Install docker on macOS with brew

install_docker_darwin.sh

#!/usr/bin/env bash

#------------------------------------------------------------------------------

YEL='\033[1;33m'
CYN='\033[0;36m'
GRN='\033[1;32m'
RED='\033[1;31m'
NRM='\033[0m'

function log {
  echo -e "${CYN}[${FUNCNAME[1]}]${NRM} $*"
}

function install_darwin_deps {
    log "Checking for external dependency: brew"
    if [[ -z "$(which brew)" && -n "$(which ruby)" ]]; then
      log "'brew' installer not found, attempting to install..."
      ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
      log "'brew' installation completed."
    fi
    if [[ "$FORCE" == true ]]; then
      log "Updating 'brew'..."
      brew update
    fi

    #-- Spring Tools Suite:
    log "Installing/updating external dependency: Docker"
    if [[ -n "$FORCE" ]]
    then
        brew cask reinstall docker
    else
        brew cask install docker
    fi

}

function print_help(){
    echo "Use --force to reinstall required dependencies."
}

while [[ "$#" > 0 ]]; do case $1 in
  --force)          export FORCE=true;             shift;;
  -h | --help)      print_help; exit 0;;
  *) echo "Unknown parameter: $1"; exit 1;;
esac; shift; done

install_darwin_deps