Hydrilla

include src/hydrilla/schemas/*/*.schema.json*

Version: 1.1b1

        * build (a PEP517 package builder)

        * babel (Python library)

        ## Building & testing & installation from wheel

        Build, test and installation processes are analogous to those described in the [README of Hydrilla server part](https://git.koszko.org/pydrilla/about).

        ``` shell

Provides-Extra: spdx

* build (a PEP517 package builder)

* babel (Python library)

## Building & testing & installation from wheel

Build, test and installation processes are analogous to those described in the [README of Hydrilla server part](https://git.koszko.org/pydrilla/about).

``` shell

# SPDX-License-Identifier: CC0-1.0

# Copyright (C) 2022 Wojtek Kosior <koszko@koszko.org>

#

# Available under the terms of Creative Commons Zero v1.0 Universal.

import sys

from pathlib import Path

import pytest

import pkgutil

import importlib

from tempfile import TemporaryDirectory

from typing import Iterable

here = Path(__file__).resolve().parent

sys.path.insert(0, str(here / 'src'))

@pytest.fixture(autouse=True)

def no_requests(monkeypatch):

    """Remove requests.sessions.Session.request for all tests."""

    if importlib.util.find_spec("requests") is not None:

        monkeypatch.delattr('requests.sessions.Session.request')

@pytest.fixture

def mock_subprocess_run(monkeypatch, request):

    """

    Temporarily replace subprocess.run() with a function supplied through pytest

    marker 'subprocess_run'.

    The marker excepts 2 arguments:

    * the module inside which the subprocess attribute should be mocked and

    * a run() function to use.

    """

    where, mocked_run = request.node.get_closest_marker('subprocess_run').args

    class MockedSubprocess:

        """Minimal mocked version of the subprocess module."""

        run = mocked_run

    monkeypatch.setattr(where, 'subprocess', MockedSubprocess)

@pytest.fixture(autouse=True)

def no_gettext(monkeypatch, request):

    """

    Make gettext return all strings untranslated unless we request otherwise.

    """

    if request.node.get_closest_marker('enable_gettext'):

        return

    import hydrilla

    modules_to_process = [hydrilla]

    def add_child_modules(parent):

        """

        Recursuvely collect all modules descending from 'parent' into an array.

        """

        try:

            load_paths = parent.__path__

        except AttributeError:

            return

        for module_info in pkgutil.iter_modules(load_paths):

            if module_info.name != '__main__':

                __import__(f'{parent.__name__}.{module_info.name}')

                modules_to_process.append(getattr(parent, module_info.name))

                add_child_modules(getattr(parent, module_info.name))

    add_child_modules(hydrilla)

    for module in modules_to_process:

        if hasattr(module, '_'):

            monkeypatch.setattr(module, '_', lambda message: message)

@pytest.fixture

def tmpdir() -> Iterable[Path]:

    """

    Provide test case with a temporary directory that will be automatically

    deleted after the test.

    """

    with TemporaryDirectory() as tmpdir:

        yield Path(tmpdir)

.TH HYDRILLA-BUILDER 1 2022-06-14 "Hydrilla 1.1" "Hydrilla Manual"

hydrilla\-builder \- Generate packages to be served by Hydrilla

.I hydrilla\-builder

The main function of

.I hydrilla\-builder

is to automate the process of computing SHA256 cryptographic sums of package

files and including them in JSON definitions.

This tool does not perform nor trigger actions like compilation, minification or

bundling of source code files. When this is needed,

.I hydrilla\-builder

instead relies on facilities already provided by other software distribution

systems like APT and extracts the requested files from .deb packages. This

feature is called \*(lqpiggybacking\*(rq.

.I hydrilla\-builder

.TP

.BI \-p " PIGGYBACK_PATH" "\fR,\fP \-\^\-piggyback\-files=" PIGGYBACK_PATH

Read and write foreign package archives under

.IR PIGGYBACK_PATH .

If not specified, a default value is computed by appending

\*(lq.foreign-packages\*(rq to the

.I SOURCE

directory path.

can then be passed to Hydrilla to serve packages from.

.I hydrilla\-builder

addopts = "-ra"

markers = [

    "subprocess_run: define how mocked subprocess.run should behave"

]

packages = find_namespace:

setup = setuptools_scm; babel

spdx = reuse

from setuptools.command.sdist import sdist

from pathlib import Path

here = Path(__file__).resolve().parent

    """The build command but runs babel before build."""

        """Wrapper around build_py's original run() method."""

        super().run(*args, **kwargs)

class CustomSdistCommand(sdist):

    """

    The sdist command but prevents compiled message catalogs from being included

    in the archive.

    """

    def run(self, *args, **kwargs):

        """Wrapper around sdist's original run() method."""

        locales_dir = here / 'src/hydrilla/builder/locales'

        locale_files = {}

        for path in locales_dir.rglob('*.mo'):

            locale_files[path] = path.read_bytes()

        for path in locale_files:

            path.unlink()

        for path, contents in locale_files.items():

            path.write_bytes(contents)

setuptools.setup(cmdclass = {

    'build_py': CustomBuildCommand,

    'sdist': CustomSdistCommand

})

Version: 1.1b1

        * build (a PEP517 package builder)

        * babel (Python library)

        ## Building & testing & installation from wheel

        Build, test and installation processes are analogous to those described in the [README of Hydrilla server part](https://git.koszko.org/pydrilla/about).

        ``` shell

Provides-Extra: spdx

conftest.py

src/hydrilla/builder/common_errors.py

src/hydrilla/builder/local_apt.py

src/hydrilla/builder/piggybacking.py

src/hydrilla/schemas/1.x/api_mapping_description-1.0.1.schema.json

src/hydrilla/schemas/1.x/api_mapping_description-1.0.1.schema.json.license

src/hydrilla/schemas/1.x/api_query_result-1.0.1.schema.json

src/hydrilla/schemas/1.x/api_query_result-1.0.1.schema.json.license

src/hydrilla/schemas/1.x/api_resource_description-1.0.1.schema.json

src/hydrilla/schemas/1.x/api_resource_description-1.0.1.schema.json.license

src/hydrilla/schemas/1.x/api_source_description-1.0.1.schema.json

src/hydrilla/schemas/1.x/api_source_description-1.0.1.schema.json.license

src/hydrilla/schemas/1.x/common_definitions-1.0.1.schema.json

src/hydrilla/schemas/1.x/common_definitions-1.0.1.schema.json.license

src/hydrilla/schemas/1.x/package_source-1.0.1.schema.json

src/hydrilla/schemas/1.x/package_source-1.0.1.schema.json.license

src/hydrilla/schemas/2.x/api_mapping_description-2.schema.json

src/hydrilla/schemas/2.x/api_mapping_description-2.schema.json.license

src/hydrilla/schemas/2.x/api_query_result-2.schema.json

src/hydrilla/schemas/2.x/api_query_result-2.schema.json.license

src/hydrilla/schemas/2.x/api_resource_description-2.schema.json

src/hydrilla/schemas/2.x/api_resource_description-2.schema.json.license

src/hydrilla/schemas/2.x/api_source_description-2.schema.json

src/hydrilla/schemas/2.x/api_source_description-2.schema.json.license

src/hydrilla/schemas/2.x/common_definitions-2.schema.json

src/hydrilla/schemas/2.x/common_definitions-2.schema.json.license

src/hydrilla/schemas/2.x/package_source-2.schema.json

src/hydrilla/schemas/2.x/package_source-2.schema.json.license

tests/__init__.py

tests/helpers.py

tests/test_build.py

tests/test_local_apt.py

babel

[spdx]

reuse

version = '1.1b1'

version_tuple = (1, '1b1')

import subprocess

from pathlib import Path, PurePosixPath

from contextlib import contextmanager

from tempfile import TemporaryDirectory, TemporaryFile

from typing import Optional, Iterable, Union

from . import local_apt

from .piggybacking import Piggybacked

from .common_errors import *

class ReuseError(SubprocessError):

def generate_spdx_report(root: Path) -> bytes:

    REUSE-compliant package, as exception is raised with linting report

    included in it.

    In case the reuse tool is not installed, an exception is also raised.

    for command in [

            ['reuse', '--root', str(root), 'lint'],

            ['reuse', '--root', str(root), 'spdx']

    ]:

        try:

            cp = subprocess.run(command, capture_output=True, text=True)

        except FileNotFoundError:

            msg = _('couldnt_execute_{}_is_it_installed').format('reuse')

            raise ReuseError(msg)

        if cp.returncode != 0:

            msg = _('command_{}_failed').format(' '.join(command))

            raise ReuseError(msg, cp)

    return cp.stdout.encode()

    def __init__(self, path: PurePosixPath, contents: bytes) -> None:

        self.include_in_distribution   = False

        self.include_in_source_archive = True

        self.path                      = path

        self.contents                  = contents

    def make_ref_dict(self) -> dict[str, str]:

            'file':   str(self.path),

@contextmanager

def piggybacked_system(piggyback_def: Optional[dict],

                       piggyback_files: Optional[Path]) \

                       -> Iterable[Piggybacked]:

    """

    Resolve resources from a foreign software packaging system. Optionally, use

    package files (.deb's, etc.) from a specified directory instead of resolving

    and downloading them.

    """

    if piggyback_def is None:

        yield Piggybacked()

    else:

        # apt is the only supported system right now

        assert piggyback_def['system'] == 'apt'

        with local_apt.piggybacked_system(piggyback_def, piggyback_files) \

             as piggybacked:

            yield piggybacked

    def __init__(self, srcdir: Path, index_json_path: Path,

                 piggyback_files: Optional[Path]=None):

        self.piggyback_files = piggyback_files

        if piggyback_files is None:

            piggyback_default_path = \

                srcdir.parent / f'{srcdir.name}.foreign-packages'

            if piggyback_default_path.exists():

                self.piggyback_files = piggyback_default_path

            index_json_path = (self.srcdir / index_json_path)

        index_obj, major = util.load_instance_from_file(index_json_path)

        if major not in (1, 2):

            msg = _('unknown_schema_package_source_{}')\

                .format(index_json_path)

            raise util.UnknownSchemaError(msg)

        index_desired_path = PurePosixPath('index.json')

        self.files_by_path[index_desired_path] = \

            FileRef(index_desired_path, index_json_path.read_bytes())

        self._process_index_json(index_obj, major)

    def _process_file(self, filename: Union[str, PurePosixPath],

                      piggybacked: Piggybacked,

                      include_in_distribution: bool=True):

        'filename' shall represent a relative path withing package directory.

        For each file an attempt is made to resolve it using 'piggybacked'

        object. If a file is found and pulled from foreign software packaging

        system this way, it gets automatically excluded from inclusion in

        Hydrilla source package's zipfile.

        include_in_source_archive = True

        desired_path = PurePosixPath(filename)

        if '..' in desired_path.parts:

            msg = _('path_contains_double_dot_{}').format(filename)

            raise FileReferenceError(msg)

        path = piggybacked.resolve_file(desired_path)

        if path is None:

            path = (self.srcdir / desired_path).resolve()

            try:

                rel_path = path.relative_to(self.srcdir)

            except ValueError:

                raise FileReferenceError(_('loading_{}_outside_package_dir')

                                         .format(filename))

            if str(rel_path) == 'index.json':

                raise FileReferenceError(_('loading_reserved_index_json'))

        else:

            include_in_source_archive = False

        file_ref = self.files_by_path.get(desired_path)

            if not path.is_file():

                msg = _('referenced_file_{}_missing').format(desired_path)

                raise FileReferenceError(msg)

            file_ref = FileRef(desired_path, path.read_bytes())

            self.files_by_path[desired_path] = file_ref

        if not include_in_source_archive:

            file_ref.include_in_source_archive = False

        return file_ref.make_ref_dict()

    def _prepare_source_package_zip(self, source_name: str,

                                    piggybacked: Piggybacked) -> str:

        'src_dir_name' shall not contain any slashes ('/').

        tf = TemporaryFile()

        source_dir_path      = PurePosixPath(source_name)

        piggybacked_dir_path = PurePosixPath(f'{source_name}.foreign-packages')

        with zipfile.ZipFile(tf, 'w') as zf:

                if file_ref.include_in_source_archive:

                    zf.writestr(str(source_dir_path / file_ref.path),

                                file_ref.contents)

            for desired_path, real_path in piggybacked.archive_files():

                zf.writestr(str(piggybacked_dir_path / desired_path),

                            real_path.read_bytes())

        tf.seek(0)

        self.source_zip_contents = tf.read()

    def _process_item(self, as_what: str, item_def: dict,

                      piggybacked: Piggybacked):

        Process 'item_def' as definition of a resource or mapping (determined by

        'as_what' param) and store in memory its processed form and files used

        by it.

        resulting_schema_version = [1]

        copy_props = ['identifier', 'long_name', 'description',

                      *filter(lambda p: p in item_def, ('comment', 'uuid'))]

        if as_what == 'resource':

            script_file_refs = [self._process_file(f['file'], piggybacked)

                'dependencies': [*piggybacked.resource_must_depend, *deps],

        if as_what == 'mapping' and item_def['type'] == "mapping_and_resource":

            new_item_obj['version'].append(item_def['revision'])

        if self.source_schema_ver >= [2]:

            # handle 'required_mappings' field

            required = [{'identifier': map_ref['identifier']}

                        for map_ref in item_def.get('required_mappings', [])]

            if required:

                resulting_schema_version = max(resulting_schema_version, [2])

                new_item_obj['required_mappings'] = required

            # handle 'permissions' field

            permissions = item_def.get('permissions', {})

            processed_permissions = {}

            if permissions.get('cors_bypass'):

                processed_permissions['cors_bypass'] = True

            if permissions.get('eval'):

                processed_permissions['eval'] = True

            if processed_permissions:

                new_item_obj['permissions'] = processed_permissions

                resulting_schema_version = max(resulting_schema_version, [2])

            # handle '{min,max}_haketilo_version' fields

            for minmax, default in ('min', [1]), ('max', [65536]):

                constraint = item_def.get(f'{minmax}_haketilo_version')

                if constraint in (None, default):

                    continue

                copy_props.append(f'{minmax}_haketilo_version')

                resulting_schema_version = max(resulting_schema_version, [2])

        new_item_obj.update((p, item_def[p]) for p in copy_props)

        new_item_obj['$schema'] = ''.join([

            schemas_root,

            f'/api_{as_what}_description',

            '-',

            util.version_string(resulting_schema_version),

            '.schema.json'

        ])

        new_item_obj['type']             = as_what

        new_item_obj['source_name']      = self.source_name

        new_item_obj['generated_by']     = generated_by

    def _process_index_json(self, index_obj: dict,

                            major_schema_version: int) -> None:

        schema_name = f'package_source-{major_schema_version}.schema.json';

        util.validator_for(schema_name).validate(index_obj)

        match = re.match(r'.*-((([1-9][0-9]*|0)\.)+)schema\.json$',

                         index_obj['$schema'])

        self.source_schema_ver = \

            [int(n) for n in filter(None, match.group(1).split('.'))]

        out_schema = f'{schemas_root}/api_source_description-1.schema.json'

            spdx_path = PurePosixPath('report.spdx')

            spdx_ref.include_in_source_archive = False

        piggyback_def = None

        if self.source_schema_ver >= [1, 1] and 'piggyback_on' in index_obj:

            piggyback_def = index_obj['piggyback_on']

        with piggybacked_system(piggyback_def, self.piggyback_files) \

             as piggybacked:

            copyright_to_process = [

                *(file_ref['file'] for file_ref in index_obj['copyright']),

                *piggybacked.package_license_files

            ]

            self.copyright_file_refs = [self._process_file(f, piggybacked)

                                        for f in copyright_to_process]

            if generate_spdx and not spdx_ref.include_in_distribution:

                raise FileReferenceError(_('report_spdx_not_in_copyright_list'))

            item_refs = []

            for item_def in index_obj['definitions']:

                if 'mapping' in item_def['type']:

                    ref = self._process_item('mapping', item_def, piggybacked)

                    item_refs.append(ref)

                if 'resource' in item_def['type']:

                    ref = self._process_item('resource', item_def, piggybacked)

                    item_refs.append(ref)

            for file_ref in index_obj.get('additional_files', []):

                self._process_file(file_ref['file'], piggybacked,

                                   include_in_distribution=False)

            zipfile_sha256 = self._prepare_source_package_zip\

                (self.source_name, piggybacked)

            source_archives_obj = {'zip' : {'sha256': zipfile_sha256}}

            '$schema':            out_schema,

@click.command(help=_('build_package_from_srcdir_to_dstdir'))

@click.option('-p', '--piggyback-files', type=click.Path(),

              help=_('path_instead_for_piggyback_files'))

def perform(srcdir, index_json, piggyback_files, dstdir):

    """

    Execute Hydrilla builder to turn source package into a distributable one.

    This command is meant to be the entry point of hydrilla-builder command

    exported by this package.

    """

    build = Build(Path(srcdir), Path(index_json),

                  piggyback_files and Path(piggyback_files))

    build.write_package_files(Path(dstdir))

# SPDX-License-Identifier: AGPL-3.0-or-later

# Error classes.

#

# This file is part of Hydrilla

#

# Copyright (C) 2022 Wojtek Kosior

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU Affero General Public License as

# published by the Free Software Foundation, either version 3 of the

# License, or (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Affero General Public License for more details.

#

# You should have received a copy of the GNU Affero General Public License

# along with this program.  If not, see <https://www.gnu.org/licenses/>.

#

#

# I, Wojtek Kosior, thereby promise not to sue for violation of this

# file's license. Although I request that you do not make use this code

# in a proprietary program, I am not going to enforce this in court.

"""

This module defines error types for use in other parts of Hydrilla builder.

"""

# Enable using with Python 3.7.

from __future__ import annotations

from pathlib import Path

from .. import util

here = Path(__file__).resolve().parent

_ = util.translation(here / 'locales').gettext

class DistroError(Exception):

    """

    Exception used to report problems when resolving an OS distribution.

    """

class FileReferenceError(Exception):

    """

    Exception used to report various problems concerning files referenced from

    source package.

    """

class SubprocessError(Exception):

    """

    Exception used to report problems related to execution of external

    processes, includes. various problems when calling apt-* and dpkg-*

    commands.

    """

    def __init__(self, msg: str, cp: Optional[CP]=None) -> None:

        """Initialize this SubprocessError"""

        if cp and cp.stdout:

            msg = '\n\n'.join([msg, _('STDOUT_OUTPUT_heading'), cp.stdout])

        if cp and cp.stderr:

            msg = '\n\n'.join([msg, _('STDERR_OUTPUT_heading'), cp.stderr])

        super().__init__(msg)

# SPDX-License-Identifier: AGPL-3.0-or-later

# Using a local APT.

#

# This file is part of Hydrilla

#

# Copyright (C) 2022 Wojtek Kosior

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU Affero General Public License as

# published by the Free Software Foundation, either version 3 of the

# License, or (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Affero General Public License for more details.

#

# You should have received a copy of the GNU Affero General Public License

# along with this program.  If not, see <https://www.gnu.org/licenses/>.

#

#

# I, Wojtek Kosior, thereby promise not to sue for violation of this

# file's license. Although I request that you do not make use this code

# in a proprietary program, I am not going to enforce this in court.

# Enable using with Python 3.7.

from __future__ import annotations

import zipfile

import shutil

import re

import subprocess

CP = subprocess.CompletedProcess

from pathlib import Path, PurePosixPath

from tempfile import TemporaryDirectory, NamedTemporaryFile

from hashlib import sha256

from urllib.parse import unquote

from contextlib import contextmanager

from typing import Optional, Iterable

from .. import util

from .piggybacking import Piggybacked

from .common_errors import *

here = Path(__file__).resolve().parent

_ = util.translation(here / 'locales').gettext

"""

Default cache directory to save APT configurations and downloaded GPG keys in.

"""

default_apt_cache_dir = Path.home() / '.cache' / 'hydrilla' / 'builder' / 'apt'

"""

Default keyserver to use.

"""

default_keyserver = 'hkps://keyserver.ubuntu.com:443'

"""

Default keys to download when using a local APT.

"""

default_keys = [

    # Trisquel

    'E6C27099CA21965B734AEA31B4EFB9F38D8AEBF1',

    '60364C9869F92450421F0C22B138CA450C05112F',

    # Ubuntu

    '630239CC130E1A7FD81A27B140976EAF437D05B5',

    '790BC7277767219C42C86F933B4FE6ACC0B21F32',

    'F6ECB3762474EDA9D21B7022871920D1991BC93C',

    # Debian

    '6D33866EDD8FFA41C0143AEDDCC9EFBF77E11517',

    '80D15823B7FD1561F9F7BCDDDC30D7C23CBBABEE',

    'AC530D520F2F3269F5E98313A48449044AAD5C5D'

]

"""sources.list file contents for known distros."""

default_lists = {

    'nabia': [f'{type} http://archive.trisquel.info/trisquel/ nabia{suf} main'

              for type in ('deb', 'deb-src')

              for suf in ('', '-updates', '-security')]

}

class GpgError(Exception):

    """

    Exception used to report various problems when calling GPG.

    """

class AptError(SubprocessError):

    """

    Exception used to report various problems when calling apt-* and dpkg-*

    commands.

    """

def run(command, **kwargs):

    """A wrapped around subprocess.run that sets some default options."""

    return subprocess.run(command, **kwargs, env={'LANG': 'en_US'},

                          capture_output=True, text=True)

class Apt:

    """

    This class represents an APT instance and can be used to call apt-get

    commands with it.

    """

    def __init__(self, apt_conf: str) -> None:

        """Initialize this Apt object."""

        self.apt_conf = apt_conf

    def get(self, *args: str, **kwargs) -> CP:

        """

        Run apt-get with the specified arguments and raise a meaningful AptError

        when something goes wrong.

        """

        command = ['apt-get', '-c', self.apt_conf, *args]

        try:

            cp = run(command, **kwargs)

        except FileNotFoundError:

            msg = _('couldnt_execute_{}_is_it_installed').format('apt-get')

            raise AptError(msg)

        if cp.returncode != 0:

            msg = _('command_{}_failed').format(' '.join(command))

            raise AptError(msg, cp)

        return cp

def cache_dir() -> Path:

    """

    Return the directory used to cache data (APT configurations, keyrings) to

    speed up repeated operations.

    This function first ensures the directory exists.

    """

    default_apt_cache_dir.mkdir(parents=True, exist_ok=True)

    return default_apt_cache_dir

class SourcesList:

    """Representation of apt's sources.list contents."""

    def __init__(self, list: [str]=[], codename: Optional[str]=None) -> None:

        """Initialize this SourcesList."""

        self.codename = None

        self.list = [*list]

        self.has_extra_entries = bool(self.list)

        if codename is not None:

            if codename not in default_lists:

                raise DistroError(_('distro_{}_unknown').format(codename))

            self.codename = codename

            self.list.extend(default_lists[codename])

    def identity(self) -> str:

        """

        Produce a string that uniquely identifies this sources.list contents.

        """

        if self.codename and not self.has_extra_entries:

            return self.codename

        return sha256('\n'.join(sorted(self.list)).encode()).digest().hex()

def apt_conf(directory: Path) -> str:

    """

    Given local APT's directory, produce a configuration suitable for running

    APT there.

    'directory' must not contain any special characters including quotes and

    spaces.

    """

    return f'''

Architecture "amd64";

Dir "{directory}";

Dir::State "{directory}/var/lib/apt";

Dir::State::status "{directory}/var/lib/dpkg/status";

Dir::Etc::SourceList "{directory}/etc/apt.sources.list";

Dir::Etc::SourceParts "";

Dir::Cache "{directory}/var/cache/apt";

pkgCacheGen::Essential "none";

Dir::Etc::Trusted "{directory}/etc/trusted.gpg";

'''

def apt_keyring(keys: [str]) -> bytes:

    """

    Download the requested keys if necessary and export them as a keyring

    suitable for passing to APT.

    The keyring is returned as a bytes value that should be written to a file.

    """

    try:

        from gnupg import GPG

    except ModuleNotFoundError:

        raise GpgError(_('couldnt_import_{}_is_it_installed').format('gnupg'))

    gpg = GPG(keyring=str(cache_dir() / 'master_keyring.gpg'))

    for key in keys:

        if gpg.list_keys(keys=[key]) != []:

            continue

        if gpg.recv_keys(default_keyserver, key).imported == 0:

            raise GpgError(_('gpg_couldnt_recv_key_{}').format(key))

    return gpg.export_keys(keys, armor=False, minimal=True)

def cache_apt_root(apt_root: Path, destination_zip: Path) -> None:

    """

    Zip an APT root directory for later use and move the zipfile to the

    requested destination.

    """

    temporary_zip_path = None

    try:

        tmpfile = NamedTemporaryFile(suffix='.zip', prefix='tmp_',

                                     dir=cache_dir(), delete=False)

        temporary_zip_path = Path(tmpfile.name)

        to_skip = {Path('etc') / 'apt.conf', Path('etc') / 'trusted.gpg'}

        with zipfile.ZipFile(tmpfile, 'w') as zf:

            for member in apt_root.rglob('*'):

                relative = member.relative_to(apt_root)

                if relative not in to_skip:

                    # This call will also properly add empty folders to zip file

                    zf.write(member, relative, zipfile.ZIP_DEFLATED)

        shutil.move(temporary_zip_path, destination_zip)

    finally:

        if temporary_zip_path is not None and temporary_zip_path.exists():

            temporary_zip_path.unlink()

def setup_local_apt(directory: Path, list: SourcesList, keys: [str]) -> Apt:

    """

    Create files and directories necessary for running APT without root rights

    inside 'directory'.

    'directory' must not contain any special characters including quotes and

    spaces and must be empty.

    Return an Apt object that can be used to call apt-get commands.

    """

    apt_root = directory / 'apt_root'

    conf_text     = apt_conf(apt_root)

    keyring_bytes = apt_keyring(keys)

    apt_zipfile = cache_dir() / f'apt_{list.identity()}.zip'

    if apt_zipfile.exists():

        with zipfile.ZipFile(apt_zipfile) as zf:

            zf.extractall(apt_root)

    for to_create in (

            apt_root / 'var' / 'lib' / 'apt' / 'partial',

            apt_root / 'var' / 'lib' / 'apt' / 'lists',

            apt_root / 'var' / 'cache' / 'apt' / 'archives' / 'partial',

            apt_root / 'etc' / 'apt' / 'preferences.d',

            apt_root / 'var' / 'lib' / 'dpkg',

            apt_root / 'var' / 'log' / 'apt'

    ):

        to_create.mkdir(parents=True, exist_ok=True)

    conf_path    = apt_root / 'etc' / 'apt.conf'

    trusted_path = apt_root / 'etc' / 'trusted.gpg'

    status_path  = apt_root / 'var' / 'lib' / 'dpkg' / 'status'

    list_path    = apt_root / 'etc' / 'apt.sources.list'

    conf_path.write_text(conf_text)

    trusted_path.write_bytes(keyring_bytes)

    status_path.touch()

    list_path.write_text('\n'.join(list.list))

    apt = Apt(str(conf_path))

    apt.get('update')

    cache_apt_root(apt_root, apt_zipfile)

    return apt

@contextmanager

def local_apt(list: SourcesList, keys: [str]) -> Iterable[Apt]:

    """

    Create a temporary directory with proper local APT configuration in it.

    Yield an Apt object that can be used to issue apt-get commands.

    This function returns a context manager that will remove the directory on

    close.

    """

    with TemporaryDirectory() as td:

        td = Path(td)

        yield setup_local_apt(td, list, keys)

def download_apt_packages(list: SourcesList, keys: [str], packages: [str],

                          destination_dir: Path, with_deps: bool) -> [str]:

    """

    Set up a local APT, update it using the specified sources.list configuration

    and use it to download the specified packages.

    This function downloads .deb files of packages matching the amd64

    architecture (which includes packages with architecture 'all') as well as

    all their corresponding source package files and (if requested) the debs

    and source files of all their declared dependencies.

    Return value is a list of names of all downloaded files.

    """

    install_line_regex = re.compile(r'^Inst (?P<name>\S+) \((?P<version>\S+) ')

    with local_apt(list, keys) as apt:

        if with_deps:

            cp = apt.get('install', '--yes', '--just-print', *packages)

            lines = cp.stdout.split('\n')

            matches = [install_line_regex.match(l) for l in lines]

            packages = [f'{m.group("name")}={m.group("version")}'

                        for m in matches if m]

            if not packages:

                raise AptError(_('apt_install_output_not_understood'), cp)

        # Download .debs to indirectly to destination_dir by first placing them

        # in a temporary subdirectory.

        with TemporaryDirectory(dir=destination_dir) as td:

            td = Path(td)

            cp = apt.get('download', *packages, cwd=td)

            deb_name_regex = re.compile(

                r'''

                ^

                (?P<name>[^_]+)

                _

                (?P<ver>[^_]+)

                _

                .+              # architecture (or 'all')

                \.deb

                $

                ''',

                re.VERBOSE)

            names_vers = []