process.

It is mandatory to run this in another process, because I want to run some concurrency tests, like opening a file that was opened exclusively by the parent process (this has to fail).

Requirements:

multiplatform: linux, osx, windows
compatible with Python 2.6-3.x

possible duplicate of [What's the best way to duplicate fork() in windows?](http://stackoverflow.com/questions/23397/whats-the-best-way-to-duplicate-fork-in-windows) — AJ., Jun 15 '11 at 12:50
@AJ that's about Windows, this is about Python. I don't see how it could possibly be a duplicate. — wheaties, Jun 15 '11 at 12:54

score 23 · Accepted Answer · answered Jun 15 '11 at 12:48

I would seriously take a look at the documentation for multiprocessing library of Python. From the first sentence of the package's description:

multiprocessing is a package that supports spawning processes using an API similar to the threading module.

It then goes on to say that it side-steps the GIL, which is what it sounds like you're trying to avoid. See their example of a trivial set up:

from multiprocessing import Process

def f(name):
    print 'hello', name

if __name__ == '__main__':
    p = Process(target=f, args=('bob',))
    p.start()
    p.join()

That's a function call being done in another process separate from the process you're inside. Again, all this from the documentation.

How do I run some python code in another process?

1 Answers1