Terminate All QThreads on GUI Close - python-2.7

Question

I have a PyQT gui that has one gui thread, and 24 "tester threads." They work fine, but still seem to stay up when I close the gui. How can I gracefully close the threads to avoid python crashing?
#!/usr/bin/python
# Standard Lib
from datetime import datetime
import logging
import os
import random
import sys
import time
# Third Party
from PyQt4 import QtGui, QtCore
# Local Kung Fu
stuff
class SSITesterThread(QtCore.QThread):
# vars for updating gui using signals
updateText = QtCore.pyqtSignal(str)
updateColor = QtCore.pyqtSignal(str)
updateSN = QtCore.pyqtSignal(str)
def __init__(self, thread_number, port, path, parent=None):
super(SSITesterThread, self).__init__(parent)
self.delay = random.random()
def run(self):
self.ssitester()
def ssitester(self):
# stuff
class SSITestSuiteGUI(QtGui.QMainWindow):
def __init__(self, parent=None):
self._threads = []
QtGui.QWidget.__init__(self, parent)
# Init class from template and paths
self.launch_tester_threads()
def init_gui_nodes(self, com_ports_list):
for num, port, in zip(range(1, 25), range(0, 24)):
label = getattr(self.ui, 'com_{}'.format(num))
label.setText("COM Port: {}".format(com_ports_list[port]["COM"]))
def launch_tester_threads(self):
logging.info("Spinning up threads...")
for num, com_port_chunk in zip(range(1, 25), self.com_ports_list):
tester_thread = SSITesterThread(thread_number=num, port=com_port_chunk["COM"], path=self.vc_test_path)
# get a reference to the associated textbox somehow...
status_box = getattr(self.ui, 'status_{}'.format(num))
tester_thread.updateText.connect(status_box.setText)
status_box = getattr(self.ui, 'status_{}'.format(num))
tester_thread.updateColor.connect(status_box.setStyleSheet)
sn_label = getattr(self.ui, 'sn_{}'.format(num))
tester_thread.updateSN.connect(sn_label.setText)
sn_label.setText("S/N: None")
tester_thread.start()
self._threads.append(tester_thread)
logging.info("Ready for tests.")
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
test_suite = SSITestSuiteGUI()
test_suite.show()
# Close app only when window is closed.
sys.exit(app.exec_())
I tried implementing this solution: https://gist.githubusercontent.com/metalman/10721983/raw/15c6f115f9918fee7c1b88d0a549d4cc59a5b346/qapplication_about_to_quit_signal.py
But got an error:
attributeerror: 'function' object has no attribute '__pyqtSignature__'
Thanks for your time.
UPDATE:
Added the suggestion below as:
#QtCore.pyqtSlot()
def stop(self):
return
in my SSITesterThread Class, and it errors out when various "emits" I've used as singals in the thread sudden try to access NoneType objects:
File in gui.py, line 75 in tester,
self.updateColor.emit("{}".format(thread_colors.green_alert)
AttributeError: "NoneType" object has no attribute 'green alert'
Did the fix work, and this is a new problem? Because it seems like things still aren't shutting down gracefully.

Answer 1

It looks like you're importing your GUI from a form generated by QTDesigner. Try this:
self.ui.closeEvent = self.closeEvent
I believe your problem is that you're editing the wrong QMainWindow instance in the wrong place.

Answer 2

You probably just need to decorate the stop method as a slot.
#QtCore.pyqtSlot()
def stop(self):
# do thread cleanup, stop thread