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[pinch] / pinch.py
1 # pinch: PIN CHannels - a replacement for `nix-channel --update`
2 #
3 # This program is free software: you can redistribute it and/or modify it
4 # under the terms of the GNU General Public License as published by the
5 # Free Software Foundation, version 3.
6
7
8 import argparse
9 import configparser
10 import filecmp
11 import functools
12 import getpass
13 import hashlib
14 import operator
15 import os
16 import os.path
17 import shlex
18 import shutil
19 import subprocess
20 import sys
21 import tarfile
22 import tempfile
23 import types
24 import urllib.parse
25 import urllib.request
26 import xml.dom.minidom
27
28 from typing import (
29 Callable,
30 Dict,
31 Iterable,
32 List,
33 Mapping,
34 NamedTuple,
35 NewType,
36 Optional,
37 Set,
38 Tuple,
39 Type,
40 TypeVar,
41 Union,
42 )
43
44 import git_cache
45
46 # Use xdg module when it's less painful to have as a dependency
47
48
49 class XDG(NamedTuple):
50 XDG_CACHE_HOME: str
51
52
53 xdg = XDG(
54 XDG_CACHE_HOME=os.getenv(
55 'XDG_CACHE_HOME',
56 os.path.expanduser('~/.cache')))
57
58
59 class VerificationError(Exception):
60 pass
61
62
63 class Verification:
64
65 def __init__(self) -> None:
66 self.line_length = 0
67
68 def status(self, s: str) -> None:
69 print(s, end=' ', file=sys.stderr, flush=True)
70 self.line_length += 1 + len(s) # Unicode??
71
72 @staticmethod
73 def _color(s: str, c: int) -> str:
74 return f'\033[{c:2d}m{s}\033[00m'
75
76 def result(self, r: bool) -> None:
77 message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r]
78 length = len(message)
79 cols = shutil.get_terminal_size().columns or 80
80 pad = (cols - (self.line_length + length)) % cols
81 print(' ' * pad + self._color(message, color), file=sys.stderr)
82 self.line_length = 0
83 if not r:
84 raise VerificationError()
85
86 def check(self, s: str, r: bool) -> None:
87 self.status(s)
88 self.result(r)
89
90 def ok(self) -> None:
91 self.result(True)
92
93
94 Digest16 = NewType('Digest16', str)
95 Digest32 = NewType('Digest32', str)
96
97
98 class ChannelTableEntry(types.SimpleNamespace):
99 absolute_url: str
100 digest: Digest16
101 file: str
102 size: int
103 url: str
104
105
106 class AliasPin(NamedTuple):
107 pass
108
109
110 class SymlinkPin(NamedTuple):
111 @property
112 def release_name(self) -> str:
113 return 'link'
114
115
116 class GitPin(NamedTuple):
117 git_revision: str
118 release_name: str
119
120
121 class ChannelPin(NamedTuple):
122 git_revision: str
123 release_name: str
124 tarball_url: str
125 tarball_sha256: str
126
127
128 Pin = Union[AliasPin, SymlinkPin, GitPin, ChannelPin]
129
130
131 def copy_to_nix_store(v: Verification, filename: str) -> str:
132 v.status('Putting tarball in Nix store')
133 process = subprocess.run(
134 ['nix-store', '--add', filename], stdout=subprocess.PIPE)
135 v.result(process.returncode == 0)
136 return process.stdout.decode().strip() # type: ignore # (for old mypy)
137
138
139 def symlink_archive(v: Verification, path: str) -> str:
140 with tempfile.TemporaryDirectory() as td:
141 archive_filename = os.path.join(td, 'link.tar.gz')
142 os.symlink(path, os.path.join(td, 'link'))
143 with tarfile.open(archive_filename, mode='x:gz') as t:
144 t.add(os.path.join(td, 'link'), arcname='link')
145 return copy_to_nix_store(v, archive_filename)
146
147
148 class AliasSearchPath(NamedTuple):
149 alias_of: str
150
151 def pin(self, _: Verification, __: Optional[Pin]) -> AliasPin:
152 return AliasPin()
153
154
155 class SymlinkSearchPath(NamedTuple):
156 path: str
157
158 def pin(self, _: Verification, __: Optional[Pin]) -> SymlinkPin:
159 return SymlinkPin()
160
161 def fetch(self, v: Verification, _: Pin) -> str:
162 return symlink_archive(v, self.path)
163
164
165 class GitSearchPath(NamedTuple):
166 git_ref: str
167 git_repo: str
168
169 def pin(self, v: Verification, old_pin: Optional[Pin]) -> GitPin:
170 _, new_revision = git_cache.fetch(self.git_repo, self.git_ref)
171 if old_pin is not None:
172 assert isinstance(old_pin, GitPin)
173 verify_git_ancestry(v, self, old_pin.git_revision, new_revision)
174 return GitPin(release_name=git_revision_name(v, self, new_revision),
175 git_revision=new_revision)
176
177 def fetch(self, v: Verification, pin: Pin) -> str:
178 assert isinstance(pin, GitPin)
179 git_cache.ensure_rev_available(
180 self.git_repo, self.git_ref, pin.git_revision)
181 return git_get_tarball(v, self, pin)
182
183
184 class ChannelSearchPath(NamedTuple):
185 channel_url: str
186 git_ref: str
187 git_repo: str
188
189 def pin(self, v: Verification, old_pin: Optional[Pin]) -> ChannelPin:
190 if old_pin is not None:
191 assert isinstance(old_pin, ChannelPin)
192
193 channel_html, forwarded_url = fetch_channel(v, self)
194 table, new_gitpin = parse_channel(v, channel_html)
195 if old_pin is not None and old_pin.git_revision == new_gitpin.git_revision:
196 return old_pin
197 fetch_resources(v, new_gitpin, forwarded_url, table)
198 git_cache.ensure_rev_available(
199 self.git_repo, self.git_ref, new_gitpin.git_revision)
200 if old_pin is not None:
201 verify_git_ancestry(
202 v, self, old_pin.git_revision, new_gitpin.git_revision)
203 check_channel_contents(v, self, table, new_gitpin)
204 return ChannelPin(
205 release_name=new_gitpin.release_name,
206 tarball_url=table['nixexprs.tar.xz'].absolute_url,
207 tarball_sha256=table['nixexprs.tar.xz'].digest,
208 git_revision=new_gitpin.git_revision)
209
210 def fetch(self, v: Verification, pin: Pin) -> str:
211 assert isinstance(pin, ChannelPin)
212
213 return fetch_with_nix_prefetch_url(
214 v, pin.tarball_url, Digest16(pin.tarball_sha256))
215
216
217 SearchPath = Union[AliasSearchPath,
218 SymlinkSearchPath,
219 GitSearchPath,
220 ChannelSearchPath]
221 TarrableSearchPath = Union[GitSearchPath, ChannelSearchPath]
222
223
224 def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]:
225
226 def throw(error: OSError) -> None:
227 raise error
228
229 def join(x: str, y: str) -> str:
230 return y if x == '.' else os.path.join(x, y)
231
232 def recursive_files(d: str) -> Iterable[str]:
233 all_files: List[str] = []
234 for path, dirs, files in os.walk(d, onerror=throw):
235 rel = os.path.relpath(path, start=d)
236 all_files.extend(join(rel, f) for f in files)
237 for dir_or_link in dirs:
238 if os.path.islink(join(path, dir_or_link)):
239 all_files.append(join(rel, dir_or_link))
240 return all_files
241
242 def exclude_dot_git(files: Iterable[str]) -> Iterable[str]:
243 return (f for f in files if not f.startswith('.git/'))
244
245 files = functools.reduce(
246 operator.or_, (set(
247 exclude_dot_git(
248 recursive_files(x))) for x in [a, b]))
249 return filecmp.cmpfiles(a, b, files, shallow=False)
250
251
252 def fetch_channel(
253 v: Verification, channel: ChannelSearchPath) -> Tuple[str, str]:
254 v.status(f'Fetching channel from {channel.channel_url}')
255 with urllib.request.urlopen(channel.channel_url, timeout=10) as request:
256 channel_html = request.read().decode()
257 forwarded_url = request.geturl()
258 v.result(request.status == 200)
259 v.check('Got forwarded', channel.channel_url != forwarded_url)
260 return channel_html, forwarded_url
261
262
263 def parse_channel(v: Verification, channel_html: str) \
264 -> Tuple[Dict[str, ChannelTableEntry], GitPin]:
265 v.status('Parsing channel description as XML')
266 d = xml.dom.minidom.parseString(channel_html)
267 v.ok()
268
269 v.status('Finding release name (1)')
270 title = d.getElementsByTagName('title')[0].firstChild
271 v.result(isinstance(title, xml.dom.minidom.CharacterData))
272 assert isinstance(title, xml.dom.minidom.CharacterData)
273 release_name = title.nodeValue.split()[2]
274 v.status('Finding release name (2)')
275 h1 = d.getElementsByTagName('h1')[0].firstChild
276 v.result(isinstance(h1, xml.dom.minidom.CharacterData))
277 assert isinstance(h1, xml.dom.minidom.CharacterData)
278 v.status('Verifying release name:')
279 v.status(release_name)
280 v.result(release_name == h1.nodeValue.split()[2])
281
282 v.status('Finding git commit')
283 git_commit_node = d.getElementsByTagName('tt')[0]
284 v.result(
285 isinstance(
286 git_commit_node.firstChild,
287 xml.dom.minidom.CharacterData))
288 assert isinstance(
289 git_commit_node.firstChild,
290 xml.dom.minidom.CharacterData)
291 v.status('Extracting git commit:')
292 git_revision = git_commit_node.firstChild.nodeValue
293 v.status(git_revision)
294 v.ok()
295 v.status('Verifying git commit label')
296 v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ')
297
298 v.status('Parsing table')
299 table: Dict[str, ChannelTableEntry] = {}
300 for row in d.getElementsByTagName('tr')[1:]:
301 name = row.childNodes[0].firstChild.firstChild.nodeValue
302 url = row.childNodes[0].firstChild.getAttribute('href')
303 size = int(row.childNodes[1].firstChild.nodeValue)
304 digest = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue)
305 table[name] = ChannelTableEntry(url=url, digest=digest, size=size)
306 v.ok()
307 return table, GitPin(release_name=release_name, git_revision=git_revision)
308
309
310 def digest_string(s: bytes) -> Digest16:
311 return Digest16(hashlib.sha256(s).hexdigest())
312
313
314 def digest_file(filename: str) -> Digest16:
315 hasher = hashlib.sha256()
316 with open(filename, 'rb') as f:
317 # pylint: disable=cell-var-from-loop
318 for block in iter(lambda: f.read(4096), b''):
319 hasher.update(block)
320 return Digest16(hasher.hexdigest())
321
322
323 @functools.lru_cache
324 def _experimental_flag_needed(v: Verification) -> bool:
325 v.status('Checking Nix version')
326 process = subprocess.run(['nix', '--help'], stdout=subprocess.PIPE)
327 v.result(process.returncode == 0)
328 return b'--experimental-features' in process.stdout
329
330
331 def _nix_command(v: Verification) -> List[str]:
332 return ['nix', '--experimental-features',
333 'nix-command'] if _experimental_flag_needed(v) else ['nix']
334
335
336 def to_Digest16(v: Verification, digest32: Digest32) -> Digest16:
337 v.status('Converting digest to base16')
338 process = subprocess.run(_nix_command(v) + [
339 'to-base16',
340 '--type',
341 'sha256',
342 digest32],
343 stdout=subprocess.PIPE)
344 v.result(process.returncode == 0)
345 return Digest16(process.stdout.decode().strip())
346
347
348 def to_Digest32(v: Verification, digest16: Digest16) -> Digest32:
349 v.status('Converting digest to base32')
350 process = subprocess.run(_nix_command(v) + [
351 'to-base32',
352 '--type',
353 'sha256',
354 digest16],
355 stdout=subprocess.PIPE)
356 v.result(process.returncode == 0)
357 return Digest32(process.stdout.decode().strip())
358
359
360 def fetch_with_nix_prefetch_url(
361 v: Verification,
362 url: str,
363 digest: Digest16) -> str:
364 v.status(f'Fetching {url}')
365 process = subprocess.run(
366 ['nix-prefetch-url', '--print-path', url, digest], stdout=subprocess.PIPE)
367 v.result(process.returncode == 0)
368 prefetch_digest, path, empty = process.stdout.decode().split('\n')
369 assert empty == ''
370 v.check("Verifying nix-prefetch-url's digest",
371 to_Digest16(v, Digest32(prefetch_digest)) == digest)
372 v.status(f"Verifying digest of {path}")
373 file_digest = digest_file(path)
374 v.result(file_digest == digest)
375 return path # type: ignore # (for old mypy)
376
377
378 def fetch_resources(
379 v: Verification,
380 pin: GitPin,
381 forwarded_url: str,
382 table: Dict[str, ChannelTableEntry]) -> None:
383 for resource in ['git-revision', 'nixexprs.tar.xz']:
384 fields = table[resource]
385 fields.absolute_url = urllib.parse.urljoin(forwarded_url, fields.url)
386 fields.file = fetch_with_nix_prefetch_url(
387 v, fields.absolute_url, fields.digest)
388 v.status('Verifying git commit on main page matches git commit in table')
389 with open(table['git-revision'].file, encoding='utf-8') as rev_file:
390 v.result(rev_file.read(999) == pin.git_revision)
391
392
393 def tarball_cache_file(channel: TarrableSearchPath, pin: GitPin) -> str:
394 return os.path.join(
395 xdg.XDG_CACHE_HOME,
396 'pinch/git-tarball',
397 f'{digest_string(channel.git_repo.encode())}-{pin.git_revision}-{pin.release_name}')
398
399
400 def verify_git_ancestry(
401 v: Verification,
402 channel: TarrableSearchPath,
403 old_revision: str,
404 new_revision: str) -> None:
405 cachedir = git_cache.git_cachedir(channel.git_repo)
406 v.status(f'Verifying rev is an ancestor of previous rev {old_revision}')
407 process = subprocess.run(['git',
408 '-C',
409 cachedir,
410 'merge-base',
411 '--is-ancestor',
412 old_revision,
413 new_revision])
414 v.result(process.returncode == 0)
415
416
417 def compare_tarball_and_git(
418 v: Verification,
419 pin: GitPin,
420 channel_contents: str,
421 git_contents: str) -> None:
422 v.status('Comparing channel tarball with git checkout')
423 match, mismatch, errors = compare(os.path.join(
424 channel_contents, pin.release_name), git_contents)
425 v.ok()
426 v.check(f'{len(match)} files match', len(match) > 0)
427 v.check(f'{len(mismatch)} files differ', len(mismatch) == 0)
428 expected_errors = [
429 '.git-revision',
430 '.version-suffix',
431 'nixpkgs',
432 'programs.sqlite',
433 'svn-revision']
434 permitted_errors = [
435 'pkgs/test/nixpkgs-check-by-name/tests/symlink-invalid/pkgs/by-name/fo/foo/foo.nix',
436 ]
437 benign_expected_errors = []
438 benign_permitted_errors = []
439 for ee in expected_errors:
440 if ee in errors:
441 errors.remove(ee)
442 benign_expected_errors.append(ee)
443 for pe in permitted_errors:
444 if pe in errors:
445 errors.remove(pe)
446 benign_permitted_errors.append(ee)
447 v.check(
448 f'{len(errors)} unexpected incomparable files: {errors}',
449 len(errors) == 0)
450 v.check(
451 f'({len(benign_expected_errors)} of {len(expected_errors)} expected incomparable files)',
452 len(benign_expected_errors) == len(expected_errors))
453 v.check(
454 f'({len(benign_permitted_errors)} of {len(permitted_errors)} permitted incomparable files)',
455 len(benign_permitted_errors) <= len(permitted_errors))
456
457
458 def extract_tarball(
459 v: Verification,
460 table: Dict[str, ChannelTableEntry],
461 dest: str) -> None:
462 v.status(f"Extracting tarball {table['nixexprs.tar.xz'].file}")
463 shutil.unpack_archive(table['nixexprs.tar.xz'].file, dest)
464 v.ok()
465
466
467 def git_checkout(
468 v: Verification,
469 channel: TarrableSearchPath,
470 pin: GitPin,
471 dest: str) -> None:
472 v.status('Checking out corresponding git revision')
473 with subprocess.Popen(
474 ['git', '-C', git_cache.git_cachedir(channel.git_repo), 'archive', pin.git_revision],
475 stdout=subprocess.PIPE) as git:
476 with subprocess.Popen(['tar', 'x', '-C', dest, '-f', '-'], stdin=git.stdout) as tar:
477 if git.stdout:
478 git.stdout.close()
479 tar.wait()
480 git.wait()
481 v.result(git.returncode == 0 and tar.returncode == 0)
482
483
484 def git_get_tarball(
485 v: Verification,
486 channel: TarrableSearchPath,
487 pin: GitPin) -> str:
488 cache_file = tarball_cache_file(channel, pin)
489 if os.path.exists(cache_file):
490 with open(cache_file, encoding='utf-8') as f:
491 cached_tarball = f.read(9999)
492 if os.path.exists(cached_tarball):
493 return cached_tarball
494
495 with tempfile.TemporaryDirectory() as output_dir:
496 output_filename = os.path.join(
497 output_dir, pin.release_name + '.tar.xz')
498 with open(output_filename, 'w', encoding='utf-8') as output_file:
499 v.status(f'Generating tarball for git revision {pin.git_revision}')
500 with subprocess.Popen(
501 ['git', '-C', git_cache.git_cachedir(channel.git_repo),
502 'archive', f'--prefix={pin.release_name}/', pin.git_revision],
503 stdout=subprocess.PIPE) as git:
504 with subprocess.Popen(['xz'], stdin=git.stdout, stdout=output_file) as xz:
505 xz.wait()
506 git.wait()
507 v.result(git.returncode == 0 and xz.returncode == 0)
508
509 store_tarball = copy_to_nix_store(v, output_filename)
510
511 os.makedirs(os.path.dirname(cache_file), exist_ok=True)
512 with open(cache_file, 'w', encoding='utf-8') as f:
513 f.write(store_tarball)
514 return store_tarball # type: ignore # (for old mypy)
515
516
517 def check_channel_metadata(
518 v: Verification,
519 pin: GitPin,
520 channel_contents: str) -> None:
521 v.status('Verifying git commit in channel tarball')
522 with open(os.path.join(channel_contents, pin.release_name, '.git-revision'),
523 encoding='utf-8') as f:
524 v.result(f.read(999) == pin.git_revision)
525
526 v.status(
527 f'Verifying version-suffix is a suffix of release name {pin.release_name}:')
528 with open(os.path.join(channel_contents, pin.release_name, '.version-suffix'),
529 encoding='utf-8') as f:
530 version_suffix = f.read(999)
531 v.status(version_suffix)
532 v.result(pin.release_name.endswith(version_suffix))
533
534
535 def check_channel_contents(
536 v: Verification,
537 channel: TarrableSearchPath,
538 table: Dict[str, ChannelTableEntry],
539 pin: GitPin) -> None:
540 with tempfile.TemporaryDirectory() as channel_contents, \
541 tempfile.TemporaryDirectory() as git_contents:
542
543 extract_tarball(v, table, channel_contents)
544 check_channel_metadata(v, pin, channel_contents)
545
546 git_checkout(v, channel, pin, git_contents)
547
548 compare_tarball_and_git(v, pin, channel_contents, git_contents)
549
550 v.status('Removing temporary directories')
551 v.ok()
552
553
554 def git_revision_name(
555 v: Verification,
556 channel: TarrableSearchPath,
557 git_revision: str) -> str:
558 v.status('Getting commit date')
559 process = subprocess.run(['git',
560 '-C',
561 git_cache.git_cachedir(channel.git_repo),
562 'log',
563 '-n1',
564 '--format=%ct-%h',
565 '--abbrev=11',
566 '--no-show-signature',
567 git_revision],
568 stdout=subprocess.PIPE)
569 v.result(process.returncode == 0 and process.stdout != b'')
570 return f'{os.path.basename(channel.git_repo)}-{process.stdout.decode().strip()}'
571
572
573 K = TypeVar('K')
574 V = TypeVar('V')
575
576
577 def partition_dict(pred: Callable[[K, V], bool],
578 d: Dict[K, V]) -> Tuple[Dict[K, V], Dict[K, V]]:
579 selected: Dict[K, V] = {}
580 remaining: Dict[K, V] = {}
581 for k, v in d.items():
582 if pred(k, v):
583 selected[k] = v
584 else:
585 remaining[k] = v
586 return selected, remaining
587
588
589 def filter_dict(d: Dict[K, V], fields: Set[K]
590 ) -> Tuple[Dict[K, V], Dict[K, V]]:
591 return partition_dict(lambda k, v: k in fields, d)
592
593
594 def read_config_section(
595 conf: configparser.SectionProxy) -> Tuple[SearchPath, Optional[Pin]]:
596 mapping: Mapping[str, Tuple[Type[SearchPath], Type[Pin]]] = {
597 'alias': (AliasSearchPath, AliasPin),
598 'channel': (ChannelSearchPath, ChannelPin),
599 'git': (GitSearchPath, GitPin),
600 'symlink': (SymlinkSearchPath, SymlinkPin),
601 }
602 SP, P = mapping[conf['type']]
603 _, all_fields = filter_dict(dict(conf.items()), set(['type']))
604 pin_fields, remaining_fields = filter_dict(all_fields, set(P._fields))
605 # Error suppression works around https://github.com/python/mypy/issues/9007
606 pin_present = pin_fields or P._fields == ()
607 pin = P(**pin_fields) if pin_present else None # type: ignore
608 return SP(**remaining_fields), pin
609
610
611 def read_pinned_config_section(
612 section: str, conf: configparser.SectionProxy) -> Tuple[SearchPath, Pin]:
613 sp, pin = read_config_section(conf)
614 if pin is None:
615 raise RuntimeError(
616 f'Cannot update unpinned channel "{section}" (Run "pin" before "update")')
617 return sp, pin
618
619
620 def read_config(filename: str) -> configparser.ConfigParser:
621 config = configparser.ConfigParser()
622 with open(filename, encoding='utf-8') as f:
623 config.read_file(f, filename)
624 return config
625
626
627 def read_config_files(
628 filenames: Iterable[str]) -> Dict[str, configparser.SectionProxy]:
629 merged_config: Dict[str, configparser.SectionProxy] = {}
630 for file in filenames:
631 config = read_config(file)
632 for section in config.sections():
633 if section in merged_config:
634 raise RuntimeError('Duplicate channel "{section}"')
635 merged_config[section] = config[section]
636 return merged_config
637
638
639 def pinCommand(args: argparse.Namespace) -> None:
640 v = Verification()
641 config = read_config(args.channels_file)
642 for section in config.sections():
643 if args.channels and section not in args.channels:
644 continue
645
646 sp, old_pin = read_config_section(config[section])
647
648 config[section].update(sp.pin(v, old_pin)._asdict())
649
650 with open(args.channels_file, 'w', encoding='utf-8') as configfile:
651 config.write(configfile)
652
653
654 def updateCommand(args: argparse.Namespace) -> None:
655 v = Verification()
656 exprs: Dict[str, str] = {}
657 profile_manifest = os.path.join(args.profile, "manifest.nix")
658 search_paths: List[str] = [
659 "-I", "pinch_profile=" + args.profile,
660 "-I", "pinch_profile_manifest=" + os.readlink(profile_manifest)
661 ] if os.path.exists(profile_manifest) else []
662 config = {
663 section: read_pinned_config_section(section, conf) for section,
664 conf in read_config_files(
665 args.channels_file).items()}
666 alias, nonalias = partition_dict(
667 lambda k, v: isinstance(v[0], AliasSearchPath), config)
668
669 for section, (sp, pin) in sorted(nonalias.items()):
670 assert not isinstance(sp, AliasSearchPath) # mypy can't see through
671 assert not isinstance(pin, AliasPin) # partition_dict()
672 tarball = sp.fetch(v, pin)
673 search_paths.extend(
674 ["-I", f"pinch_tarball_for_{pin.release_name}={tarball}"])
675 exprs[section] = (
676 f'f: f {{ name = "{pin.release_name}"; channelName = "%s"; '
677 f'src = builtins.storePath "{tarball}"; }}')
678
679 for section, (sp, pin) in alias.items():
680 assert isinstance(sp, AliasSearchPath) # For mypy
681 exprs[section] = exprs[sp.alias_of]
682
683 command = [
684 'nix-env',
685 '--profile',
686 args.profile,
687 '--show-trace',
688 '--file',
689 '<nix/unpack-channel.nix>',
690 '--install',
691 '--remove-all',
692 ] + search_paths + ['--from-expression'] + [
693 exprs[name] % name for name in sorted(exprs.keys())]
694 if args.dry_run:
695 print(' '.join(map(shlex.quote, command)))
696 else:
697 v.status('Installing channels with nix-env')
698 process = subprocess.run(command)
699 v.result(process.returncode == 0)
700
701
702 def main() -> None:
703 parser = argparse.ArgumentParser(prog='pinch')
704 subparsers = parser.add_subparsers(dest='mode', required=True)
705 parser_pin = subparsers.add_parser('pin')
706 parser_pin.add_argument('channels_file', type=str)
707 parser_pin.add_argument('channels', type=str, nargs='*')
708 parser_pin.set_defaults(func=pinCommand)
709 parser_update = subparsers.add_parser('update')
710 parser_update.add_argument('--dry-run', action='store_true')
711 parser_update.add_argument('--profile', default=(
712 f'/nix/var/nix/profiles/per-user/{getpass.getuser()}/channels'))
713 parser_update.add_argument('channels_file', type=str, nargs='+')
714 parser_update.set_defaults(func=updateCommand)
715 args = parser.parse_args()
716 args.func(args)
717
718
719 if __name__ == '__main__':
720 main()