Get installed package licenses in the current virtualenv

get_package_licenses.py

# -*- coding: utf-8 -*-
from pip import get_installed_distributions


def process_dist(dist):
    license = None
    metadata = None
    if dist.has_metadata('PKG-INFO'):
        metadata = dist.get_metadata('PKG-INFO')
    if dist.has_metadata('METADATA'):
        metadata = dist.get_metadata('METADATA')
    if metadata:
        license = find_license(metadata)
    yield (dist.project_name, license or "<no license found>")


def find_license(metadata):
    for line in metadata.splitlines():
        if line.startswith("License:"):
            license = line.split(None, 1)[-1]
            if license and "unknown" not in license.lower():
                return license
        if line.startswith("Classifier:"):
            classifier = line.split(" ", 1)[-1]
            if classifier.startswith("License"):
                return classifier.split(" :: ")[-1]


def run():
    licenses = {}

    for dist in get_installed_distributions(local_only=True):
        licenses.update(process_dist(dist))

    for project_name, version in sorted(licenses.items()):
        print("%s\t%s" % (project_name, version))


if __name__ == "__main__":
    run()