Pre-Commit License Headers

A pre-commit hook to check the license headers of your source code files.

At present, it only supports checking files that use hash mark # comment syntax. For more info, see Supported file types.

Usage

Add an entry like this to your .pre-commit-config.yaml

- repo: https://github.com/johannsdg/pre-commit-license-headers
  rev: v0.1.0 # Use the ref you want to point at
  hooks:
    - id: check-license-headers
      args:
        - "--template"
        - |
          Copyright (c) [YEARS] [OWNER]
          Use of this source code is governed by a BSD-3-clause license that can
          be found in the LICENSE file or at https://opensource.org/licenses/BSD-3-Clause
        - "--owner=The Pre-Commit License Headers Authors"

(Note that the template provided above is the default, so if you are using BSD-3-clause and are happy with the wording, you can skip --template and just provide --owner)

[YEARS] and [OWNER] are optional variables in the header template. If used, they will automatically be replaced with:

• [YEARS]: a regular expression that accepts various combinations of years, such as:
  • Single years, such as '2019' or '2021'
  • Year ranges, such as '2018-2020'
  • Combinations, such as '2014, 2016-2018, 2020'
  • Note that ranges ending in '-present' are not supported
• [OWNER]: the contents of the --owner argument
  • Note that --owner is optional unless the template uses the [OWNER] variable

Supported file types

Pre-Commit License Headers supports checking file types that use hash mark # comment syntax.

This includes:

• python
• shell
• yaml
• toml
• plain-text
• etc

For the list of file types checked by default, see file_types.py You may override the default list with your own via the -f or --file-type option (may be specified multiple times).

File types are determined using the identify library. For more information about file types, see: https://pre-commit.com/#filtering-files-with-types

As a standalone package

Pre-Commit License Headers is also available as a standalone package.

To install via pip:

pip install pre-commit-license-headers

You may also clone this repo and install via poetry:

poetry install --no-dev

Either installation option will place the check-license-headers executable in your environment's configured binary directory (e.g., '.venv/bin')

To use:

foo@bar:~$ check-license-headers --help
usage: check-license-headers [-h] [-d] [--list-file-types] [-s] [-f FILE_TYPE]
                             [-o COPYRIGHT_OWNER] -t TEMPLATE
                             [FILE [FILE ...]]

Checks if file headers match a provided template.

positional arguments:
  FILE

optional arguments:
  -h, --help            show this help message and exit
  -d, --debug
  --list-file-types     lists all text file types and exits
  -s, --summary         prints a summary after checking the files
  -f FILE_TYPE, --file-type FILE_TYPE
                        may be specified multiple times
  -o COPYRIGHT_OWNER, --owner COPYRIGHT_OWNER
  -t TEMPLATE, --template TEMPLATE