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[pinch] / pinch.py
1 import configparser
2 import filecmp
3 import functools
4 import hashlib
5 import operator
6 import os
7 import os.path
8 import shutil
9 import subprocess
10 import sys
11 import tempfile
12 import types
13 import urllib.parse
14 import urllib.request
15 import xml.dom.minidom
16
17 from typing import (
18 Dict,
19 Iterable,
20 List,
21 NewType,
22 Tuple,
23 )
24
25 Digest16 = NewType('Digest16', str)
26 Digest32 = NewType('Digest32', str)
27
28
29 class ChannelTableEntry(types.SimpleNamespace):
30 absolute_url: str
31 digest: Digest16
32 file: str
33 size: int
34 url: str
35
36
37 class Channel(types.SimpleNamespace):
38 channel_html: bytes
39 channel_url: str
40 forwarded_url: str
41 git_cachedir: 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_fetch(v: Verification, channel: Channel) -> None:
216 # It would be nice if we could share the nix git cache, but as of the time
217 # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready
218 # yet), and trying to straddle them both is too far into nix implementation
219 # details for my comfort. So we re-implement here half of nix.fetchGit.
220 # :(
221
222 # TODO: Consider using pyxdg to find this path.
223 channel.git_cachedir = os.path.expanduser(
224 '~/.cache/nix-pin-channel/git/%s' %
225 digest_string(
226 channel.git_repo.encode()))
227 if not os.path.exists(channel.git_cachedir):
228 v.status("Initializing git repo")
229 process = subprocess.run(
230 ['git', 'init', '--bare', channel.git_cachedir])
231 v.result(process.returncode == 0)
232
233 have_rev = False
234 if hasattr(channel, 'git_revision'):
235 v.status('Checking if we already have this rev:')
236 process = subprocess.run(
237 ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_revision])
238 if process.returncode == 0:
239 v.status('yes')
240 if process.returncode == 1:
241 v.status('no')
242 v.result(process.returncode == 0 or process.returncode == 1)
243 have_rev = process.returncode == 0
244
245 if not have_rev:
246 v.status('Fetching ref "%s" from %s' % (channel.git_ref, channel.git_repo))
247 # We don't use --force here because we want to abort and freak out if forced
248 # updates are happening.
249 process = subprocess.run(['git',
250 '-C',
251 channel.git_cachedir,
252 'fetch',
253 channel.git_repo,
254 '%s:%s' % (channel.git_ref,
255 channel.git_ref)])
256 v.result(process.returncode == 0)
257 if hasattr(channel, 'git_revision'):
258 v.status('Verifying that fetch retrieved this rev')
259 process = subprocess.run(
260 ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_revision])
261 v.result(process.returncode == 0)
262
263 if not hasattr(channel, 'git_revision'):
264 channel.git_revision = open(
265 os.path.join(
266 channel.git_cachedir,
267 'refs',
268 'heads',
269 channel.git_ref)).read(999).strip()
270
271 v.status('Verifying rev is an ancestor of ref')
272 process = subprocess.run(['git',
273 '-C',
274 channel.git_cachedir,
275 'merge-base',
276 '--is-ancestor',
277 channel.git_revision,
278 channel.git_ref])
279 v.result(process.returncode == 0)
280
281
282 def compare_tarball_and_git(
283 v: Verification,
284 channel: Channel,
285 channel_contents: str,
286 git_contents: str) -> None:
287 v.status('Comparing channel tarball with git checkout')
288 match, mismatch, errors = compare(os.path.join(
289 channel_contents, channel.release_name), git_contents)
290 v.ok()
291 v.check('%d files match' % len(match), len(match) > 0)
292 v.check('%d files differ' % len(mismatch), len(mismatch) == 0)
293 expected_errors = [
294 '.git-revision',
295 '.version-suffix',
296 'nixpkgs',
297 'programs.sqlite',
298 'svn-revision']
299 benign_errors = []
300 for ee in expected_errors:
301 if ee in errors:
302 errors.remove(ee)
303 benign_errors.append(ee)
304 v.check(
305 '%d unexpected incomparable files' %
306 len(errors),
307 len(errors) == 0)
308 v.check(
309 '(%d of %d expected incomparable files)' %
310 (len(benign_errors),
311 len(expected_errors)),
312 len(benign_errors) == len(expected_errors))
313
314
315 def extract_tarball(v: Verification, channel: Channel, dest: str) -> None:
316 v.status('Extracting tarball %s' %
317 channel.table['nixexprs.tar.xz'].file)
318 shutil.unpack_archive(
319 channel.table['nixexprs.tar.xz'].file,
320 dest)
321 v.ok()
322
323
324 def git_checkout(v: Verification, channel: Channel, dest: str) -> None:
325 v.status('Checking out corresponding git revision')
326 git = subprocess.Popen(['git',
327 '-C',
328 channel.git_cachedir,
329 'archive',
330 channel.git_revision],
331 stdout=subprocess.PIPE)
332 tar = subprocess.Popen(
333 ['tar', 'x', '-C', dest, '-f', '-'], stdin=git.stdout)
334 git.stdout.close()
335 tar.wait()
336 git.wait()
337 v.result(git.returncode == 0 and tar.returncode == 0)
338
339
340 def check_channel_metadata(
341 v: Verification,
342 channel: Channel,
343 channel_contents: str) -> None:
344 v.status('Verifying git commit in channel tarball')
345 v.result(
346 open(
347 os.path.join(
348 channel_contents,
349 channel.release_name,
350 '.git-revision')).read(999) == channel.git_revision)
351
352 v.status(
353 'Verifying version-suffix is a suffix of release name %s:' %
354 channel.release_name)
355 version_suffix = open(
356 os.path.join(
357 channel_contents,
358 channel.release_name,
359 '.version-suffix')).read(999)
360 v.status(version_suffix)
361 v.result(channel.release_name.endswith(version_suffix))
362
363
364 def check_channel_contents(v: Verification, channel: Channel) -> None:
365 with tempfile.TemporaryDirectory() as channel_contents, \
366 tempfile.TemporaryDirectory() as git_contents:
367
368 extract_tarball(v, channel, channel_contents)
369 check_channel_metadata(v, channel, channel_contents)
370
371 git_checkout(v, channel, git_contents)
372
373 compare_tarball_and_git(v, channel, channel_contents, git_contents)
374
375 v.status('Removing temporary directories')
376 v.ok()
377
378
379 def pin_channel(v: Verification, channel: Channel) -> None:
380 fetch(v, channel)
381 parse_channel(v, channel)
382 fetch_resources(v, channel)
383 git_fetch(v, channel)
384 check_channel_contents(v, channel)
385
386
387 def make_channel(conf: configparser.SectionProxy) -> Channel:
388 channel = Channel(**dict(conf.items()))
389 if hasattr(channel, 'git_revision'):
390 channel.old_git_revision = channel.git_revision
391 del channel.git_revision
392 return channel
393
394
395 def main(argv: List[str]) -> None:
396 v = Verification()
397 config = configparser.ConfigParser()
398 config.read_file(open(argv[1]), argv[1])
399 for section in config.sections():
400 channel = make_channel(config[section])
401 if 'channel_url' in config[section]:
402 pin_channel(v, channel)
403 config[section]['tarball_url'] = channel.table['nixexprs.tar.xz'].absolute_url
404 config[section]['tarball_sha256'] = channel.table['nixexprs.tar.xz'].digest
405 else:
406 git_fetch(v, channel)
407 config[section]['git_revision'] = channel.git_revision
408
409 with open(argv[1], 'w') as configfile:
410 config.write(configfile)
411
412
413 main(sys.argv)