build-wsl

#!/bin/sh

name="${1:-devenv}"
LOCAL_MODS="tmp_image_mod.sh"
CONTAINER_MODS="/tmp/setup.sh"
LOCAL_INIT="tmp_inital_setup.sh"
CONTAINER_INIT="/usr/local/bin/initial-setup"
PROFILE_FILE="/etc/profile.local"
repo="$(realpath $(dirname "$0"))"
containerfile="${repo}/Containerfile"


# =====================================================================================
# Get container image to use.
# =====================================================================================
# Use the last created devenv image.
image=$(podman images --format '{{.Repository}}:{{.Tag}}' $name | head -n 1)
if [ -z "$image" ]
then
	echo "Error: no image for ${name}"
	exit 1
fi
echo "Using image: $image"


# =====================================================================================
# Create pre-export setup script.
# =====================================================================================
cat > $LOCAL_MODS <<'EOF'
#!/bin/sh

ensure_line_in_file () {
	grep -qF "$1" "$2" || ( echo "$1" >> "$2" && return 10 )
}

# Install WSL compatability packages.
wsl_conf=/etc/wsl.conf
zypper install --no-recommends --no-confirm \
	aaa_base-wsl \
	patterns-wsl-base \
	patterns-wsl-systemd \
	patterns-wsl-gui
rm $wsl_conf  # The wsl patterns make it a symlink.
cat > $wsl_conf <<EOF_L
[boot]
systemd=true

EOF_L
# Install password-store (pass), required by rancher/docker desktop.
# Devcontainer builds fail to pull images without this.
zypper install --no-recommends --no-confirm password-store

# Set up environment variables.
touch /etc/profile.local
EOF

# Extract environment variables from Containerfile
# Separate on lines beginning with ENV on white space but not if inside quotes.
# Output string {2nd column}={3rd column} e.g. ENV EDITOR nvim > EDITOR=nvim
# Substitute " for \" in variable value (escape the " char)
ENVS=$(\
	awk 'BEGIN {FPAT = "([^ ]+)|(\"[^\"]+\")"} /^ENV/{ gsub(/"/, "\\\"", $3); gsub(/\$/, "\\$", $3); print $2"="$3; }' $containerfile
)

# Output commands to ensure environment variables defined in /etc/profile.local
while IFS= read -r line
do
	setvarline="export $line"
	echo ensure_line_in_file \"$setvarline\" /etc/profile.local >> $LOCAL_MODS
done <<< "$ENVS"

echo ensure_line_in_file \"export BROWSER=/mnt/c/Windows/explorer.exe\" /etc/profile.local >> $LOCAL_MODS

# Give password-less sudo. This is only acceptable as it is a private
# development environment not exposed to the outside world.
# Do NOT do this on your host machine or otherwise.
printf "\n%s\n" '# Set sudo to not require a password.' >> $LOCAL_MODS
printf "%s\n" 'echo "%wheel ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers' >> $LOCAL_MODS

chmod +x $LOCAL_MODS


# =====================================================================================
# Create script to create user when running in WSL.
# =====================================================================================
cat > $LOCAL_INIT <<'EOF'
#!/bin/sh

# Create user account.
read -p "Enter username: " user
useradd \
	--create-home \
	--groups wheel,docker \
	--shell /bin/zsh \
	$user

# Make user default.
echo [user] >> /etc/wsl.conf
echo default=$user >> /etc/wsl.conf

# Enable services.
systemctl enable docker

# Upgrade OS.
printf "\n\nUpgrading OS..."
zypper dist-upgrade

EOF

chmod +x $LOCAL_INIT


# =====================================================================================
# Create container and export to tar file.
# =====================================================================================
container=$(podman run -i --detach --entrypoint=sh $image)
# echo $container
podman cp $LOCAL_MODS $container:$CONTAINER_MODS
podman cp $LOCAL_INIT $container:$CONTAINER_INIT
echo "Running setup inside container: ${container:0:8} ($image)"
podman exec $container sh $CONTAINER_MODS
output="$(echo "${image##*/}" | tr ':.' '-_').tar"
echo "Exporting container to $output"
podman export $container > $output
echo "Stopping container: ${container:0:8}"
podman stop $container > /dev/null
echo "Removing container: ${container:0:8}"
podman rm $container > /dev/null


# =====================================================================================
# Clean up and exit.
# =====================================================================================
rm $LOCAL_MODS
rm $LOCAL_INIT
echo Done