{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Connecting to an existing IPython kernel using the Qt Console" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## The Frontend/Kernel Model" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "The traditional IPython (`ipython`) consists of a single process that combines a terminal based UI with the process that runs the users code.\n", "\n", "While this traditional application still exists, the modern IPython consists of two processes:\n", "\n", "* Kernel: this is the process that runs the users code.\n", "* Frontend: this is the process that provides the user interface where the user types code and sees results.\n", "\n", "IPython currently has 3 frontends:\n", "\n", "* Terminal Console (`ipython console`)\n", "* Qt Console (`ipython qtconsole`)\n", "* Notebook (`ipython notebook`)\n", "\n", "The Kernel and Frontend communicate over a ZeroMQ/JSON based messaging protocol, which allows multiple Frontends (even of different types) to communicate with a single Kernel. This opens the door for all sorts of interesting things, such as connecting a Console or Qt Console to a Notebook's Kernel. For example, you may want to connect a Qt console to your Notebook's Kernel and use it as a help\n", "browser, calling `??` on objects in the Qt console (whose pager is more flexible than the\n", "one in the notebook). \n", "\n", "This Notebook describes how you would connect another Frontend to a Kernel that is associated with a Notebook." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Manual connection" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "To connect another Frontend to a Kernel manually, you first need to find out the connection information for the Kernel using the `%connect_info` magic:" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "{\n", " \"stdin_port\": 52858, \n", " \"ip\": \"127.0.0.1\", \n", " \"hb_port\": 52859, \n", " \"key\": \"7efd45ca-d8a2-41b0-9cea-d9116d0fb883\", \n", " \"shell_port\": 52856, \n", " \"iopub_port\": 52857\n", "}\n", "\n", "Paste the above JSON into a file, and connect with:\n", " $> ipython --existing \n", "or, if you are local, you can connect with just:\n", " $> ipython --existing kernel-b3bac7c1-8b2c-4536-8082-8d1df24f99ac.json \n", "or even just:\n", " $> ipython --existing \n", "if this is the most recent IPython session you have started.\n" ] } ], "source": [ "%connect_info" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "You can see that this magic displays everything you need to connect to this Notebook's Kernel." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Automatic connection using a new Qt Console" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "You can also start a new Qt Console connected to your current Kernel by using the `%qtconsole` magic. This will detect the necessary connection\n", "information and start the Qt Console for you automatically." ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "collapsed": false }, "outputs": [], "source": [ "a = 10" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [], "source": [ "%qtconsole" ] } ], "metadata": {}, "nbformat": 4, "nbformat_minor": 0 }