Simple, configuration-driven backup software for servers and workstations
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How to develop on borgmatic [{key Develop on borgmatic} {parent How-to guides} {order 12}]

Source code

To get set up to hack on borgmatic, first clone master via HTTPS or SSH:

git clone


git clone ssh://

Then, install borgmatic "editable" so that you can run borgmatic commands while you're hacking on them to make sure your changes work.

cd borgmatic/
pip3 install --editable --user .

Note that this will typically install the borgmatic commands into ~/.local/bin, which may or may not be on your PATH. There are other ways to install borgmatic editable as well, for instance into the system Python install (so without --user, as root), or even into a virtualenv. How or where you install borgmatic is up to you, but generally an editable install makes development and testing easier.

Automated tests

Assuming you've cloned the borgmatic source code as described above, and you're in the borgmatic/ working copy, install tox, which is used for setting up testing environments:

pip3 install --user tox

Finally, to actually run tests, run:

cd borgmatic

Code formatting

If when running tests, you get an error from the Black code formatter about files that would be reformatted, you can ask Black to format them for you via the following:

tox -e black

Note that Black requires at minimum Python 3.6.

And if you get a complaint from the isort Python import orderer, you can ask isort to order your imports for you:

tox -e isort

End-to-end tests

borgmatic additionally includes some end-to-end tests that integration test with Borg and supported databases for a few representative scenarios. These tests don't run by default when running tox, because they're relatively slow and depend on Docker containers for runtime dependencies. These tests tests do run on the continuous integration (CI) server, and running them on your developer machine is the closest thing to CI test parity.

If you would like to run the full test suite, first install Docker and Docker Compose. Then run:


Note that this scripts assumes you have permission to run Docker. If you don't, then you may need to run with sudo.

Code style

Start with PEP 8. But then, apply the following deviations from it:

  • For strings, prefer single quotes over double quotes.
  • Limit all lines to a maximum of 100 characters.
  • Use trailing commas within multiline values or argument lists.
  • For multiline constructs, put opening and closing delimeters on lines separate from their contents.
  • Within multiline constructs, use standard four-space indentation. Don't align indentation with an opening delimeter.

borgmatic code uses the Black code formatter, the Flake8 code checker, and the isort import orderer, so certain code style requirements will be enforced when running automated tests. See the Black, Flake8, and isort documentation for more information.

Continuous integration

Each pull request triggers a continuous integration build which runs the test suite. You can view these builds on, and they're also linked from the commits list on each pull request.

Documentation development

Updates to borgmatic's documentation are welcome. It's formatted in Markdown and located in the docs/ directory in borgmatic's source, plus the file at the root.

To build and view a copy of the documentation with your local changes, run the following from the root of borgmatic's source code:

sudo scripts/dev-docs

This requires Docker to be installed on your system. You may not need to use sudo if your non-root user has permissions to run Docker.

After you run the script, you can point your web browser at http://localhost:8080 to view the documentation with your changes.

To close the documentation server, ctrl-C the script. Note that it does not currently auto-reload, so you'll need to stop it and re-run it for any additional documentation changes to take effect.