development-container

The development container allows developers to sandbox repository dependencies from their host machine while allowing them to use familiar development tools.

TL;DR

Build a new development image

mkdir -p ~/.development-container/ccache
export UID=$(id -u) export GID=$(id -g); docker compose -f compose.dev.yml build

Start an interactive development container

docker compose -f compose.dev.yml run development

Build the repository in the container

username@development-container-dev:~/ws$ colcon build

Test

To test that your container is working with graphics

username@development-container-dev:~/ws$ colcon build
username@development-container-dev:~/ws$ source install/setup.bash
username@development-container-dev:~/ws$ ros2 launch platform_description display.launch.py

Dependencies

Repository dependencies are built into the development image. This insulates the developer from potentially conflicting dependencies on their host while preventing development from accidentally depending on host packages and configurations. This uniform development environment should also make it easier for developers to collaboratively troubleshoot issues.

Rebuilding image

As repository dependencies change, the development image will have to be rebuilt. While early on this can happen frequently, dependencies tend to change more slowly later in a project. Unless otherwise noted, it is a good habit to update your image weekly.

ccache

ccache allows previous builds to speed up future builds. As the container is not persistent, we need to map the cache to the host so it can be reused in subsequent instantiations of the container. On the host, create the cache directory

mkdir -p ~/.development-container/ccache

This will then be mapped to /home/username/.ccache in the container.

Volume mapping

While the container itself by default is not persistent, several host directories are mapped into the container including

• repository source code
• ssh keys
• git configuration
• host credentials
• X11 connection

This allows for a more seamless development environment for

• building source
• in container committing with your user
• graphical tool use

The full set of volume maps can be read in the compose file.

git

Commits can be done from directly within the container, with the same host user.

username@development-container-dev:~/ws/src$ git config --list
user.email=firstname.lastname@email.com
user.name=Firstname Lastname
core.editor=vim
core.repositoryformatversion=0
core.filemode=true
core.bare=false
core.logallrefupdates=true
remote.origin.url=git@github.com:username/development-container.git
remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
branch.main.remote=origin
branch.main.merge=refs/heads/main

Graphics

Running rviz from within the container should produce a graphical window on the host.

username@development-container-dev:~/ws/src$ rviz2

Editing

As the repository source is volume mapped into the container, it can be edited outside of the container and changes are immediately reflected inside the container. This means you can use your existing host tools (vim, atom, sublime, vs code) to develop, and build in the container.

Prerequisites

docker

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

Check version

If docker is already installed, the below steps may not be required

$ docker version
Client: Docker Engine - Community
 Version:           20.10.12
 API version:       1.41
 Go version:        go1.16.12
 Git commit:        e91ed57
 Built:             Mon Dec 13 11:45:33 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.12
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.12
  Git commit:       459d0df
  Built:            Mon Dec 13 11:43:42 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.13
  GitCommit:        9cc61520f4cd876b86e77edfeb88fbcd536d1f9d
 runc:
  Version:          1.0.3
  GitCommit:        v1.0.3-0-gf46b6ba
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

The development image was tested with version 20.10.12.

Download and install

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Note, the above script does not cover removing old versions.

Post actions

Adding yourself to the docker group and refreshing shell obviates the need to run sudo with docker.

sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker

docker compose v2

Taken from https://docs.docker.com/compose/cli-command/#install-on-linux

Download release

DOCKER_CONFIG=${DOCKER_CONFIG:-$HOME/.docker}
mkdir -p $DOCKER_CONFIG/cli-plugins
curl -SL https://github.com/docker/compose/releases/download/v2.2.3/docker-compose-linux-x86_64 -o $DOCKER_CONFIG/cli-plugins/docker-compose

Apply permissions

chmod +x $DOCKER_CONFIG/cli-plugins/docker-compose

Test

docker compose version

Alias

While developing a tool on top of another tool can come with challenges, some may prefer to at least have some simple aliases to reduce the typing boilerplate.

alias builddev="export UID=$(id -u) export GID=$(id -g); docker compose -f compose.dev.yml build"
alias rundev="docker compose -f compose.dev.yml run development"

As an aside, a handy way to find a previous command is

history | grep keyword

to rerun the command using the offset number given from history

!offsetnumber

Troubleshooting

ccache cannot compile

"/usr/lib/ccache/cc"

  is not able to compile a simple test program.

Likely, the host ccache directory in your home directory was not created properly. Ensure that the directory is created and owned by the host user.

mkdir -p ~/.development-container/ccache
sudo chown -R $(id -u):$(id -g) ~/.development-container/ccache