X-Git-Url: http://git.scottworley.com/pinch/blobdiff_plain/2f96f32a70f6ed975758e2bbcd88fa5f3ee95615..17d42dd500b06196b70af99e05e9d0fffaf3f38e:/pinch.py?ds=inline diff --git a/pinch.py b/pinch.py index f974d1c..b3f65c6 100644 --- a/pinch.py +++ b/pinch.py @@ -1,3 +1,4 @@ +import configparser import filecmp import functools import hashlib @@ -5,20 +6,46 @@ import operator import os import os.path import shutil +import subprocess +import sys import tempfile +import types import urllib.parse import urllib.request import xml.dom.minidom from typing import ( - Any, Dict, Iterable, List, - Sequence, + NewType, Tuple, ) +Digest16 = NewType('Digest16', str) +Digest32 = NewType('Digest32', str) + + +class ChannelTableEntry(types.SimpleNamespace): + absolute_url: str + digest: Digest16 + file: str + size: int + url: str + + +class Channel(types.SimpleNamespace): + channel_html: bytes + channel_url: str + forwarded_url: str + git_cachedir: str + git_ref: str + git_repo: str + git_revision: str + old_git_revision: str + release_name: str + table: Dict[str, ChannelTableEntry] + class VerificationError(Exception): pass @@ -55,10 +82,7 @@ class Verification: self.result(True) -def compare(a: str, - b: str) -> Tuple[Sequence[str], - Sequence[str], - Sequence[str]]: +def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]: def throw(error: OSError) -> None: raise error @@ -86,86 +110,319 @@ def compare(a: str, return filecmp.cmpfiles(a, b, files, shallow=False) -def fetch(v: Verification, channel_url: str) -> Dict[str, Any]: - info: Dict[str, Any] = {'url': channel_url} +def fetch(v: Verification, channel: Channel) -> None: v.status('Fetching channel') - request = urllib.request.urlopen( - 'https://channels.nixos.org/nixos-20.03', timeout=10) - info['channel_html'] = request.read() - info['forwarded_url'] = request.geturl() + request = urllib.request.urlopen(channel.channel_url, timeout=10) + channel.channel_html = request.read() + channel.forwarded_url = request.geturl() v.result(request.status == 200) - v.check('Got forwarded', info['url'] != info['forwarded_url']) - return info + v.check('Got forwarded', channel.channel_url != channel.forwarded_url) -def parse(v: Verification, info: Dict[str, Any]) -> None: +def parse_channel(v: Verification, channel: Channel) -> None: v.status('Parsing channel description as XML') - d = xml.dom.minidom.parseString(info['channel_html']) + d = xml.dom.minidom.parseString(channel.channel_html) v.ok() - v.status('Extracting git commit') + v.status('Extracting release name:') + title_name = d.getElementsByTagName( + 'title')[0].firstChild.nodeValue.split()[2] + h1_name = d.getElementsByTagName('h1')[0].firstChild.nodeValue.split()[2] + v.status(title_name) + v.result(title_name == h1_name) + channel.release_name = title_name + + v.status('Extracting git commit:') git_commit_node = d.getElementsByTagName('tt')[0] - info['git_commit'] = git_commit_node.firstChild.nodeValue + channel.git_revision = git_commit_node.firstChild.nodeValue + v.status(channel.git_revision) v.ok() v.status('Verifying git commit label') v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ') v.status('Parsing table') - info['table'] = {} + channel.table = {} for row in d.getElementsByTagName('tr')[1:]: name = row.childNodes[0].firstChild.firstChild.nodeValue url = row.childNodes[0].firstChild.getAttribute('href') size = int(row.childNodes[1].firstChild.nodeValue) - digest = row.childNodes[2].firstChild.firstChild.nodeValue - info['table'][name] = {'url': url, 'digest': digest, 'size': size} + digest = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue) + channel.table[name] = ChannelTableEntry( + url=url, digest=digest, size=size) v.ok() -def fetch_resources(v: Verification, info: Dict[str, Any]) -> None: +def digest_string(s: bytes) -> Digest16: + return Digest16(hashlib.sha256(s).hexdigest()) + + +def digest_file(filename: str) -> Digest16: + hasher = hashlib.sha256() + with open(filename, 'rb') as f: + # pylint: disable=cell-var-from-loop + for block in iter(lambda: f.read(4096), b''): + hasher.update(block) + return Digest16(hasher.hexdigest()) + + +def to_Digest16(v: Verification, digest32: Digest32) -> Digest16: + v.status('Converting digest to base16') + process = subprocess.run( + ['nix', 'to-base16', '--type', 'sha256', digest32], capture_output=True) + v.result(process.returncode == 0) + return Digest16(process.stdout.decode().strip()) + + +def to_Digest32(v: Verification, digest16: Digest16) -> Digest32: + v.status('Converting digest to base32') + process = subprocess.run( + ['nix', 'to-base32', '--type', 'sha256', digest16], capture_output=True) + v.result(process.returncode == 0) + return Digest32(process.stdout.decode().strip()) + + +def fetch_with_nix_prefetch_url( + v: Verification, + url: str, + digest: Digest16) -> str: + v.status('Fetching %s' % url) + process = subprocess.run( + ['nix-prefetch-url', '--print-path', url, digest], capture_output=True) + v.result(process.returncode == 0) + prefetch_digest, path, empty = process.stdout.decode().split('\n') + assert empty == '' + v.check("Verifying nix-prefetch-url's digest", + to_Digest16(v, Digest32(prefetch_digest)) == digest) + v.status("Verifying file digest") + file_digest = digest_file(path) + v.result(file_digest == digest) + return path + +def fetch_resources(v: Verification, channel: Channel) -> None: for resource in ['git-revision', 'nixexprs.tar.xz']: - fields = info['table'][resource] - v.status('Fetching resource "%s"' % resource) - url = urllib.parse.urljoin(info['forwarded_url'], fields['url']) - request = urllib.request.urlopen(url, timeout=10) - if fields['size'] < 4096: - fields['content'] = request.read() - else: - with tempfile.NamedTemporaryFile(suffix='.nixexprs.tar.xz', delete=False) as tmp_file: - shutil.copyfileobj(request, tmp_file) - fields['file'] = tmp_file.name - v.result(request.status == 200) - v.status('Verifying digest for "%s"' % resource) - if fields['size'] < 4096: - actual_hash = hashlib.sha256(fields['content']).hexdigest() - else: - hasher = hashlib.sha256() - with open(fields['file'], 'rb') as f: - # pylint: disable=cell-var-from-loop - for block in iter(lambda: f.read(4096), b''): - hasher.update(block) - actual_hash = hasher.hexdigest() - v.result(actual_hash == fields['digest']) - v.check('Verifying git commit on main page matches git commit in table', - info['table']['git-revision']['content'].decode() == info['git_commit']) - - -def extract_channel(v: Verification, info: Dict[str, Any]) -> None: - with tempfile.TemporaryDirectory() as d: - v.status('Extracting nixexprs.tar.xz') - shutil.unpack_archive(info['table']['nixexprs.tar.xz']['file'], d) - v.ok() - v.status('Removing temporary directory') + fields = channel.table[resource] + fields.absolute_url = urllib.parse.urljoin( + channel.forwarded_url, fields.url) + fields.file = fetch_with_nix_prefetch_url( + v, fields.absolute_url, fields.digest) + v.status('Verifying git commit on main page matches git commit in table') + v.result( + open( + channel.table['git-revision'].file).read(999) == channel.git_revision) + + +def git_fetch(v: Verification, channel: Channel) -> None: + # It would be nice if we could share the nix git cache, but as of the time + # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready + # yet), and trying to straddle them both is too far into nix implementation + # details for my comfort. So we re-implement here half of nix.fetchGit. + # :( + + # TODO: Consider using pyxdg to find this path. + channel.git_cachedir = os.path.expanduser( + '~/.cache/nix-pin-channel/git/%s' % + digest_string( + channel.git_repo.encode())) + if not os.path.exists(channel.git_cachedir): + v.status("Initializing git repo") + process = subprocess.run( + ['git', 'init', '--bare', channel.git_cachedir]) + v.result(process.returncode == 0) + + have_rev = False + if hasattr(channel, 'git_revision'): + v.status('Checking if we already have this rev:') + process = subprocess.run( + ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_revision]) + if process.returncode == 0: + v.status('yes') + if process.returncode == 1: + v.status('no') + v.result(process.returncode == 0 or process.returncode == 1) + have_rev = process.returncode == 0 + + if not have_rev: + v.status( + 'Fetching ref "%s" from %s' % + (channel.git_ref, channel.git_repo)) + # We don't use --force here because we want to abort and freak out if forced + # updates are happening. + process = subprocess.run(['git', + '-C', + channel.git_cachedir, + 'fetch', + channel.git_repo, + '%s:%s' % (channel.git_ref, + channel.git_ref)]) + v.result(process.returncode == 0) + if hasattr(channel, 'git_revision'): + v.status('Verifying that fetch retrieved this rev') + process = subprocess.run( + ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_revision]) + v.result(process.returncode == 0) + + if not hasattr(channel, 'git_revision'): + channel.git_revision = open( + os.path.join( + channel.git_cachedir, + 'refs', + 'heads', + channel.git_ref)).read(999).strip() + + v.status('Verifying rev is an ancestor of ref') + process = subprocess.run(['git', + '-C', + channel.git_cachedir, + 'merge-base', + '--is-ancestor', + channel.git_revision, + channel.git_ref]) + v.result(process.returncode == 0) + + if hasattr(channel, 'old_git_revision'): + v.status( + 'Verifying rev is an ancestor of previous rev %s' % + channel.old_git_revision) + process = subprocess.run(['git', + '-C', + channel.git_cachedir, + 'merge-base', + '--is-ancestor', + channel.old_git_revision, + channel.git_revision]) + v.result(process.returncode == 0) + + +def compare_tarball_and_git( + v: Verification, + channel: Channel, + channel_contents: str, + git_contents: str) -> None: + v.status('Comparing channel tarball with git checkout') + match, mismatch, errors = compare(os.path.join( + channel_contents, channel.release_name), git_contents) + v.ok() + v.check('%d files match' % len(match), len(match) > 0) + v.check('%d files differ' % len(mismatch), len(mismatch) == 0) + expected_errors = [ + '.git-revision', + '.version-suffix', + 'nixpkgs', + 'programs.sqlite', + 'svn-revision'] + benign_errors = [] + for ee in expected_errors: + if ee in errors: + errors.remove(ee) + benign_errors.append(ee) + v.check( + '%d unexpected incomparable files' % + len(errors), + len(errors) == 0) + v.check( + '(%d of %d expected incomparable files)' % + (len(benign_errors), + len(expected_errors)), + len(benign_errors) == len(expected_errors)) + + +def extract_tarball(v: Verification, channel: Channel, dest: str) -> None: + v.status('Extracting tarball %s' % + channel.table['nixexprs.tar.xz'].file) + shutil.unpack_archive( + channel.table['nixexprs.tar.xz'].file, + dest) + v.ok() + + +def git_checkout(v: Verification, channel: Channel, dest: str) -> None: + v.status('Checking out corresponding git revision') + git = subprocess.Popen(['git', + '-C', + channel.git_cachedir, + 'archive', + channel.git_revision], + stdout=subprocess.PIPE) + tar = subprocess.Popen( + ['tar', 'x', '-C', dest, '-f', '-'], stdin=git.stdout) + git.stdout.close() + tar.wait() + git.wait() + v.result(git.returncode == 0 and tar.returncode == 0) + + +def check_channel_metadata( + v: Verification, + channel: Channel, + channel_contents: str) -> None: + v.status('Verifying git commit in channel tarball') + v.result( + open( + os.path.join( + channel_contents, + channel.release_name, + '.git-revision')).read(999) == channel.git_revision) + + v.status( + 'Verifying version-suffix is a suffix of release name %s:' % + channel.release_name) + version_suffix = open( + os.path.join( + channel_contents, + channel.release_name, + '.version-suffix')).read(999) + v.status(version_suffix) + v.result(channel.release_name.endswith(version_suffix)) + + +def check_channel_contents(v: Verification, channel: Channel) -> None: + with tempfile.TemporaryDirectory() as channel_contents, \ + tempfile.TemporaryDirectory() as git_contents: + + extract_tarball(v, channel, channel_contents) + check_channel_metadata(v, channel, channel_contents) + + git_checkout(v, channel, git_contents) + + compare_tarball_and_git(v, channel, channel_contents, git_contents) + + v.status('Removing temporary directories') v.ok() -def main() -> None: +def pin_channel(v: Verification, channel: Channel) -> None: + fetch(v, channel) + parse_channel(v, channel) + fetch_resources(v, channel) + git_fetch(v, channel) + check_channel_contents(v, channel) + + +def make_channel(conf: configparser.SectionProxy) -> Channel: + channel = Channel(**dict(conf.items())) + if hasattr(channel, 'git_revision'): + channel.old_git_revision = channel.git_revision + del channel.git_revision + return channel + + +def main(argv: List[str]) -> None: v = Verification() - info = fetch(v, 'https://channels.nixos.org/nixos-20.03') - parse(v, info) - fetch_resources(v, info) - extract_channel(v, info) - print(info) + config = configparser.ConfigParser() + config.read_file(open(argv[1]), argv[1]) + for section in config.sections(): + channel = make_channel(config[section]) + if 'channel_url' in config[section]: + pin_channel(v, channel) + config[section]['tarball_url'] = channel.table['nixexprs.tar.xz'].absolute_url + config[section]['tarball_sha256'] = channel.table['nixexprs.tar.xz'].digest + else: + git_fetch(v, channel) + config[section]['git_revision'] = channel.git_revision + + with open(argv[1], 'w') as configfile: + config.write(configfile) -main() +main(sys.argv)