zfsbak

#!/usr/local/bin/bash

function help() {
cat << EOF
Usage:
- create: zfsbak DATASET [ROTATION_CNT]
- list: zfsbak -l|--list [DATASET|ID|DATASET ID]
- delete: zfsbak -d|--delete [DATASET|ID|DATASET ID...]
- export: zfsbak -e|--export DATASET [ID]
- import: zfsbak -i|--import FILENAME DATASET
EOF
}

function datetime() {
  date '+%Y-%m-%d-%H:%M:%S'
}

function zfs_snap() {
  echo "Snap $1"
  zfs snapshot "$1"
}

function zfs_destroy() {
  echo "Destroy $1"
  zfs destroy "$1"
}

function zfs_list() {
  zfs list -H -o name -r -t snapshot "$1" | sort -t '@' -k 2 | awk '{print NR "\t" $0}' | grep "^$2"
}

function zfsbak_create() {
  dataset="$1"
  rotation="${2-12}"
  zfs_snap "$dataset@$(datetime)"

  for snap in $(zfs_list "$dataset" | awk '{ print $2 }' | tail -r | tail -n "+$((rotation+1))" | tail -r); do
    zfs_destroy "$snap"
  done
}

function parse_dataset_id() {
  dataset="${1-mypool}"
  id=""
  if [[ "$dataset" != mypool* ]]; then
    id="$dataset"
    dataset="mypool"
  fi
  if [ $# = 2 ]; then
    id="$2"
  fi
}

function zfsbak_list() {
  parse_dataset_id "$@"
  echo -e "ID\tDATASET\t\tTIME"
  zfs_list "$dataset" "$id" | tr '@' '\t'
}

function zfsbak_delete() {
  parse_dataset_id "$@"
  for snap in $(zfs_list "$dataset" "$id" | awk '{ print $2 }'); do
    zfs_destroy "$snap"
  done
}

function zfsbak_export() {
  dataset="${1?'dataset'}"
  id="${2-1}"
  snapname="$(zfs_list "$dataset" "$id" | awk '{ print $2 }')"
  pathname="$(getent passwd "$SUDO_USER" | cut -d: -f6)/${snapname/\//_}.zstd.gpg"
  rm -fr "$pathname"
  zfs send "$snapname" | zstd -qc - | gpg --encrypt -r 'ta@nasa.cs.nctu.edu.tw' --batch -q -o "$pathname" - # &> /dev/null
  echo "Export $snapname to $pathname"
}

function zfsbak_import() {
  filename="${1?'filename'}"
  dataset="${2?'dataset'}"
  # cp "$filename" /tmp
  echo "Import $filename to $dataset"
  zstd -qcd "$filename" | zfs receive "$dataset@$(datetime)"
}

case "$1" in
  -l|--list)   shift; zfsbak_list   "$@" ;;
  -d|--delete) shift; zfsbak_delete "$@" ;;
  -e|--export) shift; zfsbak_export "$@" ;;
  -i|--import) shift; zfsbak_import "$@" ;;
  *)
    if [ $# == 0 ]; then
      help
    else
      zfsbak_create "$@"
    fi
    ;;
esac