mkvenv: add console script entry point generation

When creating a virtual environment that inherits system packages,
script entry points (like "meson", "sphinx-build", etc) are not
re-generated with the correct shebang. When you are *inside* of the
venv, this is not a problem, but if you are *outside* of it, you will
not have a script that engages the virtual environment appropriately.

Add a mechanism that generates new entry points for pre-existing
packages so that we can use these scripts to run "meson",
"sphinx-build", "pip", unambiguously inside the venv.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20230511035435.734312-9-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
John Snow 2023-05-16 12:08:11 +02:00 committed by Paolo Bonzini
parent 4695a22e9a
commit 928348949d
2 changed files with 117 additions and 0 deletions

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@ -60,6 +60,7 @@ import sysconfig
from types import SimpleNamespace
from typing import (
Any,
Iterator,
Optional,
Sequence,
Tuple,
@ -69,6 +70,7 @@ import venv
import warnings
import distlib.database
import distlib.scripts
import distlib.version
@ -334,6 +336,113 @@ def make_venv( # pylint: disable=too-many-arguments
print(builder.get_value("env_exe"))
def _gen_importlib(packages: Sequence[str]) -> Iterator[str]:
# pylint: disable=import-outside-toplevel
# pylint: disable=no-name-in-module
# pylint: disable=import-error
try:
# First preference: Python 3.8+ stdlib
from importlib.metadata import ( # type: ignore
PackageNotFoundError,
distribution,
)
except ImportError as exc:
logger.debug("%s", str(exc))
# Second preference: Commonly available PyPI backport
from importlib_metadata import ( # type: ignore
PackageNotFoundError,
distribution,
)
def _generator() -> Iterator[str]:
for package in packages:
try:
entry_points = 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 _gen_pkg_resources(packages: Sequence[str]) -> Iterator[str]:
# pylint: disable=import-outside-toplevel
# Bundled with setuptools; has a good chance of being available.
import pkg_resources
def _generator() -> Iterator[str]:
for package in packages:
try:
eps = pkg_resources.get_entry_map(package, "console_scripts")
except pkg_resources.DistributionNotFound:
continue
for entry_point in eps.values():
yield str(entry_point)
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
def _get_entry_points() -> Iterator[str]:
"""Python 3.7 compatibility shim for iterating entry points."""
# Python 3.8+, or Python 3.7 with importlib_metadata installed.
try:
return _gen_importlib(packages)
except ImportError as exc:
logger.debug("%s", str(exc))
# Python 3.7 with setuptools installed.
try:
return _gen_pkg_resources(packages)
except ImportError as exc:
logger.debug("%s", str(exc))
raise Ouch(
"Neither importlib.metadata nor pkg_resources found, "
"can't generate console script shims.\n"
"Use Python 3.8+, or install importlib-metadata or setuptools."
) from exc
maker = distlib.scripts.ScriptMaker(None, bin_path)
maker.variants = {""}
maker.clobber = False
for entry_point in _get_entry_points():
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.
@ -512,6 +621,7 @@ def _do_ensure(
)
dist_path = distlib.database.DistributionPath(include_egg=True)
absent = []
present = []
for spec in dep_specs:
matcher = distlib.version.LegacyMatcher(spec)
dist = dist_path.get_distribution(matcher.name)
@ -519,6 +629,10 @@ def _do_ensure(
absent.append(spec)
else:
logger.info("found %s", dist)
present.append(matcher.name)
if present:
generate_console_scripts(present)
if absent:
# Some packages are missing or aren't a suitable version,

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@ -119,6 +119,9 @@ ignore_missing_imports = True
[mypy-distlib.database]
ignore_missing_imports = True
[mypy-distlib.scripts]
ignore_missing_imports = True
[mypy-distlib.version]
ignore_missing_imports = True