git.scottworley.com Git - pinch/blob - pinch.py

   1 import argparse
   2 import configparser
   3 import filecmp
   4 import functools
   5 import getpass
   6 import hashlib
   7 import operator
   8 import os
   9 import os.path
  10 import shutil
  11 import subprocess
  12 import tempfile
  13 import types
  14 import urllib.parse
  15 import urllib.request
  16 import xml.dom.minidom
  17
  18 from typing import (
  19     Dict,
  20     Iterable,
  21     List,
  22     NewType,
  23     Tuple,
  24 )
  25
  26 Digest16 = NewType('Digest16', str)
  27 Digest32 = NewType('Digest32', str)
  28
  29
  30 class ChannelTableEntry(types.SimpleNamespace):
  31     absolute_url: str
  32     digest: Digest16
  33     file: str
  34     size: int
  35     url: str
  36
  37
  38 class Channel(types.SimpleNamespace):
  39     channel_html: bytes
  40     channel_url: str
  41     forwarded_url: str
  42     git_ref: str
  43     git_repo: str
  44     git_revision: str
  45     old_git_revision: str
  46     release_name: str
  47     table: Dict[str, ChannelTableEntry]
  48
  49
  50 class VerificationError(Exception):
  51     pass
  52
  53
  54 class Verification:
  55
  56     def __init__(self) -> None:
  57         self.line_length = 0
  58
  59     def status(self, s: str) -> None:
  60         print(s, end=' ', flush=True)
  61         self.line_length += 1 + len(s)  # Unicode??
  62
  63     @staticmethod
  64     def _color(s: str, c: int) -> str:
  65         return '\033[%2dm%s\033[00m' % (c, s)
  66
  67     def result(self, r: bool) -> None:
  68         message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r]
  69         length = len(message)
  70         cols = shutil.get_terminal_size().columns
  71         pad = (cols - (self.line_length + length)) % cols
  72         print(' ' * pad + self._color(message, color))
  73         self.line_length = 0
  74         if not r:
  75             raise VerificationError()
  76
  77     def check(self, s: str, r: bool) -> None:
  78         self.status(s)
  79         self.result(r)
  80
  81     def ok(self) -> None:
  82         self.result(True)
  83
  84
  85 def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]:
  86
  87     def throw(error: OSError) -> None:
  88         raise error
  89
  90     def join(x: str, y: str) -> str:
  91         return y if x == '.' else os.path.join(x, y)
  92
  93     def recursive_files(d: str) -> Iterable[str]:
  94         all_files: List[str] = []
  95         for path, dirs, files in os.walk(d, onerror=throw):
  96             rel = os.path.relpath(path, start=d)
  97             all_files.extend(join(rel, f) for f in files)
  98             for dir_or_link in dirs:
  99                 if os.path.islink(join(path, dir_or_link)):
 100                     all_files.append(join(rel, dir_or_link))
 101         return all_files
 102
 103     def exclude_dot_git(files: Iterable[str]) -> Iterable[str]:
 104         return (f for f in files if not f.startswith('.git/'))
 105
 106     files = functools.reduce(
 107         operator.or_, (set(
 108             exclude_dot_git(
 109                 recursive_files(x))) for x in [a, b]))
 110     return filecmp.cmpfiles(a, b, files, shallow=False)
 111
 112
 113 def fetch(v: Verification, channel: Channel) -> None:
 114     v.status('Fetching channel')
 115     request = urllib.request.urlopen(channel.channel_url, timeout=10)
 116     channel.channel_html = request.read()
 117     channel.forwarded_url = request.geturl()
 118     v.result(request.status == 200)
 119     v.check('Got forwarded', channel.channel_url != channel.forwarded_url)
 120
 121
 122 def parse_channel(v: Verification, channel: Channel) -> None:
 123     v.status('Parsing channel description as XML')
 124     d = xml.dom.minidom.parseString(channel.channel_html)
 125     v.ok()
 126
 127     v.status('Extracting release name:')
 128     title_name = d.getElementsByTagName(
 129         'title')[0].firstChild.nodeValue.split()[2]
 130     h1_name = d.getElementsByTagName('h1')[0].firstChild.nodeValue.split()[2]
 131     v.status(title_name)
 132     v.result(title_name == h1_name)
 133     channel.release_name = title_name
 134
 135     v.status('Extracting git commit:')
 136     git_commit_node = d.getElementsByTagName('tt')[0]
 137     channel.git_revision = git_commit_node.firstChild.nodeValue
 138     v.status(channel.git_revision)
 139     v.ok()
 140     v.status('Verifying git commit label')
 141     v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ')
 142
 143     v.status('Parsing table')
 144     channel.table = {}
 145     for row in d.getElementsByTagName('tr')[1:]:
 146         name = row.childNodes[0].firstChild.firstChild.nodeValue
 147         url = row.childNodes[0].firstChild.getAttribute('href')
 148         size = int(row.childNodes[1].firstChild.nodeValue)
 149         digest = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue)
 150         channel.table[name] = ChannelTableEntry(
 151             url=url, digest=digest, size=size)
 152     v.ok()
 153
 154
 155 def digest_string(s: bytes) -> Digest16:
 156     return Digest16(hashlib.sha256(s).hexdigest())
 157
 158
 159 def digest_file(filename: str) -> Digest16:
 160     hasher = hashlib.sha256()
 161     with open(filename, 'rb') as f:
 162         # pylint: disable=cell-var-from-loop
 163         for block in iter(lambda: f.read(4096), b''):
 164             hasher.update(block)
 165     return Digest16(hasher.hexdigest())
 166
 167
 168 def to_Digest16(v: Verification, digest32: Digest32) -> Digest16:
 169     v.status('Converting digest to base16')
 170     process = subprocess.run(
 171         ['nix', 'to-base16', '--type', 'sha256', digest32], capture_output=True)
 172     v.result(process.returncode == 0)
 173     return Digest16(process.stdout.decode().strip())
 174
 175
 176 def to_Digest32(v: Verification, digest16: Digest16) -> Digest32:
 177     v.status('Converting digest to base32')
 178     process = subprocess.run(
 179         ['nix', 'to-base32', '--type', 'sha256', digest16], capture_output=True)
 180     v.result(process.returncode == 0)
 181     return Digest32(process.stdout.decode().strip())
 182
 183
 184 def fetch_with_nix_prefetch_url(
 185         v: Verification,
 186         url: str,
 187         digest: Digest16) -> str:
 188     v.status('Fetching %s' % url)
 189     process = subprocess.run(
 190         ['nix-prefetch-url', '--print-path', url, digest], capture_output=True)
 191     v.result(process.returncode == 0)
 192     prefetch_digest, path, empty = process.stdout.decode().split('\n')
 193     assert empty == ''
 194     v.check("Verifying nix-prefetch-url's digest",
 195             to_Digest16(v, Digest32(prefetch_digest)) == digest)
 196     v.status("Verifying file digest")
 197     file_digest = digest_file(path)
 198     v.result(file_digest == digest)
 199     return path
 200
 201
 202 def fetch_resources(v: Verification, channel: Channel) -> None:
 203     for resource in ['git-revision', 'nixexprs.tar.xz']:
 204         fields = channel.table[resource]
 205         fields.absolute_url = urllib.parse.urljoin(
 206             channel.forwarded_url, fields.url)
 207         fields.file = fetch_with_nix_prefetch_url(
 208             v, fields.absolute_url, fields.digest)
 209     v.status('Verifying git commit on main page matches git commit in table')
 210     v.result(
 211         open(
 212             channel.table['git-revision'].file).read(999) == channel.git_revision)
 213
 214
 215 def git_cachedir(git_repo: str) -> str:
 216     # TODO: Consider using pyxdg to find this path.
 217     return os.path.expanduser(
 218         '~/.cache/nix-pin-channel/git/%s' %
 219         digest_string(
 220             git_repo.encode()))
 221
 222
 223 def verify_git_ancestry(v: Verification, channel: Channel) -> None:
 224     cachedir = git_cachedir(channel.git_repo)
 225     v.status('Verifying rev is an ancestor of ref')
 226     process = subprocess.run(['git',
 227                               '-C',
 228                               cachedir,
 229                               'merge-base',
 230                               '--is-ancestor',
 231                               channel.git_revision,
 232                               channel.git_ref])
 233     v.result(process.returncode == 0)
 234
 235     if hasattr(channel, 'old_git_revision'):
 236         v.status(
 237             'Verifying rev is an ancestor of previous rev %s' %
 238             channel.old_git_revision)
 239         process = subprocess.run(['git',
 240                                   '-C',
 241                                   cachedir,
 242                                   'merge-base',
 243                                   '--is-ancestor',
 244                                   channel.old_git_revision,
 245                                   channel.git_revision])
 246         v.result(process.returncode == 0)
 247
 248
 249 def git_fetch(v: Verification, channel: Channel) -> None:
 250     # It would be nice if we could share the nix git cache, but as of the time
 251     # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready
 252     # yet), and trying to straddle them both is too far into nix implementation
 253     # details for my comfort.  So we re-implement here half of nix.fetchGit.
 254     # :(
 255
 256     cachedir = git_cachedir(channel.git_repo)
 257     if not os.path.exists(cachedir):
 258         v.status("Initializing git repo")
 259         process = subprocess.run(
 260             ['git', 'init', '--bare', cachedir])
 261         v.result(process.returncode == 0)
 262
 263     v.status('Fetching ref "%s" from %s' % (channel.git_ref, channel.git_repo))
 264     # We don't use --force here because we want to abort and freak out if forced
 265     # updates are happening.
 266     process = subprocess.run(['git',
 267                               '-C',
 268                               cachedir,
 269                               'fetch',
 270                               channel.git_repo,
 271                               '%s:%s' % (channel.git_ref,
 272                                          channel.git_ref)])
 273     v.result(process.returncode == 0)
 274
 275     if hasattr(channel, 'git_revision'):
 276         v.status('Verifying that fetch retrieved this rev')
 277         process = subprocess.run(
 278             ['git', '-C', cachedir, 'cat-file', '-e', channel.git_revision])
 279         v.result(process.returncode == 0)
 280     else:
 281         channel.git_revision = open(
 282             os.path.join(
 283                 cachedir,
 284                 'refs',
 285                 'heads',
 286                 channel.git_ref)).read(999).strip()
 287
 288     verify_git_ancestry(v, channel)
 289
 290
 291 def ensure_git_rev_available(v: Verification, channel: Channel) -> None:
 292     cachedir = git_cachedir(channel.git_repo)
 293     if os.path.exists(cachedir):
 294         v.status('Checking if we already have this rev:')
 295         process = subprocess.run(
 296             ['git', '-C', cachedir, 'cat-file', '-e', channel.git_revision])
 297         if process.returncode == 0:
 298             v.status('yes')
 299         if process.returncode == 1:
 300             v.status('no')
 301         v.result(process.returncode == 0 or process.returncode == 1)
 302         if process.returncode == 0:
 303             verify_git_ancestry(v, channel)
 304             return
 305     git_fetch(v, channel)
 306
 307
 308 def compare_tarball_and_git(
 309         v: Verification,
 310         channel: Channel,
 311         channel_contents: str,
 312         git_contents: str) -> None:
 313     v.status('Comparing channel tarball with git checkout')
 314     match, mismatch, errors = compare(os.path.join(
 315         channel_contents, channel.release_name), git_contents)
 316     v.ok()
 317     v.check('%d files match' % len(match), len(match) > 0)
 318     v.check('%d files differ' % len(mismatch), len(mismatch) == 0)
 319     expected_errors = [
 320         '.git-revision',
 321         '.version-suffix',
 322         'nixpkgs',
 323         'programs.sqlite',
 324         'svn-revision']
 325     benign_errors = []
 326     for ee in expected_errors:
 327         if ee in errors:
 328             errors.remove(ee)
 329             benign_errors.append(ee)
 330     v.check(
 331         '%d unexpected incomparable files' %
 332         len(errors),
 333         len(errors) == 0)
 334     v.check(
 335         '(%d of %d expected incomparable files)' %
 336         (len(benign_errors),
 337          len(expected_errors)),
 338         len(benign_errors) == len(expected_errors))
 339
 340
 341 def extract_tarball(v: Verification, channel: Channel, dest: str) -> None:
 342     v.status('Extracting tarball %s' %
 343              channel.table['nixexprs.tar.xz'].file)
 344     shutil.unpack_archive(
 345         channel.table['nixexprs.tar.xz'].file,
 346         dest)
 347     v.ok()
 348
 349
 350 def git_checkout(v: Verification, channel: Channel, dest: str) -> None:
 351     v.status('Checking out corresponding git revision')
 352     git = subprocess.Popen(['git',
 353                             '-C',
 354                             git_cachedir(channel.git_repo),
 355                             'archive',
 356                             channel.git_revision],
 357                            stdout=subprocess.PIPE)
 358     tar = subprocess.Popen(
 359         ['tar', 'x', '-C', dest, '-f', '-'], stdin=git.stdout)
 360     git.stdout.close()
 361     tar.wait()
 362     git.wait()
 363     v.result(git.returncode == 0 and tar.returncode == 0)
 364
 365
 366 def git_get_tarball(v: Verification, channel: Channel) -> str:
 367     with tempfile.TemporaryDirectory() as output_dir:
 368         output_filename = os.path.join(
 369             output_dir, channel.release_name + '.tar.xz')
 370         with open(output_filename, 'w') as output_file:
 371             v.status(
 372                 'Generating tarball for git revision %s' %
 373                 channel.git_revision)
 374             git = subprocess.Popen(['git',
 375                                     '-C',
 376                                     git_cachedir(channel.git_repo),
 377                                     'archive',
 378                                     '--prefix=%s/' % channel.release_name,
 379                                     channel.git_revision],
 380                                    stdout=subprocess.PIPE)
 381             xz = subprocess.Popen(['xz'], stdin=git.stdout, stdout=output_file)
 382             xz.wait()
 383             git.wait()
 384             v.result(git.returncode == 0 and xz.returncode == 0)
 385
 386         v.status('Putting tarball in Nix store')
 387         process = subprocess.run(
 388             ['nix-store', '--add', output_filename], capture_output=True)
 389         v.result(process.returncode == 0)
 390         return process.stdout.decode().strip()
 391
 392
 393 def check_channel_metadata(
 394         v: Verification,
 395         channel: Channel,
 396         channel_contents: str) -> None:
 397     v.status('Verifying git commit in channel tarball')
 398     v.result(
 399         open(
 400             os.path.join(
 401                 channel_contents,
 402                 channel.release_name,
 403                 '.git-revision')).read(999) == channel.git_revision)
 404
 405     v.status(
 406         'Verifying version-suffix is a suffix of release name %s:' %
 407         channel.release_name)
 408     version_suffix = open(
 409         os.path.join(
 410             channel_contents,
 411             channel.release_name,
 412             '.version-suffix')).read(999)
 413     v.status(version_suffix)
 414     v.result(channel.release_name.endswith(version_suffix))
 415
 416
 417 def check_channel_contents(v: Verification, channel: Channel) -> None:
 418     with tempfile.TemporaryDirectory() as channel_contents, \
 419             tempfile.TemporaryDirectory() as git_contents:
 420
 421         extract_tarball(v, channel, channel_contents)
 422         check_channel_metadata(v, channel, channel_contents)
 423
 424         git_checkout(v, channel, git_contents)
 425
 426         compare_tarball_and_git(v, channel, channel_contents, git_contents)
 427
 428         v.status('Removing temporary directories')
 429     v.ok()
 430
 431
 432 def pin_channel(v: Verification, channel: Channel) -> None:
 433     fetch(v, channel)
 434     parse_channel(v, channel)
 435     fetch_resources(v, channel)
 436     ensure_git_rev_available(v, channel)
 437     check_channel_contents(v, channel)
 438
 439
 440 def git_revision_name(v: Verification, channel: Channel) -> str:
 441     v.status('Getting commit date')
 442     process = subprocess.run(['git',
 443                               '-C',
 444                               git_cachedir(channel.git_repo),
 445                               'lo',
 446                               '-n1',
 447                               '--format=%ct-%h',
 448                               '--abbrev=11',
 449                               channel.git_revision],
 450                              capture_output=True)
 451     v.result(process.returncode == 0 and process.stdout != '')
 452     return '%s-%s' % (os.path.basename(channel.git_repo),
 453                       process.stdout.decode().strip())
 454
 455
 456 def pin(args: argparse.Namespace) -> None:
 457     v = Verification()
 458     config = configparser.ConfigParser()
 459     config.read_file(open(args.channels_file), args.channels_file)
 460     for section in config.sections():
 461
 462         channel = Channel(**dict(config[section].items()))
 463         if hasattr(channel, 'git_revision'):
 464             channel.old_git_revision = channel.git_revision
 465             del channel.git_revision
 466
 467         if 'channel_url' in config[section]:
 468             pin_channel(v, channel)
 469             config[section]['release_name'] = channel.release_name
 470             config[section]['tarball_url'] = channel.table['nixexprs.tar.xz'].absolute_url
 471             config[section]['tarball_sha256'] = channel.table['nixexprs.tar.xz'].digest
 472         else:
 473             git_fetch(v, channel)
 474             config[section]['release_name'] = git_revision_name(v, channel)
 475         config[section]['git_revision'] = channel.git_revision
 476
 477     with open(args.channels_file, 'w') as configfile:
 478         config.write(configfile)
 479
 480
 481 def update(args: argparse.Namespace) -> None:
 482     v = Verification()
 483     config = configparser.ConfigParser()
 484     config.read_file(open(args.channels_file), args.channels_file)
 485     exprs = []
 486     for section in config.sections():
 487         if 'channel_url' in config[section]:
 488             tarball = fetch_with_nix_prefetch_url(
 489                 v, config[section]['tarball_url'], Digest16(
 490                     config[section]['tarball_sha256']))
 491         else:
 492             channel = Channel(**dict(config[section].items()))
 493             ensure_git_rev_available(v, channel)
 494             tarball = git_get_tarball(v, channel)
 495         exprs.append(
 496             'f: f { name = "%s"; channelName = "%s"; src = builtins.storePath "%s"; }' %
 497             (config[section]['release_name'], section, tarball))
 498     v.status('Installing channels with nix-env')
 499     process = subprocess.run(
 500         [
 501             'nix-env',
 502             '--profile',
 503             '/nix/var/nix/profiles/per-user/%s/channels' %
 504             getpass.getuser(),
 505             '--show-trace',
 506             '--file',
 507             '<nix/unpack-channel.nix>',
 508             '--install',
 509             '--from-expression'] +
 510         exprs)
 511     v.result(process.returncode == 0)
 512
 513
 514 def main() -> None:
 515     parser = argparse.ArgumentParser(prog='pinch')
 516     subparsers = parser.add_subparsers(dest='mode', required=True)
 517     parser_pin = subparsers.add_parser('pin')
 518     parser_pin.add_argument('channels_file', type=str)
 519     parser_pin.set_defaults(func=pin)
 520     parser_update = subparsers.add_parser('update')
 521     parser_update.add_argument('channels_file', type=str)
 522     parser_update.set_defaults(func=update)
 523     args = parser.parse_args()
 524     args.func(args)
 525
 526
 527 main()