linux-utils

linux-utils: Linux system administration tools for Python

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The Python package linux-utils provides utility functions that make it easy to script system administration tasks on Linux_ systems in Python. The following functionality is currently implemented:

• Parsing of the /etc/fstab_ and /etc/crypttab_ configuration files.
• A basic Python API for cryptsetup_ and a Python implementation of cryptdisks_start_ and cryptdisks_stop_ (with a command line interface).
• Atomic filesystem operations for Linux in Python.
• Simple network location awareness / discovery.

The package is currently tested on cPython 2.7, 3.4, 3.5, 3.6, 3.7 and PyPy (2.7) on Ubuntu Linux (using Travis CI_).

.. contents:: :local:

Installation

The linux-utils package is available on PyPI_ which means installation should be as simple as:

.. code-block:: console

$ pip install linux-utils

There's actually a multitude of ways to install Python packages (e.g. the per user site-packages directory, virtual environments or just installing system wide) and I have no intention of getting into that discussion here, so if this intimidates you then read up on your options before returning to these instructions 😉.

Usage

For details about the Python API please refer to the API documentation available on Read the Docs. The Python implementation of cryptdisks_start and cryptdisks_stop_ is available on the command line as the following two programs:

.. contents:: :local:

As the names imply these programs are not functional equivalents of their "official" counterparts, because they only support LUKS encryption and a small subset of the available encryption options.

cryptdisks-start-fallback

.. A DRY solution to avoid duplication of the `cryptdisks-start-fallback --help' text:
..
.. [[[cog
.. import cog
.. from humanfriendly.text import dedent
.. from humanfriendly.usage import render_usage
.. from linux_utils.cli import cryptdisks_start_cli
.. cog.out("\n" + render_usage(dedent(cryptdisks_start_cli.__doc__)) + "\n")
.. ]]]

**Usage:** `cryptdisks-start-fallback NAME`

Reads /etc/crypttab and unlocks the encrypted filesystem with the given NAME.

This program emulates the functionality of Debian's cryptdisks_start program,
but it only supports LUKS encryption and a small subset of the available
encryption options.

.. [[[end]]]

cryptdisks-stop-fallback
~~~~~~~~~~~~~~~~~~~~~~~~

.. A DRY solution to avoid duplication of the `cryptdisks-stop-fallback --help' text:
..
.. [[[cog
.. import cog
.. from humanfriendly.text import dedent
.. from humanfriendly.usage import render_usage
.. from linux_utils.cli import cryptdisks_stop_cli
.. cog.out("\n" + render_usage(dedent(cryptdisks_stop_cli.__doc__)) + "\n")
.. ]]]

**Usage:** `cryptdisks-stop-fallback NAME`

Reads /etc/crypttab and locks the encrypted filesystem with the given NAME.

This program emulates the functionality of Debian's cryptdisks_stop program,
but it only supports LUKS encryption and a small subset of the available
encryption options.

.. [[[end]]]

.. _History:

History
-------

Back in 2015 I wrote some Python code to parse the Linux configuration files
`/etc/fstab`_ and `/etc/crypttab`_ for use in crypto-drive-manager_. Fast
forward to 2017 and I found myself wanting to use the same functionality
in rsync-system-backup_. Three options presented themselves to me:

**Copy/paste the relevant code**
 Having to maintain the same code in multiple places causes lower quality code
 because having to duplicate the effort of writing documentation, developing
 tests and fixing bugs is a very demotivating endeavor. In fact sometime in
 2016 I *did* copy/paste parts of this code into a project at work, because I
 needed similar functionality there. Of course since then the two
 implementations have started diverging 😛.

**Make crypto-drive-manager a dependency of rsync-system-backup**
 Although this approach is less ugly than copy/pasting the code, it still isn't
 exactly elegant because the two projects have nothing to do with each other
 apart from working with LUKS encrypted disks on Linux.

**Extract the functionality into a new package**
 In my opinion this is clearly the most elegant approach, unfortunately it also
 requires the most work from me 😇. On the plus side I'm publishing the new
 package with a test suite which means less untested code remains in
 crypto-drive-manager_ (which doesn't have a test suite at the time of
 writing).

While extracting the code I shortly considered integrating the functionality
into debuntu-tools_, however the `/etc/fstab`_ and `/etc/crypttab`_ parsing
isn't specific to Debian or Ubuntu at all and debuntu-tools_ has several
dependencies that aren't relevant to Linux configuration file parsing.

Since then it has become clear that this was a good choice (not merging the
functionality into debuntu-tools_) because `linux-utils` now provides a Python
implementation of cryptdisks_start_ and cryptdisks_stop_, which is mostly
useful on Linux systems that *aren't* based on Debian 🙂.

Contact
-------

The latest version of `linux-utils` is available on PyPI_ and GitHub_. The
documentation is available on `Read the Docs`_ and includes a changelog_. For
bug reports please create an issue on GitHub_. If you have questions,
suggestions, etc. feel free to send me an e-mail at `[e-mail]`_.

License
-------

This software is licensed under the `MIT license`_.

© 2020 Peter Odding.

.. _/etc/crypttab: https://manpages.debian.org/crypttab
.. _/etc/fstab: https://manpages.debian.org/fstab
.. _changelog: https://linux-utils.readthedocs.org/en/latest/changelog.html
.. _cryptdisks_start: https://manpages.debian.org/cryptdisks_start
.. _cryptdisks_stop: https://manpages.debian.org/cryptdisks_stop
.. _crypto-drive-manager: https://pypi.python.org/pypi/crypto-drive-manager
.. _cryptsetup: https://manpages.debian.org/cryptsetup
.. _debuntu-tools: https://pypi.python.org/pypi/debuntu-tools
.. _GitHub: https://github.com/xolox/python-linux-utils
.. _Linux: https://en.wikipedia.org/wiki/Linux
.. _MIT license: http://en.wikipedia.org/wiki/MIT_License
.. _per user site-packages directory: https://www.python.org/dev/peps/pep-0370/
.. [e-mail]: [e-mail]
.. _PyPI: https://pypi.python.org/pypi/linux-utils
.. _Python Package Index: https://pypi.python.org/pypi/linux-utils
.. _Python: https://www.python.org/
.. _Read the Docs: https://linux-utils.readthedocs.io/en/latest/
.. _rsync-system-backup: https://pypi.python.org/pypi/rsync-system-backup
.. _Travis CI: https://travis-ci.org/xolox/python-linux-utils/builds
.. _virtual environments: http://docs.python-guide.org/en/latest/dev/virtualenvs/