Moved to procedural style, using Events to sync

import krpc

import zmq

import argparse

from threading import Lock, Event

class ModelRocket:

    socket = None

    realRocket = None 

def main():

    parser = argparse.ArgumentParser(description='')

    parser.add_argument('addr', type=str, default="localhost:5556", nargs="?")

    args = parser.parse_args()

    host = "*"

    port = "5556"

    topic = "events"

    states = { -1:"abort", 0:"pre_launch",1:"liftoff", 2:"stage_1_separation", 3:"stage_2_separation"}

    stage_map = {0:0,1:1,2:2,3:3}

    states = {-1: "abort",

              0: "pre_launch",

              1: "liftoff",

              2: "stage_1_separation",

              3: "stage_2_separation"}

    stage_map = dict([(i,i) for i in range(10)])

    def send(self,stage):

        self.socket.send("%d %d" % (self.topic, self.stage_map[stage]))

    def __init__(self,addr="localhost:5556"):

    context = zmq.Context()

        self.socket = context.socket(zmq.PUB)

        self.socket.bind("tcp://%s" % addr)

    socket = context.socket(zmq.PUB)

    socket.bind(f"tcp://{host}:{port}")

    conn = krpc.connect()

    running = Event()

    stopping = Event()

    def unlock(scene):

        print(f"In GameScene {scene.name}")

        if (scene == conn.krpc.GameScene.flight):

            running.set()

            stopping.clear()

        else:

            running.clear()

            stopping.set()

if __name__ == "__main__":

    parser = argparse.ArgumentParser(description='')

    parser.add_argument('addr', type=str, default="localhost:5556", nargs="?")

    args = parser.parse_args()

    def stage_changed(new_stage):

        try:

            socket.send_string(f"{topic} {stage_map[new_stage]}")

            print(f"Sending event {topic} {new_stage}")

        except Exception as e:

            pass

    conn = krpc.connect()

    scene = conn.add_stream(getattr, conn.krpc, 'current_game_scene')

    scene.add_callback(unlock)

    scene.start()

    while True:

        running.wait()

        running.clear()

        vessel = conn.space_center.active_vessel

        control = vessel.control

    rocket = ModelRocket(args.addr)

    stage = conn.add_stream(getattr, control, 'current_stage')

    stage.add_callback(rocket.send)

        stage = conn.add_stream(getattr, control, 'current_stage', scene)

    def activate_callback(scene):

        if(scene == conn.krpc.GameScene.flight):

        stage.add_callback(stage_changed)

        stage.start()

        else:

            stage.wait()

    scene = conn.add_stream(getattr, conn.krpc, 'current_game_scene')

    scene.add_callback(activate_callback)

        stopping.wait()

        stopping.clear()

        print("Removing callback...")

        stage.remove_callback(stage_changed)

        stage.remove()

    while 42:

        pass

if __name__ == "__main__":

    main()