Show licenses for all packages in requirements.txt

show_licenses_for_requirements.py

#Usage: python show_licenses_for_requirements.py ./requirements.txt

# Setup:
# pip install requirements-parser

import sys
import pkg_resources
import requirements

def get_modules(requirements_file_path):

    reqfile = open(requirements_file_path,'r')
    
    reqs = []
    
    for req in requirements.parse(reqfile):
    
        #reqs.name, reqs.specs, reqs.extras
        reqs.append(req)
    
    return reqs

def get_pkg_license(pkgname):
    """
    Given a package reference (as from requirements.txt),
    return license listed in package metadata.
    NOTE: This function does no error checking and is for
    demonstration purposes only.
    """
    pkgs = pkg_resources.require(pkgname)
    pkg = pkgs[0]
    for line in pkg.get_metadata_lines('METADATA'):
        (k, v) = line.split(': ', 1)
        if k == "License":
            return v
    return None
    
requirements = get_modules(sys.argv[1])

for index, requirement in enumerate(requirements):
    
    try:
        license = get_pkg_license(requirement.name)
    except:
        license = 'UNKNOWN'
        
    print(requirement.name + ' ('+''.join(list(requirement.specs[0]))+')' + ': ' + license)