Python - Can't run a timer in Tornado without blocking the clients from connecting to the server

Question

Not very experienced in Tornado so sorry if it sounds like a newbie question. I am building a card game with the clients using standard html/js code and tornado on the server. Everything is working fine however I need to implement a countdown on the server where after a certain amount of time a certain code runs. I am using the following python code and calling it from the tornado after a request has been made ``` import time class StartTimer(object): timerSeconds = 0 def __init__(self): print "start timer initiated" def initiateTime(self, countDownSeconds): self.timerSeconds = countDownSeconds while self.timerSeconds >= 0: time.sleep(1) print self.timerSeconds self.timerSeconds -=1 if self.timerSeconds == 0: #countdown finishes print "timer finished run the code" def getTimer(self): return self.timerSeconds ``` The countdown works fine however I have two issues firstly, while the timer is counting down the server blocks any other connection and puts them in the queue and runs the cod…

Accepted Answer

`time.sleep()` will block, use `add_timeout()` instead check here

Edit: sorry, it has been answered by @Armin Rigo

here is an example:

```
import time
import tornado.ioloop

def delayed_print(s):
    if len(s) == 0:
        ioloop.stop()
    else:
        print s[0]
        ioloop.add_timeout(time.time() + 1, lambda:delayed_print(s[1:]))

ioloop = tornado.ioloop.IOLoop()
delayed_print('hello world')
ioloop.start()
```

Python - Can't run a timer in Tornado without blocking the clients from connecting to the server

Solution

Problem