[Tkinter] Updating Tkinter label using multiprocessing

[Tkinter] Updating Tkinter label using multiprocessing - Printable Version

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Updating Tkinter label using multiprocessing - Agusms - Aug-12-2022

Hi!
I'm having trouble updating a label depending on a result from a function from one of the two processes I'm running. I'm trying using Queues, but can't make it work.

This is a simplified example of the code:

import multiprocessing as mp
from tkinter import DISABLED, NORMAL, Label, LabelFrame, Tk
import queue

class Gui(object):
    def __init__(self, q):
        self.root = Tk()
        self.root.geometry('150x100')

        self.frameP1 = LabelFrame(self.root, text="Process1", font=("Helvetica", 14, "bold"), bd=0)
        self.frameP1.pack(padx=12)
        self.currentUserProcess1 = Label(self.frameP1, text="Current User p1", font=("Helvetica", 10, "bold"))
        self.currentUserProcess1.pack()
        
        self.frameP2 = LabelFrame(self.root, text="Process2", font=("Helvetica", 14, "bold"), bd=0)
        self.frameP2.pack()
        self.currentUserProcess2 = Label(self.frameP2, text="Current User p2", font=("Helvetica", 10, "bold"))
        self.currentUserProcess2.pack()
        self.root.after(100,self.CheckQueuePoll,q)
    

    def CheckQueuePoll(self, c_queue):
        try:
            str = c_queue(0)
            self.currentUserProcess2.configure(text=str)
        except queue.Empty:
            pass
        finally:
            self.root.after(100, self.CheckQueuePoll, q)

def process1():
    print("Executing process1")
    
    #doSomething

def process2():
    print("Executing process2")
    log = "Current User Process 2"
    q.put(log)

def startProcesses():
    global p1
    global p2
    p1 = mp.Process(target = process1)
    p2 = mp.Process(target = process2)
    p1.start()
    p2.start()


def stopProcesses():
    p1.terminate()
    p2.terminate()
       
if __name__ == '__main__':
    q = mp.Queue()
    gui = Gui(q)
    p1 = mp.Process(target = process1, args=(q,))
    p2 = mp.Process(target = process2, args=(q,))
    p1.start()
    p2.start()
    gui.root.mainloop()

This is giving me this error:

Error:
TypeError: 'Queue' object is not callable

This happens when trying to execute "str = c_queue(0)" on CheckQueuePoll function.
I tried different ways of importing Queue, but I always get errors. I'd appreciate any help or hint in what I'm doing wrong.
Thanks in advance!

RE: Updating Tkinter label using multiprocessing - Gribouillis - Aug-12-2022

The object c_queue is not callable. Try this perhaps

    def CheckQueuePoll(self, c_queue):
        try:
            str = c_queue.get_nowait()
            c_queue.task_done()
            self.currentUserProcess2.configure(text=str)
        except queue.Empty:
            pass
        finally:
            self.root.after(100, self.CheckQueuePoll, q)

RE: Updating Tkinter label using multiprocessing - woooee - Aug-12-2022

Pass gui.currentUserProcess 1 or 2 to the process as an arg. Each process can then update it.

RE: Updating Tkinter label using multiprocessing - Agusms - Aug-12-2022

(Aug-12-2022, 02:37 PM)Gribouillis Wrote: The object c_queue is not callable. Try this perhaps

    def CheckQueuePoll(self, c_queue):
        try:
            str = c_queue.get_nowait()
            c_queue.task_done()
            self.currentUserProcess2.configure(text=str)


        except queue.Empty:
            pass
        finally:
            self.root.after(100, self.CheckQueuePoll, q)

I tried it but now it gives me this errors:

Error:
TypeError: process1() takes 0 positional arguments but 1 was given

Error:
TypeError: process2() takes 0 positional arguments but 1 was given

So I tried passing the "q" as an argument to process1() and process2() and now I have this error:

Error:
AttributeError: 'Queue' object has no attribute 'task_done'

There is maybe a problem with the import? I tried importing queue in different ways though.

RE: Updating Tkinter label using multiprocessing - Agusms - Aug-12-2022

(Aug-12-2022, 07:04 PM)woooee Wrote: Pass gui.currentUserProcess 1 or 2 to the process as an arg. Each process can then update it.

I tried it. This is the code I got, in case I did something wrong:

class Gui(object):
    def __init__(self, q):
        self.root = Tk()
        self.root.geometry('150x100')

        self.frameP1 = LabelFrame(self.root, text="Process1", font=("Helvetica", 14, "bold"), bd=0)
        self.frameP1.pack(padx=12)
        self.currentUserProcess1 = Label(self.frameP1, text="Current User p1", font=("Helvetica", 10, "bold"))
        self.currentUserProcess1.pack()
        
        self.frameP2 = LabelFrame(self.root, text="Process2", font=("Helvetica", 14, "bold"), bd=0)
        self.frameP2.pack()
        self.currentUserProcess2 = Label(self.frameP2, text="Current User p2", font=("Helvetica", 10, "bold"))
        self.currentUserProcess2.pack()

def process1():
    print("Executing process1")
    
    #doSomething

def process2(currentUserProcess2):
    print("Executing process2")
    log = "Current user process 2"
    currentUserProcess2.configure(text=log)

def startProcesses():
    global p1
    global p2
    p1 = mp.Process(target = process1, args=(gui.currentUserProcess2,))
    p2 = mp.Process(target = process2, args=(gui.currentUserProcess2,))
    p1.start()
    p2.start()


def stopProcesses():
    p1.terminate()
    p2.terminate()
       
if __name__ == '__main__':
    q = mp.Queue()
    gui = Gui(q)
    p1 = mp.Process(target = process1, args=(gui.currentUserProcess2,))
    p2 = mp.Process(target = process2, args=(gui.currentUserProcess2,))
    p1.start()
    p2.start()
    gui.root.mainloop()

I got this:

Error:Traceback (most recent call last):
  File "c:\Users\User1\Desktop\MultiTkinter\main.py", line 63, in <module>
    p1.start()
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\process.py", line 121, in start
    self._popen = self._Popen(self)
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\context.py", line 327, in _Popen
    return Popen(process_obj)
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\popen_spawn_win32.py", line 93, in __init__  
    reduction.dump(process_obj, to_child)
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
TypeError: cannot pickle '_tkinter.tkapp' object
PS C:\Users\User1\Desktop\MultiTkinter> Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\spawn.py", line 107, in spawn_main
    new_handle = reduction.duplicate(pipe_handle,
  File "C:\Users\User1\AppData\Local\Programs\Python\Python310\lib\multiprocessing\reduction.py", line 79, in duplicate
    return _winapi.DuplicateHandle(
PermissionError: [WinError 5] Access is denied

I deleted CheckQueuePoll function as I understand it wouldn't be needed if I'm passing "gui.CurrenUserProcess2" in the parameters.

RE: Updating Tkinter label using multiprocessing - woooee - Aug-12-2022

I see at least 2 problems

        self.currentUserProcess1 = Label(self.frameP1, text="Current User p1", font=("Helvetica", 10, "bold"))
        self.currentUserProcess2 = Label(self.frameP2, text="Current User p2", font=("Helvetica", 10, "bold"))
 
p1 = mp.Process(target = process1, args=(gui.currentUserProcess2,))
p2 = mp.Process(target = process2, args=(gui.currentUserProcess2,))
                                                                                                        ===
def process1():

RE: Updating Tkinter label using multiprocessing - menator01 - Aug-15-2022

Are you trying to do something like this?

import multiprocessing as mp
import random as rnd
import tkinter as tk

'''
    Function for updating labels
    Creates the que
    Add to the que
    Set label text for que
    Call root.after for continuous call
'''
def get_num(root, label):
    myque = mp.Queue()
    myque.put(rnd.randint(1, 100))
    label['text'] = f'Process {myque.get()} running...'
    root.after(1000, lambda: get_num(root, label))

'''
    Tkinter window
'''
root = tk.Tk()
root.title('Running Processes')
root.columnconfigure(0, weight=1)
root.geometry('+300+300')

'''
    Two list, one to hold labelframes and one to hold labels
'''
labels = []
labelframes = []

'''
    Set variable j to for labelframe numbers
'''
j = 1

'''
    Using for loop to add 10 labels
    using j to number labelframes
    create and append labelframes to the labelframes list
'''
for i in range(10):
    j = j if i % 2 == 0 else(j if i % 3 == 0 else j+1)
    labelframes.append(tk.LabelFrame(root, text=f'Processes for frame {j}'))
    labelframes[i].grid(column=0, row=i, sticky='new', pady=5, padx=5)

    '''
    parent is used to place labels in the labelframes. Using i % n in this example
    '''
    parent = labelframes[0] if i % 2 == 0 else(labelframes[1] if i % 3 == 0 else labelframes[i])

    '''
    Create and append labels to the labels list
    Using parent to color background of grouped labels in labelframe
    '''
    labels.append(tk.Label(parent, anchor='w', padx=5, width=50))
    labels[i]['bg'] = 'sandybrown' if parent == labelframes[0] \
    else('tan' if parent == labelframes[1] else 'ivory2')
    labels[i]['relief'] = 'ridge'
    labels[i].grid(column=0, row=i, sticky='new', pady=5, padx=5)

    '''
    Create and start the process
    '''
    process = mp.Process(target=get_num, args=(root, labels[i],))
    process.start()
    process.join()

    '''
    Use root.after to call the get_num function
    '''
    root.after(1, get_num, root, labels[i])
root.mainloop()