Script to setup vagga on Debian based systems

setup_vagga.sh

#! /bin/sh

red_color="\033[1;31m"
green_color="\033[1;32m"
no_color="\033[0m"

throw_error() {
  if [ ! -z "$1" ]; then
    printf "${red_color}$1${no_color}\n"
  fi

  printf "\n${red_color}Vagga installation failed!${no_color}\n"
  exit 1
}

## Commodity function to ensure that an error is thrown if a command fails to execute
## Usage: run (command) [error message if it fails]
run() {
  eval "$1" || throw_error "$2"
}

ensure_tool_is_avaiable() {
  if [ -z "$(which $1)" ]; then
    echo "Installing $1:"
    run \
    "sudo apt-get install $1 -y" \
    "\
    Failed to install $1: check that you have an internet connection or\n\
    that you have the rights to run 'sudo apt-get install $1'"
  fi
}

ensure_tools_are_available() {
  for tool in "$@"; do
    ensure_tool_is_avaiable "$1"
  done
}

## Installation steps @ref: http://vagga.readthedocs.org/en/latest/installation.html
install_uidmap() {
  echo "Copying uidmap(vagga dependency) neccessary to run containers without root rights"

  ## Copying and installing uidmap
  local uidmap_filename="uidmap_4.1.5.1-1ubuntu9_amd64.deb"
  rm -f "$uidmap_filename"

  run \
  "wget -c \"http://gr.archive.ubuntu.com/ubuntu/pool/main/s/shadow/$uidmap_filename\"" \
  "\
  Failed to download uidmap:\n\
  check that (1)you have internet connection, (2)the link is valid"

  run \
  "sudo dpkg -i \"$uidmap_filename\"" \
  "Failed to install uidmap"
  rm -f "$uidmap_filename"

  ## Registering current user
  local output="$(id -un):100000:65536"
  echo "$output" | sudo tee /etc/subuid /etc/subgid

  assert_content() {
    if [ -z "$(cat $1 | grep "$output")" ]; then
      throw_error "Failed to setup uidmap(vagga dependency): $1 does not contain the expected data"
    fi
  }

  assert_content "/etc/subuid"
  assert_content "/etc/subgid"

  printf "${green_color}Finished installing uidmap(vagga dependency)${no_color}\n"
}

install_vagga() {
  echo "Installing vagga:"

  ## Downloading the latest stable version of vagga
  run \
  "vagga_archive_name=\"$(basename $(curl -s http://files.zerogw.com/vagga/latest.html | cut -d '"' -f 2))\"" \
  "\
  Failed to find out the latest version of vagga:\n\
  check that you have internet connection or that the link is correct"

  run \
  "wget \"http://files.zerogw.com/vagga/$vagga_archive_name\"" \
  "Failed to download vagga: check if you have internet connection or that the link is correct"


  ## Setting up vagga settings file
  ## Settings file path @ref: http://vagga.readthedocs.org/en/latest/settings.html#global-settings
  mkdir -p $HOME/.vagga/.cache

  ## Chaging the default location of the .vagga folder, from project path -> to home path
  echo "storage-dir: $HOME/.vagga"       > $HOME/.vagga/settings.yaml
  echo "cache-dir: $HOME/.vagga/.cache" >> $HOME/.vagga/settings.yaml

  if [ ! -f "$HOME/.vagga/settings.yaml" ]; then
    throw_error "Failed to create vagga's settings file"
  fi


  ## Installing vagga
  run "tar xf \"$vagga_archive_name\""
  rm -f "$vagga_archive_name"

  run "cd vagga"
  run "sudo ./install.sh"
  cd ..
  rm -rf vagga

  if [ ! -z "$(which vagga)" ]; then
    printf "\n${green_color}Finished installing vagga${no_color}\n"
  else
    throw_error
  fi
}

main() {
  ## Ensuring wget, curl and tar are available
  ## wget   - to copy uidmap and vagga
  ## curl   - to extract the latest stable vagga
  ## tar    - to extract vagga archive
  ensure_tools_are_available wget curl tar

  ## Installing uidmap - a vagga dependency needed to run containers without root rights
  install_uidmap

  ## Installing vagga
  install_vagga
}

## Start of the script
main