Script to encrypt password for Travis

travis_encrypt_password.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Script to encrypt a string for Travis config file
"""


from __future__ import print_function
import base64
import json
from getpass import getpass
from cryptography.hazmat.primitives.serialization import load_pem_public_key
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric.padding import PKCS1v15


try:
    from urllib import urlopen
except:
    from urllib.request import urlopen


def load_key(pubkey):
    """Load public RSA key, with work-around for keys using
    incorrect header/footer format.

    Read more about RSA encryption with cryptography:
    https://cryptography.io/latest/hazmat/primitives/asymmetric/rsa/
    """
    try:
        return load_pem_public_key(pubkey.encode(), default_backend())
    except ValueError:
        # workaround for https://github.com/travis-ci/travis-api/issues/196
        pubkey = pubkey.replace('BEGIN RSA', 'BEGIN').replace('END RSA', 'END')
        return load_pem_public_key(pubkey.encode(), default_backend())


def encrypt(pubkey, password):
    """Encrypt password using given RSA public key and encode it with base64.

    The encrypted password can only be decrypted by someone with the
    private key (in this case, only Travis).
    """
    key = load_key(pubkey)
    encrypted_password = key.encrypt(password, PKCS1v15())
    return base64.b64encode(encrypted_password)


def fetch_public_key(repo):
    """Download RSA public key Travis will use for this repo.

    Travis API docs: http://docs.travis-ci.com/api/#repository-keys
    """
    keyurl = 'https://api.travis-ci.org/repos/{0}/key'.format(repo)
    data = json.loads(urlopen(keyurl).read())
    if 'key' not in data:
        errmsg = "Could not find public key for repo: {}.\n".format(repo)
        errmsg += "Have you already added your GitHub repo to Travis?"
        raise ValueError(errmsg)
    return data['key']


def prepend_line(filepath, line):
    """Rewrite a file adding a line to its beginning.
    """
    with open(filepath) as f:
        lines = f.readlines()

    lines.insert(0, line)

    with open(filepath, 'w') as f:
        f.writelines(lines)


def main(args):
    public_key = fetch_public_key(args.repo)
    password = getpass('PyPI password: ')
    print(encrypt(public_key, password))


if '__main__' == __name__:
    import argparse
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('repo', help='GitHub repo')

    args = parser.parse_args()
    main(args)