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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 digest: Digest16
31 file: str
32 size: int
33 url: str
34
35
36 class Channel(types.SimpleNamespace):
37 channel_html: bytes
38 forwarded_url: str
39 git_cachedir: str
40 git_ref: str
41 git_repo: str
42 git_revision: str
43 release_name: str
44 table: Dict[str, ChannelTableEntry]
45 url: str
46
47
48 class VerificationError(Exception):
49 pass
50
51
52 class Verification:
53
54 def __init__(self) -> None:
55 self.line_length = 0
56
57 def status(self, s: str) -> None:
58 print(s, end=' ', flush=True)
59 self.line_length += 1 + len(s) # Unicode??
60
61 @staticmethod
62 def _color(s: str, c: int) -> str:
63 return '\033[%2dm%s\033[00m' % (c, s)
64
65 def result(self, r: bool) -> None:
66 message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r]
67 length = len(message)
68 cols = shutil.get_terminal_size().columns
69 pad = (cols - (self.line_length + length)) % cols
70 print(' ' * pad + self._color(message, color))
71 self.line_length = 0
72 if not r:
73 raise VerificationError()
74
75 def check(self, s: str, r: bool) -> None:
76 self.status(s)
77 self.result(r)
78
79 def ok(self) -> None:
80 self.result(True)
81
82
83 def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]:
84
85 def throw(error: OSError) -> None:
86 raise error
87
88 def join(x: str, y: str) -> str:
89 return y if x == '.' else os.path.join(x, y)
90
91 def recursive_files(d: str) -> Iterable[str]:
92 all_files: List[str] = []
93 for path, dirs, files in os.walk(d, onerror=throw):
94 rel = os.path.relpath(path, start=d)
95 all_files.extend(join(rel, f) for f in files)
96 for dir_or_link in dirs:
97 if os.path.islink(join(path, dir_or_link)):
98 all_files.append(join(rel, dir_or_link))
99 return all_files
100
101 def exclude_dot_git(files: Iterable[str]) -> Iterable[str]:
102 return (f for f in files if not f.startswith('.git/'))
103
104 files = functools.reduce(
105 operator.or_, (set(
106 exclude_dot_git(
107 recursive_files(x))) for x in [a, b]))
108 return filecmp.cmpfiles(a, b, files, shallow=False)
109
110
111 def fetch(v: Verification, channel: Channel) -> None:
112 v.status('Fetching channel')
113 request = urllib.request.urlopen(channel.url, timeout=10)
114 channel.channel_html = request.read()
115 channel.forwarded_url = request.geturl()
116 v.result(request.status == 200)
117 v.check('Got forwarded', channel.url != channel.forwarded_url)
118
119
120 def parse_channel(v: Verification, channel: Channel) -> None:
121 v.status('Parsing channel description as XML')
122 d = xml.dom.minidom.parseString(channel.channel_html)
123 v.ok()
124
125 v.status('Extracting release name:')
126 title_name = d.getElementsByTagName(
127 'title')[0].firstChild.nodeValue.split()[2]
128 h1_name = d.getElementsByTagName('h1')[0].firstChild.nodeValue.split()[2]
129 v.status(title_name)
130 v.result(title_name == h1_name)
131 channel.release_name = title_name
132
133 v.status('Extracting git commit:')
134 git_commit_node = d.getElementsByTagName('tt')[0]
135 channel.git_revision = git_commit_node.firstChild.nodeValue
136 v.status(channel.git_revision)
137 v.ok()
138 v.status('Verifying git commit label')
139 v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ')
140
141 v.status('Parsing table')
142 channel.table = {}
143 for row in d.getElementsByTagName('tr')[1:]:
144 name = row.childNodes[0].firstChild.firstChild.nodeValue
145 url = row.childNodes[0].firstChild.getAttribute('href')
146 size = int(row.childNodes[1].firstChild.nodeValue)
147 digest = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue)
148 channel.table[name] = ChannelTableEntry(
149 url=url, digest=digest, size=size)
150 v.ok()
151
152
153 def digest_string(s: bytes) -> Digest16:
154 return Digest16(hashlib.sha256(s).hexdigest())
155
156
157 def digest_file(filename: str) -> Digest16:
158 hasher = hashlib.sha256()
159 with open(filename, 'rb') as f:
160 # pylint: disable=cell-var-from-loop
161 for block in iter(lambda: f.read(4096), b''):
162 hasher.update(block)
163 return Digest16(hasher.hexdigest())
164
165
166 def to_Digest16(v: Verification, digest32: Digest32) -> Digest16:
167 v.status('Converting digest to base16')
168 process = subprocess.run(
169 ['nix', 'to-base16', '--type', 'sha256', digest32], capture_output=True)
170 v.result(process.returncode == 0)
171 return Digest16(process.stdout.decode().strip())
172
173
174 def to_Digest32(v: Verification, digest16: Digest16) -> Digest32:
175 v.status('Converting digest to base32')
176 process = subprocess.run(
177 ['nix', 'to-base32', '--type', 'sha256', digest16], capture_output=True)
178 v.result(process.returncode == 0)
179 return Digest32(process.stdout.decode().strip())
180
181
182 def fetch_with_nix_prefetch_url(
183 v: Verification,
184 url: str,
185 digest: Digest16) -> str:
186 v.status('Fetching %s' % url)
187 process = subprocess.run(
188 ['nix-prefetch-url', '--print-path', url, digest], capture_output=True)
189 v.result(process.returncode == 0)
190 prefetch_digest, path, empty = process.stdout.decode().split('\n')
191 assert empty == ''
192 v.check("Verifying nix-prefetch-url's digest",
193 to_Digest16(v, Digest32(prefetch_digest)) == digest)
194 v.status("Verifying file digest")
195 file_digest = digest_file(path)
196 v.result(file_digest == digest)
197 return path
198
199
200 def fetch_resources(v: Verification, channel: Channel) -> None:
201 for resource in ['git-revision', 'nixexprs.tar.xz']:
202 fields = channel.table[resource]
203 url = urllib.parse.urljoin(channel.forwarded_url, fields.url)
204 fields.file = fetch_with_nix_prefetch_url(v, url, fields.digest)
205 v.status('Verifying git commit on main page matches git commit in table')
206 v.result(
207 open(
208 channel.table['git-revision'].file).read(999) == channel.git_revision)
209
210
211 def git_fetch(v: Verification, channel: Channel) -> None:
212 # It would be nice if we could share the nix git cache, but as of the time
213 # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready
214 # yet), and trying to straddle them both is too far into nix implementation
215 # details for my comfort. So we re-implement here half of nix.fetchGit.
216 # :(
217
218 # TODO: Consider using pyxdg to find this path.
219 channel.git_cachedir = os.path.expanduser(
220 '~/.cache/nix-pin-channel/git/%s' %
221 digest_string(
222 channel.url.encode()))
223 if not os.path.exists(channel.git_cachedir):
224 v.status("Initializing git repo")
225 process = subprocess.run(
226 ['git', 'init', '--bare', channel.git_cachedir])
227 v.result(process.returncode == 0)
228
229 v.status('Checking if we already have this rev:')
230 process = subprocess.run(
231 ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_revision])
232 if process.returncode == 0:
233 v.status('yes')
234 if process.returncode == 1:
235 v.status('no')
236 v.result(process.returncode == 0 or process.returncode == 1)
237 if process.returncode == 1:
238 v.status('Fetching ref "%s"' % channel.git_ref)
239 # We don't use --force here because we want to abort and freak out if forced
240 # updates are happening.
241 process = subprocess.run(['git',
242 '-C',
243 channel.git_cachedir,
244 'fetch',
245 channel.git_repo,
246 '%s:%s' % (channel.git_ref,
247 channel.git_ref)])
248 v.result(process.returncode == 0)
249 v.status('Verifying that fetch retrieved this rev')
250 process = subprocess.run(
251 ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_revision])
252 v.result(process.returncode == 0)
253
254 v.status('Verifying rev is an ancestor of ref')
255 process = subprocess.run(['git',
256 '-C',
257 channel.git_cachedir,
258 'merge-base',
259 '--is-ancestor',
260 channel.git_revision,
261 channel.git_ref])
262 v.result(process.returncode == 0)
263
264
265 def compare_tarball_and_git(
266 v: Verification,
267 channel: Channel,
268 channel_contents: str,
269 git_contents: str) -> None:
270 v.status('Comparing channel tarball with git checkout')
271 match, mismatch, errors = compare(os.path.join(
272 channel_contents, channel.release_name), git_contents)
273 v.ok()
274 v.check('%d files match' % len(match), len(match) > 0)
275 v.check('%d files differ' % len(mismatch), len(mismatch) == 0)
276 expected_errors = [
277 '.git-revision',
278 '.version-suffix',
279 'nixpkgs',
280 'programs.sqlite',
281 'svn-revision']
282 benign_errors = []
283 for ee in expected_errors:
284 if ee in errors:
285 errors.remove(ee)
286 benign_errors.append(ee)
287 v.check(
288 '%d unexpected incomparable files' %
289 len(errors),
290 len(errors) == 0)
291 v.check(
292 '(%d of %d expected incomparable files)' %
293 (len(benign_errors),
294 len(expected_errors)),
295 len(benign_errors) == len(expected_errors))
296
297
298 def extract_tarball(v: Verification, channel: Channel, dest: str) -> None:
299 v.status('Extracting tarball %s' %
300 channel.table['nixexprs.tar.xz'].file)
301 shutil.unpack_archive(
302 channel.table['nixexprs.tar.xz'].file,
303 dest)
304 v.ok()
305
306
307 def git_checkout(v: Verification, channel: Channel, dest: str) -> None:
308 v.status('Checking out corresponding git revision')
309 git = subprocess.Popen(['git',
310 '-C',
311 channel.git_cachedir,
312 'archive',
313 channel.git_revision],
314 stdout=subprocess.PIPE)
315 tar = subprocess.Popen(
316 ['tar', 'x', '-C', dest, '-f', '-'], stdin=git.stdout)
317 git.stdout.close()
318 tar.wait()
319 git.wait()
320 v.result(git.returncode == 0 and tar.returncode == 0)
321
322
323 def check_channel_metadata(
324 v: Verification,
325 channel: Channel,
326 channel_contents: str) -> None:
327 v.status('Verifying git commit in channel tarball')
328 v.result(
329 open(
330 os.path.join(
331 channel_contents,
332 channel.release_name,
333 '.git-revision')).read(999) == channel.git_revision)
334
335 v.status(
336 'Verifying version-suffix is a suffix of release name %s:' %
337 channel.release_name)
338 version_suffix = open(
339 os.path.join(
340 channel_contents,
341 channel.release_name,
342 '.version-suffix')).read(999)
343 v.status(version_suffix)
344 v.result(channel.release_name.endswith(version_suffix))
345
346
347 def check_channel_contents(v: Verification, channel: Channel) -> None:
348 with tempfile.TemporaryDirectory() as channel_contents, \
349 tempfile.TemporaryDirectory() as git_contents:
350
351 extract_tarball(v, channel, channel_contents)
352 check_channel_metadata(v, channel, channel_contents)
353
354 git_checkout(v, channel, git_contents)
355
356 compare_tarball_and_git(v, channel, channel_contents, git_contents)
357
358 v.status('Removing temporary directories')
359 v.ok()
360
361
362 def main(argv: List[str]) -> None:
363 v = Verification()
364 config = configparser.ConfigParser()
365 config.read_file(open(argv[1]), argv[1])
366 channel = Channel(**dict(config['nixos'].items()))
367 fetch(v, channel)
368 parse_channel(v, channel)
369 fetch_resources(v, channel)
370 git_fetch(v, channel)
371 check_channel_contents(v, channel)
372 print(channel)
373
374
375 main(sys.argv)