Spacemacs in a Docker Container Ep 1 – Install, Build and Run

This blog is the first episode of a multi part series detailing the Harmonic Software Systems setup that allows our engineers to quickly and easily spin up a development environment that utilises the power of Spacemacs, configured to use additional tools to provide top quality software development and testing to our customers.

Docker and spacemacs, two of the most powerful and desirable tools in the ever evolving world of technology. Docker, which is an open-source software platform that makes it easier to create, operate, manage, test, and distribute applications. Spacemacs, which if you didn’t know by now, is one of the best editors in the market. It combines the best features of Vim and Emacs into a fantastic editor.

This blog is divided into several sections, each of which explains the features of Docker and how we used Docker to build a spacemacs editor within a Docker container.

2 Prerequisites

One of the great advantages of Docker is how easy it is to set up and use. So users can follow the instructions on windows, Linux and Mac easily using the command line.

These instructions assume that you are using:

• A Linux Machine (Ubuntu 22.04 Virtual Machine in our case)
• Git installed

Docker is defined as “an open-source project that automates the deployment of software applications inside containers by providing an additional layer of abstraction and automation of OS-level virtualization on Linux.” Docker essentially runs the host computer’s operating system as a virtual machine to run applications within a container, rather than the traditional virtualisation of hardware elements.

The process table, network interface, and file system directories mounted, would all be virtual copies. These are carried over from the host’s operating system, where the container is hosted and executed. But, all running containers on the host share the operating system’s kernel. As a result, each container that is present on the same host can be separated from the others. As long as they all have the same operating system needs, it allows numerous containers with various application requirements and dependencies to operate on the same host.

4 Advantages of using Docker

Some of the key benefits of Docker are listed below:

Robust – An operating system is not present on a container. Therefore, compared to a virtual machine, it uses extremely less memory. As opposed to the few minutes needed to start up a virtual computer, this cuts down the bootup time to only a few seconds for helping in faster deployment.

Reduced Cost – In terms of the hardware needed to execute multiple applications, Docker is less hardware demanding compared to a Virtual Machine.

Optimized Storage – Since containers are often only a few megabytes in size and take up relatively little disc space, a large number of programmes may be hosted on the same host.

Scalability – As long as all of the application have the same operating system needs, Docker permits hosting many applications and containers with various application requirements and dependencies on the same host.

Standardisation – One of the big reasons we found for using Docker was to standardise the environment and minimise the inconsistencies when running or setting up on different hosts. This is a big help to ensure all the colleagues working on the same project would have the same standard work environment.

Security – Applications and resources are separated and isolated of each container. You may easily remove an application’s container if you no longer require it and it won’t leave any temporary or configuration files. Each application can only use the resources that have been allocated to them and no Docker container has access to another container’s running processes.

5 Spacemacs

Vim or emacs. A ‘heated’ debate that most of the software community have either heard of or partaken. Spacemacs is the solution. With spacemacs, you get the best of both worlds. As our MD would say, “the business runs on spacemacs”.

Spacemacs could be set up to have as many features and be as powerful as an IDE or a simple text editor or anything in between. One of the biggest pluses is the customisation a user is able to do via the. spacemacs file to add any features that they desire. There is a big online community of experts releasing new tools and addons you can incorporate.

Two things that are guaranteed once you take on spacemacs are, a boost in productivity and unlimited fun

6 Installing Docker

Use the following link to install Docker engine on different platforms.

https://docs.docker.com/engine/install/

Use the link below for the instructions on installing the Docker engine on ubuntu. The command line instructions we used, and our notes are also listed below.

https://docs.docker.com/engine/install/ubuntu/

// Install
sudo apt-get update
sudo apt-get install ca-certificates curl gnupg lsb-release
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo   "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \ $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
// Installing the latest Docker 
sudo apt-get update
sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin
// Listing the Docker version 
apt-cache madison docker-ce
// Installing specific Docker version
sudo apt-get install docker-ce=5:20.10.20~3-0~ubuntu-focal
// Running Docker 
sudo service docker start
sudo docker run hello-world
// Add the user. Ensure the host machine is restarted post adding the user.
sudo groupadd docker
sudo usermod -aG docker $USER
// Run 
docker run hello-world

These sections will go into details on how to create a Docker file that will be used to build and run a spacemacs Docker image in ubuntu.

Use the following command to pull the latest Dockerfile entry from our git repository.

git clone https://github.com/harmonicss/docker-spacemacs.git

################################################################################
#
# Spacemacs Docker Container
# ==========================
#
# Ed Liversidge, Harmonic Software Systems Ltd harmonicss.co.uk
#
# Installs a spacemacs docker continer with the following features:
#
# - fixed spacemacs version as of Nov 12 2022
# - .spacemacs config file used at HSS
# - git
# - gnu global for tagging
# - clangd, gcc and cppcheck for live syntax checking usng lsp-mode 
# - source code pro font
#
#
#  build using : (dont forget the .)
#  ===========
#
#  docker build -t harmonicss/spacemacs --build-arg XAUTHORITY=$XAUTHORITY --build-arg USERNAME=$USER .
#
#  Run using :
#  ===========
#
#  docker run  -it --rm  -e DISPLAY --net=host -v ~/Projects:/home/$USER/Projects harmonicss/spacemacs
#
#
################################################################################

################################################################################
# Change this to use fast emacs-native-comp, needs to be
# built from docker beforehand. Not on dockerhub yet, but on
# github here : https://github.com/harmonicss/docker-emacs-native
################################################################################
FROM ubuntu:latest
################################################################################
# Install emacs and git
################################################################################
RUN apt update && \
    apt install -y software-properties-common
RUN add-apt-repository ppa:kelleyk/emacs
RUN apt update
RUN apt install -y git
RUN apt install -y emacs28
RUN apt install -y global

################################################################################
# Install lsp clangd-13 (C language LSP server for code completion)
# and gcc for syntax checking
################################################################################
RUN apt install -y gcc
RUN apt update
RUN apt install -y pip
RUN apt install -y clangd-13
RUN apt install -y cppcheck
RUN pip install python-lsp-server

################################################################################
# To Remove emacs loading warnings
################################################################################
RUN apt install -y libcanberra-gtk-module libcanberra-gtk3-module 

################################################################################
# XAUTHORITY and USERNAME is passsed in via cmd line
# eg docker build -t spacemacs --build-arg XAUTHORITY=$XAUTHORITY \
#    --build-arg USERNAME=$USERNAME .
################################################################################
ARG XAUTHORITY
ARG USERNAME

################################################################################
# Add a new user with the USERID of XAUTHORITY thats parsed
# from the string passed in and also give it group privileges
################################################################################
RUN useradd -d /home/"$USERNAME" -u $(echo $XAUTHORITY | awk -F/ '{print $4}') -ms /bin/bash "$USERNAME" && usermod -aG "$USERNAME" "$USERNAME"

################################################################################
# Configure file system properties 
################################################################################
USER root
RUN mkdir /home/$USERNAME || echo "Skip over build error"
RUN chown -R $USERNAME /home/$USERNAME

################################################################################
# Install source code pro font
# https://askubuntu.com/questions/193072/how-to-use-the-adobe-source-code-pro-font
################################################################################
RUN apt update
RUN apt install -y wget
RUN wget --content-disposition -P /usr/share/fonts/opentype/source-code-pro https://github.com/adobe-fonts/source-code-pro/blob/29fdb884c6e9dc2a312f4a5e2bb3b2dad2350777/OTF/SourceCodePro-Regular.otf?raw=true

################################################################################
# Setup the environment
################################################################################
USER $USERNAME
WORKDIR /home/$USERNAME
ENV UNAME $USERNAME 
ENV GNAME $USERNAME

################################################################################
# Mounting the XAUTHORITY file allow the x11 graphics to work
################################################################################
VOLUME $XAUTHORITY 

################################################################################
# Configure .bashrc properties
################################################################################
RUN echo 'alias ll="ls -hal --color"' >> ~/.bashrc

################################################################################
# Set the prompt for the bash shell
################################################################################
RUN echo 'export PS1="\[\033[01;31m\]\u@docker\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ "' >> /home/$USERNAME/.bashrc

################################################################################
# get .spacemacs
################################################################################
RUN git clone https://github.com/syl20bnr/spacemacs ~/.emacs.d
################################################################################
# lock spacemacs at latest as of Nov 13 2022
################################################################################
RUN cd .emacs.d && git checkout 57a7a0e63c4aecf810b19ca3fd49e5ae1a838126
RUN cd ~
RUN git init
RUN git remote add origin https://github.com/harmonicss/spacemacs.git
RUN git pull origin master
RUN cp .spacemacs.linux .spacemacs
RUN mkdir ~/.emacs.d/backup
RUN mkdir ~/.emacs.d/undo
################################################################################
# Install all the .spacemacs packages, twice as there as always stragglers to update
################################################################################
RUN emacs -nw -batch -u "$USERNAME" -q -kill
RUN emacs -nw -batch -u "$USERNAME" -q -kill

################################################################################
# Configure git
################################################################################
RUN git config --global user.name $USERNAME \
    && git config --global user.email $USERNAME@harmonicss.co.uk
ENTRYPOINT ["emacs"]

For more information on docker, refer to:

https://docs.docker.com/get-started/overview/

https://docs.docker.com/engine/reference/builder/

https://develop.spacemacs.org/doc/BEGINNERS_TUTORIAL.html

https://simpletutorials.com/c/spacemacs