Multiprocessing in Tkinter - python-3.x

Question

I have this following code where I am calling the function from the button which takes input from the widgets. It's a function which takes about 4 minutes to run and for solving the 'not responding' problem of tkinter window, I want to get the func process running on the different core and terminate as it can be called again via the application running on mainloop with a different argument. I read the documentation of multiprocessing and Pool seemed to be the choice here but I don't know how to frame it here. Tried a few things with error.
class database(tk.Tk):
def __init__(self, *args, *kwargs):
tk.Tk.__init__(self, *args, **kwargs):
container= tk.Frame(self, width=1000, height=1000)
container.pack(side="top", fill="both", expand= True)
container.grid_rowconfigure(0, weight=1)
container.grid_columnconfigure(0, weight=1)
self.frames = {}
for F in ( msPage): #many more pages here
frame = F(container, self)
self.frames[F] = frame
frame.grid(row=0, column=0, sticky="nsew")
self.show_frame(msPage)
def show_frame(self,cont):
frame = self,frames[cont]
frame.tkraise()
def MarkS(msVar):
ms.func(msVar.get()) # func takes about 4 mins
class msPage(tk.Frame):
def __init__(self, parent, controller):
tk.Frame.__init__(self, parent)
msVar = StringVar()
msCal = Calendar(self, selectmode='day'
textvariable=msVar).pack(fill="both", expand=True)
# button2 calls MarkS
button2 = ttk.Button(self,
text="Get Data",
command=lambda: MarkS(msVar)).pack(pady=30, padx=10)
app = database()
app.geometry("1066x568")
app.minsize(width=670, height=550)
app.mainloop()

Answer 1

This is a standalone example that might help you get started:
from multiprocessing import Process
class ms_var_class():
value = None
def __init__(self, value):
self.value = value
def get(self):
return self.value
# This is to simulate type(ms)
class ms_class():
process = None
# This is for simulating your long running function
def func(self, ms_var):
print(ms_var)
def MarkS(msVar):
ms.process = Process(target=ms.func, args=(msVar.get(),))
ms.process.start()
# Call ms.process.join() later
ms_var = ms_var_class("bogus")
ms = ms_class()
MarkS(ms_var)
if ms.process is not None:
ms.process.join()

Answer 2

Thank you Mike for commenting and helping me get towards the solution
Here's how I did it
Create a global queue
q= queue.Queue()
Defined the function MarkS within the class msPage
def MarkS(msVar):
q.put([7 , datetime.datetime.strptime(msVar.get(), '%x').strftime('%d-%b-%Y').upper(),0])
ThreadedTask(q).start()
7 is the unique number of the 9 functions that I had for each page (class)
Made another class of ThreadedTask as in the link below
Tkinter: How to use threads to preventing main event loop from "freezing"
class ThreadedTask(threading.Thread):
def __init__(self,queue):
threading.Thread.__init__(self)
q = queue
def run(self):
items = q.get()
if items[0]==7:
ms.func(items[1])
ThreadedTask(q).start() creates a constructor object and the run function automatically starts depending on the argument here which is of course the 1st element of q which is a list of 3 in my case. It is detected and the desired function is run in another thread which prevents the tkinter window from closing.
Hope this helps! :)