multiprocessing_widgets.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# User friendly multiprocessing in Jupyter with ipywidgets"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### by Micah ([@micahscopes](http://wondering.xyz))\n",
    "11/15/2017"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### A stoppable `multiprocessing.Process` subclass that displays its status:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "run_control": {
     "frozen": false,
     "read_only": false
    }
   },
   "outputs": [],
   "source": [
    "from multiprocessing import Process, Event\n",
    "from ipywidgets import Output\n",
    "from IPython.display import display\n",
    "from time import sleep\n",
    "\n",
    "class ProcessWithStatus(Process):\n",
    "    def __init__(self):\n",
    "        self.output = Output()\n",
    "        self.exit = Event()\n",
    "        self.exited = Event()\n",
    "        super().__init__()\n",
    "        \n",
    "        with self.output:\n",
    "            print(self)\n",
    "        \n",
    "    def status(self):\n",
    "        display(self.output)\n",
    "    \n",
    "    def start(self):            \n",
    "        super().start()\n",
    "        with self.output:\n",
    "            print(self)\n",
    "            print('running...')\n",
    "    \n",
    "    def stop(self):\n",
    "#         with self.output:\n",
    "        with self.output:\n",
    "            print('letting work finish before stopping...')\n",
    "        self.exit.set()\n",
    "        \n",
    "        self.exited.wait()\n",
    "        sleep(0.1) # Need to wait a little bit before the status is `stopped`\n",
    "        with self.output:\n",
    "            print(self)\n",
    "    \n",
    "    def work(self):\n",
    "        sleep(5)\n",
    "        pass\n",
    "    \n",
    "    def run(self):\n",
    "        while not self.exit.is_set():\n",
    "            # do the work\n",
    "            self.work()\n",
    "        \n",
    "        # when the work is done, signal that we are finished\n",
    "        self.exited.set()\n",
    "\n",
    "p = ProcessWithStatus()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "7849905d904142a79b2a73c7731bfd86"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "p.status()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "p.start()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "p.stop()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "7849905d904142a79b2a73c7731bfd86"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "p.status()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### Adding start and stop buttons:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "from ipywidgets import Button\n",
    "\n",
    "class ProcessWithControls(ProcessWithStatus):\n",
    "    def __init__(self):\n",
    "        self.start_button = Button(description='start')\n",
    "        self.start_button.on_click(lambda evt: self.start())\n",
    "        self.stop_button = Button(description='stop')\n",
    "        self.stop_button.on_click(lambda evt: self.stop())\n",
    "        \n",
    "        super().__init__()\n",
    "        \n",
    "    def controls(self):\n",
    "        display(self.start_button)\n",
    "        display(self.stop_button)\n",
    "        \n",
    "    def control_panel(self):\n",
    "        self.controls()\n",
    "        self.status()\n",
    "    \n",
    "        \n",
    "    "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "89711ccf151b4903b4c686b802e743e2"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "p = ProcessWithControls()\n",
    "p.status()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "58330af2e099454090fedc2013f0ef55"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "abe76bba34364dd5be13aab7fdb01207"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "p.controls()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "58330af2e099454090fedc2013f0ef55"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "abe76bba34364dd5be13aab7fdb01207"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "89711ccf151b4903b4c686b802e743e2"
      }
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "p.control_panel()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### P.S. there's no reason you couldn't do something like this with multiple threads!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
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   "codemirror_mode": {
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  "latex_envs": {
   "LaTeX_envs_menu_present": true,
   "autocomplete": true,
   "bibliofile": "biblio.bib",
   "cite_by": "apalike",
   "current_citInitial": 1,
   "eqLabelWithNumbers": true,
   "eqNumInitial": 1,
   "hotkeys": {
    "equation": "Ctrl-E",
    "itemize": "Ctrl-I"
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   "labels_anchors": false,
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}

Sadly, it seem this no longer works, at least on windows (py 3.8.1/win64).
p.start() returns error: PicklingError: Can't pickle : it's not the same object as builtins.input

Hey there, Thanks for letting me know. Hopefully I can get to it some time, but no guarantees, as I have a full time job I don't always have leftover energy to keep up with all the open source stuff I'd like to work on. Feel free to submit a PR if you happen to figure out a solution! Micah

…

It still works perfectly (ubuntu 20.0, python 3.8.7). Thank you!