Running your own kernel

If you need to work with different language then Python, the Jupyter ecosystem provides you with a vast selection of other kernels. You can now run them in Deepnote! 
Deepnote uses the environment variable DEFAULT_KERNEL_NAME that you set in the Dockerfile and uses it to create new notebooks with that kernel.
The best way to run a custom kernel is to find an existing image, for example on Dockerhub, and then set the environment variable DEFAULT_KERNEL_NAME.
To override the default kernel, modify the metadata in the .ipynb file. 
An alternative way is to install the kernel into the default Deepnote image, see examples below.
R kernel
Pick your preferred version of R in the dropdown in the environment tab. 
Installing R packages
In the default R environments
You can simply use the install.packages and library commands the way you normally would. 
R packages often take a long time to install. We install them to your work folder by setting your environment variable R_LIBS_USER="~/work/.R/library", so they stay there during hardware restarts. 
In your custom environment
If you're comfortable using your own Docker image, the preferred way would be to install the packages at build time, or pick from the large selection on Dockerhub. 
Julia kernel
Use custom Dockerfile in the environment tab, and build an image with the following code:
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FROM deepnote/python:3.7
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RUN wget https://julialang-s3.julialang.org/bin/linux/x64/1.6/julia-1.6.2-linux-x86_64.tar.gz && \
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    tar -xvzf julia-1.6.2-linux-x86_64.tar.gz && \
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    mv julia-1.6.2 /usr/lib/ && \
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    ln -s /usr/lib/julia-1.6.2/bin/julia /usr/bin/julia && \
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    rm julia-1.6.2-linux-x86_64.tar.gz && \
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    julia  -e "using Pkg;pkg\"add IJulia\""
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ENV DEFAULT_KERNEL_NAME "julia-1.6"
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Bash kernel
Use custom Dockerfile in the environment tab, and build an image with the following code:
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FROM deepnote/python:3.7
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RUN pip install notebook
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RUN pip install bash_kernel && python -m bash_kernel.install
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ENV DEFAULT_KERNEL_NAME "bash"
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Scala 2.12.12 kernel (Almond 0.10.9)
Use custom Dockerfile in the environment tab, and build an image with the following code:
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FROM deepnote/python:3.7
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RUN wget -qO - https://adoptopenjdk.jfrog.io/adoptopenjdk/api/gpg/key/public | sudo apt-key add -
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RUN apt update
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RUN apt install -y software-properties-common
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RUN add-apt-repository --yes https://adoptopenjdk.jfrog.io/adoptopenjdk/deb/
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RUN apt update
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RUN mkdir /usr/share/man/man1
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RUN apt install -y adoptopenjdk-8-hotspot
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​
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RUN curl -Lo coursier https://git.io/coursier-cli
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RUN chmod +x coursier
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RUN ./coursier launch --fork almond:0.10.9 --scala 2.12.12 -- --install
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RUN rm -f coursier
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​
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ENV DEFAULT_KERNEL_NAME "scala"
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Or clone this project from Deepnote.
Racket kernel
Use custom Dockerfile in the environment tab, and build an image with the following code:
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FROM deepnote/python:3.7
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# The following snippet is licensed under MIT license
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# SEE: https://github.com/jackfirth/racket-docker
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​
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RUN apt-get update && \
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    apt-get install -y libzmq5
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​
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RUN pip install notebook
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​
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ENV RACKET_INSTALLER_URL=http://mirror.racket-lang.org/installers/7.8/racket-7.8-x86_64-linux-natipkg.sh 
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ENV RACKET_VERSION=7.8
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RUN wget --output-document=racket-install.sh -q ${RACKET_INSTALLER_URL} && \
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    echo "yes\n1\n" | sh racket-install.sh --create-dir --unix-style --dest /usr/ && \
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    rm racket-install.sh
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​
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ENV SSL_CERT_FILE="/etc/ssl/certs/ca-certificates.crt"
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ENV SSL_CERT_DIR="/etc/ssl/certs"
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​
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RUN raco setup
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RUN raco pkg config --set catalogs \
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    "https://download.racket-lang.org/releases/${RACKET_VERSION}/catalog/" \
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    "https://pkg-build.racket-lang.org/server/built/catalog/" \
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    "https://pkgs.racket-lang.org" \
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    "https://planet-compats.racket-lang.org"
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​
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RUN raco pkg install --auto iracket
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RUN raco iracket install
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​
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ENV DEFAULT_KERNEL_NAME "racket"
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Thanks, @dkvasnickajr for sharing this!
You can clone this project from Deepnote.
Ruby
Use custom Dockerfile in the environment tab, and build an image with the following code:
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FROM deepnote/python:3.7
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RUN apt-get update -qq && apt-get install -y libtool libffi-dev make libzmq3-dev libczmq-dev
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RUN apt-get install ruby-full -y
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RUN gem install ffi-rzmq
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RUN gem install iruby --pre
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ENV DEFAULT_KERNEL_NAME=ruby
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Then replace init.ipynb content with following:
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!iruby register --force
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After reseting the project state, you should be able to use Ruby in your notebooks.
Ruby On Rails
We have published a tutorial to help your run an existing Ruby on Rails project in Deepnote. One of the use cases is querying your data based on the existing ActiveRecord models, theirs scopes and relations.
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