Python third_party_license_file_generator

The Python third_party_license_file_generator is aimed at distilling down the appropriate license for one or many pip "requirements" files into a single file; it supports Python2.7 and Python3.

How do I install it?

$ pip install third-party-license-file-generator

How do I use it?

$ python -m third_party_license_file_generator -h

How does it work?

With no arguments (other than a pip "requirements" file and a Python executable path that has those requirements installed), the process is as follows:

• walk the given Python executable's site-packages folder and build up package metadata (and license files, if present)
• filter down by packages that are listed in the pip "requirements" file (and those packages dependencies, and their dependencies, and their dependencies... you get the gist)
  • note: it follows "-r some_file.txt" references found in the pip "requirements" files
• if a license name could not be secured for a package, try to gather that from the package's PyPI web page
  • if a license name has still not been secured and the package lists a GitHub home page, try to find a license from there
    • otherwise, assume the package to be commercially licensed (as it is legally understood that is the case)
• if a license file could not be secured for a package and the package lists a GitHub home page, try to find a license from there
  • otherwise, create a license (for the known license name) from a local collection of licenses (within the Python Third Party License Generator)
• show a summary of packages against licenses to the user
• build a THIRDPARTYLICENSES file in the current folder
• give a return code of zero for success or non-zero for failures (e.g. GPL-licensed packages detected when specified to not permit GPL)

It's worth noting that information learned about packages is cached- so if you have to build one third party licenses file for a large project that has many components with many dependencies (but some overlap) then it's best to specify all those pip "requirements" files and Python executable paths in a single call to the Python third_party_license_file_generator as it will take less time overall.

You can specify a number of command line options (check syntax with -h) to do things like the following:

• handle multiple pip "requirements" files
• handle multiple Python executable paths
• whether or not to permit GPL-licensed packages (default no)
• specific GPL-licensed package exceptions (e.g. if a package lists exceptions to the GPL that may suit your needs but is still GPL-licensed)
• whether or not to permit comercially-licensed packages (default no)
• specific comercially-licensed package exceptions (e.g. if you have a license for a package or if you own a package)
• a "skip prefix" (e.g. if you want to skip all packages starting with a certain string)
• disable internet lookups (if you don't want to pull data from PyPI and GitHub)
• disable skipping of not required packages (packages that are not requirements of other packages are skipped by default during license file generation)

Examples

Two different pip "requirements" files, two different Python paths (Virtualenvs) and a skip prefix:

python -m third_party_license_file_generator \
    -r requirements-py.txt \
    -p ~/.virtualenvs/backend_py/bin/python \
    -r requirements-pypy.txt \
    -p ~/.virtualenvs/backend_pypy/bin/python \
    -s ims-

Please note that pip "requirements" files and Python executable paths are paired together in the order they're specified.

Three different pip "requirements" files, two different Python paths (need to repeat), a GPL exception and a custom output file:

python -m third_party_license_file_generator \
    -r requirements.txt \
    -p ~/.virtualenvs/api_pypy/bin/python \
    -r pypy_requirements.txt \
    -p ~/.virtualenvs/api_pypy/bin/python \
    -r cpython_requirements.txt \
    -p ~/.virtualenvs/api_py/bin/python \
    -x uWSGI \ 
    -o ThirdPartyLicenses.txt

Three different pip "requirements" files, two different Python paths (need to repeat), a GPL exception, a custom output file and a license override file:

# contents of license_override_file.yml
uWSGI: 
    license_name: GPL-2.0 w/ linking exception
    license_file: https://raw.githubusercontent.com/unbit/uwsgi/master/LICENSE

python -m third_party_license_file_generator \
    -r requirements.txt \
    -p ~/.virtualenvs/api_pypy/bin/python \
    -r pypy_requirements.txt \
    -p ~/.virtualenvs/api_pypy/bin/python \
    -r cpython_requirements.txt \
    -p ~/.virtualenvs/api_py/bin/python \
    -x uWSGI \ 
    -o ThirdPartyLicenses.txt \
    -l license_override_file.yml

An example of the structure of the generated third party license file is as follows:

Start of 'ThirdPartyLicenses.txt' generated by Python third_party_license_generator at 2018-04-19 12:36:58.627421

----------------------------------------

Package: Django
License: BSD-3-clause
Requires: pytz
Author: Django Software Foundation <foundation@djangoproject.com>
Home page: https://www.djangoproject.com/

(license content appears here in full)

----------------------------------------

End of 'ThirdPartyLicenses.txt' generated by Python third_party_license_generator at 2018-04-19 12:36:58.627825