xref: /openbmc/qemu/python/scripts/mkvenv.py (revision bad5cfcd)
1"""
2mkvenv - QEMU pyvenv bootstrapping utility
3
4usage: mkvenv [-h] command ...
5
6QEMU pyvenv bootstrapping utility
7
8options:
9  -h, --help  show this help message and exit
10
11Commands:
12  command     Description
13    create    create a venv
14    post_init
15              post-venv initialization
16    ensure    Ensure that the specified package is installed.
17    ensuregroup
18              Ensure that the specified package group is installed.
19
20--------------------------------------------------
21
22usage: mkvenv create [-h] target
23
24positional arguments:
25  target      Target directory to install virtual environment into.
26
27options:
28  -h, --help  show this help message and exit
29
30--------------------------------------------------
31
32usage: mkvenv post_init [-h]
33
34options:
35  -h, --help         show this help message and exit
36
37--------------------------------------------------
38
39usage: mkvenv ensure [-h] [--online] [--dir DIR] dep_spec...
40
41positional arguments:
42  dep_spec    PEP 508 Dependency specification, e.g. 'meson>=0.61.5'
43
44options:
45  -h, --help  show this help message and exit
46  --online    Install packages from PyPI, if necessary.
47  --dir DIR   Path to vendored packages where we may install from.
48
49--------------------------------------------------
50
51usage: mkvenv ensuregroup [-h] [--online] [--dir DIR] file group...
52
53positional arguments:
54  file        pointer to a TOML file
55  group       section name in the TOML file
56
57options:
58  -h, --help  show this help message and exit
59  --online    Install packages from PyPI, if necessary.
60  --dir DIR   Path to vendored packages where we may install from.
61
62"""
63
64# Copyright (C) 2022-2023 Red Hat, Inc.
65#
66# Authors:
67#  John Snow <jsnow@redhat.com>
68#  Paolo Bonzini <pbonzini@redhat.com>
69#
70# This work is licensed under the terms of the GNU GPL, version 2 or
71# later. See the COPYING file in the top-level directory.
72
73import argparse
74from importlib.metadata import (
75    Distribution,
76    EntryPoint,
77    PackageNotFoundError,
78    distribution,
79    version,
80)
81from importlib.util import find_spec
82import logging
83import os
84from pathlib import Path
85import re
86import shutil
87import site
88import subprocess
89import sys
90import sysconfig
91from types import SimpleNamespace
92from typing import (
93    Any,
94    Dict,
95    Iterator,
96    Optional,
97    Sequence,
98    Tuple,
99    Union,
100)
101import venv
102
103
104# Try to load distlib, with a fallback to pip's vendored version.
105# HAVE_DISTLIB is checked below, just-in-time, so that mkvenv does not fail
106# outside the venv or before a potential call to ensurepip in checkpip().
107HAVE_DISTLIB = True
108try:
109    import distlib.scripts
110    import distlib.version
111except ImportError:
112    try:
113        # Reach into pip's cookie jar.  pylint and flake8 don't understand
114        # that these imports will be used via distlib.xxx.
115        from pip._vendor import distlib
116        import pip._vendor.distlib.scripts  # noqa, pylint: disable=unused-import
117        import pip._vendor.distlib.version  # noqa, pylint: disable=unused-import
118    except ImportError:
119        HAVE_DISTLIB = False
120
121# Try to load tomllib, with a fallback to tomli.
122# HAVE_TOMLLIB is checked below, just-in-time, so that mkvenv does not fail
123# outside the venv or before a potential call to ensurepip in checkpip().
124HAVE_TOMLLIB = True
125try:
126    import tomllib
127except ImportError:
128    try:
129        import tomli as tomllib
130    except ImportError:
131        HAVE_TOMLLIB = False
132
133# Do not add any mandatory dependencies from outside the stdlib:
134# This script *must* be usable standalone!
135
136DirType = Union[str, bytes, "os.PathLike[str]", "os.PathLike[bytes]"]
137logger = logging.getLogger("mkvenv")
138
139
140def inside_a_venv() -> bool:
141    """Returns True if it is executed inside of a virtual environment."""
142    return sys.prefix != sys.base_prefix
143
144
145class Ouch(RuntimeError):
146    """An Exception class we can't confuse with a builtin."""
147
148
149class QemuEnvBuilder(venv.EnvBuilder):
150    """
151    An extension of venv.EnvBuilder for building QEMU's configure-time venv.
152
153    The primary difference is that it emulates a "nested" virtual
154    environment when invoked from inside of an existing virtual
155    environment by including packages from the parent.  Also,
156    "ensurepip" is replaced if possible with just recreating pip's
157    console_scripts inside the virtual environment.
158
159    Parameters for base class init:
160      - system_site_packages: bool = False
161      - clear: bool = False
162      - symlinks: bool = False
163      - upgrade: bool = False
164      - with_pip: bool = False
165      - prompt: Optional[str] = None
166      - upgrade_deps: bool = False             (Since 3.9)
167    """
168
169    def __init__(self, *args: Any, **kwargs: Any) -> None:
170        logger.debug("QemuEnvBuilder.__init__(...)")
171
172        # For nested venv emulation:
173        self.use_parent_packages = False
174        if inside_a_venv():
175            # Include parent packages only if we're in a venv and
176            # system_site_packages was True.
177            self.use_parent_packages = kwargs.pop(
178                "system_site_packages", False
179            )
180            # Include system_site_packages only when the parent,
181            # The venv we are currently in, also does so.
182            kwargs["system_site_packages"] = sys.base_prefix in site.PREFIXES
183
184        # ensurepip is slow: venv creation can be very fast for cases where
185        # we allow the use of system_site_packages. Therefore, ensurepip is
186        # replaced with our own script generation once the virtual environment
187        # is setup.
188        self.want_pip = kwargs.get("with_pip", False)
189        if self.want_pip:
190            if (
191                kwargs.get("system_site_packages", False)
192                and not need_ensurepip()
193            ):
194                kwargs["with_pip"] = False
195            else:
196                check_ensurepip()
197
198        super().__init__(*args, **kwargs)
199
200        # Make the context available post-creation:
201        self._context: Optional[SimpleNamespace] = None
202
203    def get_parent_libpath(self) -> Optional[str]:
204        """Return the libpath of the parent venv, if applicable."""
205        if self.use_parent_packages:
206            return sysconfig.get_path("purelib")
207        return None
208
209    @staticmethod
210    def compute_venv_libpath(context: SimpleNamespace) -> str:
211        """
212        Compatibility wrapper for context.lib_path for Python < 3.12
213        """
214        # Python 3.12+, not strictly necessary because it's documented
215        # to be the same as 3.10 code below:
216        if sys.version_info >= (3, 12):
217            return context.lib_path
218
219        # Python 3.10+
220        if "venv" in sysconfig.get_scheme_names():
221            lib_path = sysconfig.get_path(
222                "purelib", scheme="venv", vars={"base": context.env_dir}
223            )
224            assert lib_path is not None
225            return lib_path
226
227        # For Python <= 3.9 we need to hardcode this. Fortunately the
228        # code below was the same in Python 3.6-3.10, so there is only
229        # one case.
230        if sys.platform == "win32":
231            return os.path.join(context.env_dir, "Lib", "site-packages")
232        return os.path.join(
233            context.env_dir,
234            "lib",
235            "python%d.%d" % sys.version_info[:2],
236            "site-packages",
237        )
238
239    def ensure_directories(self, env_dir: DirType) -> SimpleNamespace:
240        logger.debug("ensure_directories(env_dir=%s)", env_dir)
241        self._context = super().ensure_directories(env_dir)
242        return self._context
243
244    def create(self, env_dir: DirType) -> None:
245        logger.debug("create(env_dir=%s)", env_dir)
246        super().create(env_dir)
247        assert self._context is not None
248        self.post_post_setup(self._context)
249
250    def post_post_setup(self, context: SimpleNamespace) -> None:
251        """
252        The final, final hook. Enter the venv and run commands inside of it.
253        """
254        if self.use_parent_packages:
255            # We're inside of a venv and we want to include the parent
256            # venv's packages.
257            parent_libpath = self.get_parent_libpath()
258            assert parent_libpath is not None
259            logger.debug("parent_libpath: %s", parent_libpath)
260
261            our_libpath = self.compute_venv_libpath(context)
262            logger.debug("our_libpath: %s", our_libpath)
263
264            pth_file = os.path.join(our_libpath, "nested.pth")
265            with open(pth_file, "w", encoding="UTF-8") as file:
266                file.write(parent_libpath + os.linesep)
267
268        if self.want_pip:
269            args = [
270                context.env_exe,
271                __file__,
272                "post_init",
273            ]
274            subprocess.run(args, check=True)
275
276    def get_value(self, field: str) -> str:
277        """
278        Get a string value from the context namespace after a call to build.
279
280        For valid field names, see:
281        https://docs.python.org/3/library/venv.html#venv.EnvBuilder.ensure_directories
282        """
283        ret = getattr(self._context, field)
284        assert isinstance(ret, str)
285        return ret
286
287
288def need_ensurepip() -> bool:
289    """
290    Tests for the presence of setuptools and pip.
291
292    :return: `True` if we do not detect both packages.
293    """
294    # Don't try to actually import them, it's fraught with danger:
295    # https://github.com/pypa/setuptools/issues/2993
296    if find_spec("setuptools") and find_spec("pip"):
297        return False
298    return True
299
300
301def check_ensurepip() -> None:
302    """
303    Check that we have ensurepip.
304
305    Raise a fatal exception with a helpful hint if it isn't available.
306    """
307    if not find_spec("ensurepip"):
308        msg = (
309            "Python's ensurepip module is not found.\n"
310            "It's normally part of the Python standard library, "
311            "maybe your distribution packages it separately?\n"
312            "Either install ensurepip, or alleviate the need for it in the "
313            "first place by installing pip and setuptools for "
314            f"'{sys.executable}'.\n"
315            "(Hint: Debian puts ensurepip in its python3-venv package.)"
316        )
317        raise Ouch(msg)
318
319    # ensurepip uses pyexpat, which can also go missing on us:
320    if not find_spec("pyexpat"):
321        msg = (
322            "Python's pyexpat module is not found.\n"
323            "It's normally part of the Python standard library, "
324            "maybe your distribution packages it separately?\n"
325            "Either install pyexpat, or alleviate the need for it in the "
326            "first place by installing pip and setuptools for "
327            f"'{sys.executable}'.\n\n"
328            "(Hint: NetBSD's pkgsrc debundles this to e.g. 'py310-expat'.)"
329        )
330        raise Ouch(msg)
331
332
333def make_venv(  # pylint: disable=too-many-arguments
334    env_dir: Union[str, Path],
335    system_site_packages: bool = False,
336    clear: bool = True,
337    symlinks: Optional[bool] = None,
338    with_pip: bool = True,
339) -> None:
340    """
341    Create a venv using `QemuEnvBuilder`.
342
343    This is analogous to the `venv.create` module-level convenience
344    function that is part of the Python stdblib, except it uses
345    `QemuEnvBuilder` instead.
346
347    :param env_dir: The directory to create/install to.
348    :param system_site_packages:
349        Allow inheriting packages from the system installation.
350    :param clear: When True, fully remove any prior venv and files.
351    :param symlinks:
352        Whether to use symlinks to the target interpreter or not. If
353        left unspecified, it will use symlinks except on Windows to
354        match behavior with the "venv" CLI tool.
355    :param with_pip:
356        Whether to install "pip" binaries or not.
357    """
358    logger.debug(
359        "%s: make_venv(env_dir=%s, system_site_packages=%s, "
360        "clear=%s, symlinks=%s, with_pip=%s)",
361        __file__,
362        str(env_dir),
363        system_site_packages,
364        clear,
365        symlinks,
366        with_pip,
367    )
368
369    if symlinks is None:
370        # Default behavior of standard venv CLI
371        symlinks = os.name != "nt"
372
373    builder = QemuEnvBuilder(
374        system_site_packages=system_site_packages,
375        clear=clear,
376        symlinks=symlinks,
377        with_pip=with_pip,
378    )
379
380    style = "non-isolated" if builder.system_site_packages else "isolated"
381    nested = ""
382    if builder.use_parent_packages:
383        nested = f"(with packages from '{builder.get_parent_libpath()}') "
384    print(
385        f"mkvenv: Creating {style} virtual environment"
386        f" {nested}at '{str(env_dir)}'",
387        file=sys.stderr,
388    )
389
390    try:
391        logger.debug("Invoking builder.create()")
392        try:
393            builder.create(str(env_dir))
394        except SystemExit as exc:
395            # Some versions of the venv module raise SystemExit; *nasty*!
396            # We want the exception that prompted it. It might be a subprocess
397            # error that has output we *really* want to see.
398            logger.debug("Intercepted SystemExit from EnvBuilder.create()")
399            raise exc.__cause__ or exc.__context__ or exc
400        logger.debug("builder.create() finished")
401    except subprocess.CalledProcessError as exc:
402        logger.error("mkvenv subprocess failed:")
403        logger.error("cmd: %s", exc.cmd)
404        logger.error("returncode: %d", exc.returncode)
405
406        def _stringify(data: Union[str, bytes]) -> str:
407            if isinstance(data, bytes):
408                return data.decode()
409            return data
410
411        lines = []
412        if exc.stdout:
413            lines.append("========== stdout ==========")
414            lines.append(_stringify(exc.stdout))
415            lines.append("============================")
416        if exc.stderr:
417            lines.append("========== stderr ==========")
418            lines.append(_stringify(exc.stderr))
419            lines.append("============================")
420        if lines:
421            logger.error(os.linesep.join(lines))
422
423        raise Ouch("VENV creation subprocess failed.") from exc
424
425    # print the python executable to stdout for configure.
426    print(builder.get_value("env_exe"))
427
428
429def _get_entry_points(packages: Sequence[str]) -> Iterator[str]:
430
431    def _generator() -> Iterator[str]:
432        for package in packages:
433            try:
434                entry_points: Iterator[EntryPoint] = \
435                    iter(distribution(package).entry_points)
436            except PackageNotFoundError:
437                continue
438
439            # The EntryPoints type is only available in 3.10+,
440            # treat this as a vanilla list and filter it ourselves.
441            entry_points = filter(
442                lambda ep: ep.group == "console_scripts", entry_points
443            )
444
445            for entry_point in entry_points:
446                yield f"{entry_point.name} = {entry_point.value}"
447
448    return _generator()
449
450
451def generate_console_scripts(
452    packages: Sequence[str],
453    python_path: Optional[str] = None,
454    bin_path: Optional[str] = None,
455) -> None:
456    """
457    Generate script shims for console_script entry points in @packages.
458    """
459    if python_path is None:
460        python_path = sys.executable
461    if bin_path is None:
462        bin_path = sysconfig.get_path("scripts")
463        assert bin_path is not None
464
465    logger.debug(
466        "generate_console_scripts(packages=%s, python_path=%s, bin_path=%s)",
467        packages,
468        python_path,
469        bin_path,
470    )
471
472    if not packages:
473        return
474
475    maker = distlib.scripts.ScriptMaker(None, bin_path)
476    maker.variants = {""}
477    maker.clobber = False
478
479    for entry_point in _get_entry_points(packages):
480        for filename in maker.make(entry_point):
481            logger.debug("wrote console_script '%s'", filename)
482
483
484def pkgname_from_depspec(dep_spec: str) -> str:
485    """
486    Parse package name out of a PEP-508 depspec.
487
488    See https://peps.python.org/pep-0508/#names
489    """
490    match = re.match(
491        r"^([A-Z0-9]([A-Z0-9._-]*[A-Z0-9])?)", dep_spec, re.IGNORECASE
492    )
493    if not match:
494        raise ValueError(
495            f"dep_spec '{dep_spec}'"
496            " does not appear to contain a valid package name"
497        )
498    return match.group(0)
499
500
501def _path_is_prefix(prefix: Optional[str], path: str) -> bool:
502    try:
503        return (
504            prefix is not None and os.path.commonpath([prefix, path]) == prefix
505        )
506    except ValueError:
507        return False
508
509
510def _is_system_package(dist: Distribution) -> bool:
511    path = str(dist.locate_file("."))
512    return not (
513        _path_is_prefix(sysconfig.get_path("purelib"), path)
514        or _path_is_prefix(sysconfig.get_path("platlib"), path)
515    )
516
517
518def diagnose(
519    dep_spec: str,
520    online: bool,
521    wheels_dir: Optional[Union[str, Path]],
522    prog: Optional[str],
523) -> Tuple[str, bool]:
524    """
525    Offer a summary to the user as to why a package failed to be installed.
526
527    :param dep_spec: The package we tried to ensure, e.g. 'meson>=0.61.5'
528    :param online: Did we allow PyPI access?
529    :param prog:
530        Optionally, a shell program name that can be used as a
531        bellwether to detect if this program is installed elsewhere on
532        the system. This is used to offer advice when a program is
533        detected for a different python version.
534    :param wheels_dir:
535        Optionally, a directory that was searched for vendored packages.
536    """
537    # pylint: disable=too-many-branches
538
539    # Some errors are not particularly serious
540    bad = False
541
542    pkg_name = pkgname_from_depspec(dep_spec)
543    pkg_version: Optional[str] = None
544    try:
545        pkg_version = version(pkg_name)
546    except PackageNotFoundError:
547        pass
548
549    lines = []
550
551    if pkg_version:
552        lines.append(
553            f"Python package '{pkg_name}' version '{pkg_version}' was found,"
554            " but isn't suitable."
555        )
556    else:
557        lines.append(
558            f"Python package '{pkg_name}' was not found nor installed."
559        )
560
561    if wheels_dir:
562        lines.append(
563            "No suitable version found in, or failed to install from"
564            f" '{wheels_dir}'."
565        )
566        bad = True
567
568    if online:
569        lines.append("A suitable version could not be obtained from PyPI.")
570        bad = True
571    else:
572        lines.append(
573            "mkvenv was configured to operate offline and did not check PyPI."
574        )
575
576    if prog and not pkg_version:
577        which = shutil.which(prog)
578        if which:
579            if sys.base_prefix in site.PREFIXES:
580                pypath = Path(sys.executable).resolve()
581                lines.append(
582                    f"'{prog}' was detected on your system at '{which}', "
583                    f"but the Python package '{pkg_name}' was not found by "
584                    f"this Python interpreter ('{pypath}'). "
585                    f"Typically this means that '{prog}' has been installed "
586                    "against a different Python interpreter on your system."
587                )
588            else:
589                lines.append(
590                    f"'{prog}' was detected on your system at '{which}', "
591                    "but the build is using an isolated virtual environment."
592                )
593            bad = True
594
595    lines = [f" • {line}" for line in lines]
596    if bad:
597        lines.insert(0, f"Could not provide build dependency '{dep_spec}':")
598    else:
599        lines.insert(0, f"'{dep_spec}' not found:")
600    return os.linesep.join(lines), bad
601
602
603def pip_install(
604    args: Sequence[str],
605    online: bool = False,
606    wheels_dir: Optional[Union[str, Path]] = None,
607) -> None:
608    """
609    Use pip to install a package or package(s) as specified in @args.
610    """
611    loud = bool(
612        os.environ.get("DEBUG")
613        or os.environ.get("GITLAB_CI")
614        or os.environ.get("V")
615    )
616
617    full_args = [
618        sys.executable,
619        "-m",
620        "pip",
621        "install",
622        "--disable-pip-version-check",
623        "-v" if loud else "-q",
624    ]
625    if not online:
626        full_args += ["--no-index"]
627    if wheels_dir:
628        full_args += ["--find-links", f"file://{str(wheels_dir)}"]
629    full_args += list(args)
630    subprocess.run(
631        full_args,
632        check=True,
633    )
634
635
636def _make_version_constraint(info: Dict[str, str], install: bool) -> str:
637    """
638    Construct the version constraint part of a PEP 508 dependency
639    specification (for example '>=0.61.5') from the accepted and
640    installed keys of the provided dictionary.
641
642    :param info: A dictionary corresponding to a TOML key-value list.
643    :param install: True generates install constraints, False generates
644        presence constraints
645    """
646    if install and "installed" in info:
647        return "==" + info["installed"]
648
649    dep_spec = info.get("accepted", "")
650    dep_spec = dep_spec.strip()
651    # Double check that they didn't just use a version number
652    if dep_spec and dep_spec[0] not in "!~><=(":
653        raise Ouch(
654            "invalid dependency specifier " + dep_spec + " in dependency file"
655        )
656
657    return dep_spec
658
659
660def _do_ensure(
661    group: Dict[str, Dict[str, str]],
662    online: bool = False,
663    wheels_dir: Optional[Union[str, Path]] = None,
664) -> Optional[Tuple[str, bool]]:
665    """
666    Use pip to ensure we have the packages specified in @group.
667
668    If the packages are already installed, do nothing. If online and
669    wheels_dir are both provided, prefer packages found in wheels_dir
670    first before connecting to PyPI.
671
672    :param group: A dictionary of dictionaries, corresponding to a
673        section in a pythondeps.toml file.
674    :param online: If True, fall back to PyPI.
675    :param wheels_dir: If specified, search this path for packages.
676    """
677    absent = []
678    present = []
679    canary = None
680    for name, info in group.items():
681        constraint = _make_version_constraint(info, False)
682        matcher = distlib.version.LegacyMatcher(name + constraint)
683        print(f"mkvenv: checking for {matcher}", file=sys.stderr)
684
685        dist: Optional[Distribution] = None
686        try:
687            dist = distribution(matcher.name)
688        except PackageNotFoundError:
689            pass
690
691        if (
692            dist is None
693            # Always pass installed package to pip, so that they can be
694            # updated if the requested version changes
695            or not _is_system_package(dist)
696            or not matcher.match(distlib.version.LegacyVersion(dist.version))
697        ):
698            absent.append(name + _make_version_constraint(info, True))
699            if len(absent) == 1:
700                canary = info.get("canary", None)
701        else:
702            logger.info("found %s %s", name, dist.version)
703            present.append(name)
704
705    if present:
706        generate_console_scripts(present)
707
708    if absent:
709        if online or wheels_dir:
710            # Some packages are missing or aren't a suitable version,
711            # install a suitable (possibly vendored) package.
712            print(f"mkvenv: installing {', '.join(absent)}", file=sys.stderr)
713            try:
714                pip_install(args=absent, online=online, wheels_dir=wheels_dir)
715                return None
716            except subprocess.CalledProcessError:
717                pass
718
719        return diagnose(
720            absent[0],
721            online,
722            wheels_dir,
723            canary,
724        )
725
726    return None
727
728
729def ensure(
730    dep_specs: Sequence[str],
731    online: bool = False,
732    wheels_dir: Optional[Union[str, Path]] = None,
733    prog: Optional[str] = None,
734) -> None:
735    """
736    Use pip to ensure we have the package specified by @dep_specs.
737
738    If the package is already installed, do nothing. If online and
739    wheels_dir are both provided, prefer packages found in wheels_dir
740    first before connecting to PyPI.
741
742    :param dep_specs:
743        PEP 508 dependency specifications. e.g. ['meson>=0.61.5'].
744    :param online: If True, fall back to PyPI.
745    :param wheels_dir: If specified, search this path for packages.
746    :param prog:
747        If specified, use this program name for error diagnostics that will
748        be presented to the user. e.g., 'sphinx-build' can be used as a
749        bellwether for the presence of 'sphinx'.
750    """
751
752    if not HAVE_DISTLIB:
753        raise Ouch("a usable distlib could not be found, please install it")
754
755    # Convert the depspecs to a dictionary, as if they came
756    # from a section in a pythondeps.toml file
757    group: Dict[str, Dict[str, str]] = {}
758    for spec in dep_specs:
759        name = distlib.version.LegacyMatcher(spec).name
760        group[name] = {}
761
762        spec = spec.strip()
763        pos = len(name)
764        ver = spec[pos:].strip()
765        if ver:
766            group[name]["accepted"] = ver
767
768        if prog:
769            group[name]["canary"] = prog
770            prog = None
771
772    result = _do_ensure(group, online, wheels_dir)
773    if result:
774        # Well, that's not good.
775        if result[1]:
776            raise Ouch(result[0])
777        raise SystemExit(f"\n{result[0]}\n\n")
778
779
780def _parse_groups(file: str) -> Dict[str, Dict[str, Any]]:
781    if not HAVE_TOMLLIB:
782        if sys.version_info < (3, 11):
783            raise Ouch("found no usable tomli, please install it")
784
785        raise Ouch(
786            "Python >=3.11 does not have tomllib... what have you done!?"
787        )
788
789    # Use loads() to support both tomli v1.2.x (Ubuntu 22.04,
790    # Debian bullseye-backports) and v2.0.x
791    with open(file, "r", encoding="ascii") as depfile:
792        contents = depfile.read()
793        return tomllib.loads(contents)  # type: ignore
794
795
796def ensure_group(
797    file: str,
798    groups: Sequence[str],
799    online: bool = False,
800    wheels_dir: Optional[Union[str, Path]] = None,
801) -> None:
802    """
803    Use pip to ensure we have the package specified by @dep_specs.
804
805    If the package is already installed, do nothing. If online and
806    wheels_dir are both provided, prefer packages found in wheels_dir
807    first before connecting to PyPI.
808
809    :param dep_specs:
810        PEP 508 dependency specifications. e.g. ['meson>=0.61.5'].
811    :param online: If True, fall back to PyPI.
812    :param wheels_dir: If specified, search this path for packages.
813    """
814
815    if not HAVE_DISTLIB:
816        raise Ouch("found no usable distlib, please install it")
817
818    parsed_deps = _parse_groups(file)
819
820    to_install: Dict[str, Dict[str, str]] = {}
821    for group in groups:
822        try:
823            to_install.update(parsed_deps[group])
824        except KeyError as exc:
825            raise Ouch(f"group {group} not defined") from exc
826
827    result = _do_ensure(to_install, online, wheels_dir)
828    if result:
829        # Well, that's not good.
830        if result[1]:
831            raise Ouch(result[0])
832        raise SystemExit(f"\n{result[0]}\n\n")
833
834
835def post_venv_setup() -> None:
836    """
837    This is intended to be run *inside the venv* after it is created.
838    """
839    logger.debug("post_venv_setup()")
840    # Generate a 'pip' script so the venv is usable in a normal
841    # way from the CLI. This only happens when we inherited pip from a
842    # parent/system-site and haven't run ensurepip in some way.
843    generate_console_scripts(["pip"])
844
845
846def _add_create_subcommand(subparsers: Any) -> None:
847    subparser = subparsers.add_parser("create", help="create a venv")
848    subparser.add_argument(
849        "target",
850        type=str,
851        action="store",
852        help="Target directory to install virtual environment into.",
853    )
854
855
856def _add_post_init_subcommand(subparsers: Any) -> None:
857    subparsers.add_parser("post_init", help="post-venv initialization")
858
859
860def _add_ensuregroup_subcommand(subparsers: Any) -> None:
861    subparser = subparsers.add_parser(
862        "ensuregroup",
863        help="Ensure that the specified package group is installed.",
864    )
865    subparser.add_argument(
866        "--online",
867        action="store_true",
868        help="Install packages from PyPI, if necessary.",
869    )
870    subparser.add_argument(
871        "--dir",
872        type=str,
873        action="store",
874        help="Path to vendored packages where we may install from.",
875    )
876    subparser.add_argument(
877        "file",
878        type=str,
879        action="store",
880        help=("Path to a TOML file describing package groups"),
881    )
882    subparser.add_argument(
883        "group",
884        type=str,
885        action="store",
886        help="One or more package group names",
887        nargs="+",
888    )
889
890
891def _add_ensure_subcommand(subparsers: Any) -> None:
892    subparser = subparsers.add_parser(
893        "ensure", help="Ensure that the specified package is installed."
894    )
895    subparser.add_argument(
896        "--online",
897        action="store_true",
898        help="Install packages from PyPI, if necessary.",
899    )
900    subparser.add_argument(
901        "--dir",
902        type=str,
903        action="store",
904        help="Path to vendored packages where we may install from.",
905    )
906    subparser.add_argument(
907        "--diagnose",
908        type=str,
909        action="store",
910        help=(
911            "Name of a shell utility to use for "
912            "diagnostics if this command fails."
913        ),
914    )
915    subparser.add_argument(
916        "dep_specs",
917        type=str,
918        action="store",
919        help="PEP 508 Dependency specification, e.g. 'meson>=0.61.5'",
920        nargs="+",
921    )
922
923
924def main() -> int:
925    """CLI interface to make_qemu_venv. See module docstring."""
926    if os.environ.get("DEBUG") or os.environ.get("GITLAB_CI"):
927        # You're welcome.
928        logging.basicConfig(level=logging.DEBUG)
929    else:
930        if os.environ.get("V"):
931            logging.basicConfig(level=logging.INFO)
932
933    parser = argparse.ArgumentParser(
934        prog="mkvenv",
935        description="QEMU pyvenv bootstrapping utility",
936    )
937    subparsers = parser.add_subparsers(
938        title="Commands",
939        dest="command",
940        required=True,
941        metavar="command",
942        help="Description",
943    )
944
945    _add_create_subcommand(subparsers)
946    _add_post_init_subcommand(subparsers)
947    _add_ensure_subcommand(subparsers)
948    _add_ensuregroup_subcommand(subparsers)
949
950    args = parser.parse_args()
951    try:
952        if args.command == "create":
953            make_venv(
954                args.target,
955                system_site_packages=True,
956                clear=True,
957            )
958        if args.command == "post_init":
959            post_venv_setup()
960        if args.command == "ensure":
961            ensure(
962                dep_specs=args.dep_specs,
963                online=args.online,
964                wheels_dir=args.dir,
965                prog=args.diagnose,
966            )
967        if args.command == "ensuregroup":
968            ensure_group(
969                file=args.file,
970                groups=args.group,
971                online=args.online,
972                wheels_dir=args.dir,
973            )
974        logger.debug("mkvenv.py %s: exiting", args.command)
975    except Ouch as exc:
976        print("\n*** Ouch! ***\n", file=sys.stderr)
977        print(str(exc), "\n\n", file=sys.stderr)
978        return 1
979    except SystemExit:
980        raise
981    except:  # pylint: disable=bare-except
982        logger.exception("mkvenv did not complete successfully:")
983        return 2
984    return 0
985
986
987if __name__ == "__main__":
988    sys.exit(main())
989