polymorphic fetch()

[pinch] / pinch.py

diff --git a/pinch.py b/pinch.py
index 24e132aad745caa820c05d34461b8523fc83ec32..58f7a3290cc507760303858cd90ba351f118d0e0 100644 (file)
--- a/pinch.py
+++ b/pinch.py
@@ -1,3 +1,4 @@
+from abc import ABC, abstractmethod

 import argparse
 import configparser
 import filecmp
 import argparse
 import configparser
 import filecmp


@@ -38,31 +39,6 @@ xdg = XDG(
         os.path.expanduser('~/.cache')))
 
 
         os.path.expanduser('~/.cache')))
 
 

-Digest16 = NewType('Digest16', str)
-Digest32 = NewType('Digest32', str)
-
-
-class ChannelTableEntry(types.SimpleNamespace):
-    absolute_url: str
-    digest: Digest16
-    file: str
-    size: int
-    url: str
-
-
-class Channel(types.SimpleNamespace):
-    alias_of: str
-    channel_html: bytes
-    channel_url: str
-    forwarded_url: str
-    git_ref: str
-    git_repo: str
-    git_revision: str
-    old_git_revision: str
-    release_name: str
-    table: Dict[str, ChannelTableEntry]
-
-

 class VerificationError(Exception):
     pass
 
 class VerificationError(Exception):
     pass
 


@@ -83,7 +59,7 @@ class Verification:
     def result(self, r: bool) -> None:
         message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r]
         length = len(message)
     def result(self, r: bool) -> None:
         message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r]
         length = len(message)

-        cols = shutil.get_terminal_size().columns
+        cols = shutil.get_terminal_size().columns or 80

         pad = (cols - (self.line_length + length)) % cols
         print(' ' * pad + self._color(message, color), file=sys.stderr)
         self.line_length = 0
         pad = (cols - (self.line_length + length)) % cols
         print(' ' * pad + self._color(message, color), file=sys.stderr)
         self.line_length = 0


@@ -98,6 +74,93 @@ class Verification:
         self.result(True)
 
 
         self.result(True)
 
 

+Digest16 = NewType('Digest16', str)
+Digest32 = NewType('Digest32', str)
+
+
+class ChannelTableEntry(types.SimpleNamespace):
+    absolute_url: str
+    digest: Digest16
+    file: str
+    size: int
+    url: str
+
+
+class SearchPath(types.SimpleNamespace, ABC):
+    release_name: str
+
+    @abstractmethod
+    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+        pass
+
+
+class AliasSearchPath(SearchPath):
+    alias_of: str
+
+    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+        assert not hasattr(self, 'git_repo')
+
+
+# (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
+    git_ref: str
+    git_repo: str
+    git_revision: str
+    old_git_revision: str
+    table: Dict[str, ChannelTableEntry]
+
+
+class GitSearchPath(TarrableSearchPath):
+    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+        if hasattr(self, 'git_revision'):
+            self.old_git_revision = self.git_revision
+            del self.git_revision
+
+        git_fetch(v, self)
+        conf['release_name'] = git_revision_name(v, self)
+        conf['git_revision'] = self.git_revision
+
+    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)
+
+        ensure_git_rev_available(v, self)
+        return git_get_tarball(v, self)
+
+
+class ChannelSearchPath(TarrableSearchPath):
+    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+        if hasattr(self, 'git_revision'):
+            self.old_git_revision = self.git_revision
+            del self.git_revision
+
+        pin_channel(v, self)
+        conf['release_name'] = self.release_name
+        conf['tarball_url'] = self.table['nixexprs.tar.xz'].absolute_url
+        conf['tarball_sha256'] = self.table['nixexprs.tar.xz'].digest
+        conf['git_revision'] = self.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)
+
+        return fetch_with_nix_prefetch_url(
+            v, conf['tarball_url'], Digest16(
+                conf['tarball_sha256']))
+
+

 def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]:
 
     def throw(error: OSError) -> None:
 def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]:
 
     def throw(error: OSError) -> None:


@@ -126,16 +189,16 @@ def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]:
     return filecmp.cmpfiles(a, b, files, shallow=False)
 
 
     return filecmp.cmpfiles(a, b, files, shallow=False)
 
 

-def fetch(v: Verification, channel: Channel) -> None:
+def fetch(v: Verification, channel: TarrableSearchPath) -> None:

     v.status('Fetching channel')
     request = urllib.request.urlopen(channel.channel_url, timeout=10)
     channel.channel_html = request.read()
     channel.forwarded_url = request.geturl()
     v.status('Fetching channel')
     request = urllib.request.urlopen(channel.channel_url, timeout=10)
     channel.channel_html = request.read()
     channel.forwarded_url = request.geturl()

-    v.result(request.status == 200)
+    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 != channel.forwarded_url)
 
 

-def parse_channel(v: Verification, channel: Channel) -> None:
+def parse_channel(v: Verification, channel: TarrableSearchPath) -> None:

     v.status('Parsing channel description as XML')
     d = xml.dom.minidom.parseString(channel.channel_html)
     v.ok()
     v.status('Parsing channel description as XML')
     d = xml.dom.minidom.parseString(channel.channel_html)
     v.ok()


@@ -184,7 +247,7 @@ def digest_file(filename: str) -> Digest16:
 def to_Digest16(v: Verification, digest32: Digest32) -> Digest16:
     v.status('Converting digest to base16')
     process = subprocess.run(
 def to_Digest16(v: Verification, digest32: Digest32) -> Digest16:
     v.status('Converting digest to base16')
     process = subprocess.run(

-        ['nix', 'to-base16', '--type', 'sha256', digest32], capture_output=True)
+        ['nix', 'to-base16', '--type', 'sha256', digest32], stdout=subprocess.PIPE)

     v.result(process.returncode == 0)
     return Digest16(process.stdout.decode().strip())
 
     v.result(process.returncode == 0)
     return Digest16(process.stdout.decode().strip())
 


@@ -192,7 +255,7 @@ def to_Digest16(v: Verification, digest32: Digest32) -> Digest16:
 def to_Digest32(v: Verification, digest16: Digest16) -> Digest32:
     v.status('Converting digest to base32')
     process = subprocess.run(
 def to_Digest32(v: Verification, digest16: Digest16) -> Digest32:
     v.status('Converting digest to base32')
     process = subprocess.run(

-        ['nix', 'to-base32', '--type', 'sha256', digest16], capture_output=True)
+        ['nix', 'to-base32', '--type', 'sha256', digest16], stdout=subprocess.PIPE)

     v.result(process.returncode == 0)
     return Digest32(process.stdout.decode().strip())
 
     v.result(process.returncode == 0)
     return Digest32(process.stdout.decode().strip())
 


@@ -203,7 +266,7 @@ def fetch_with_nix_prefetch_url(
         digest: Digest16) -> str:
     v.status('Fetching %s' % url)
     process = subprocess.run(
         digest: Digest16) -> str:
     v.status('Fetching %s' % url)
     process = subprocess.run(

-        ['nix-prefetch-url', '--print-path', url, digest], capture_output=True)
+        ['nix-prefetch-url', '--print-path', url, digest], stdout=subprocess.PIPE)

     v.result(process.returncode == 0)
     prefetch_digest, path, empty = process.stdout.decode().split('\n')
     assert empty == ''
     v.result(process.returncode == 0)
     prefetch_digest, path, empty = process.stdout.decode().split('\n')
     assert empty == ''


@@ -212,10 +275,10 @@ def fetch_with_nix_prefetch_url(
     v.status("Verifying file digest")
     file_digest = digest_file(path)
     v.result(file_digest == digest)
     v.status("Verifying file digest")
     file_digest = digest_file(path)
     v.result(file_digest == digest)

-    return path
+    return path  # type: ignore  # (for old mypy)

 
 
 
 

-def fetch_resources(v: Verification, channel: Channel) -> None:
+def fetch_resources(v: Verification, channel: TarrableSearchPath) -> None:

     for resource in ['git-revision', 'nixexprs.tar.xz']:
         fields = channel.table[resource]
         fields.absolute_url = urllib.parse.urljoin(
     for resource in ['git-revision', 'nixexprs.tar.xz']:
         fields = channel.table[resource]
         fields.absolute_url = urllib.parse.urljoin(


@@ -235,7 +298,7 @@ def git_cachedir(git_repo: str) -> str:
         digest_string(git_repo.encode()))
 
 
         digest_string(git_repo.encode()))
 
 

-def tarball_cache_file(channel: Channel) -> str:
+def tarball_cache_file(channel: TarrableSearchPath) -> str:

     return os.path.join(
         xdg.XDG_CACHE_HOME,
         'pinch/git-tarball',
     return os.path.join(
         xdg.XDG_CACHE_HOME,
         'pinch/git-tarball',


@@ -245,7 +308,7 @@ def tarball_cache_file(channel: Channel) -> str:
          channel.release_name))
 
 
          channel.release_name))
 
 

-def verify_git_ancestry(v: Verification, channel: Channel) -> None:
+def verify_git_ancestry(v: Verification, channel: TarrableSearchPath) -> None:

     cachedir = git_cachedir(channel.git_repo)
     v.status('Verifying rev is an ancestor of ref')
     process = subprocess.run(['git',
     cachedir = git_cachedir(channel.git_repo)
     v.status('Verifying rev is an ancestor of ref')
     process = subprocess.run(['git',


@@ -271,7 +334,7 @@ def verify_git_ancestry(v: Verification, channel: Channel) -> None:
         v.result(process.returncode == 0)
 
 
         v.result(process.returncode == 0)
 
 

-def git_fetch(v: Verification, channel: Channel) -> None:
+def git_fetch(v: Verification, channel: TarrableSearchPath) -> None:

     # It would be nice if we could share the nix git cache, but as of the time
     # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready
     # yet), and trying to straddle them both is too far into nix implementation
     # It would be nice if we could share the nix git cache, but as of the time
     # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready
     # yet), and trying to straddle them both is too far into nix implementation


@@ -313,7 +376,9 @@ def git_fetch(v: Verification, channel: Channel) -> None:
     verify_git_ancestry(v, channel)
 
 
     verify_git_ancestry(v, channel)
 
 

-def ensure_git_rev_available(v: Verification, channel: Channel) -> None:
+def ensure_git_rev_available(
+        v: Verification,
+        channel: TarrableSearchPath) -> None:

     cachedir = git_cachedir(channel.git_repo)
     if os.path.exists(cachedir):
         v.status('Checking if we already have this rev:')
     cachedir = git_cachedir(channel.git_repo)
     if os.path.exists(cachedir):
         v.status('Checking if we already have this rev:')


@@ -332,7 +397,7 @@ def ensure_git_rev_available(v: Verification, channel: Channel) -> None:
 
 def compare_tarball_and_git(
         v: Verification,
 
 def compare_tarball_and_git(
         v: Verification,

-        channel: Channel,
+        channel: TarrableSearchPath,

         channel_contents: str,
         git_contents: str) -> None:
     v.status('Comparing channel tarball with git checkout')
         channel_contents: str,
         git_contents: str) -> None:
     v.status('Comparing channel tarball with git checkout')


@@ -363,7 +428,10 @@ def compare_tarball_and_git(
         len(benign_errors) == len(expected_errors))
 
 
         len(benign_errors) == len(expected_errors))
 
 

-def extract_tarball(v: Verification, channel: Channel, dest: str) -> None:
+def extract_tarball(
+        v: Verification,
+        channel: TarrableSearchPath,
+        dest: str) -> None:

     v.status('Extracting tarball %s' %
              channel.table['nixexprs.tar.xz'].file)
     shutil.unpack_archive(
     v.status('Extracting tarball %s' %
              channel.table['nixexprs.tar.xz'].file)
     shutil.unpack_archive(


@@ -372,7 +440,10 @@ def extract_tarball(v: Verification, channel: Channel, dest: str) -> None:
     v.ok()
 
 
     v.ok()
 
 

-def git_checkout(v: Verification, channel: Channel, dest: str) -> None:
+def git_checkout(
+        v: Verification,
+        channel: TarrableSearchPath,
+        dest: str) -> None:

     v.status('Checking out corresponding git revision')
     git = subprocess.Popen(['git',
                             '-C',
     v.status('Checking out corresponding git revision')
     git = subprocess.Popen(['git',
                             '-C',


@@ -389,7 +460,7 @@ def git_checkout(v: Verification, channel: Channel, dest: str) -> None:
     v.result(git.returncode == 0 and tar.returncode == 0)
 
 
     v.result(git.returncode == 0 and tar.returncode == 0)
 
 

-def git_get_tarball(v: Verification, channel: Channel) -> str:
+def git_get_tarball(v: Verification, channel: TarrableSearchPath) -> str:

     cache_file = tarball_cache_file(channel)
     if os.path.exists(cache_file):
         cached_tarball = open(cache_file).read(9999)
     cache_file = tarball_cache_file(channel)
     if os.path.exists(cache_file):
         cached_tarball = open(cache_file).read(9999)


@@ -417,18 +488,18 @@ def git_get_tarball(v: Verification, channel: Channel) -> str:
 
         v.status('Putting tarball in Nix store')
         process = subprocess.run(
 
         v.status('Putting tarball in Nix store')
         process = subprocess.run(

-            ['nix-store', '--add', output_filename], capture_output=True)
+            ['nix-store', '--add', output_filename], stdout=subprocess.PIPE)

         v.result(process.returncode == 0)
         store_tarball = process.stdout.decode().strip()
 
         os.makedirs(os.path.dirname(cache_file), exist_ok=True)
         open(cache_file, 'w').write(store_tarball)
         v.result(process.returncode == 0)
         store_tarball = process.stdout.decode().strip()
 
         os.makedirs(os.path.dirname(cache_file), exist_ok=True)
         open(cache_file, 'w').write(store_tarball)

-        return store_tarball
+        return store_tarball  # type: ignore  # (for old mypy)

 
 
 def check_channel_metadata(
         v: Verification,
 
 
 def check_channel_metadata(
         v: Verification,

-        channel: Channel,
+        channel: TarrableSearchPath,

         channel_contents: str) -> None:
     v.status('Verifying git commit in channel tarball')
     v.result(
         channel_contents: str) -> None:
     v.status('Verifying git commit in channel tarball')
     v.result(


@@ -450,7 +521,9 @@ def check_channel_metadata(
     v.result(channel.release_name.endswith(version_suffix))
 
 
     v.result(channel.release_name.endswith(version_suffix))
 
 

-def check_channel_contents(v: Verification, channel: Channel) -> None:
+def check_channel_contents(
+        v: Verification,
+        channel: TarrableSearchPath) -> None:

     with tempfile.TemporaryDirectory() as channel_contents, \
             tempfile.TemporaryDirectory() as git_contents:
 
     with tempfile.TemporaryDirectory() as channel_contents, \
             tempfile.TemporaryDirectory() as git_contents:
 


@@ -465,7 +538,7 @@ def check_channel_contents(v: Verification, channel: Channel) -> None:
     v.ok()
 
 
     v.ok()
 
 

-def pin_channel(v: Verification, channel: Channel) -> None:
+def pin_channel(v: Verification, channel: TarrableSearchPath) -> None:

     fetch(v, channel)
     parse_channel(v, channel)
     fetch_resources(v, channel)
     fetch(v, channel)
     parse_channel(v, channel)
     fetch_resources(v, channel)


@@ -473,7 +546,7 @@ def pin_channel(v: Verification, channel: Channel) -> None:
     check_channel_contents(v, channel)
 
 
     check_channel_contents(v, channel)
 
 

-def git_revision_name(v: Verification, channel: Channel) -> str:
+def git_revision_name(v: Verification, channel: TarrableSearchPath) -> str:

     v.status('Getting commit date')
     process = subprocess.run(['git',
                               '-C',
     v.status('Getting commit date')
     process = subprocess.run(['git',
                               '-C',


@@ -482,19 +555,40 @@ def git_revision_name(v: Verification, channel: Channel) -> str:
                               '-n1',
                               '--format=%ct-%h',
                               '--abbrev=11',
                               '-n1',
                               '--format=%ct-%h',
                               '--abbrev=11',

+                              '--no-show-signature',

                               channel.git_revision],
                               channel.git_revision],

-                             capture_output=True)
+                             stdout=subprocess.PIPE)

     v.result(process.returncode == 0 and process.stdout != b'')
     return '%s-%s' % (os.path.basename(channel.git_repo),
                       process.stdout.decode().strip())
 
 
     v.result(process.returncode == 0 and process.stdout != b'')
     return '%s-%s' % (os.path.basename(channel.git_repo),
                       process.stdout.decode().strip())
 
 

+def read_search_path(conf: configparser.SectionProxy) -> SearchPath:
+    if 'alias_of' in conf:
+        return AliasSearchPath(**dict(conf.items()))
+    if 'channel_url' in conf:
+        return ChannelSearchPath(**dict(conf.items()))
+    return GitSearchPath(**dict(conf.items()))
+
+

 def read_config(filename: str) -> configparser.ConfigParser:
     config = configparser.ConfigParser()
     config.read_file(open(filename), filename)
     return config
 
 
 def read_config(filename: str) -> configparser.ConfigParser:
     config = configparser.ConfigParser()
     config.read_file(open(filename), filename)
     return config
 
 

+def read_config_files(
+        filenames: Iterable[str]) -> Dict[str, configparser.SectionProxy]:
+    merged_config: Dict[str, configparser.SectionProxy] = {}
+    for file in filenames:
+        config = read_config(file)
+        for section in config.sections():
+            if section in merged_config:
+                raise Exception('Duplicate channel "%s"' % section)
+            merged_config[section] = config[section]
+    return merged_config
+
+

 def pin(args: argparse.Namespace) -> None:
     v = Verification()
     config = read_config(args.channels_file)
 def pin(args: argparse.Namespace) -> None:
     v = Verification()
     config = read_config(args.channels_file)


@@ -502,72 +596,31 @@ def pin(args: argparse.Namespace) -> None:
         if args.channels and section not in args.channels:
             continue
 
         if args.channels and section not in args.channels:
             continue
 

-        channel = Channel(**dict(config[section].items()))
-
-        if hasattr(channel, 'alias_of'):
-            assert not hasattr(channel, 'git_repo')
-            continue
+        sp = read_search_path(config[section])

 
 

-        if hasattr(channel, 'git_revision'):
-            channel.old_git_revision = channel.git_revision
-            del channel.git_revision
-
-        if 'channel_url' in config[section]:
-            pin_channel(v, channel)
-            config[section]['release_name'] = channel.release_name
-            config[section]['tarball_url'] = channel.table['nixexprs.tar.xz'].absolute_url
-            config[section]['tarball_sha256'] = channel.table['nixexprs.tar.xz'].digest
-        else:
-            git_fetch(v, channel)
-            config[section]['release_name'] = git_revision_name(v, channel)
-        config[section]['git_revision'] = channel.git_revision
+        sp.pin(v, config[section])

 
     with open(args.channels_file, 'w') as configfile:
         config.write(configfile)
 
 
 
     with open(args.channels_file, 'w') as configfile:
         config.write(configfile)
 
 

-def fetch_channel(
-        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)
-
-    if 'channel_url' in conf:
-        return fetch_with_nix_prefetch_url(
-            v, conf['tarball_url'], Digest16(
-                conf['tarball_sha256']))
-
-    channel = Channel(**dict(conf.items()))
-    ensure_git_rev_available(v, channel)
-    return git_get_tarball(v, channel)
-
-

 def update(args: argparse.Namespace) -> None:
     v = Verification()
 def update(args: argparse.Namespace) -> None:
     v = Verification()

-    config = configparser.ConfigParser()

     exprs: Dict[str, str] = {}
     exprs: Dict[str, str] = {}

-    configs = [read_config(filename) for filename in args.channels_file]
-    for config in configs:
-        for section in config.sections():
-            if 'alias_of' in config[section]:
-                assert 'git_repo' not in config[section]
-                continue
-            tarball = fetch_channel(v, section, config[section])
-            if section in exprs:
-                raise Exception('Duplicate channel "%s"' % section)
-            exprs[section] = (
-                'f: f { name = "%s"; channelName = "%%s"; src = builtins.storePath "%s"; }' %
-                (config[section]['release_name'], tarball))
+    config = read_config_files(args.channels_file)
+    for section in config:
+        sp = read_search_path(config[section])
+        if isinstance(sp, AliasSearchPath):
+            assert 'git_repo' not in config[section]
+            continue
+        tarball = sp.fetch(v, section, config[section])
+        exprs[section] = (
+            'f: f { name = "%s"; channelName = "%%s"; src = builtins.storePath "%s"; }' %
+            (config[section]['release_name'], tarball))

 
 

-    for config in configs:
-        for section in config.sections():
-            if 'alias_of' in config[section]:
-                if section in exprs:
-                    raise Exception('Duplicate channel "%s"' % section)
-                exprs[section] = exprs[str(config[section]['alias_of'])]
+    for section in config:
+        if 'alias_of' in config[section]:
+            exprs[section] = exprs[str(config[section]['alias_of'])]

 
     command = [
         'nix-env',
 
     command = [
         'nix-env',


@@ -602,4 +655,5 @@ def main() -> None:
     args.func(args)
 
 
     args.func(args)
 
 

-main()
+if __name__ == '__main__':
+    main()