install_docker.sh

#!/bin/bash
################################################################################
# Copyright © 2022 JonnyS
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
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# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in all
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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################################################################################
# Almost unnecessary copyright notice which is required for public repo.
# This is a convenient script to install Docker Engine silently.

if [[ $EUID -eq 0 ]]; then
   echo "This script must NOT be run as root!"
   exit 1
fi

# Add GPG Key
# https://docs.docker.com/engine/install/ubuntu/#install-using-the-repository
sudo mkdir -p /etc/apt/trusted.gpg.d/

if [[ -z "`apt-key list | grep -i docker`" ]]; then
    if ! command -v curl &> /dev/null; then
        sudo apt install -y curl
    fi
    curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/docker.gpg
fi

# Add Docker repo
source /etc/os-release
sudo add-apt-repository "deb https://download.docker.com/linux/ubuntu ${UBUNTU_CODENAME} stable"

# @todo use new alternative method to add-apt-repository instead of apt-key which is deprecated
# echo "deb [signed-by=/etc/apt/trusted.gpg.d/docker.gpg] https://download.docker.com/linux/ubuntu ${UBUNTU_CODENAME} stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

# Install Docker Engine
sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin

# Add docker subgroup to simplify use without sudo
# https://docs.docker.com/engine/install/linux-postinstall/
sudo groupadd docker 2>/dev/null
sudo usermod -aG docker `whoami`
# commented out because this command is not useful in a script
# newgrp docker

# Reclaim ownership of docker subdirectory if ran erroneously in an earlier installation
if [[ -d ~/.docker ]]; then
    sudo chown -R `whoami`:`whoami` ~/.docker
    sudo chmod -R g+rwx ~/.docker
fi

# Run something docker-related to initialize its socket and ignore output (most likely RW error anyway)
docker images

# Allow RW for docker socket
if [[ -e /var/run/docker.sock ]]; then
    sudo chmod a+rw /var/run/docker.sock
fi