问题
Below is my code my function receives data blocks from the server and puts them in a FIFO buffer after which two functions are called in parallel,
recvData() #to keep receiving data blocks from the server and put in the FIFO buffer
calculate_threshold() #to remove data blocks from the FIFO buffer and perform some calculation, give a real time display on the GUI, and write the result in the file
Code
import socket
import turtle
#import timeit
import queue
import multiprocessing
from tkinter import *
class GUI:
def __init__(self, master):
self.master = master
master.title("Collision Detection")
self.buff_data = queue.Queue()
self.p1 = multiprocessing.Process(target = self.recvData)
self.p1 = multiprocessing.Process(target=self.calculate_threshold)
self.input_label = Label(root, text = "Input all the gratings set straight wavelength values in nm")
self.input_label.grid(row = 0)
self.core_string = "Core "
self.entries = []
self.label_col_inc = 0
self.entry_col_inc = 1
self.core_range = range(1, 5)
for y in self.core_range:
self.core_text = self.core_string + str(y) + '_' + '25'
self.core_label = Label(root, text = self.core_text)
self.entry = Entry(root)
self.core_label.grid(row=1, column=self.label_col_inc, sticky=E)
self.entry.grid(row=1, column=self.entry_col_inc)
self.entries.append(self.entry)
self.label_col_inc += 2
self.entry_col_inc += 2
self.threshold_label = Label(root, text = "Threshold in nm")
self.entry_threshold = Entry(root)
self.threshold_label.grid(row = 2, sticky = E)
self.entry_threshold.grid(row = 2, column = 1)
self.light_label = Label(root, text = 'Status')
self.light_label.grid(row = 3, column = 3)
self.canvas = Canvas(root, width = 150, height = 50)
self.canvas.grid(row = 4, column = 3)
# Green light
self.green_light = turtle.RawTurtle(self.canvas)
self.green_light.shape('circle')
self.green_light.color('grey')
self.green_light.penup()
self.green_light.goto(0,0)
# Red light
self.red_light = turtle.RawTurtle(self.canvas)
self.red_light.shape('circle')
self.red_light.color('grey')
self.red_light.penup()
self.red_light.goto(40,0)
self.data_button = Button(root, text = "Get data above threshold", command = self.getData)
self.data_button.grid(row = 5, column = 0)
# function to receive TCP data blocks
def getData(self):
host = '127.0.0.1'
port = 5000
s = socket.socket()
s.connect((host, port))
len_message = s.recv(4)
bytes_length = int(len_message.decode('utf-8')) # for the self-made server
recvd_data = s.recv(bytes_length)
self.buff_data.put(recvd_data)
self.p1.start()
self.p2.start()
self.p1.join()
self.p2.join()
def recvData(self):
len_message = s.recv(4)
while len_message:
bytes_length = int(len_message.decode('utf-8')) # for the self-made server
recvd_data = s.recv(bytes_length)
self.buff_data.put(recvd_data)
len_message = s.recv(4)
else:
print('out of loop')
s.close()
def calculate_threshold(self):
rmv_data = self.buff_data.get()
stringdata = rmv_data.decode('utf-8')
rep_str = stringdata.replace(",", ".")
splitstr = rep_str.split()
# received wavelength values
inc = 34
wav_threshold = []
for y in self.entries:
straight_wav = float(y.get())
wav = float(splitstr[inc])
wav_diff = wav - straight_wav
if wav_diff < 0:
wav_diff = wav_diff * (-1)
wav_threshold.append(wav_diff)
inc += 56
threshold = float(self.entry_threshold.get())
# writing into the file
data = []
inc1 = 0
col1 = 2
col2 = 6
data.insert(0, (str(splitstr[0])))
data.insert(1, (str(splitstr[1])))
for x in wav_threshold:
if (x > threshold):
self.red_light.color('red')
self.green_light.color('grey')
data.insert(col1, (str(splitstr[34 + inc1])))
data.insert(col2,(str(x)))
else:
self.red_light.color('grey')
self.green_light.color('green')
data.insert(col1,'-')
data.insert(col2,'-')
inc1 += 56
col1 += 1
col2 += 1
self.write_file(data)
# function to write into the file
def write_file(self,data):
with open("Output.txt", "a") as text_file:
text_file.write('\t'.join(data[0:]))
text_file.write('\n')
if __name__ == '__main__':
root = Tk()
gui = GUI(root)
root.mainloop()
But I get the following error:
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 1883, in __call__
return self.func(*args)
File "C:/Users/PycharmProjects/GUI/GUI_v4.py", line 88, in getData
self.p1.start()
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\process.py", line 121, in start
self._popen = self._Popen(self)
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\context.py", line 224, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\context.py", line 326, in _Popen
return Popen(process_obj)
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\popen_spawn_win32.py", line 93, in __init__
reduction.dump(process_obj, to_child)
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\reduction.py", line 60, in dump
ForkingPickler(file, protocol).dump(obj)
TypeError: cannot pickle '_tkinter.tkapp' object
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\spawn.py", line 116, in spawn_main
exitcode = _main(fd, parent_sentinel)
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\spawn.py", line 126, in _main
self = reduction.pickle.load(from_parent)
EOFError: Ran out of input
Can someone tell where exactly am I going wrong here?
回答1:
The error is telling you that you can't use multiprocessing for an object that includes tkinter widgets. You're trying to use self.recvData in a separate process. That requires that self be pickled so that it can be sent to the other process. However, python can't do it because it contains tkinter widgets which cannot be pickled.
You will need to move the code which runs in another process to a separate class that does not contain any tkinter widgets.
回答2:
Code changed after creating a new class:
import socket
import turtle
# import timeit
import queue
import multiprocessing
from tkinter import *
class GUI:
def __init__(self, master):
self.master = master
master.title("Collision Detection")
self.input_label = Label(root, text="Input all the gratings set straight wavelength values in nm")
self.input_label.grid(row=0)
self.core_string = "Core "
self.entries = []
self.label_col_inc = 0
self.entry_col_inc = 1
self.core_range = range(1, 5)
for y in self.core_range:
self.core_text = self.core_string + str(y) + '_' + '25'
self.core_label = Label(root, text=self.core_text)
self.entry = Entry(root)
self.core_label.grid(row=1, column=self.label_col_inc, sticky=E)
self.entry.grid(row=1, column=self.entry_col_inc)
self.entries.append(self.entry)
self.label_col_inc += 2
self.entry_col_inc += 2
self.threshold_label = Label(root, text="Threshold in nm")
self.entry_threshold = Entry(root)
self.threshold_label.grid(row=2, sticky=E)
self.entry_threshold.grid(row=2, column=1)
self.light_label = Label(root, text='Status')
self.light_label.grid(row=3, column=3)
self.canvas = Canvas(root, width=150, height=50)
self.canvas.grid(row=4, column=3)
# Green light
self.green_light = turtle.RawTurtle(self.canvas)
self.green_light.shape('circle')
self.green_light.color('grey')
self.green_light.penup()
self.green_light.goto(0, 0)
# Red light
self.red_light = turtle.RawTurtle(self.canvas)
self.red_light.shape('circle')
self.red_light.color('grey')
self.red_light.penup()
self.red_light.goto(40, 0)
self.data_button = Button(root, text="Get data above threshold", command=recv_data.getData)
self.data_button.grid(row=5, column=0)
class recv_data:
def __init__(self):
self.buff_data = queue.Queue()
self.p1 = multiprocessing.Process(target=self.recvData)
self.p1 = multiprocessing.Process(target=self.calculate_threshold)
self.host = '127.0.0.1'
self.port = 5002
self.s = socket.socket()
self.s.connect((self.host, self.port))
# function to receive TCP data blocks
def getData(self):
len_message = self.s.recv(4)
bytes_length = int(len_message.decode('utf-8')) # for the self-made server
recvd_data = self.s.recv(bytes_length)
self.buff_data.put(recvd_data)
self.p1.start()
self.p2.start()
self.p1.join()
self.p2.join()
def recvData(self):
len_message = self.s.recv(4)
while len_message:
bytes_length = int(len_message.decode('utf-8')) # for the self-made server
recvd_data = self.s.recv(bytes_length)
self.buff_data.put(recvd_data)
len_message = self.s.recv(4)
else:
print('out of loop')
self.s.close()
def calculate_threshold(self):
rmv_data = self.buff_data.get()
stringdata = rmv_data.decode('utf-8')
rep_str = stringdata.replace(",", ".")
splitstr = rep_str.split()
# received wavelength values
inc = 34
wav_threshold = []
for y in gui.entries:
straight_wav = float(y.get())
wav = float(splitstr[inc])
wav_diff = wav - straight_wav
if wav_diff < 0:
wav_diff = wav_diff * (-1)
wav_threshold.append(wav_diff)
inc += 56
threshold = float(gui.entry_threshold.get())
# writing into the file
data = []
inc1 = 0
col1 = 2
col2 = 6
data.insert(0, (str(splitstr[0])))
data.insert(1, (str(splitstr[1])))
for x in wav_threshold:
if (x > threshold):
gui.red_light.color('red')
gui.green_light.color('grey')
data.insert(col1, (str(splitstr[34 + inc1])))
data.insert(col2, (str(x)))
else:
gui.red_light.color('grey')
gui.green_light.color('green')
data.insert(col1, '-')
data.insert(col2, '-')
inc1 += 56
col1 += 1
col2 += 1
self.write_file(data)
# function to write into the file
def write_file(self, data):
with open("Output.txt", "a") as text_file:
text_file.write('\t'.join(data[0:]))
text_file.write('\n')
if __name__ == '__main__':
root = Tk()
gui1 = GUI(root)
rec_data = recv_data()
root.mainloop()
Error that I get:
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Users\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 1883, in __call__
return self.func(*args)
TypeError: getData() missing 1 required positional argument: 'self'
来源：https://stackoverflow.com/questions/62811594/forkingpicklerfile-protocol-dumpobj-typeerror-cannot-pickle-tkinter-tkap