From: Scott Worley Date: Tue, 16 Jun 2020 11:17:27 +0000 (-0700) Subject: Immutable SearchPaths X-Git-Tag: 2.0.0~8 X-Git-Url: http://git.scottworley.com/pinch/commitdiff_plain/567a67835a75aac5522261e1cdccfed319a8087b?ds=sidebyside Immutable SearchPaths --- diff --git a/pinch.py b/pinch.py index 8fe7df1..e1d8d3b 100644 --- a/pinch.py +++ b/pinch.py @@ -1,4 +1,3 @@ -from abc import ABC, abstractmethod import argparse import configparser import filecmp @@ -26,8 +25,10 @@ from typing import ( NamedTuple, NewType, Optional, + Set, Tuple, Type, + TypeVar, Union, ) @@ -110,87 +111,64 @@ class ChannelPin(NamedTuple): Pin = Union[AliasPin, GitPin, ChannelPin] -class SearchPath(types.SimpleNamespace, ABC): - - @abstractmethod - def pin(self, v: Verification) -> Pin: - pass - - -class AliasSearchPath(SearchPath): +class AliasSearchPath(NamedTuple): alias_of: str - def pin(self, v: Verification) -> AliasPin: - assert not hasattr(self, 'git_repo') + # pylint: disable=no-self-use + def pin(self, _: Verification, __: Optional[Pin]) -> AliasPin: return AliasPin() -# (This lint-disable is for pylint bug https://github.com/PyCQA/pylint/issues/179 -# which is fixed in pylint 2.5.) -class TarrableSearchPath(SearchPath, ABC): # pylint: disable=abstract-method - channel_html: bytes - channel_url: str - forwarded_url: str +class GitSearchPath(NamedTuple): git_ref: str git_repo: str - table: Dict[str, ChannelTableEntry] - -class GitSearchPath(TarrableSearchPath): - def pin(self, v: Verification) -> GitPin: - old_revision = ( - self.git_revision if hasattr(self, 'git_revision') else None) - if hasattr(self, 'git_revision'): - del self.git_revision + def pin(self, v: Verification, old_pin: Optional[Pin]) -> GitPin: + if old_pin is not None: + assert isinstance(old_pin, GitPin) + old_revision = old_pin.git_revision if old_pin is not None else None new_revision = git_fetch(v, self, None, old_revision) return GitPin(release_name=git_revision_name(v, self, new_revision), git_revision=new_revision) - def fetch(self, v: Verification, section: str, - conf: configparser.SectionProxy) -> str: - if 'git_revision' not in conf or 'release_name' not in conf: - raise Exception( - 'Cannot update unpinned channel "%s" (Run "pin" before "update")' % - section) - the_pin = GitPin( - release_name=conf['release_name'], - git_revision=conf['git_revision']) + def fetch(self, v: Verification, pin: Pin) -> str: + assert isinstance(pin, GitPin) + ensure_git_rev_available(v, self, pin, None) + return git_get_tarball(v, self, pin) - ensure_git_rev_available(v, self, the_pin, None) - return git_get_tarball(v, self, the_pin) +class ChannelSearchPath(NamedTuple): + channel_url: str + git_ref: str + git_repo: str -class ChannelSearchPath(TarrableSearchPath): - def pin(self, v: Verification) -> ChannelPin: - old_revision = ( - self.git_revision if hasattr(self, 'git_revision') else None) - if hasattr(self, 'git_revision'): - del self.git_revision + def pin(self, v: Verification, old_pin: Optional[Pin]) -> ChannelPin: + if old_pin is not None: + assert isinstance(old_pin, ChannelPin) + old_revision = old_pin.git_revision if old_pin is not None else None - fetch(v, self) - new_gitpin = parse_channel(v, self) - fetch_resources(v, self, new_gitpin) + channel_html, forwarded_url = fetch_channel(v, self) + table, new_gitpin = parse_channel(v, channel_html) + fetch_resources(v, new_gitpin, forwarded_url, table) ensure_git_rev_available(v, self, new_gitpin, old_revision) - check_channel_contents(v, self, new_gitpin) + check_channel_contents(v, self, table, new_gitpin) return ChannelPin( release_name=new_gitpin.release_name, - tarball_url=self.table['nixexprs.tar.xz'].absolute_url, - tarball_sha256=self.table['nixexprs.tar.xz'].digest, + tarball_url=table['nixexprs.tar.xz'].absolute_url, + tarball_sha256=table['nixexprs.tar.xz'].digest, git_revision=new_gitpin.git_revision) - # Lint TODO: Put tarball_url and tarball_sha256 in ChannelSearchPath # pylint: disable=no-self-use - def fetch(self, v: Verification, section: str, - conf: configparser.SectionProxy) -> str: - if 'git_repo' not in conf or 'release_name' not in conf: - raise Exception( - 'Cannot update unpinned channel "%s" (Run "pin" before "update")' % - section) + def fetch(self, v: Verification, pin: Pin) -> str: + assert isinstance(pin, ChannelPin) return fetch_with_nix_prefetch_url( - v, conf['tarball_url'], Digest16( - conf['tarball_sha256'])) + v, pin.tarball_url, Digest16(pin.tarball_sha256)) + + +SearchPath = Union[AliasSearchPath, GitSearchPath, ChannelSearchPath] +TarrableSearchPath = Union[GitSearchPath, ChannelSearchPath] def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]: @@ -221,18 +199,21 @@ def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]: return filecmp.cmpfiles(a, b, files, shallow=False) -def fetch(v: Verification, channel: TarrableSearchPath) -> None: +def fetch_channel( + v: Verification, channel: ChannelSearchPath) -> Tuple[str, str]: v.status('Fetching channel') request = urllib.request.urlopen(channel.channel_url, timeout=10) - channel.channel_html = request.read() - channel.forwarded_url = request.geturl() + channel_html = request.read() + forwarded_url = request.geturl() v.result(request.status == 200) # type: ignore # (for old mypy) - v.check('Got forwarded', channel.channel_url != channel.forwarded_url) + v.check('Got forwarded', channel.channel_url != forwarded_url) + return channel_html, forwarded_url -def parse_channel(v: Verification, channel: TarrableSearchPath) -> GitPin: +def parse_channel(v: Verification, channel_html: str) \ + -> Tuple[Dict[str, ChannelTableEntry], GitPin]: v.status('Parsing channel description as XML') - d = xml.dom.minidom.parseString(channel.channel_html) + d = xml.dom.minidom.parseString(channel_html) v.ok() v.status('Extracting release name:') @@ -251,16 +232,15 @@ def parse_channel(v: Verification, channel: TarrableSearchPath) -> GitPin: v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ') v.status('Parsing table') - channel.table = {} + table: Dict[str, ChannelTableEntry] = {} for row in d.getElementsByTagName('tr')[1:]: name = row.childNodes[0].firstChild.firstChild.nodeValue url = row.childNodes[0].firstChild.getAttribute('href') size = int(row.childNodes[1].firstChild.nodeValue) digest = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue) - channel.table[name] = ChannelTableEntry( - url=url, digest=digest, size=size) + table[name] = ChannelTableEntry(url=url, digest=digest, size=size) v.ok() - return GitPin(release_name=title_name, git_revision=git_revision) + return table, GitPin(release_name=title_name, git_revision=git_revision) def digest_string(s: bytes) -> Digest16: @@ -312,18 +292,16 @@ def fetch_with_nix_prefetch_url( def fetch_resources( v: Verification, - channel: ChannelSearchPath, - pin: GitPin) -> None: + pin: GitPin, + forwarded_url: str, + table: Dict[str, ChannelTableEntry]) -> None: for resource in ['git-revision', 'nixexprs.tar.xz']: - fields = channel.table[resource] - fields.absolute_url = urllib.parse.urljoin( - channel.forwarded_url, fields.url) + fields = table[resource] + fields.absolute_url = urllib.parse.urljoin(forwarded_url, fields.url) fields.file = fetch_with_nix_prefetch_url( v, fields.absolute_url, fields.digest) v.status('Verifying git commit on main page matches git commit in table') - v.result( - open( - channel.table['git-revision'].file).read(999) == pin.git_revision) + v.result(open(table['git-revision'].file).read(999) == pin.git_revision) def git_cachedir(git_repo: str) -> str: @@ -477,13 +455,10 @@ def compare_tarball_and_git( def extract_tarball( v: Verification, - channel: TarrableSearchPath, + table: Dict[str, ChannelTableEntry], dest: str) -> None: - v.status('Extracting tarball %s' % - channel.table['nixexprs.tar.xz'].file) - shutil.unpack_archive( - channel.table['nixexprs.tar.xz'].file, - dest) + v.status('Extracting tarball %s' % table['nixexprs.tar.xz'].file) + shutil.unpack_archive(table['nixexprs.tar.xz'].file, dest) v.ok() @@ -575,11 +550,12 @@ def check_channel_metadata( def check_channel_contents( v: Verification, channel: TarrableSearchPath, + table: Dict[str, ChannelTableEntry], pin: GitPin) -> None: with tempfile.TemporaryDirectory() as channel_contents, \ tempfile.TemporaryDirectory() as git_contents: - extract_tarball(v, channel, channel_contents) + extract_tarball(v, table, channel_contents) check_channel_metadata(v, pin, channel_contents) git_checkout(v, channel, pin, git_contents) @@ -610,13 +586,36 @@ def git_revision_name( process.stdout.decode().strip()) -def read_search_path(conf: configparser.SectionProxy) -> SearchPath: - mapping: Mapping[str, Type[SearchPath]] = { - 'alias': AliasSearchPath, - 'channel': ChannelSearchPath, - 'git': GitSearchPath, +K = TypeVar('K') +V = TypeVar('V') + + +def filter_dict(d: Dict[K, V], fields: Set[K] + ) -> Tuple[Dict[K, V], Dict[K, V]]: + selected: Dict[K, V] = {} + remaining: Dict[K, V] = {} + for k, v in d.items(): + if k in fields: + selected[k] = v + else: + remaining[k] = v + return selected, remaining + + +def read_search_path( + conf: configparser.SectionProxy) -> Tuple[SearchPath, Optional[Pin]]: + mapping: Mapping[str, Tuple[Type[SearchPath], Type[Pin]]] = { + 'alias': (AliasSearchPath, AliasPin), + 'channel': (ChannelSearchPath, ChannelPin), + 'git': (GitSearchPath, GitPin), } - return mapping[conf['type']](**dict(conf.items())) + SP, P = mapping[conf['type']] + _, all_fields = filter_dict(dict(conf.items()), set(['type'])) + pin_fields, remaining_fields = filter_dict(all_fields, set(P._fields)) + # Error suppression works around https://github.com/python/mypy/issues/9007 + pin_present = pin_fields != {} or P._fields == () + pin = P(**pin_fields) if pin_present else None # type:ignore[call-arg] + return SP(**remaining_fields), pin def read_config(filename: str) -> configparser.ConfigParser: @@ -644,9 +643,9 @@ def pinCommand(args: argparse.Namespace) -> None: if args.channels and section not in args.channels: continue - sp = read_search_path(config[section]) + sp, old_pin = read_search_path(config[section]) - config[section].update(sp.pin(v)._asdict()) + config[section].update(sp.pin(v, old_pin)._asdict()) with open(args.channels_file, 'w') as configfile: config.write(configfile) @@ -657,11 +656,15 @@ def updateCommand(args: argparse.Namespace) -> None: exprs: Dict[str, str] = {} config = read_config_files(args.channels_file) for section in config: - sp = read_search_path(config[section]) + sp, pin = read_search_path(config[section]) + if pin is None: + raise Exception( + 'Cannot update unpinned channel "%s" (Run "pin" before "update")' % + section) if isinstance(sp, AliasSearchPath): assert 'git_repo' not in config[section] continue - tarball = sp.fetch(v, section, config[section]) + tarball = sp.fetch(v, pin) exprs[section] = ( 'f: f { name = "%s"; channelName = "%%s"; src = builtins.storePath "%s"; }' % (config[section]['release_name'], tarball))