Duplicity wrapper to manage S3 backups for media files

s3helper

#!/bin/bash
#
# Duplicity wrapper to manage S3 backups for media files.
#
#     aptitude install duplicity python-boto
#
# Configure the settings below then run a test backup AND a test restore.
# Once working, schedule a regular backup with cron. Only one backup will
# run at a time so set a short cron period if you want.
#
# Example usage:
#
#     s3helper backup
#     s3helper restore path/to/file /path/to/restored/file
#     s3helper list
#     s3helper status
#
# Example crontab to backup every hour:
#
#     MAILTO=you@example.com
#     0 * * * * $HOME/bin/s3helper backup 2>&1
#
script_name=${0##*/}

# Configure your S3 settings below then comment this line out.
echo "Edit this script to configure your S3 settings" && exit 1

# S3 settings.
export AWS_ACCESS_KEY_ID=changeme
export AWS_SECRET_ACCESS_KEY=changeme
dst=s3+http://changeme/changeme
src=/srv/myapp/shared/system/content

lockfile=/tmp/${script_name}.lock

# Normal use should not require editing beyond this point.
cleanup () {
  export AWS_ACCESS_KEY_ID=
  export AWS_SECRET_ACCESS_KEY=
}

cleanup_and_unlock () {
  cleanup; rm -f ${lockfile}
}

die () {
  echo "$*" >&2; exit 1
}


trap cleanup EXIT

case $1 in

  backup)
    # Duplicity backs up symlinks as symlinks. We're backing up media
    # files only, so we resolve symlinks as a precaution.
    src=$(readlink -f $src)

    # Lock to prevent concurrent backups.
    lockfile -r 0 ${lockfile} || exit 1
    trap cleanup_and_unlock EXIT

    /usr/bin/duplicity \
      --s3-use-new-style \
      --no-encryption \
      --asynchronous-upload \
      --volsize 25 \
      "--full-if-older-than" 1M incremental \
      --include ${src} \
      --exclude '**' $(dirname ${src}) ${dst}
    ;;

  restore)
    remote_path=$2
    local_path=$3
    [ "$local_path" = "" ] && \
      die "usage: ${script_name} restore remote_path local_path"

    /usr/bin/duplicity \
      --s3-use-new-style \
      --no-encryption \
      --file-to-restore=${remote_path} restore ${dst} ${local_path}
    ;;

  status)
    /usr/bin/duplicity \
      --s3-use-new-style \
      --no-encryption \
      collection-status ${dst}
    ;;

  list)
    /usr/bin/duplicity \
      --s3-use-new-style \
      --no-encryption \
      list-current-files ${dst}
    ;;

  *)
    die "usage: ${script_name} {backup|status|list|restore}"
    ;;

esac