expire

This is a program for expiring old backup files. It is modeled on dirvish-expire, part of dirvish, a rotating backup system. A good explanation of the expiration rules is in the Debian HOWTO; note that this system does not use dirvish's expire-default mechanism, so to accomplish the default expiration of 15 days, the last line in the set of example rules would need to be uncommented:

#       MIN HR    DOM MON       DOW  STRFTIME_FMT
	*   *     *   *         1    +3 months
	*   *     1-7 *         1    +1 year
	*   *     1-7 1,4,7,10  1
	*   10-20 *   *         *    +4 days
#	*   *     *   *         2-7  +15 days

The basic idea is that files whose creation times match the crontab in the first five fields of a given rule are kept for the duration of the last field, or indefinitely if the last field is empty.

Note that this kind of scheme will not necessarily play nicely with a group of files that has previously been thinned according to some other plan. For instance, a directory containing only files from the first of the month will get over-thinned by rules set up to keep Monday files.

Installation

For regular use, start a virtual environment and install this package and its requirements, something like this:

python3 -m venv env
. env/bin/activate
pip install git+https://github.com/harvard-lil/expire#egg=expire

Usage

$ expire --help
Usage: expire [OPTIONS]

  A tool for expiring old backups.

Options:
  -r, --rules TEXT              A single rule (repeatable)
  --rulefile FILENAME           File of rules
  -d, --directory TEXT          Directory containing files to be considered
                                for deletion
  --recursive / --no-recursive  [default: no-recursive]
  -f, --files TEXT              A single file to be considered for deletion
                                (repeatable)
  --dryrun / --no-dryrun        [default: dryrun]
  -v, --verbosity LVL           Either CRITICAL, ERROR, WARNING, INFO or DEBUG
  --help                        Show this message and exit.

Typically, you would run with --rules or --rulefile (or both) and --directory or --files (or both) with the implicit defaults for --dryrun and --verbosity, in order to see what would happen; then you might run the same command again with --no-dryrun --verbosity WARNING to perform the actual deletion.

Development

For development, install Poetry and clone this repository. Then, in the repo's directory, install the package and its requirements like this:

poetry install

Keep it clean with poetry run pflake8.

Add dependencies with poetry add, and keep requirements.txt up-to-date with poetry export -o requirements.txt.

Run tests with poetry run pytest.

TODO

Improve testing.