:PROPERTIES:
:ID:       8135ece9-0dc0-4799-ac63-a24f9486ddd2
:END:
#+title: BorgBackup
#+date: "2021-05-30 21:40:24 +08:00"
#+date_modified: "2021-06-05 09:11:53 +08:00"
#+language: en
#+property: header_args :eval no
#+property: header_args:bash  :results silent  :exports code


BorgBackup is a deduplicating archiver with compression and encryption.
In other words, this is the best backup tool (as of 2021-05-30).

In this note, we'll be covering the following v1.1.16 and above.

For more information, you can view =borg.1= manual page.
It has all of the information you can possibly know about the tool, making it a perfect reference.
This note rips off a few relevant pages from there.




* Synopsis

#+begin_src shell  :results silent
borg [options...] [subcommand [subcommand_options...] [subcommand_positional_args...]]
#+end_src

Borg recommends to pass the options before the positional arguments.
It can be picky with certain subcommands output being affected from the order of the arguments but you should be safe when you do the recommended practice.



* Options

Borg uses a Git-style command-line interface with subcommands and some common options to choose from.

- You can set the log level of the program with ~--debug~, ~--info~, ~--warning~, ~--error~, and ~--critical~.
- ~-v, --verbose~ - alias for ~--info~
- ~-p, --progress~ - show progress information; will be slower on certain operations due to additional passing of the metadata

Keep in mind, Borg doesn't have global configuration files, only per-repo configurations.
You can create configurations with a little hard work and shell scripts.
But if you want a tool that already does that, you have [[https://torsion.org/borgmatic/][Borgmatic]] as an option with plain-text files in YAML format.


** Repositories and archives

Most of the subcommands take the repository path with a certain format.

#+begin_src
${REPOSITORY_URL}::${ARCHIVE_NAME}
#+end_src

#+begin_src
# Points to an repo
/home/foo-dogsquared/backup

# Points to an archive named '2021-03-02' from the previous repo.
/home/foo-dogsquared/backup::2021-03-02
#+end_src

You can also refer to a name dynamically with placeholders.

#+begin_src
/home/{user}/backup::{hostname}-{user}-{now}
#+end_src

For more information, you can see the related section for Borg placeholders.
Or you can run ~borg help placeholders~.






* Environment variables

Borg will also take environment variables being used by most (if not all) of the subcommands.
Very useful for scripting and saving time not repeating the same arguments.

- =BORG_REPO= - the repo URL
- =BORG_PASSPHRASE= - the repo passphrase, if it has encryption enabled
- =BORG_PASSCOMMAND= - the command used to get the passphrase




* Examples

Borg is a comprehensive tool for a comprehensive backup system.
Here are some of the real-life examples of using the program.


** Quickstart

Just from how I imagined I would start using this tool, anyway.

#+begin_src shell
# Initialize the Borg repo in the specified path with a simple passphrase.
borg init --encryption repokey ${REPO_PATH}

# Create an archive in the repo and save the documents, pictures, and videos folder.
# This will prompt you into entering the passphrase.
borg create --verbose --progress ${REPO_PATH}::{hostname}-{now:%F-%T-%z} ~/Documents ~/Pictures ~/Videos

# Entering the passphrase can be annoying so let's save that into a variable.
# Luckily, Borg already handles this by setting BORG_PASSPHRASE.
# Thus, it will not bother us again.
BORG_PASSPHRASE='gum cavity cabinet auditorium'

# List all of the archives saved so far.
borg list ${REPO_PATH}

# List the files in the specified archive.
borg list ${REPO_PATH}::${ARCHIVE_NAME}

# Extract only the documents folder.
borg extract --verbose --progress ${REPO_PATH}::{hostname}-{now:%F-%T-%z} ~/Documents
#+end_src


** Practicing safe backup script

Better be safe than sorry.
Here's the safe backup in all of its glory in Bash.

#+begin_src bash  :tangle (my/concat-assets-folder "safe-borg-backup")  :shebang "#/usr/bin/env bash"
if $# -eq 1; then echo "No directories and files to be saved." && exit 1; fi

locations=$@

borg create --verbose --stats --compression lz4 --exclude '**/.node_modules' ::{hostname}-{now:%F-%H-%M-%S-%z} ${locations[@]}
borg check --verbose --verify-data
borg prune --verbose --keep-daily 7 --keep-hourly 7 --keep-weekly 6 --keep-monthly 6
#+end_src

#+results:

Since the script only lets you enter arguments used for saving into the archive, you have to use environment variables.

#+begin_src shell
BORG_REPO="$HOME/backups" BORG_PASSCOMMAND='gopass show misc/personal-borgbackup-repo' safe-borg-backup ~/projects ~/library ~/writings
#+end_src


** An interactive interface for extracting archives

All-time favorite [[id:4eb1f8b1-bc12-4a6c-8fa4-20e4c3542cf2][fzf]] (and xargs) is required.

#+begin_src bash
export BORG_PASSPHRASE="oral hygiene"
export BORG_REPO="${REPO_PATH}"

borg list --format="{name}{NL}" \
    | fzf \
    | xargs --replace="{}" borg extract --verbose --progress ::{}
#+end_src
