[python] Is there an equivalent to CTRL+C in IPython Notebook in Firefox to break cells that are running?

I've started to use the IPython Notebook and am enjoying it. Sometimes, I write buggy code that takes massive memory requirements or has an infinite loop. I find the "interrupt kernel" option sluggish or unreliable, and sometimes I have to restart the kernel, losing everything in memory.

I also sometimes write scripts that cause OS X to run out of memory, and I have to do a hard reboot. I'm not 100% sure, but when I've written bugs like this before and ran Python in the terminal, I can usually CTRL+C my scripts.

I am using the Anaconda distribution of IPython notebook with Firefox on Mac OS X.

You can press I twice to interrupt the kernel.

This only works if you're in Command mode. If not already enabled, press Esc to enable it.

Here are shortcuts for the IPython Notebook.

Ctrl-m i interrupts the kernel. (that is, the sole letter i after Ctrl-m)

According to this answer, I twice works as well.

To add to the above: If interrupt is not working, you can restart the kernel.

Go to the kernel dropdown >> restart >> restart and clear output. This usually does the trick. If this still doesn't work, kill the kernel in the terminal (or task manager) and then restart.

Interrupt doesn't work well for all processes. I especially have this problem using the R kernel.

UPDATE: Turned my solution into a stand-alone python script.

This solution has saved me more than once. Hopefully others find it useful. This python script will find any jupyter kernel using more than cpu_threshold CPU and prompts the user to send a SIGINT to the kernel (KeyboardInterrupt). It will keep sending SIGINT until the kernel's cpu usage goes below cpu_threshold. If there are multiple misbehaving kernels it will prompt the user to interrupt each of them (ordered by highest CPU usage to lowest). A big thanks goes to gcbeltramini for writing code to find the name of a jupyter kernel using the jupyter api. This script was tested on MACOS with python3 and requires jupyter notebook, requests, json and psutil.

Put the script in your home directory and then usage looks like:

python ~/interrupt_bad_kernels.py
Interrupt kernel chews cpu.ipynb; PID: 57588; CPU: 2.3%? (y/n) y

Script code below:

from os import getpid, kill
from time import sleep
import re
import signal

from notebook.notebookapp import list_running_servers
from requests import get
from requests.compat import urljoin
import ipykernel
import json
import psutil


def get_active_kernels(cpu_threshold):
    """Get a list of active jupyter kernels."""
    active_kernels = []
    pids = psutil.pids()
    my_pid = getpid()

    for pid in pids:
        if pid == my_pid:
            continue
        try:
            p = psutil.Process(pid)
            cmd = p.cmdline()
            for arg in cmd:
                if arg.count('ipykernel'):
                    cpu = p.cpu_percent(interval=0.1)
                    if cpu > cpu_threshold:
                        active_kernels.append((cpu, pid, cmd))
        except psutil.AccessDenied:
            continue
    return active_kernels


def interrupt_bad_notebooks(cpu_threshold=0.2):
    """Interrupt active jupyter kernels. Prompts the user for each kernel."""

    active_kernels = sorted(get_active_kernels(cpu_threshold), reverse=True)

    servers = list_running_servers()
    for ss in servers:
        response = get(urljoin(ss['url'].replace('localhost', '127.0.0.1'), 'api/sessions'),
                       params={'token': ss.get('token', '')})
        for nn in json.loads(response.text):
            for kernel in active_kernels:
                for arg in kernel[-1]:
                    if arg.count(nn['kernel']['id']):
                        pid = kernel[1]
                        cpu = kernel[0]
                        interrupt = input(
                            'Interrupt kernel {}; PID: {}; CPU: {}%? (y/n) '.format(nn['notebook']['path'], pid, cpu))
                        if interrupt.lower() == 'y':
                            p = psutil.Process(pid)
                            while p.cpu_percent(interval=0.1) > cpu_threshold:
                                kill(pid, signal.SIGINT)
                                sleep(0.5)

if __name__ == '__main__':
    interrupt_bad_notebooks()