Circe Colab Demo.ipynb

circe-colab-demo.ipynb

{
  "nbformat": 4,
  "nbformat_minor": 0,
  "metadata": {
    "colab": {
      "name": "Circe Colab Demo.ipynb",
      "version": "0.3.2",
      "provenance": [],
      "collapsed_sections": [],
      "toc_visible": true,
      "include_colab_link": true
    },
    "kernelspec": {
      "display_name": "Scala",
      "language": "scala",
      "name": "scala"
    }
  },
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
        "colab_type": "text"
      },
      "source": [
        "<a href=\"https://colab.research.google.com/gist/shadaj/0af341e0d82b838f52f56423950365b4/circe-colab-demo.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "up2G8zDbhsEN",
        "colab_type": "text"
      },
      "source": [
        "# Running Circe in Colab\n",
        "\n",
        "In this notebook, we'll take a look at how to import libraries into a Scala notebook. Here, we'll load up [Circe](https://circe.github.io/circe/), a library for handling JSON data in Scala."
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "sL1Vq6r6J6dA",
        "colab_type": "text"
      },
      "source": [
        "## Install the Scala Kernel\n",
        "If you get a \"scala\" kernel not recognized warning when loading up the notebook for the first time, start by running the two cells below. Once you are done **reload the page** to load the notebook in the installed Scala kernel."
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "RoCcdvTCAqeR",
        "colab_type": "code",
        "colab": {}
      },
      "source": [
        "%%shell\n",
        "SCALA_VERSION=2.12.8 ALMOND_VERSION=0.3.0+16-548dc10f-SNAPSHOT\n",
        "curl -Lo coursier https://git.io/coursier-cli\n",
        "chmod +x coursier\n",
        "./coursier bootstrap \\\n",
        "    -r jitpack -r sonatype:snapshots \\\n",
        "    -i user -I user:sh.almond:scala-kernel-api_$SCALA_VERSION:$ALMOND_VERSION \\\n",
        "    sh.almond:scala-kernel_$SCALA_VERSION:$ALMOND_VERSION \\\n",
        "    --sources --default=true \\\n",
        "    -o almond-snapshot --embed-files=false\n",
        "rm coursier\n",
        "./almond-snapshot --install --global --force\n",
        "rm almond-snapshot"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "BZchIo9sArF4",
        "colab_type": "code",
        "colab": {}
      },
      "source": [
        "%%shell\n",
        "echo \"{\n",
        "  \\\"language\\\" : \\\"scala\\\",\n",
        "  \\\"display_name\\\" : \\\"Scala\\\",\n",
        "  \\\"argv\\\" : [\n",
        "    \\\"bash\\\",\n",
        "    \\\"-c\\\",\n",
        "    \\\"env LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libpython3.6m.so:\\$LD_PRELOAD java -jar /usr/local/share/jupyter/kernels/scala/launcher.jar --connection-file {connection_file}\\\"\n",
        "  ]\n",
        "}\" > /usr/local/share/jupyter/kernels/scala/kernel.json"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "sgPteJTmOkhU",
        "colab_type": "text"
      },
      "source": [
        "## Use Circe"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "p-0RXR7aFFDA",
        "colab_type": "text"
      },
      "source": [
        "First, we'll import Circe into the notebook."
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "a9z0PxRg_iOp",
        "colab_type": "code",
        "outputId": "9eed0f5d-2883-4c0d-e336-90e684b998c0",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 85
        }
      },
      "source": [
        "import $ivy.`io.circe::circe-core:0.10.0`, $ivy.`io.circe::circe-generic:0.10.0`, $ivy.`io.circe::circe-parser:0.10.0`\n",
        "\n",
        "import io.circe._, io.circe.generic.auto._, io.circe.parser._, io.circe.syntax._"
      ],
      "execution_count": 0,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "\u001b[32mimport \u001b[39m\u001b[36m$ivy.$                            , $ivy.$                               , $ivy.$                              \n",
              "\n",
              "\u001b[39m\n",
              "\u001b[32mimport \u001b[39m\u001b[36mio.circe._, io.circe.generic.auto._, io.circe.parser._, io.circe.syntax._\u001b[39m"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 1
        }
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "L8qlVXHYFHkq",
        "colab_type": "text"
      },
      "source": [
        "With Circe loaded, we can convert a Scala object to JSON!"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "XRUL2lxrFKi5",
        "colab_type": "code",
        "outputId": "c2cc2120-6351-4333-b785-1818bf575c8a",
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 102
        }
      },
      "source": [
        "case class Qux(i: Int, d: Option[Double])\n",
        "\n",
        "val json = Qux(13, Some(14.0)).asJson.spaces2"
      ],
      "execution_count": 0,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "defined \u001b[32mclass\u001b[39m \u001b[36mQux\u001b[39m\n",
              "\u001b[36mjson\u001b[39m: \u001b[32mString\u001b[39m = \u001b[32m\"\"\"{\n",
              "  \"i\" : 13,\n",
              "  \"d\" : 14.0\n",
              "}\"\"\"\u001b[39m"
            ]
          },
          "metadata": {
            "tags": []
          },
          "execution_count": 2
        }
      ]
    }
  ]
}

Thank you for your sharing, it is an awesome work!
However I encountered the following error and wonder if you can help to sort it out? Screenshot is below:
https://snipboard.io/ZCueN8.jpg

@mdvik did you run the installer cells first and then reload the page? The error you saw is usually what happens when the Scala kernel isn't detected.