Python multiprocessing Pool apply async wait for process to complete

[sunny9495]

I have coded a simple program of run through the list, but apply_sync isn't waiting until the list is complete, here is the code

import itertools
import multiprocessing
from multiprocessing import Pool
import time
from tkinter import *
from tkinter import ttk
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
import os
from tkinter import messagebox


x= ['annah', 'reena', 'jermy', 'sunny', 'chinni']


def next_name(name):
    options = Options()
    options.binary_location = r'drivers/Browser/chrome.exe'
    driver = webdriver.Chrome(executable_path=r'drivers/chromedriver.exe', options=options)
    driver.get('http://google.com')
    time.sleep(2)
    driver.find_element(By.XPATH, '//input[@name="q"]').send_keys(name)
    time.sleep(2)
    driver.find_element(By.XPATH, '//input[@name="q"]').send_keys(Keys.ENTER)
    time.sleep(3)
    driver.close()

def start():
    global y
    y = Pool(processes=2)
    for usr in itertools.zip_longest(x):
        y.apply_async(next_name, args=(usr, ))
    #messagebox has to popup when list is completed
    messagebox.showinfo("Sample Program", "List Completed")

def stop():
    y.terminate()
    os.system("taskkill /F /IM chromedriver.exe /T")
root = Tk()
startbtn = ttk.Button(root, text="start", command=start)
startbtn.pack()
stopbtn = ttk.Button(root, text="stop", command=stop)
stopbtn.pack()
root.geometry('300x300')
if __name__ == '__main__':
    multiprocessing.freeze_support()
    root.mainloop()

I just want the program to show message box when list was completed.

Any help would be appreciated.

Thank you

[deanhystad]

If you call the function directly the program will wait and draw the message block when the processes are done. By using apply_async() you are telling python to not wait for completion of the tasks. apply_async() returns an AsyncResult object. This can be used to wait for the process to complete. You can also specify a callback function that is called when the task completes.

You should not block as this will make the user interface unresponsive. I think using the callback is a better idea.

apply_async() is not a good choice for what you are doing. I would go with map_async()

https://docs.python.org/3/library/multiprocessing.html

[sunny9495]

Thanks for the help deanhystad, i modify the code with map_async, it works fine

def mycallback(x):
    messagebox.showinfo("Sample Program", "Completed")

def start():
    global y
    pool = Pool(processes=2)
    pool.map_async(next_name, x, callback=mycallback)

If you call the function directly the program will wait and draw the message block when the processes are done. By using apply_async() you are telling python to not wait for completion of the tasks. apply_async() returns an AsyncResult object. This can be used to wait for the process to complete. You can also specify a callback function that is called when the task completes.

You should not block as this will make the user interface unresponsive. I think using the callback is a better idea.

apply_async() is not a good choice for what you are doing. I would go with map_async()

https://docs.python.org/3/library/multiprocessing.html

[sunny9495]

How we can pass multiple lists in map_async, example

x= ['annah', 'reena', 'jermy', 'sunny', 'chinni']
proxies = ["ip:port:username:password", "ip:port:username:password"]


I want to use the proxies randomly for every launch

[sunny9495]

Still looking for solution on how to add multiple args to map_async

[deanhystad]

Lots of choices. I'm sure one fits you needs.

https://docs.python.org/3/library/multip...1a25acdf81

Maybe one of the starmap functions.

[sunny9495]

Thanks alot @deanhystad i found the solution