Experiment

Habitat was an experiement which aimed to dockerise (with configuration persistance) my entire development environment. The aim was to be able to quickly setup my environment on any machine running docker, regardless of base operating system. The environments would then be able to be configured on a project, or organisation basis.

What I hit however was performance and X-11 rendering resolution issues. The required machine hardware to be productive simply didn't outweigh the maintenance of simple dotfiles.

Habitat

STATUS: In Development. Not yet ready for Production

A Dockerized (Ubuntu based) Developer Environment with assistive CLI Tooling

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Reasoning

As a developer, I'm frequently switching between Windows, Linux, and MacOS. In each environment, I may need to perform the same tasks, leverage the same automation, or just want a consistent experience. But it can become a PIMA when the environments are not configured to be identical, or when a tool doesn't operate in the same way (looking at you CLI flags).

Dotfile repositories really only solve half the problem. They fall short when you need to start applying OS specific tools and configuration. Docker might be a step in the right direction.

Docker takes away repetitive, mundane configuration tasks and is used throughout the development lifecycle for fast, easy and portable application development - desktop and cloud ~ https://www.docker.com/

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CLI

Habitat CLI is a tool (written in .NET) for building, running, and managing Dockerized Developer Environments.

Building for Release

dotnet publish -c release -r win-x64 --output ./target --self-contained=true /p:PublishSingleFile=true

Core Dependencies

• CommandDotNet
• Docker.DotNet

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Docker Base

Usage

Using Basic Docker markup, we can take a basic Dockerfile foundation and customize the Environments to suit our needs. We can either create a single all inclusive Environment for developing multiple projects and languages, or build a specific container per project or language.

The habitat CLI will

• At build - Provide build-args at Environment Build time to supply the Image definition with:
  • HABITAT_USER - The Environments intended user name
  • HABITAT_USER_PASSWORD - The Environments user password
• At start - Read the Image definition, looking for specific labels to control how the Container should be started
  • HABITAT_WITH_X11=true starts the Container with the environment variable DISPLAY="host.docker.internal:0" for X11 display binding.
  • HABITAT_WITH_DOCKER=true starts the Container with the hosts /var/run/docker.sock bound. Providing Container->Host Docker access.
  • HABITAT_NETWORKS=network1,network2 starts the Container and attaches it to the specified Networks. If the networks do not exists, they will be created as bridges.
  • HABITAT_VOLUMES=volume1,volume2 starts the Container with the specified named Volumes mounted to HABITAT_VOLUME_ROOT=<path>. Note: If the volumes do not exist, they will be created with the local driver for persistence.

Example Dockerfile

FROM ardourtech/habitat:2021-09-19
LABEL maintainer="Alexander Scott <[email protected]>"

# Build Arguments provided (and if necessary prompted for) by the Habitat CLI
ARG HABITAT_USER
ARG HABITAT_USER_PASSWORD

#Instructs the Habitat CLI to bind the Hosts Display for X11 on Container Start
LABEL HABITAT_WITH_X11=true

#Instructs the Habitat CLI to bind the Hosts Docker sock on Container Start
LABEL HABITAT_WITH_DOCKER=true

#Instructs the Habitat CLI to create the Networks and attach the Container to them
LABEL HABITAT_NETWORKS=habitat,dev

#Instructs the Habitat CLI to create Volumes and to attach them on Contianer Start
# - Volumes are unique by name
# - Volumes can be shared with multiple containers
LABEL HABITAT_VOLUME_ROOT="/volumes/"
LABEL HABITAT_VOLUMES=projects,maven-cache

# Add the User as a new Ubuntu User
USER root
RUN groupmod --new-name $HABITAT_USER docker
RUN usermod \
    --home /home/$HABITAT_USER \
    --move-home \
    --gid $HABITAT_USER \
    --login $HABITAT_USER \
    docker
RUN echo "${HABITAT_USER}:${HABITAT_USER_PASSWORD}" | chpasswd

# Create the volume mount points for Habitat. This can resolve some permission
# issues when using non-root users
RUN mkdir -p /volumes/projects /volumes/maven-cache
RUN chown -R ${HABITAT_USER}:${HABITAT_USER} /volumes \
    && chmod -R 775 /volumes \
    && chmod -R g+s /volumes

USER $HABITAT_USER
WORKDIR /home/$HABITAT_USER

# The default Entrypoint. Habitat will detect this and supply it when using the
# `connect` command
ENTRYPOINT ["fish"]

Building the Environment

With a Developer Environment Image defined we can use the habitat CLI to start the Docker Build process. It is during this time that the habitat CLI will prompt for the HABITAT_USER and HABITAT_PASSWORD values.

habitat[.exe] build \
  --user <environment-user-name> \
  --password <environment-user-password> \
  --directory <path-to-docker-build-context> \
  --file <habitat-docker-file> \
  --tag <docker-image-tag>

Starting the Environment

Finally with an Environment Built, we can start a Container and establish a connection.

habitat[.exe] start \
  --image <docker-image-tag> \
  --name <docker-container-name>

# Windows
iex "$(habitat.exe connect --name <env-name>)"

# MacOS/Unix
eval "$(habitat connect --name <env-name>)"