duplicity-backup.pl - wrapper around "duplicity"

General functionality

The backup software is built on top of an open source software called "duplicity". The website of the software is:

http://duplicity.nongnu.org/

The backup program controls the following characteristics:

• size of backup archives
• configuration of multiple backups
• encryption
• creation of incremental backups and full backups
• automatically deletion of obsolete backups
• inclusion and exclusion of directories
• backup status

License

"duplicity-backup.pl" is released under the PostgreSQL License, a liberal Open Source license, similar to the BSD or MIT licenses.

Copyright (c) 2012, Andreas Scherbaum

Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies.

IN NO EVENT SHALL Andreas Scherbaum BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF Andreas Scherbaum HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Andreas Scherbaum SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND Andreas Scherbaum HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

Sponsor

I would like to take this opportunity to thank the sponsor of this software:

Eisbaer Media GmbH http://www.eisbaer.de/

Additional required software

The following packages are required on Debian/Ubuntu:

• duplicity
• ncftp
• libyaml-libyaml-perl
• libyaml-tiny-perl
• libregexp-common-perl
• libdate-manip-perl
• libtime-duration-parse-perl

Using cron to run the backup

An example cronjob using "duplicity-backup.pl":

0 2 * * * root /root/duplicity-backup.pl -c /root/duplicity.conf -s --cleanup-old-logs

With this call, the program starts every night at 2 o `clock.

Command line parameters

"duplicity-backup.pl" accepts the following command line parameters: -h / --help Display help -d / --debug Debug mode -c / --config Configuration file (required) -l / --logfile logfile -s / --status Output the status at the end of the backup --cleanup-old-logs Deletes all log files older than 4 weeks

Configuration file format

The configuration file uses YAML and is easy to change using an editor. There are two main categories:

• "config:" contains general configuration parameters
  • "duplicity:" specifies the path to the "duplicity" program
  • "volsize:" specifies the size of each backup archive, in MB
  • "password:" is optional and specifies the password used to encrypt the backup
  • "log-directory:" specifies the directory for logfiles
• "backup" is composed of sub-categories, one for each backup job names are unique across all backup definitions any definition may contain the following parameters:
  • "type:" defines the type of backup, currently only "file" is supported
  • "disabled:" determines whether a backup job is disabled the default is "no", by indicating "yes" the job is disabled
  • "cd-backup-directory" is the directory where the program will chdir into prior to any other operation
  • "backup-this-directory:" specifies the directory, relative to "backup-cd-directory" which should be backed up
  • "backup-target" specifies the backup destination, i.e. where the files are backed up currently, "file:" and "ftp:" supported as target all login information are related to this parameter
  • "backup-target-sub-directory:" specifies the subdirectory where this backup is to be created in "backup-target" if not present, it is automatically created
  • "ftp-password" is the password for the FTP server
  • "incremental" specifies whether incremental backups allowed default is "yes", "no" disables incremental backups
  • "full-every:" specifies a time after which a new full backup is created the time can be specified in regular English language
  • "incremental-every" specifies a time after which a new incremental backup is created when a full backup is created, the program will not create an incremental backup during the same run
  • "exclude:" specifies a comma-separated list of files and directories which should be excluded from the backup
  • "include:" specifies a comma-separated list of files and directories which should be included in the backup

See the "duplicity-backup.conf" example file. Note: the password in this file is not my regular backup password ;-)

Other operations

Since "duplicity-backup.pl" is just a wrapper around "duplicity" to create backups, the restore of a file is done using "duplicity". Following are some examples how to use "duplicity":

List all backups

export PASSPHRASE="backup password" export FTP_PASSWORD="ftp password" duplicity collection-status /

Specifying PASSPHRASE is only required if the backups are encrypted. Specifying FTP_PASSWORD is only required if a FTP server is used as backup target.

List all files in a backup

export PASSPHRASE="backup password" export FTP_PASSWORD="ftp password" duplicity list-current /

Restore a file from backup

export PASSPHRASE="backup password" export FTP_PASSWORD="ftp password" duplicity --file-to-restore /path/to/file / /tmp/file

This will restore "/path/to/file" as "file" in "/tmp". In addition, by using the option "-tD" it is possible to restore an older version of a file from the backup.

Further readings

• http://duplicity.nongnu.org/
• https://help.ubuntu.com/community/DuplicityBackupHowto
• http://en.wikipedia.org/wiki/Duplicity_(software)