borg-backup.sh

#!/bin/bash

# Exit immediately on errors
set -e

function check_last () {
  if ps ax | grep $0 | grep -v $$ | grep bash | grep -v grep > /dev/null; then
    echo 'Backup already running'
    exit 1;
  fi
}

function check_requirements () {
  which aws > /dev/null
  if [ $? -ne 0 ]; then
    fail 'aws cli tool needs to be installed. See documentation.'
  fi

  which base64 > /dev/null
  if [ $? -ne 0 ]; then
    fail 'base64 tool needs to be installed. See documentation.'
  fi

  # Test for environment variables file
  if [ ! -f "$BORG_ENV_FILE" ]; then
    fail 'No environment variables file. Copy and edit the provided environment variables sample file. See documentation.'
  fi

  # Test for log file
  if [ ! -f "$BORG_LOG_FILE" ]; then
    fail 'No log file defined. Fill out the .env file. See documentation.'
  fi

  # Test for includes file
  if [ ! -f "$BORG_INCLUDES" ]; then
    fail 'No includes file. Copy and edit the provided sample includes file. See documentation.'
  fi

  # Test for excludes file
  if [ ! -f "$BORG_EXCLUDES" ]; then
    fail 'No excludes file. Copy and edit the provided sample excludes file. See documentation.'
  fi

  # Test for backup repository
  if [ -z "${BORG_REPO}" ]; then
    fail 'No backup repository defined. Fill out the .env file. See documentation.'
  fi

  # Test for backup name prefix
  if [ -z "$BORG_BACKUP_NAME_PREFIX" ]; then
    fail 'No backup name prefix defined. Fill out the .env file. See documentation.'
  fi

  # Test for S3 bucket
  if [ -z "$BORG_S3_BUCKET" ]; then
    fail 'No S3 bucket defined. Fill out the .env file. See documentation.'
  fi

  # Test for emails
  if [ -z "$BORG_FROM_EMAIL" -o -z "$BORG_TO_EMAIL" ]; then
    fail 'No From or To defined. Fill out the .env file. See documentation.'
  fi
}

function main () {
  # Truncate log file
  : > $BORG_LOG_FILE

  # Backup
  borg create                                                   \
    --compression zlib,6                                        \
    --exclude-caches                                            \
    --exclude-from $BORG_EXCLUDES                               \
    --filter AME                                                \
    --list                                                      \
    --patterns-from $BORG_INCLUDES                              \
    --show-rc                                                   \
    --stats                                                     \
    --verbose                                                   \
    ::${BORG_BACKUP_NAME}                                       \
    2>> $BORG_LOG_FILE

  success 'Backup complete'

  # Prune
  borg prune                                                    \
    --keep-within 2d                                            \
    --keep-hourly=${12:-$KEEP_HOURLY}                           \
    --keep-daily=${5:-$KEEP_DAILY}                              \
    --keep-weekly=${2:-$KEEP_WEEKLY}                            \
    --keep-monthly=${1:-$KEEP_MONTHLY}                          \
    --list ${BORG_REPO}                                         \
    --prefix $BORG_BACKUP_NAME_PREFIX                           \
    --verbose                                                   \
    2>> $BORG_LOG_FILE
    # logging: https://borgbackup.readthedocs.io/en/stable/usage/general.html#logging

  success 'Prune complete'

  # Sync to S3
  borg with-lock ${BORG_REPO}                                   \
    aws s3 sync ${BORG_REPO} s3://$BORG_S3_BUCKET               \
      --delete                                                  \
      --no-progress                                             \
      --storage-class=STANDARD_IA                               \
      >> $BORG_LOG_FILE

  success 'Sync complete'
}

function alert () {
  SUBJECT=$1
  BODY=`echo "$1" | /usr/bin/base64`
  FILENAME=$(basename "${BORG_LOG_FILE%}")
  ATTACHMENT=`/usr/bin/base64 -i -0 $BORG_LOG_FILE`

  TMPFILE="/tmp/ses-${RN}"

  echo -E '{"Data": "From:'$BORG_FROM_EMAIL'\nTo:'$BORG_TO_EMAIL'\nSubject:'${SUBJECT}'\nMIME-Version: 1.0\nContent-type: Multipart/Mixed; boundary=\"NextPart\"\n\n--NextPart\nContent-Type: text/plain\nContent-Transfer-Encoding: base64\n\n['$BODY']\n\n--NextPart\nContent-Type: text/plain;\nContent-Disposition: attachment; filename=\"'$FILENAME'\"\nContent-Transfer-Encoding: base64\n\n'$ATTACHMENT'\n--NextPart--"}' > $TMPFILE

  aws ses send-raw-email --raw-message file://$TMPFILE > /dev/null
}

# return codes: https://borgbackup.readthedocs.io/en/stable/usage/general.html#return-codes
function success () {
  printf "\n%s\n\n" "[ OK ] $1" \
    2>&1 | tee -a $BORG_LOG_FILE
}

function fail () {
  printf "\n%s\n\n" "[ FAIL ] $1"  \
    2>&1 | tee -a $BORG_LOG_FILE

  exit 1
}

# Set up the environment
RN=$(date '+%Y-%m-%d--%H-%M-%S')

BORG_ENV_FILE='.env'
source $BORG_ENV_FILE

# Exit if borg is already running
check_last

# Check for require tools and environment variables
check_requirements

# Run the backup
main "$@";

# Let me know how it went
alert "Borg backup complete at $(date '+%Y-%m-%d-%H:%M:%S')"

# l8
exit 0;