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[pinch] / 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()