cloud-tar.sh

#!/bin/bash
# Note: to list or restore files, simple cat (shell expansion sorts files in the correct alphabetical order)
# cat backup-name-####.backup* | gpg -d - | tar -tvz
# cat backup-name-####.backup* | gpg -d - | tar -xvz
# do the above with each subsequent incremental backup, but decrypt the \
# snapshot first, and use -g.  We'll add a restore feature shortly.
# This is required in order to detect which files were deleted between each
# backup, and have tar remove them for you automatically as part of the restore.
# gpg -d backup-name-####.spb > backup-name-####.sp
# cat backup-name-####.backup* | gpg -d - | tar -xvzg backup-name-####.sp
# The following URL provides a good breakdown of the tar incremental
# functionality
# https://www.gnu.org/software/tar/manual/html_node/Incremental-Dumps.html

# This script is based on simple concepts
# 1. start with level 0 backup, meaning initial backup.  it's backup_index is 0,
#    in the form backup_name.0.backup??
# 2. subsequent backups get a ms timestamp since 1970 as their backup_index
#    value, in the form backup_name.1622047204.backup??
# 3. to start over just delete home.sp, resulting in a new backup_index 0
#    backup, and tar will automatically create a new level 0.
# 4. make sure you are backing up to a new bucket or folder if starting over, so
#    that you don't get confused on which timestamped backups are
#    relevant to your current level 0.
# 5. We support splitting backups at 4G by default, so if you wanted you could
#    copy them to a FAT32 USB drive.
#

# WARNING these source commands must remain exactly the same, otherwise an
# update to the cloud-tar target in the Makefile must be made.
source components/show-help.sh

source components/parse-backup-args.sh

source components/parse-restore-args.sh

source components/parse-commands.sh

source components/backup.sh

source components/restore.sh

function exitWith() {
  echo "$1"
  echo
  show_help
  exit 99
}

function verifyRequiredCommands() {
  command -v split >/dev/null || { exitWith "split command not installed"; }
  command -v aws >/dev/null || { exitWith "aws cli not installed"; }
  command -v tar >/dev/null || { exitWith "tar not installed"; }
  command -v stat >/dev/null || { exitWith "stat not installed"; }
  command -v split >/dev/null || { exitWith "split not installed"; }
  command -v mktemp >/dev/null || { exitWith "mktemp not installed"; }
}

# test parseCommands mock parseCommands
#    output mode
#    stub everything else and ignore
# test mode backup
#    test that parseBackupsArgs was called
#    test that doBackup was called
# test mode restore
#    test that parseRestoreArgs was called
#    test that doRestore was called
# test aws was called when skip_s3 != true
function cloudTar() {
  skip_s3="true"
  my_args=$(parseCommands "$@")
  eval "${my_args}"

  if [[ "${mode}" == "backup" ]]; then
    my_args=$(parseBackupArgs "$@")
    eval "${my_args}"
    [[ -z "${gpg_recipients}" ]] &&
      echo "WARNING your backup will not be encrypted, as no gpg recipient was specified"
  elif [[ "${mode}" == "restore" ]]; then
    my_args=$(parseRestoreArgs "$@")
    eval "${my_args}"
  fi;

  verifyArgs
  verifyRequiredCommands

  if [[ "${mode}" == "backup" ]]; then
    doBackup
  elif [[ "${mode}" == "restore" ]]; then
    doRestore
  fi;

  # ${backup_name}.sp stays unencrypted for next round, so we don't upload it
  [[ "$skip_s3" != "true" ]] &&
    aws s3 sync "${destination_folder}/" "s3://${s3_bucket_name}/" --exclude '*.sp'
}

# only run cloudTar if this script was executed (not sourced)
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
  cloudTar "$@"
fi