X-Git-Url: http://git.scottworley.com/pinch/blobdiff_plain/73bec7e8e5b260f38f7a907ad1b5e17457596dbf..971d3659a4f2ba4e3daeba142668809529ff65c1:/pinch.py?ds=inline diff --git a/pinch.py b/pinch.py index dfdedac..0f8f00a 100644 --- a/pinch.py +++ b/pinch.py @@ -1,3 +1,5 @@ +import argparse +import configparser import filecmp import functools import hashlib @@ -17,7 +19,6 @@ from typing import ( Iterable, List, NewType, - Sequence, Tuple, ) @@ -25,19 +26,24 @@ Digest16 = NewType('Digest16', str) Digest32 = NewType('Digest32', str) -class InfoTableEntry(types.SimpleNamespace): +class ChannelTableEntry(types.SimpleNamespace): + absolute_url: str digest: Digest16 file: str size: int url: str -class Info(types.SimpleNamespace): +class Channel(types.SimpleNamespace): channel_html: bytes + channel_url: str forwarded_url: str + git_ref: str + git_repo: str git_revision: str - table: Dict[str, InfoTableEntry] - url: str + old_git_revision: str + release_name: str + table: Dict[str, ChannelTableEntry] class VerificationError(Exception): @@ -75,10 +81,7 @@ 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 @@ -106,42 +109,52 @@ def compare(a: str, return filecmp.cmpfiles(a, b, files, shallow=False) -def fetch(v: Verification, channel_url: str) -> Info: - info = Info() - info.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_table(v: Verification, info: Info) -> 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 = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue) - info.table[name] = InfoTableEntry(url=url, digest=digest, size=size) + channel.table[name] = ChannelTableEntry( + url=url, digest=digest, size=size) v.ok() +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: @@ -185,33 +198,269 @@ def fetch_with_nix_prefetch_url( return path -def fetch_resources(v: Verification, info: Info) -> None: +def fetch_resources(v: Verification, channel: Channel) -> None: for resource in ['git-revision', 'nixexprs.tar.xz']: - fields = info.table[resource] - url = urllib.parse.urljoin(info.forwarded_url, fields.url) - fields.file = fetch_with_nix_prefetch_url(v, url, fields.digest) + 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( - info.table['git-revision'].file).read(999) == info.git_commit) + channel.table['git-revision'].file).read(999) == channel.git_revision) + + +def git_cachedir(git_repo: str) -> str: + # TODO: Consider using pyxdg to find this path. + return os.path.expanduser( + '~/.cache/nix-pin-channel/git/%s' % + digest_string( + git_repo.encode())) + + +def verify_git_ancestry(v: Verification, channel: Channel) -> None: + cachedir = git_cachedir(channel.git_repo) + v.status('Verifying rev is an ancestor of ref') + process = subprocess.run(['git', + '-C', + 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', + cachedir, + 'merge-base', + '--is-ancestor', + channel.old_git_revision, + channel.git_revision]) + v.result(process.returncode == 0) + + +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. + # :( + + cachedir = git_cachedir(channel.git_repo) + if not os.path.exists(cachedir): + v.status("Initializing git repo") + process = subprocess.run( + ['git', 'init', '--bare', cachedir]) + v.result(process.returncode == 0) + + 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', + cachedir, + 'fetch', + channel.git_repo, + '%s:%s' % (channel.git_ref, + channel.git_ref)]) + v.result(process.returncode == 0) -def extract_channel(v: Verification, info: Info) -> 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') + if hasattr(channel, 'git_revision'): + v.status('Verifying that fetch retrieved this rev') + process = subprocess.run( + ['git', '-C', cachedir, 'cat-file', '-e', channel.git_revision]) + v.result(process.returncode == 0) + else: + channel.git_revision = open( + os.path.join( + cachedir, + 'refs', + 'heads', + channel.git_ref)).read(999).strip() + + verify_git_ancestry(v, channel) + + +def ensure_git_rev_available(v: Verification, channel: Channel) -> None: + cachedir = git_cachedir(channel.git_repo) + if os.path.exists(cachedir): + v.status('Checking if we already have this rev:') + process = subprocess.run( + ['git', '-C', 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) + if process.returncode == 0: + verify_git_ancestry(v, channel) + return + git_fetch(v, channel) + + +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 main() -> None: +def git_checkout(v: Verification, channel: Channel, dest: str) -> None: + v.status('Checking out corresponding git revision') + git = subprocess.Popen(['git', + '-C', + git_cachedir(channel.git_repo), + '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 pin_channel(v: Verification, channel: Channel) -> None: + fetch(v, channel) + parse_channel(v, channel) + fetch_resources(v, channel) + ensure_git_rev_available(v, channel) + check_channel_contents(v, channel) + + +def git_revision_name(v: Verification, channel: Channel) -> str: + v.status('Getting commit date') + process = subprocess.run(['git', + '-C', + git_cachedir(channel.git_repo), + 'lo', + '-n1', + '--format=%ct-%h', + '--abbrev=11', + channel.git_revision], + capture_output=True) + v.result(process.returncode == 0 and process.stdout != '') + return '%s-%s' % (os.path.basename(channel.git_repo), + process.stdout.decode().strip()) + + +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 pin(args: argparse.Namespace) -> None: v = Verification() - info = fetch(v, 'https://channels.nixos.org/nixos-20.03') - parse_table(v, info) - fetch_resources(v, info) - extract_channel(v, info) - print(info) + config = configparser.ConfigParser() + config.read_file(open(args.channels_file), args.channels_file) + for section in config.sections(): + channel = make_channel(config[section]) + if 'channel_url' in config[section]: + pin_channel(v, channel) + config[section]['name'] = channel.release_name + 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]['name'] = git_revision_name(v, channel) + config[section]['git_revision'] = channel.git_revision + + with open(args.channels_file, 'w') as configfile: + config.write(configfile) + + +def main() -> None: + parser = argparse.ArgumentParser(prog='pinch') + subparsers = parser.add_subparsers(dest='mode', required=True) + parser_pin = subparsers.add_parser('pin') + parser_pin.add_argument('channels_file', type=str) + parser_pin.set_defaults(func=pin) + args = parser.parse_args() + args.func(args) main()