import time
import socketio

sio = socketio.Client()
start_timer = None


def send_ping():
    global start_timer
    start_timer = time.time()
    sio.emit('ping_from_client')


@sio.on('connect')
def on_connect():
    print('connected to server')
    send_ping()


@sio.on('pong_from_server')
def on_pong(data):
    global start_timer
    latency = time.time() - start_timer
    print('latency is {0:.2f} ms'.format(latency * 1000))
    sio.sleep(1)
    send_ping()


if __name__ == '__main__':
    sio.connect('http://localhost:5000')
    sio.wait()