here is a simple example:
from collections import deque
from multiprocessing import Process
global_dequeue = deque([])
def push():
global_dequeue.append('message')
p = Process(target=push)
p.start()
def pull():
print(global_dequeue)
pull()
the output is deque([])
if I was to call push function directly, not as a separate process, the output would be deque(['message'])
How can get the message into deque, but still run push function in a separate process?
You can share data by using multiprocessing Queue object which is designed to share data between processes:
from multiprocessing import Process, Queue
import time
def push(q): # send Queue to function as argument
for i in range(10):
q.put(str(i)) # put element in Queue
time.sleep(0.2)
q.put("STOP") # put poison pillow to stop taking elements from Queue in master
if __name__ == "__main__":
q = Queue() # create Queue instance
p = Process(target=push, args=(q,),) # create Process
p.start() # start it
while True:
x = q.get()
if x == "STOP":
break
print(x)
p.join() # join process to our master process and continue master run
print("Finish")
Let me know if it helped, feel free to ask questions.
You can also use Managers to achieve this.
Python 2: https://docs.python.org/2/library/multiprocessing.html#managers
Python 3:https://docs.python.org/3.8/library/multiprocessing.html#managers
Example of usage:
https://pymotw.com/2/multiprocessing/communication.html#managing-shared-state
