Using Multiprocessing with Tkinter and Selenium

Question

Okay, so I am trying to create a Tkinter GUI that is used to control Selenium processes. I want to add a label to the GUI that shows the runtime from the moment I press the start button. What I want is the runtime clock to update itself WHILE the code is running Selenium processes. The problem is that when I press the "Start" button, the runtime clock will update the first second, and will not update again until the Selenium processes are finished. Here is a minimal reproducible example:

NOTE: IF YOU RUN THIS CODE, PLEASE NOTE THE connect_driver() FUNCTION INSTALLS CHOMEDRIVER

import tkinter as tk
from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager


class GUI():
    def __init__(self):
        self.root = tk.Tk()
        self.root.geometry("200x200")

        # run-time clock
        self.run_time_label = tk.Label(self.root, text="Run Time:")
        self.run_time_label.pack()
        self.run_time = tk.Label(self.root, text="00:00:00:00")
        self.run_time.pack()
        self.run_time_data = {"days":0, "hours":0, "minutes":0, "seconds":0}  

        # start button
        self.start_button = tk.Button(self.root, text="Start", bg="green", height=1, width=10, command=self.start)
        self.start_button.pack()

        self.root.mainloop()

    def start(self):
        self.update_runtime()
        self.change_state()
        self.connect_driver()
        self.work()

    def stop(self):
        driver.close()
        driver.quit()
        self.change_state()

    def update_runtime(self):
        if self.run_time_data["seconds"] < 59:
            self.run_time_data["seconds"] += 1
        elif self.run_time_data["seconds"] == 59:
            self.run_time_data["seconds"] = 0
            if self.run_time_data["minutes"] < 59:
                self.run_time_data["minutes"] += 1
            elif self.run_time_data["minutes"] == 59:
                self.run_time_data["minutes"] = 0
                if self.run_time_data["hours"] < 24:
                    self.run_time_data["hours"] += 1
                elif self.run_time_data["hours"] == 23:
                    self.run_time_data["hours"] = 0
                    self.run_time_data["days"] += 1
        
        time_string = "{:02d}:{:02d}:{:02d}:{:02d}".format(self.run_time_data["days"],self.run_time_data["hours"],self.run_time_data["minutes"],self.run_time_data["seconds"])
        self.run_time.config(text=time_string)
        self.root.after(1000, self.update_runtime)

    def change_state(self):
        if self.start_button.cget("text") == "Start":
            self.start_button.configure(text="Stop", bg="red", command=self.stop)
        elif self.start_button.cget("text") == "Stop":
            self.start_button.configure(text="Start", bg="green", command=self.start)
        self.root.update_idletasks()

    def connect_driver(self):
        global driver
        driver = webdriver.Chrome(ChromeDriverManager().install())

    def work(self):
        for _ in range(3):
            driver.get("http://www.google.com")
            driver.get("https://stackoverflow.com")
            driver.get("https://www.youtube.com")

if __name__ == "__main__":
    app = GUI()

When running this code, as you can see the runtime clock will update to 1 second after pressing "Start", and then continue to do the selenium processes but will not update the runtime clock again until the very end. So I tried to look for a solution to this and figured I would probably need to use Multiprocessing to run the update_runtime() function independently. The problem is, I am very new to Multiprocessing (obviously) and it's not immediately obvious to me how I should use it here. Here is what I tried:

import tkinter as tk
from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager
import multiprocessing as mp


class GUI():
    def __init__(self):
        self.root = tk.Tk()
        self.root.geometry("200x200")

        # run-time clock
        self.run_time_label = tk.Label(self.root, text="Run Time:")
        self.run_time_label.pack()
        self.run_time = tk.Label(self.root, text="00:00:00:00")
        self.run_time.pack()
        self.run_time_data = {"days":0, "hours":0, "minutes":0, "seconds":0}  

        # start button
        self.start_button = tk.Button(self.root, text="Start", bg="green", height=1, width=10, command=self.start)
        self.start_button.pack()

        self.root.mainloop()

    def start(self):
        self.process = mp.Process(target=self.update_runtime)
        self.process.start()
        self.process.join()
        self.change_state()
        self.connect_driver()
        self.work()

    def stop(self):
        driver.close()
        driver.quit()
        self.change_state()

    def update_runtime(self):
        if self.run_time_data["seconds"] < 59:
            self.run_time_data["seconds"] += 1
        elif self.run_time_data["seconds"] == 59:
            self.run_time_data["seconds"] = 0
            if self.run_time_data["minutes"] < 59:
                self.run_time_data["minutes"] += 1
            elif self.run_time_data["minutes"] == 59:
                self.run_time_data["minutes"] = 0
                if self.run_time_data["hours"] < 24:
                    self.run_time_data["hours"] += 1
                elif self.run_time_data["hours"] == 23:
                    self.run_time_data["hours"] = 0
                    self.run_time_data["days"] += 1
        
        time_string = "{:02d}:{:02d}:{:02d}:{:02d}".format(self.run_time_data["days"],self.run_time_data["hours"],self.run_time_data["minutes"],self.run_time_data["seconds"])
        self.run_time.config(text=time_string)
        self.root.after(1000, self.update_runtime)

    def change_state(self):
        if self.start_button.cget("text") == "Start":
            self.start_button.configure(text="Stop", bg="red", command=self.stop)
        elif self.start_button.cget("text") == "Stop":
            self.start_button.configure(text="Start", bg="green", command=self.start)
        self.root.update_idletasks()

    def connect_driver(self):
        global driver
        driver = webdriver.Chrome(ChromeDriverManager().install())

    def work(self):
        for _ in range(3):
            driver.get("http://www.google.com")
            driver.get("https://stackoverflow.com")
            driver.get("https://www.youtube.com")

if __name__ == "__main__":
    app = GUI()

But when I run this, I get an error : EOFError: Ran out of input

Please please help! :)

M Z G · Accepted Answer · 2021-11-28 15:53:16Z

1

Instead of using multiprocessing, try using threading as for something as simple as updating one label it will work better.

https://realpython.com/intro-to-python-threading/

This way you can create a new function just for updating the label with a loop and call it in the start() function.

answered Nov 28, 2021 at 15:53

M Z G

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4 Comments

bobtho'-' Over a year ago

Dang I was gonna say to use Threading. But provide an example, and not just a link please?

M Z G Over a year ago

The link provides examples and will actually explain how to use it, instead of someone just fixing your code.

vexem Over a year ago

@M Z G Thanks! I never even looked at Multithreading before, I always just figured it was the same as Multiprocessing. Just implemented and it works perfectly! Also, welcome to the community!

acw1668 Over a year ago

Using an external link as an answer is not recommended because the external link may be dead in the future.

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