How can I capture 'Ctrl-D' in python interactive console?

Question

I have a server which runs in a thread in the background, and I start it using python -i so I can get an interactive console where I can type in commands and easily debug it. But when I hit Ctrl-D, since the server is still running in a background thread, the console will not quit. How can I capture the Ctrl-D event so that I can shut down the server and quit gracefully? I know how to capture Ctrl-C with signals, but due to my habbit of pressing Ctrl-D I usually get a 'stuck' terminal which is really annoying.

Thanks!

The server code (simplified) is like this:

import threading
import atexit

class WorkerThread(threading.Thread):
    def __init__(self):
        super(WorkerThread, self).__init__()
        self.quit = False

    def run(self):
        while not self.quit:
            pass

    def stop(self):
        self.quit = True

def q():
    print "Goodbye!"
    t.stop()

atexit.register(q)

t = WorkerThread()
t.start()

and I run it using python -i test.py to get a python console.

falsetru · Accepted Answer · 2013-07-15T10:23:13.260

17

Use raw_input (Use input in Python 3.x). Pressing Ctrl+D will cause EOFError exception.

try:
    raw_input()
except EOFError:
    pass

UPDATE

Use atexit - Exit handlers:

import atexit

def quit_gracefully():
    print 'Bye'

atexit.register(quit_gracefully)

edited Jul 15 '13 at 10:23

answered Jul 15 '13 at 09:24

falsetru

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The server does not read any input, but runs within a python console using python -i. The console is for I to type python expressions to debug the server. – Chi Zhang Jul 15 '13 at 10:17
2

@ChiZhang, Call `t.setDaemon(True)` before `t.start()`. – falsetru Jul 16 '13 at 01:24
Can I capture it using `Getch`(https://stackoverflow.com/a/510364/2402577)? @falsetru – alper Jun 16 '20 at 14:44
@alper, Please post a separate question instead of comment, so that others can answer you. – falsetru Jun 16 '20 at 15:18
1

I was able to handle it by comparing the captured char with `"\x04"` – alper Jun 16 '20 at 15:23
raw_input (and input in python3) both block. Meaning if you have an program that runs in a loop this will not work – Charles D Pantoga May 27 '23 at 02:19

score 3 · Answer 2 · edited Sep 01 '22 at 21:17

3

I have exactly the same problem like you and I've fixed it. I've found a good answer in a comment located here : http://www.regexprn.com/2010/05/killing-multithreaded-python-programs.html?showComment=1336485652446#c8921788477121158557

Here, the comment :

"You can always set your threads to "daemon" threads like:

t.daemon = True
t.start()

And whenever the main thread dies all threads will die with him"

edited Sep 01 '22 at 21:17

S.B

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answered Dec 15 '17 at 09:06

MlleParker

51
3

IMO this is the correct answer here, if there's a non-daemon thread running and you press `^D` then `atexit` will not save you. – MoxieBall Jun 04 '18 at 15:42

How can I capture 'Ctrl-D' in python interactive console?

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