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qemu/python/scripts/mkvenv.py

887 lines
27 KiB
Python

"""
mkvenv - QEMU pyvenv bootstrapping utility
usage: mkvenv [-h] command ...
QEMU pyvenv bootstrapping utility
options:
-h, --help show this help message and exit
Commands:
command Description
create create a venv
post_init
post-venv initialization
ensuregroup
Ensure that the specified package group is installed.
--------------------------------------------------
usage: mkvenv create [-h] target
positional arguments:
target Target directory to install virtual environment into.
options:
-h, --help show this help message and exit
--------------------------------------------------
usage: mkvenv post_init [-h]
options:
-h, --help show this help message and exit
--------------------------------------------------
usage: mkvenv ensuregroup [-h] [--online] [--dir DIR] file group...
positional arguments:
file pointer to a TOML file
group section name in the TOML file
options:
-h, --help show this help message and exit
--online Install packages from PyPI, if necessary.
--dir DIR Path to vendored packages where we may install from.
"""
# Copyright (C) 2022-2023 Red Hat, Inc.
#
# Authors:
# John Snow <jsnow@redhat.com>
# Paolo Bonzini <pbonzini@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2 or
# later. See the COPYING file in the top-level directory.
import argparse
from importlib.metadata import (
Distribution,
EntryPoint,
PackageNotFoundError,
distribution,
version,
)
from importlib.util import find_spec
import logging
import os
from pathlib import Path
import re
import shutil
import site
import subprocess
import sys
import sysconfig
from types import SimpleNamespace
from typing import (
Any,
Dict,
Iterator,
Optional,
Sequence,
Tuple,
Union,
)
import venv
# Try to load distlib, with a fallback to pip's vendored version.
# HAVE_DISTLIB is checked below, just-in-time, so that mkvenv does not fail
# outside the venv or before a potential call to ensurepip in checkpip().
HAVE_DISTLIB = True
try:
import distlib.scripts
import distlib.version
except ImportError:
try:
# Reach into pip's cookie jar. pylint and flake8 don't understand
# that these imports will be used via distlib.xxx.
from pip._vendor import distlib
import pip._vendor.distlib.scripts # noqa, pylint: disable=unused-import
import pip._vendor.distlib.version # noqa, pylint: disable=unused-import
except ImportError:
HAVE_DISTLIB = False
# Try to load tomllib, with a fallback to tomli.
# HAVE_TOMLLIB is checked below, just-in-time, so that mkvenv does not fail
# outside the venv or before a potential call to ensurepip in checkpip().
HAVE_TOMLLIB = True
try:
import tomllib
except ImportError:
try:
import tomli as tomllib
except ImportError:
HAVE_TOMLLIB = False
# Do not add any mandatory dependencies from outside the stdlib:
# This script *must* be usable standalone!
DirType = Union[str, bytes, "os.PathLike[str]", "os.PathLike[bytes]"]
logger = logging.getLogger("mkvenv")
def inside_a_venv() -> bool:
"""Returns True if it is executed inside of a virtual environment."""
return sys.prefix != sys.base_prefix
class Ouch(RuntimeError):
"""An Exception class we can't confuse with a builtin."""
class QemuEnvBuilder(venv.EnvBuilder):
"""
An extension of venv.EnvBuilder for building QEMU's configure-time venv.
The primary difference is that it emulates a "nested" virtual
environment when invoked from inside of an existing virtual
environment by including packages from the parent. Also,
"ensurepip" is replaced if possible with just recreating pip's
console_scripts inside the virtual environment.
Parameters for base class init:
- system_site_packages: bool = False
- clear: bool = False
- symlinks: bool = False
- upgrade: bool = False
- with_pip: bool = False
- prompt: Optional[str] = None
- upgrade_deps: bool = False (Since 3.9)
"""
def __init__(self, *args: Any, **kwargs: Any) -> None:
logger.debug("QemuEnvBuilder.__init__(...)")
# For nested venv emulation:
self.use_parent_packages = False
if inside_a_venv():
# Include parent packages only if we're in a venv and
# system_site_packages was True.
self.use_parent_packages = kwargs.pop(
"system_site_packages", False
)
# Include system_site_packages only when the parent,
# The venv we are currently in, also does so.
kwargs["system_site_packages"] = sys.base_prefix in site.PREFIXES
# ensurepip is slow: venv creation can be very fast for cases where
# we allow the use of system_site_packages. Therefore, ensurepip is
# replaced with our own script generation once the virtual environment
# is setup.
self.want_pip = kwargs.get("with_pip", False)
if self.want_pip:
if (
kwargs.get("system_site_packages", False)
and not need_ensurepip()
):
kwargs["with_pip"] = False
else:
check_ensurepip()
super().__init__(*args, **kwargs)
# Make the context available post-creation:
self._context: Optional[SimpleNamespace] = None
def get_parent_libpath(self) -> Optional[str]:
"""Return the libpath of the parent venv, if applicable."""
if self.use_parent_packages:
return sysconfig.get_path("purelib")
return None
@staticmethod
def compute_venv_libpath(context: SimpleNamespace) -> str:
"""
Compatibility wrapper for context.lib_path for Python < 3.12
"""
# Python 3.12+, not strictly necessary because it's documented
# to be the same as 3.10 code below:
if sys.version_info >= (3, 12):
return context.lib_path
# Python 3.10+
if "venv" in sysconfig.get_scheme_names():
lib_path = sysconfig.get_path(
"purelib", scheme="venv", vars={"base": context.env_dir}
)
assert lib_path is not None
return lib_path
# For Python <= 3.9 we need to hardcode this. Fortunately the
# code below was the same in Python 3.6-3.10, so there is only
# one case.
if sys.platform == "win32":
return os.path.join(context.env_dir, "Lib", "site-packages")
return os.path.join(
context.env_dir,
"lib",
"python%d.%d" % sys.version_info[:2],
"site-packages",
)
def ensure_directories(self, env_dir: DirType) -> SimpleNamespace:
logger.debug("ensure_directories(env_dir=%s)", env_dir)
self._context = super().ensure_directories(env_dir)
return self._context
def create(self, env_dir: DirType) -> None:
logger.debug("create(env_dir=%s)", env_dir)
super().create(env_dir)
assert self._context is not None
self.post_post_setup(self._context)
def post_post_setup(self, context: SimpleNamespace) -> None:
"""
The final, final hook. Enter the venv and run commands inside of it.
"""
if self.use_parent_packages:
# We're inside of a venv and we want to include the parent
# venv's packages.
parent_libpath = self.get_parent_libpath()
assert parent_libpath is not None
logger.debug("parent_libpath: %s", parent_libpath)
our_libpath = self.compute_venv_libpath(context)
logger.debug("our_libpath: %s", our_libpath)
pth_file = os.path.join(our_libpath, "nested.pth")
with open(pth_file, "w", encoding="UTF-8") as file:
file.write(parent_libpath + os.linesep)
if self.want_pip:
args = [
context.env_exe,
__file__,
"post_init",
]
subprocess.run(args, check=True)
def get_value(self, field: str) -> str:
"""
Get a string value from the context namespace after a call to build.
For valid field names, see:
https://docs.python.org/3/library/venv.html#venv.EnvBuilder.ensure_directories
"""
ret = getattr(self._context, field)
assert isinstance(ret, str)
return ret
def need_ensurepip() -> bool:
"""
Tests for the presence of setuptools and pip.
:return: `True` if we do not detect both packages.
"""
# Don't try to actually import them, it's fraught with danger:
# https://github.com/pypa/setuptools/issues/2993
if find_spec("setuptools") and find_spec("pip"):
return False
return True
def check_ensurepip() -> None:
"""
Check that we have ensurepip.
Raise a fatal exception with a helpful hint if it isn't available.
"""
if not find_spec("ensurepip"):
msg = (
"Python's ensurepip module is not found.\n"
"It's normally part of the Python standard library, "
"maybe your distribution packages it separately?\n"
"Either install ensurepip, or alleviate the need for it in the "
"first place by installing pip and setuptools for "
f"'{sys.executable}'.\n"
"(Hint: Debian puts ensurepip in its python3-venv package.)"
)
raise Ouch(msg)
# ensurepip uses pyexpat, which can also go missing on us:
if not find_spec("pyexpat"):
msg = (
"Python's pyexpat module is not found.\n"
"It's normally part of the Python standard library, "
"maybe your distribution packages it separately?\n"
"Either install pyexpat, or alleviate the need for it in the "
"first place by installing pip and setuptools for "
f"'{sys.executable}'.\n\n"
"(Hint: NetBSD's pkgsrc debundles this to e.g. 'py310-expat'.)"
)
raise Ouch(msg)
def make_venv( # pylint: disable=too-many-arguments
env_dir: Union[str, Path],
system_site_packages: bool = False,
clear: bool = True,
symlinks: Optional[bool] = None,
with_pip: bool = True,
) -> None:
"""
Create a venv using `QemuEnvBuilder`.
This is analogous to the `venv.create` module-level convenience
function that is part of the Python stdblib, except it uses
`QemuEnvBuilder` instead.
:param env_dir: The directory to create/install to.
:param system_site_packages:
Allow inheriting packages from the system installation.
:param clear: When True, fully remove any prior venv and files.
:param symlinks:
Whether to use symlinks to the target interpreter or not. If
left unspecified, it will use symlinks except on Windows to
match behavior with the "venv" CLI tool.
:param with_pip:
Whether to install "pip" binaries or not.
"""
logger.debug(
"%s: make_venv(env_dir=%s, system_site_packages=%s, "
"clear=%s, symlinks=%s, with_pip=%s)",
__file__,
str(env_dir),
system_site_packages,
clear,
symlinks,
with_pip,
)
if symlinks is None:
# Default behavior of standard venv CLI
symlinks = os.name != "nt"
builder = QemuEnvBuilder(
system_site_packages=system_site_packages,
clear=clear,
symlinks=symlinks,
with_pip=with_pip,
)
style = "non-isolated" if builder.system_site_packages else "isolated"
nested = ""
if builder.use_parent_packages:
nested = f"(with packages from '{builder.get_parent_libpath()}') "
print(
f"mkvenv: Creating {style} virtual environment"
f" {nested}at '{str(env_dir)}'",
file=sys.stderr,
)
try:
logger.debug("Invoking builder.create()")
try:
builder.create(str(env_dir))
except SystemExit as exc:
# pylint 3.3 bug:
# pylint: disable=raising-non-exception, raise-missing-from
# Some versions of the venv module raise SystemExit; *nasty*!
# We want the exception that prompted it. It might be a subprocess
# error that has output we *really* want to see.
logger.debug("Intercepted SystemExit from EnvBuilder.create()")
raise exc.__cause__ or exc.__context__ or exc
logger.debug("builder.create() finished")
except subprocess.CalledProcessError as exc:
logger.error("mkvenv subprocess failed:")
logger.error("cmd: %s", exc.cmd)
logger.error("returncode: %d", exc.returncode)
def _stringify(data: Union[str, bytes]) -> str:
if isinstance(data, bytes):
return data.decode()
return data
lines = []
if exc.stdout:
lines.append("========== stdout ==========")
lines.append(_stringify(exc.stdout))
lines.append("============================")
if exc.stderr:
lines.append("========== stderr ==========")
lines.append(_stringify(exc.stderr))
lines.append("============================")
if lines:
logger.error(os.linesep.join(lines))
raise Ouch("VENV creation subprocess failed.") from exc
# print the python executable to stdout for configure.
print(builder.get_value("env_exe"))
def _get_entry_points(packages: Sequence[str]) -> Iterator[str]:
def _generator() -> Iterator[str]:
for package in packages:
try:
entry_points: Iterator[EntryPoint] = \
iter(distribution(package).entry_points)
except PackageNotFoundError:
continue
# The EntryPoints type is only available in 3.10+,
# treat this as a vanilla list and filter it ourselves.
entry_points = filter(
lambda ep: ep.group == "console_scripts", entry_points
)
for entry_point in entry_points:
yield f"{entry_point.name} = {entry_point.value}"
return _generator()
def generate_console_scripts(
packages: Sequence[str],
python_path: Optional[str] = None,
bin_path: Optional[str] = None,
) -> None:
"""
Generate script shims for console_script entry points in @packages.
"""
if python_path is None:
python_path = sys.executable
if bin_path is None:
bin_path = sysconfig.get_path("scripts")
assert bin_path is not None
logger.debug(
"generate_console_scripts(packages=%s, python_path=%s, bin_path=%s)",
packages,
python_path,
bin_path,
)
if not packages:
return
maker = distlib.scripts.ScriptMaker(None, bin_path)
maker.variants = {""}
maker.clobber = False
for entry_point in _get_entry_points(packages):
for filename in maker.make(entry_point):
logger.debug("wrote console_script '%s'", filename)
def pkgname_from_depspec(dep_spec: str) -> str:
"""
Parse package name out of a PEP-508 depspec.
See https://peps.python.org/pep-0508/#names
"""
match = re.match(
r"^([A-Z0-9]([A-Z0-9._-]*[A-Z0-9])?)", dep_spec, re.IGNORECASE
)
if not match:
raise ValueError(
f"dep_spec '{dep_spec}'"
" does not appear to contain a valid package name"
)
return match.group(0)
def _path_is_prefix(prefix: Optional[str], path: str) -> bool:
try:
return (
prefix is not None and os.path.commonpath([prefix, path]) == prefix
)
except ValueError:
return False
def _is_system_package(dist: Distribution) -> bool:
path = str(dist.locate_file("."))
return not (
_path_is_prefix(sysconfig.get_path("purelib"), path)
or _path_is_prefix(sysconfig.get_path("platlib"), path)
)
def diagnose(
dep_spec: str,
online: bool,
wheels_dir: Optional[Union[str, Path]],
prog: Optional[str],
) -> Tuple[str, bool]:
"""
Offer a summary to the user as to why a package failed to be installed.
:param dep_spec: The package we tried to ensure, e.g. 'meson>=0.61.5'
:param online: Did we allow PyPI access?
:param prog:
Optionally, a shell program name that can be used as a
bellwether to detect if this program is installed elsewhere on
the system. This is used to offer advice when a program is
detected for a different python version.
:param wheels_dir:
Optionally, a directory that was searched for vendored packages.
"""
# pylint: disable=too-many-branches
# Some errors are not particularly serious
bad = False
pkg_name = pkgname_from_depspec(dep_spec)
pkg_version: Optional[str] = None
try:
pkg_version = version(pkg_name)
except PackageNotFoundError:
pass
lines = []
if pkg_version:
lines.append(
f"Python package '{pkg_name}' version '{pkg_version}' was found,"
" but isn't suitable."
)
else:
lines.append(
f"Python package '{pkg_name}' was not found nor installed."
)
if wheels_dir:
lines.append(
"No suitable version found in, or failed to install from"
f" '{wheels_dir}'."
)
bad = True
if online:
lines.append("A suitable version could not be obtained from PyPI.")
bad = True
else:
lines.append(
"mkvenv was configured to operate offline and did not check PyPI."
)
if prog and not pkg_version:
which = shutil.which(prog)
if which:
if sys.base_prefix in site.PREFIXES:
pypath = Path(sys.executable).resolve()
lines.append(
f"'{prog}' was detected on your system at '{which}', "
f"but the Python package '{pkg_name}' was not found by "
f"this Python interpreter ('{pypath}'). "
f"Typically this means that '{prog}' has been installed "
"against a different Python interpreter on your system."
)
else:
lines.append(
f"'{prog}' was detected on your system at '{which}', "
"but the build is using an isolated virtual environment."
)
bad = True
lines = [f"{line}" for line in lines]
if bad:
lines.insert(0, f"Could not provide build dependency '{dep_spec}':")
else:
lines.insert(0, f"'{dep_spec}' not found:")
return os.linesep.join(lines), bad
def pip_install(
args: Sequence[str],
online: bool = False,
wheels_dir: Optional[Union[str, Path]] = None,
) -> None:
"""
Use pip to install a package or package(s) as specified in @args.
"""
loud = bool(
os.environ.get("DEBUG")
or os.environ.get("GITLAB_CI")
or os.environ.get("V")
)
full_args = [
sys.executable,
"-m",
"pip",
"install",
"--disable-pip-version-check",
"-v" if loud else "-q",
]
if not online:
full_args += ["--no-index"]
if wheels_dir:
full_args += ["--find-links", f"file://{str(wheels_dir)}"]
full_args += list(args)
subprocess.run(
full_args,
check=True,
)
def _make_version_constraint(info: Dict[str, str], install: bool) -> str:
"""
Construct the version constraint part of a PEP 508 dependency
specification (for example '>=0.61.5') from the accepted and
installed keys of the provided dictionary.
:param info: A dictionary corresponding to a TOML key-value list.
:param install: True generates install constraints, False generates
presence constraints
"""
if install and "installed" in info:
return "==" + info["installed"]
dep_spec = info.get("accepted", "")
dep_spec = dep_spec.strip()
# Double check that they didn't just use a version number
if dep_spec and dep_spec[0] not in "!~><=(":
raise Ouch(
"invalid dependency specifier " + dep_spec + " in dependency file"
)
return dep_spec
def _do_ensure(
group: Dict[str, Dict[str, str]],
online: bool = False,
wheels_dir: Optional[Union[str, Path]] = None,
) -> Optional[Tuple[str, bool]]:
"""
Use pip to ensure we have the packages specified in @group.
If the packages are already installed, do nothing. If online and
wheels_dir are both provided, prefer packages found in wheels_dir
first before connecting to PyPI.
:param group: A dictionary of dictionaries, corresponding to a
section in a pythondeps.toml file.
:param online: If True, fall back to PyPI.
:param wheels_dir: If specified, search this path for packages.
"""
absent = []
present = []
canary = None
for name, info in group.items():
constraint = _make_version_constraint(info, False)
matcher = distlib.version.LegacyMatcher(name + constraint)
print(f"mkvenv: checking for {matcher}", file=sys.stderr)
dist: Optional[Distribution] = None
try:
dist = distribution(matcher.name)
except PackageNotFoundError:
pass
if (
dist is None
# Always pass installed package to pip, so that they can be
# updated if the requested version changes
or not _is_system_package(dist)
or not matcher.match(distlib.version.LegacyVersion(dist.version))
):
absent.append(name + _make_version_constraint(info, True))
if len(absent) == 1:
canary = info.get("canary", None)
else:
logger.info("found %s %s", name, dist.version)
present.append(name)
if present:
generate_console_scripts(present)
if absent:
if online or wheels_dir:
# Some packages are missing or aren't a suitable version,
# install a suitable (possibly vendored) package.
print(f"mkvenv: installing {', '.join(absent)}", file=sys.stderr)
try:
pip_install(args=absent, online=online, wheels_dir=wheels_dir)
return None
except subprocess.CalledProcessError:
pass
return diagnose(
absent[0],
online,
wheels_dir,
canary,
)
return None
def _parse_groups(file: str) -> Dict[str, Dict[str, Any]]:
if not HAVE_TOMLLIB:
if sys.version_info < (3, 11):
raise Ouch("found no usable tomli, please install it")
raise Ouch(
"Python >=3.11 does not have tomllib... what have you done!?"
)
# Use loads() to support both tomli v1.2.x (Ubuntu 22.04,
# Debian bullseye-backports) and v2.0.x
with open(file, "r", encoding="ascii") as depfile:
contents = depfile.read()
return tomllib.loads(contents) # type: ignore
def ensure_group(
file: str,
groups: Sequence[str],
online: bool = False,
wheels_dir: Optional[Union[str, Path]] = None,
) -> None:
"""
Use pip to ensure we have the package specified by @dep_specs.
If the package is already installed, do nothing. If online and
wheels_dir are both provided, prefer packages found in wheels_dir
first before connecting to PyPI.
:param dep_specs:
PEP 508 dependency specifications. e.g. ['meson>=0.61.5'].
:param online: If True, fall back to PyPI.
:param wheels_dir: If specified, search this path for packages.
"""
if not HAVE_DISTLIB:
raise Ouch("found no usable distlib, please install it")
parsed_deps = _parse_groups(file)
to_install: Dict[str, Dict[str, str]] = {}
for group in groups:
try:
to_install.update(parsed_deps[group])
except KeyError as exc:
raise Ouch(f"group {group} not defined") from exc
result = _do_ensure(to_install, online, wheels_dir)
if result:
# Well, that's not good.
if result[1]:
raise Ouch(result[0])
raise SystemExit(f"\n{result[0]}\n\n")
def post_venv_setup() -> None:
"""
This is intended to be run *inside the venv* after it is created.
"""
logger.debug("post_venv_setup()")
# Generate a 'pip' script so the venv is usable in a normal
# way from the CLI. This only happens when we inherited pip from a
# parent/system-site and haven't run ensurepip in some way.
generate_console_scripts(["pip"])
def _add_create_subcommand(subparsers: Any) -> None:
subparser = subparsers.add_parser("create", help="create a venv")
subparser.add_argument(
"target",
type=str,
action="store",
help="Target directory to install virtual environment into.",
)
def _add_post_init_subcommand(subparsers: Any) -> None:
subparsers.add_parser("post_init", help="post-venv initialization")
def _add_ensuregroup_subcommand(subparsers: Any) -> None:
subparser = subparsers.add_parser(
"ensuregroup",
help="Ensure that the specified package group is installed.",
)
subparser.add_argument(
"--online",
action="store_true",
help="Install packages from PyPI, if necessary.",
)
subparser.add_argument(
"--dir",
type=str,
action="store",
help="Path to vendored packages where we may install from.",
)
subparser.add_argument(
"file",
type=str,
action="store",
help=("Path to a TOML file describing package groups"),
)
subparser.add_argument(
"group",
type=str,
action="store",
help="One or more package group names",
nargs="+",
)
def main() -> int:
"""CLI interface to make_qemu_venv. See module docstring."""
if os.environ.get("DEBUG") or os.environ.get("GITLAB_CI"):
# You're welcome.
logging.basicConfig(level=logging.DEBUG)
else:
if os.environ.get("V"):
logging.basicConfig(level=logging.INFO)
parser = argparse.ArgumentParser(
prog="mkvenv",
description="QEMU pyvenv bootstrapping utility",
)
subparsers = parser.add_subparsers(
title="Commands",
dest="command",
required=True,
metavar="command",
help="Description",
)
_add_create_subcommand(subparsers)
_add_post_init_subcommand(subparsers)
_add_ensuregroup_subcommand(subparsers)
args = parser.parse_args()
try:
if args.command == "create":
make_venv(
args.target,
system_site_packages=True,
clear=True,
)
if args.command == "post_init":
post_venv_setup()
if args.command == "ensuregroup":
ensure_group(
file=args.file,
groups=args.group,
online=args.online,
wheels_dir=args.dir,
)
logger.debug("mkvenv.py %s: exiting", args.command)
except Ouch as exc:
print("\n*** Ouch! ***\n", file=sys.stderr)
print(str(exc), "\n\n", file=sys.stderr)
return 1
except SystemExit:
raise
except: # pylint: disable=bare-except
logger.exception("mkvenv did not complete successfully:")
return 2
return 0
if __name__ == "__main__":
sys.exit(main())