image-update

#!/bin/bash
#
# Download the latest CentOS, Debian, Fedora or Ubuntu cloud image
# Source: https://github.com/trfore/proxmox-template-scripts
#
# Copyright 2022 Taylor Fore
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

set -e

APPEND_DATE=false
BACKUP_IMAGES=false
REMOVE_OLD_IMAGE=false
STORAGE_PATH='/var/lib/vz/template/iso'

function err() {
  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')] ${0##*/} Error: $*" >&2
  exit 2
}

function help() {
  echo "
  Usage: ${0##*/} -d <DISTRO_NAME> -r <RELEASE_NAME> [ARGS]
  Examples:
    ${0##*/} -d ubuntu -r 20
    ${0##*/} -d ubuntu -r 20 --remove
    ${0##*/} -d ubuntu -r 20 --storage /tmp
    ${0##*/} -d debian -r 11 --remove

  Arguments:
    --help,    -h  Display this help message and exit
    --backup,  -b  Backup the existing image before creating a new one (default: false)
                    This flag is not compatiable with --remove flag.
    --date         Append the date to the image name, e.g. 'ubuntu*-\$DATE.img' (default: false)
    --distro,  -d  Specify the distribution name, e.g. 'ubuntu'.
    --remove       Remove old images before updating (default: false)
                    This flag is not compatiable with --backup flag.
    --release, -r  Specify the release version, e.g. 'focal' or '20'
    --storage, -s  Specify a storage path for the image (default: '/var/lib/vz/template/iso')


  Alternative Usage: ${0##*/} <DISTRO_NAME>-<RELEASE_NAME> [ARGS]
  Examples:
    ${0##*/} ubuntu-20
    ${0##*/} debian-11 --remove
  "
  exit 1
}

function usage() {
  printf "Usage: %s -d <DISTRO_NAME> -r <RELEASE_NAME> [ARGS] \n" "${0##*/}" >&2
  exit 1
}

#######################################
# Backup image files.
# Arguments:
#   $1 - file, string.
# Outputs:
#   Writes files to the current directory.
#######################################
function backup_images() {
  shopt -s extglob

  # avoid overwriting existing backups
  files="${1%.*}!(*.backup.*)"
  for file in $files; do
    echo "Backing up ${file}"
    cp -nv "$file" "${file%.*}.backup.${file##*.}"
  done

  shopt -u extglob
}

#######################################
# Compare the SHASUM of a local cloud image to remote image.
# Globals:
#   file_basename
#   file_name
#   remote_shasum_url
#   shasum_algorithm
# Returns:
#   0 if SHASUM matches.
#   1 if SHASUM does not match.
#######################################
function check_shasum() {
  local current_shasum latest_shasum

  tmpfile=$(mktemp /tmp/pve-image-shasum.XXXXXX)

  # get latest shasums
  curl -sL "${remote_shasum_url}" -o "${tmpfile}"
  latest_shasum=$(grep "${file_name}" "${tmpfile}" | grep -oE '[a-z0-9]{64,128}' -)

  # qcow2 images are expected to be converted into a raw format (*.img) on PVE
  current_shasum=$(shasum -a "${shasum_algorithm}" "${file_basename}".img | awk '{print $1}')

  echo "Current SHASUM: ${current_shasum}"
  echo "Latest  SHASUM: ${latest_shasum}"

  rm "$tmpfile"

  if [[ $latest_shasum == "${current_shasum}" ]]; then
    echo "SHASUM match, image is up-to-date."
    return 0
  else
    echo "No SHASUM match, image is outdated."
    return 1
  fi
}

#######################################
# Get Cloud Image Release Date
# Arguments:
#   $1 - url of the cloud image, string.
#   $2 - file name of the cloud image, string.
# Outputs:
#   file_date, string.
#######################################
function get_image_date() {
  local url file_date

  url=$(dirname "${1}")
  # get dates in YYYY-MM-DD or YYYY-MMM-DD format
  file_date=$(curl -sL "${url}" | grep "${2}" | grep -oiEm 1 '[0-9]{4}-([0-9]{2}-[0-9]{2}|[a-z]{3}-[0-9]{2})')

  echo "${file_date}"
}

#######################################
# Set Cloud Image Values
# Globals:
#   DISTRO_NAME
#   RELEASE_NAME
# Returns:
#   file_name, string.
#   remote_url, string.
#   remote_shasum_url, string.
#   shasum_algorithm, string.
#######################################
function set_image_values() {
  if [[ "${DISTRO_NAME}" == "debian" ]]; then
    case $RELEASE_NAME in
    buster | 10)
      file_name="debian-10-generic-amd64.qcow2"
      remote_url="https://cloud.debian.org/images/cloud/buster/latest/debian-10-generic-amd64.qcow2"
      remote_shasum_url="https://cloud.debian.org/images/cloud/buster/latest/SHA512SUMS"
      shasum_algorithm="512"
      ;;
    bullseye | 11)
      file_name="debian-11-generic-amd64.qcow2"
      remote_url="https://cloud.debian.org/images/cloud/bullseye/latest/debian-11-generic-amd64.qcow2"
      remote_shasum_url="https://cloud.debian.org/images/cloud/bullseye/latest/SHA512SUMS"
      shasum_algorithm="512"
      ;;
    bookworm | 12)
      file_name="debian-12-generic-amd64.qcow2"
      remote_url="https://cloud.debian.org/images/cloud/bookworm/latest/debian-12-generic-amd64.qcow2"
      remote_shasum_url="https://cloud.debian.org/images/cloud/bookworm/latest/SHA512SUMS"
      shasum_algorithm="512"
      ;;
    trixie | 13)
      err "Debian 13 'Trixie' is not available"
      # file_name="debian-13-generic-amd64.qcow2"
      # remote_url= "https://cloud.debian.org/images/cloud/trixie/latest/debian-13-generic-amd64.qcow2"
      # remote_shasum_url="https://cloud.debian.org/images/cloud/trixie/latest/SHA512SUMS"
      # shasum_algorithm="512"
      ;;
    *)
      err "Unknown distro, only works for Debian 10-12"
      ;;
    esac
  elif [[ "${DISTRO_NAME}" == "centos" ]]; then
    case $RELEASE_NAME in
    9)
      file_name="CentOS-Stream-GenericCloud-9-latest.x86_64.qcow2"
      remote_url="https://cloud.centos.org/centos/9-stream/x86_64/images/CentOS-Stream-GenericCloud-9-latest.x86_64.qcow2"
      remote_shasum_url="https://cloud.centos.org/centos/9-stream/x86_64/images/CentOS-Stream-GenericCloud-9-latest.x86_64.qcow2.SHA256SUM"
      shasum_algorithm="256"
      ;;
    *)
      err "Unknown distro, only works for CentOS Stream 9"
      ;;
    esac
  elif [[ "${DISTRO_NAME}" == "fedora" ]]; then
    case $RELEASE_NAME in
    40)
      file_name="Fedora-Cloud-Base-Generic.x86_64-40-1.14.qcow2"
      remote_url="https://download.fedoraproject.org/pub/fedora/linux/releases/40/Cloud/x86_64/images/Fedora-Cloud-Base-Generic.x86_64-40-1.14.qcow2"
      remote_shasum_url="https://download.fedoraproject.org/pub/fedora/linux/releases/40/Cloud/x86_64/images/Fedora-Cloud-40-1.14-x86_64-CHECKSUM"
      shasum_algorithm="256"
      ;;
    41)
      file_name="Fedora-Cloud-Base-Generic-41-1.4.x86_64.qcow2"
      remote_url="https://download.fedoraproject.org/pub/fedora/linux/releases/41/Cloud/x86_64/images/Fedora-Cloud-Base-Generic-41-1.4.x86_64.qcow2"
      remote_shasum_url="https://download.fedoraproject.org/pub/fedora/linux/releases/41/Cloud/x86_64/images/Fedora-Cloud-41-1.4-x86_64-CHECKSUM"
      shasum_algorithm="256"
      ;;
    *)
      err "Unknown distro, only works for Fedora 40+"
      ;;
    esac
  elif [[ "${DISTRO_NAME}" == "ubuntu" ]]; then
    case $RELEASE_NAME in
    focal | 20)
      file_name="ubuntu-20.04-server-cloudimg-amd64.img"
      remote_url="https://cloud-images.ubuntu.com/releases/focal/release/ubuntu-20.04-server-cloudimg-amd64.img"
      remote_shasum_url="https://cloud-images.ubuntu.com/releases/focal/release/SHA256SUMS"
      shasum_algorithm="256"
      ;;
    jammy | 22)
      file_name="ubuntu-22.04-server-cloudimg-amd64.img"
      remote_url="https://cloud-images.ubuntu.com/releases/jammy/release/ubuntu-22.04-server-cloudimg-amd64.img"
      remote_shasum_url="https://cloud-images.ubuntu.com/releases/jammy/release/SHA256SUMS"
      shasum_algorithm="256"
      ;;
    noble | 24)
      file_name="ubuntu-24.04-server-cloudimg-amd64.img"
      remote_url="https://cloud-images.ubuntu.com/releases/noble/release/ubuntu-24.04-server-cloudimg-amd64.img"
      remote_shasum_url="https://cloud-images.ubuntu.com/releases/noble/release/SHA256SUMS"
      shasum_algorithm="256"
      ;;
    *)
      err "Unknown distro, only works for Ubuntu LTS 20+"
      ;;
    esac
  else
    err "Unsupported distro. Please specify 'centos', 'debian', 'fedora' or 'ubuntu'."
  fi

  readonly file_name remote_url remote_shasum_url shasum_algorithm
  return 0
}

#######################################
# Allow users to pass a single arg for distro and release
# This is a workaround for naming systemd timers
# Arguments:
#   $1 - string, ex: ubuntu-20
# Returns:
#   DISTRO_NAME, string.
#   RELEASE_NAME, string.
#######################################
function split_arg() {
  DISTRO_NAME=${1%-*}
  RELEASE_NAME=${1#*-}
}

function main() {
  if [[ ($? -ne 0) || ($# -eq 0) ]]; then
    usage
  fi

  OPTIONS=hd:r:s:b
  LONGOPTS=help,distro:,release:,storage:,backup,date,remove
  NOARG_OPTS=(-h --help -b --backup --date --remove)

  TEMP=$(getopt -n "${0##*/}" -o $OPTIONS --long $LONGOPTS -- "${@}") || exit 2
  eval set -- "$TEMP"
  unset TEMP

  while true; do
    [[ ! ${NOARG_OPTS[*]} =~ ${1} ]] && [[ ${2} == -* ]] && {
      err "Missing argument for ${1}"
    }
    case "${1}" in
    -h | --help)
      help
      ;;
    --backup | -b)
      BACKUP_IMAGES=true
      shift
      continue
      ;;
    --date)
      APPEND_DATE=true
      shift
      continue
      ;;
    --distro | -d)
      DISTRO_NAME=${2,,}
      shift 2
      continue
      ;;
    --release | -r)
      RELEASE_NAME=${2,,}
      shift 2
      continue
      ;;
    --remove)
      REMOVE_OLD_IMAGE=true
      shift
      continue
      ;;
    --storage | -s)
      STORAGE_PATH=${2}
      shift 2
      continue
      ;;
    --)
      if [ -n "${2}" ]; then
        split_arg "${2,,}"
      fi
      shift
      break
      ;;
    *)
      err "Parsing arguments in main()"
      ;;
    esac
  done

  readonly DISTRO_NAME RELEASE_NAME REMOVE_OLD_IMAGE STORAGE_PATH

  if [ -z "${DISTRO_NAME}" ] || [ -z "${RELEASE_NAME}" ]; then
    if [ -z "${DISTRO_NAME}" ]; then err "Missing Distribution"; fi
    if [ -z "${RELEASE_NAME}" ]; then err "Missing Release"; fi
    usage
  fi

  if [ ! -d "${STORAGE_PATH}" ]; then
    err "Storage path does not exist! Value: ${STORAGE_PATH}"
  fi

  if [ ! -w "${STORAGE_PATH}" ]; then
    err "You do not have write permission to ${STORAGE_PATH}, are you root?"
  fi

  if [ ${REMOVE_OLD_IMAGE} = true ] && [ ${BACKUP_IMAGES} = true ]; then
    err "Cannot remove old images and backup new ones at the same time!"
  fi

  echo "Distribution:      ${DISTRO_NAME}"
  echo "Release:           ${RELEASE_NAME}"
  echo "Storage:           ${STORAGE_PATH}"
  echo "Remove Old Images: ${REMOVE_OLD_IMAGE}"

  set_image_values "$@"

  if [ ${APPEND_DATE} = true ]; then
    image_date=$(get_image_date "${remote_url}" "${file_name}")
    file_basename="${file_name%.*}-${image_date}"
  else
    file_basename="${file_name%.*}"
  fi

  readonly file_basename

  cd "${STORAGE_PATH}"

  if [[ ! -e "${file_basename}.img" ]]; then
    echo "Downloading image..."
    curl -L "${remote_url}" -o "${file_basename}.img"

    echo "Done, new image downloaded!"
  else
    if check_shasum "$@"; then
      echo "Done, image is current."
    else
      if [ ${REMOVE_OLD_IMAGE} = true ]; then
        echo "Removing old images..."
        # remove original and backup images
        rm "${file_name%.*}"*
      elif [ ${BACKUP_IMAGES} = true ]; then
        # backup all images with or without date
        backup_images "${file_name}"
      fi

      echo "Downloading image..."
      curl -L "${remote_url}" -o "${file_basename}.img"

      echo "Done, new image downloaded!"
    fi
  fi

  exit
}

main "$@"