Using python how can I pass data between child and main processes with Queue?

Desired goal

pass information to other sub processes or main process

Concerns

-Is it a problem that the processes never finish?

-Is it a problem the class methods never return/finish?

will this cause stack overflow? ( I expect to run for hours).

Alternative

Would it be appropriate to have several different scripts and save to, load from a database/pickle?

What works

If I swap the multiprocessing for threading the desired output is achieved.

Have tried

-Tried switching the multiprocessing for threading which seems to give me the desired outcome, but would like to understand why multiprocessing is not giving the same output.

-Tried using Queue() instead or LifoQueue()

-Tried running and printing Queue.get() from another child subprocess instead of the main script

-Tried .join() all tasks

Desired output

I expect the color to be changed within a subprocess and passed to the Queue, I expect to retrieve the new color with Queue.get().

Example

import multiprocessing
import threading
import time

class MyClass:
    def __init__(self):
        self.color = 'gray'
    
    def task_blue(self,q):
        print('sleeping 5..')
        time.sleep(5)
        while True:     
            time.sleep(1)
            self.color = 'blue'
            q.put([self.color])

    def task_red(self,q):
        print('sleeping 5..')
        time.sleep(5)
        while True:
            time.sleep(3)
            self.color = 'red'
            q.put([self.color])
        
    def printer(self,q):
        while True:
            time.sleep(.1)
            if q.empty():
                print('<empty>')
            else:
    
                print(q.get())

from queue import LifoQueue, Queue        
q = LifoQueue()
my_class = MyClass()

p1 = multiprocessing.Process(target=my_class.task_blue,args=(q,),name='BLUE')
p2 = multiprocessing.Process(target=my_class.task_red,args=(q,),name='RED')
# p3 = multiprocessing.Process(target=my_class.printer,args=(q,),name='PRINTER')

tasks = []
tasks.append(p1)
tasks.append(p2)
# tasks.append(p3)

for task in tasks:
    task.start()

while True:
    time.sleep(.2)
    if q.empty():
        print(['empty'])
    else:
        print(q.get())

output

Is it a problem that the processes never finish?

It's OK for a process to run forever.

Is it a problem the class methods never return/finish?

No. If you want your program to run forever, there is going to be some section of code that doesn't return. It's OK if this area of code is inside a method.

I like the idea of the entire program being one script/class

You can do it many ways. There's no correct answer here, especially absent other requirements.

Tried using Queue() instead or LifoQueue() -Tried running and printing Queue.get() from another child subprocess instead of the main script -Tried .join() all the tasks

when using the multiprocessing package, you should use the Queue class from the multiprocessing package. E.g. queue = multiprocessing.Queue(). Docs here: https://docs.python.org/3/library/multiprocessing.html#multiprocessing.Queue