Synchronize two functions into separate classes

Question

In a class there are different functions. In a separate file in another class I want to catch the messages and print to gui. As a simulation I have the following code:

import threading
import time
import logging

logging.basicConfig(level=logging.DEBUG, format='(%(threadName)-9s) %(message)s',)

message = None


def messages_generator(condition):
    global message
    with condition:
        logging.debug('Condition: {}'.format(condition))
        for i in range(5):
            message = 'i = ' + str(i)
            time.sleep(1)
            logging.debug('Condition wait')
            condition.wait()


def messages_sow(condition):
    global message
    with condition:
        print(message)
        logging.debug('Condition notify')
        condition.notify()
    logging.debug('Tread finished')


condition = threading.Condition()
messages_generator_thread = threading.Thread(name='Message Generator', target=messages_generator, args=(condition,))
messages_sow_thread = threading.Thread(name='Message Sow', target=messages_sow, args=(condition,))

messages_generator_thread.start()
messages_sow_thread.start()

What I want is the messages_generator to wait for the message to be printed by the messages_sow emphasized text and continue until it is completed. When I run the above code, the program freezes on the second 'Condition wait'. Any advice to be welcomed.

Answer 1

I finally managed to work the code above, but not on the basic program which I develop based on the Model - View - Controller programming model. I quote the code that works.

import threading
import time
import logging

logging.basicConfig(level=logging.DEBUG, format='(%(threadName)-9s) %(message)s',)

message = None


def messages_generator(condition):
    logging.debug('--- Start ---')
    global message
    messages_number = 5
    for i in range(messages_number):
        logging.debug('Inside For. i = {}'.format(i))
        condition.acquire()
        if message is not None:
            logging.debug('Condition wait')
            condition.wait()
        if i == (messages_number - 1):
            message = 'end'
            logging.debug('Message = {}'.format(message))
        else:
            message = 'i = ' + str(i)
            time.sleep(1)
        logging.debug('Condition notify')
        condition.notify()
        logging.debug('Condition release')
        condition.release()

def messages_sow(condition):
    logging.debug('--- Start ---')
    global message
    while True:
        logging.debug('Inside While. stop = {}'.format(True))
        condition.acquire()
        if message is None:
            logging.debug('Condition wait')
            condition.wait()
        else:
            print(message)
        if message == 'end':
            break
        message = None

        condition.notify()
        condition.release()
    logging.debug('Tread finished')


condition = threading.Condition()
messages_generator_thread = threading.Thread(name='Message Generator', target=messages_generator, args=(condition,))
messages_sow_thread = threading.Thread(name='Message Sow', target=messages_sow, args=(condition,))

messages_generator_thread.start()
messages_sow_thread.start()