pypi-publish/attestations.py

115 lines
4 KiB
Python
Raw Permalink Normal View History

import logging
import os
import sys
from pathlib import Path
from typing import NoReturn
from pypi_attestations import Attestation, Distribution
from sigstore.oidc import IdentityError, IdentityToken, detect_credential
from sigstore.sign import Signer, SigningContext
# Be very verbose.
sigstore_logger = logging.getLogger('sigstore')
sigstore_logger.setLevel(logging.DEBUG)
sigstore_logger.addHandler(logging.StreamHandler())
_GITHUB_STEP_SUMMARY = Path(os.getenv('GITHUB_STEP_SUMMARY'))
# The top-level error message that gets rendered.
# This message wraps one of the other templates/messages defined below.
_ERROR_SUMMARY_MESSAGE = """
Attestation generation failure:
{message}
You're seeing this because the action attempted to generated PEP 740
attestations for its inputs, but failed to do so.
"""
# Rendered if OIDC identity token retrieval fails for any reason.
_TOKEN_RETRIEVAL_FAILED_MESSAGE = """
OpenID Connect token retrieval failed: {identity_error}
This failure occurred after a successful Trusted Publishing Flow,
suggesting a transient error.
""" # noqa: S105; not a password
def die(msg: str) -> NoReturn:
with _GITHUB_STEP_SUMMARY.open('a', encoding='utf-8') as io:
print(_ERROR_SUMMARY_MESSAGE.format(message=msg), file=io)
# HACK: GitHub Actions' annotations don't work across multiple lines naively;
# translating `\n` into `%0A` (i.e., HTML percent-encoding) is known to work.
# See: https://github.com/actions/toolkit/issues/193
msg = msg.replace('\n', '%0A')
print(f'::error::Attestation generation failure: {msg}', file=sys.stderr)
sys.exit(1)
def debug(msg: str):
print(f'::debug::{msg}', file=sys.stderr)
def collect_dists(packages_dir: Path) -> list[Path]:
# Collect all sdists and wheels.
dist_paths = [sdist.resolve() for sdist in packages_dir.glob('*.tar.gz')]
dist_paths.extend(whl.resolve() for whl in packages_dir.glob('*.whl'))
# Make sure everything that looks like a dist actually is one.
# We do this up-front to prevent partial signing.
if (invalid_dists := [path for path in dist_paths if not path.is_file()]):
invalid_dist_list = ', '.join(map(str, invalid_dists))
die(
'The following paths look like distributions but '
f'are not actually files: {invalid_dist_list}',
)
return dist_paths
def attest_dist(dist_path: Path, signer: Signer) -> None:
# We are the publishing step, so there should be no pre-existing publish
# attestation. The presence of one indicates user confusion.
attestation_path = Path(f'{dist_path}.publish.attestation')
if attestation_path.exists():
die(f'{dist_path} already has a publish attestation: {attestation_path}')
dist = Distribution.from_file(dist_path)
attestation = Attestation.sign(signer, dist)
attestation_path.write_text(attestation.model_dump_json(), encoding='utf-8')
debug(f'saved publish attestation: {dist_path=} {attestation_path=}')
def get_identity_token() -> IdentityToken:
# Will raise `sigstore.oidc.IdentityError` if it fails to get the token
# from the environment or if the token is malformed.
# NOTE: audience is always sigstore.
oidc_token = detect_credential()
return IdentityToken(oidc_token)
def main() -> None:
packages_dir = Path(sys.argv[1])
try:
identity = get_identity_token()
except IdentityError as identity_error:
# NOTE: We only perform attestations in trusted publishing flows, so we
# don't need to re-check for the "PR from fork" error mode, only
# generic token retrieval errors. We also render a simpler error,
# since permissions can't be to blame at this stage.
die(_TOKEN_RETRIEVAL_FAILED_MESSAGE.format(identity_error=identity_error))
dist_paths = collect_dists(packages_dir)
with SigningContext.production().signer(identity, cache=True) as s:
debug(f'attesting to dists: {dist_paths}')
for dist_path in dist_paths:
attest_dist(dist_path, s)
if __name__ == '__main__':
main()