]> git.scottworley.com Git - pinch/commitdiff
Start
authorScott Worley <scottworley@scottworley.com>
Tue, 7 Apr 2020 23:53:21 +0000 (16:53 -0700)
committerScott Worley <scottworley@scottworley.com>
Wed, 8 Apr 2020 23:27:14 +0000 (16:27 -0700)
pinch.py [new file with mode: 0644]
test.sh [new file with mode: 0755]

diff --git a/pinch.py b/pinch.py
new file mode 100644 (file)
index 0000000..f974d1c
--- /dev/null
+++ b/pinch.py
@@ -0,0 +1,171 @@
+import filecmp
+import functools
+import hashlib
+import operator
+import os
+import os.path
+import shutil
+import tempfile
+import urllib.parse
+import urllib.request
+import xml.dom.minidom
+
+from typing import (
+    Any,
+    Dict,
+    Iterable,
+    List,
+    Sequence,
+    Tuple,
+)
+
+
+class VerificationError(Exception):
+    pass
+
+
+class Verification:
+
+    def __init__(self) -> None:
+        self.line_length = 0
+
+    def status(self, s: str) -> None:
+        print(s, end=' ', flush=True)
+        self.line_length += 1 + len(s)  # Unicode??
+
+    @staticmethod
+    def _color(s: str, c: int) -> str:
+        return '\033[%2dm%s\033[00m' % (c, s)
+
+    def result(self, r: bool) -> None:
+        message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r]
+        length = len(message)
+        cols = shutil.get_terminal_size().columns
+        pad = (cols - (self.line_length + length)) % cols
+        print(' ' * pad + self._color(message, color))
+        self.line_length = 0
+        if not r:
+            raise VerificationError()
+
+    def check(self, s: str, r: bool) -> None:
+        self.status(s)
+        self.result(r)
+
+    def ok(self) -> None:
+        self.result(True)
+
+
+def compare(a: str,
+            b: str) -> Tuple[Sequence[str],
+                             Sequence[str],
+                             Sequence[str]]:
+
+    def throw(error: OSError) -> None:
+        raise error
+
+    def join(x: str, y: str) -> str:
+        return y if x == '.' else os.path.join(x, y)
+
+    def recursive_files(d: str) -> Iterable[str]:
+        all_files: List[str] = []
+        for path, dirs, files in os.walk(d, onerror=throw):
+            rel = os.path.relpath(path, start=d)
+            all_files.extend(join(rel, f) for f in files)
+            for dir_or_link in dirs:
+                if os.path.islink(join(path, dir_or_link)):
+                    all_files.append(join(rel, dir_or_link))
+        return all_files
+
+    def exclude_dot_git(files: Iterable[str]) -> Iterable[str]:
+        return (f for f in files if not f.startswith('.git/'))
+
+    files = functools.reduce(
+        operator.or_, (set(
+            exclude_dot_git(
+                recursive_files(x))) for x in [a, b]))
+    return filecmp.cmpfiles(a, b, files, shallow=False)
+
+
+def fetch(v: Verification, channel_url: str) -> Dict[str, Any]:
+    info: Dict[str, Any] = {'url': channel_url}
+    v.status('Fetching channel')
+    request = urllib.request.urlopen(
+        'https://channels.nixos.org/nixos-20.03', timeout=10)
+    info['channel_html'] = request.read()
+    info['forwarded_url'] = request.geturl()
+    v.result(request.status == 200)
+    v.check('Got forwarded', info['url'] != info['forwarded_url'])
+    return info
+
+
+def parse(v: Verification, info: Dict[str, Any]) -> None:
+    v.status('Parsing channel description as XML')
+    d = xml.dom.minidom.parseString(info['channel_html'])
+    v.ok()
+
+    v.status('Extracting git commit')
+    git_commit_node = d.getElementsByTagName('tt')[0]
+    info['git_commit'] = git_commit_node.firstChild.nodeValue
+    v.ok()
+    v.status('Verifying git commit label')
+    v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ')
+
+    v.status('Parsing table')
+    info['table'] = {}
+    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 = row.childNodes[2].firstChild.firstChild.nodeValue
+        info['table'][name] = {'url': url, 'digest': digest, 'size': size}
+    v.ok()
+
+
+def fetch_resources(v: Verification, info: Dict[str, Any]) -> None:
+
+    for resource in ['git-revision', 'nixexprs.tar.xz']:
+        fields = info['table'][resource]
+        v.status('Fetching resource "%s"' % resource)
+        url = urllib.parse.urljoin(info['forwarded_url'], fields['url'])
+        request = urllib.request.urlopen(url, timeout=10)
+        if fields['size'] < 4096:
+            fields['content'] = request.read()
+        else:
+            with tempfile.NamedTemporaryFile(suffix='.nixexprs.tar.xz', delete=False) as tmp_file:
+                shutil.copyfileobj(request, tmp_file)
+                fields['file'] = tmp_file.name
+        v.result(request.status == 200)
+        v.status('Verifying digest for "%s"' % resource)
+        if fields['size'] < 4096:
+            actual_hash = hashlib.sha256(fields['content']).hexdigest()
+        else:
+            hasher = hashlib.sha256()
+            with open(fields['file'], 'rb') as f:
+                # pylint: disable=cell-var-from-loop
+                for block in iter(lambda: f.read(4096), b''):
+                    hasher.update(block)
+            actual_hash = hasher.hexdigest()
+        v.result(actual_hash == fields['digest'])
+    v.check('Verifying git commit on main page matches git commit in table',
+            info['table']['git-revision']['content'].decode() == info['git_commit'])
+
+
+def extract_channel(v: Verification, info: Dict[str, Any]) -> None:
+    with tempfile.TemporaryDirectory() as d:
+        v.status('Extracting nixexprs.tar.xz')
+        shutil.unpack_archive(info['table']['nixexprs.tar.xz']['file'], d)
+        v.ok()
+        v.status('Removing temporary directory')
+    v.ok()
+
+
+def main() -> None:
+    v = Verification()
+    info = fetch(v, 'https://channels.nixos.org/nixos-20.03')
+    parse(v, info)
+    fetch_resources(v, info)
+    extract_channel(v, info)
+    print(info)
+
+
+main()
diff --git a/test.sh b/test.sh
new file mode 100755 (executable)
index 0000000..cea63ba
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+set -e
+
+PARALLELISM=4
+
+find . -name '*.py' -print0 | xargs -0 mypy --strict --ignore-missing-imports
+
+find . -name '*_test.py' -print0 | xargs -0 -r -n1 python3
+
+find . -name '*.py' -print0 | xargs -0 pylint --reports=n --persistent=n --ignore-imports=y -d invalid-name,missing-docstring
+
+formatting_needs_fixing=$(
+  find . -name '*.py' -print0 |
+    xargs -P "$PARALLELISM" -0 -n1 autopep8 --diff -aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+)
+if [[ "$formatting_needs_fixing" ]];then
+  echo "Formatting needs fixing:"
+  echo "$formatting_needs_fixing"
+  exit 1
+fi