CODEWITHSUNDEEP
pythonmultithreadingcherrypy
Bart Friederichs
Bart Friederichs

Reputation: 33521

CherryPy waits for extra thread to end that is stopped later

I am building a application that uses CherryPy to serve a REST API, and another thread that does background work (in fact, it reads data from a serial port). 

import cherrypy
import threading

class main:
    @cherrypy.expose
    def index(self):
        return "Hello World."

def run():
   while running == True:
       # read data from serial port and store in a variable

running = True
t = threading.Thread(target = run)
t.start()

if __name__ == '__main__':
    cherrypy.quickstart(main())

running = False

Both api.pc_main() and run work fine. The trouble is, I use a running boolean to stop my thread, but that piece of code is never reached, because CherryPy waits for that thread to finish when I push Ctrl-C. I actually have to use kill -9 to stop the process.

Upvotes: 1

Views: 749

Answers (1)

Bart Friederichs
Bart Friederichs

Reputation: 33521

I fixed it by making my thread a CherryPy plugin. I used the code found here: Why is CTRL-C not captured and signal_handler called?

from cherrypy.process.plugins import SimplePlugin

class myplugin(SimplePlugin):
    running = False
    thread = None

    def __init__(self, bus):
        SimplePlugin.__init__(self, bus)

    def start(self):
        print "Starting thread."
        self.running = True
        if not self.thread:
            self.thread = threading.Thread(target = self.run)
            self.thread.start()

    def stop(self):
        print "Stopping thread."
        self.running = False

        if self.thread:
            self.thread.join()
            self.thread = None


    def run(self):
        while self.running == True:
            print "Thread runs."
            time.sleep(1)

then in the main script:

if __name__ == '__main__':
    mythread(cherrypy.engine).subscribe()
    cherrypy.quickstart(main())

Upvotes: 2

Related Questions