Tukukkk

ive done two opc-ua servers one that reads the tag value from a textfile and another that reads the value from SQL. Now ive done a "server menu" in tkinter that can start the servers among other things.
The problem is that i cant turn one of them off and leave the other one running,
i want something like this:

import subprocess



def start_txt():

    txt = subprocess.Popen("python TAG_TXT.py &", shell=True)

    return txt



def stop_txt():

     subprocess.Popen('taskkill /F /PID {0}'.format(start_txt(txt)),

                                                         shell=True)



def start_SQL():

    SQL = subprocess.Popen("python TAG_SQL.py &", shell=True)

    return SQL



def stop_SQL():

    subprocess.Popen('taskkill /F /PID {0}'.format(start_SQL(txt)), 

                                                        shell=True)

if i use this:

os.system("taskkill /f /im python.exe")

i kill both servers

error msg:

Exception in Tkinter callback

 Traceback (most recent call last):

   File "C:UsersadminAppDataLocalProgramsPythonPython37- 

32libtkinter__init__.py", line 1702, in __call__

    return self.func(*args)

  File "C:PY_OPCUAservermeny_GUI.py", line 237, in kill_txt

    subprocess.Popen('taskkill /F /PID {0}'.format(textfile_server(txt)), 

                                                              shell=True)

NameError: name 'txt' is not defined

ive only used tkinter once before so it is probably very easy fix

You haven't defined txt.

In your stop functions you call:

subprocess.Popen('taskkill /F /PID {0}'.format(start_SQL(txt)), shell=True)

txt has not been defined before, I guess you forgot to add it as a function parameter