python singleton into multiprocessing

Question

How can I code to share the same instance of a \"singletonic\" class among processes?

Answer 1

You could also use one of the multiprocessing.manager shareable data types

import multiprocessing as mp
manager = mp.Manager()
shared_list = manager.list()

def worker1(l):
    l.append(1)

def worker2(l):
    l.append(2)

process1 = mp.Process(target=worker1, args=[shared_list])
process2 = mp.Process(target=worker2, args=[shared_list])

process1.start()
process2.start()
process1.join()
process2.join()

print shared_list

output would look like:

[1, 2]

There are a variety of data structures on offer but you'll need the parent process to pass in the shared object to the child objects.