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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
# This file contains code for managing the Python import scope for Mach. This
# generally involves populating a Python virtualenv.
from __future__ import absolute_import, print_function, unicode_literals
import ast
import enum
import functools
import json
import os
import platform
import shutil
import site
import subprocess
import sys
import sysconfig
from pathlib import Path
import tempfile
from contextlib import contextmanager
from typing import Optional, Callable
from mach.requirements import (
MachEnvRequirements,
UnexpectedFlexibleRequirementException,
)
PTH_FILENAME = "mach.pth"
METADATA_FILENAME = "moz_virtualenv_metadata.json"
# The following virtualenvs *may* be used in a context where they aren't allowed to
# install pip packages over the network. In such a case, they must access unvendored
# python packages via the system environment.
PIP_NETWORK_INSTALL_RESTRICTED_VIRTUALENVS = ("mach", "build", "common")
class VirtualenvOutOfDateException(Exception):
pass
class MozSiteMetadataOutOfDateError(Exception):
pass
class InstallPipRequirementsException(Exception):
pass
class SiteUpToDateResult:
def __init__(self, is_up_to_date, reason=None):
self.is_up_to_date = is_up_to_date
self.reason = reason
class SitePackagesSource(enum.Enum):
NONE = "none"
SYSTEM = "system"
VENV = "pip"
@classmethod
def for_mach(cls):
source = os.environ.get("MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE", "").lower()
if source == "system":
source = SitePackagesSource.SYSTEM
elif source == "none":
source = SitePackagesSource.NONE
elif source == "pip":
source = SitePackagesSource.VENV
elif source:
raise Exception(
"Unexpected MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE value, expected one "
'of "system", "pip", "none", or to not be set'
)
mach_use_system_python = bool(os.environ.get("MACH_USE_SYSTEM_PYTHON"))
if source:
if mach_use_system_python:
raise Exception(
"The MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE environment variable is "
"set, so the MACH_USE_SYSTEM_PYTHON variable is redundant and "
"should be unset."
)
return source
# Only print this warning once for the Mach site, so we don't spam it every
# time a site handle is created.
if mach_use_system_python:
print(
'The "MACH_USE_SYSTEM_PYTHON" environment variable is deprecated, '
"please unset it or replace it with either "
'"MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE=system" or '
'"MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE=none"'
)
return (
SitePackagesSource.NONE
if (mach_use_system_python or os.environ.get("MOZ_AUTOMATION"))
else SitePackagesSource.VENV
)
class MozSiteMetadata:
"""Details about a Moz-managed python site
When a Moz-managed site is active, its associated metadata is available
at "MozSiteMetadata.current".
Sites that have associated virtualenvs (so, those that aren't strictly leaning on
the external python packages) will have their metadata written to
<prefix>/moz_virtualenv_metadata.json.
"""
# Used to track which which virtualenv has been activated in-process.
current: Optional["MozSiteMetadata"] = None
def __init__(
self,
hex_version: int,
site_name: str,
mach_site_packages_source: SitePackagesSource,
original_python: "ExternalPythonSite",
prefix: str,
):
"""
Args:
hex_version: The python version number from sys.hexversion
site_name: The name of the site this metadata is associated with
site_packages_source: Where this site imports its
pip-installed dependencies from
mach_site_packages_source: Where the Mach site imports
its pip-installed dependencies from
original_python: The external Python site that was
used to invoke Mach. Usually the system Python, such as /usr/bin/python3
prefix: The same value as "sys.prefix" is when running within the
associated Python site. The same thing as the "virtualenv root".
"""
self.hex_version = hex_version
self.site_name = site_name
self.mach_site_packages_source = mach_site_packages_source
# original_python is needed for commands that tweak the system, such
# as "./mach install-moz-phab".
self.original_python = original_python
self.prefix = prefix
def write(self, is_finalized):
raw = {
"hex_version": self.hex_version,
"virtualenv_name": self.site_name,
"mach_site_packages_source": self.mach_site_packages_source.name,
"original_python_executable": self.original_python.python_path,
"is_finalized": is_finalized,
}
with open(os.path.join(self.prefix, METADATA_FILENAME), "w") as file:
json.dump(raw, file)
def __eq__(self, other):
return (
type(self) == type(other)
and self.hex_version == other.hex_version
and self.site_name == other.site_name
and self.mach_site_packages_source == other.mach_site_packages_source
# On Windows, execution environment can lead to different cases. Normalize.
and Path(self.original_python.python_path)
== Path(other.original_python.python_path)
)
@classmethod
def from_runtime(cls):
if cls.current:
return cls.current
return cls.from_path(sys.prefix)
@classmethod
def from_path(cls, prefix):
metadata_path = os.path.join(prefix, METADATA_FILENAME)
out_of_date_exception = MozSiteMetadataOutOfDateError(
f'The virtualenv at "{prefix}" is out-of-date.'
)
try:
with open(metadata_path, "r") as file:
raw = json.load(file)
if not raw.get("is_finalized", False):
raise out_of_date_exception
return cls(
raw["hex_version"],
raw["virtualenv_name"],
SitePackagesSource[raw["mach_site_packages_source"]],
ExternalPythonSite(raw["original_python_executable"]),
metadata_path,
)
except FileNotFoundError:
return None
except KeyError:
raise out_of_date_exception
@contextmanager
def update_current_site(self, executable):
"""Updates necessary global state when a site is activated
Due to needing to fetch some state before the actual activation happens, this
is represented as a context manager and should be used as follows:
with metadata.update_current_site(executable):
# Perform the actual implementation of changing the site, whether that is
# by exec-ing "activate_this.py" in a virtualenv, modifying the sys.path
# directly, or some other means
...
"""
try:
import pkg_resources
except ModuleNotFoundError:
pkg_resources = None
yield
MozSiteMetadata.current = self
sys.executable = executable
if pkg_resources:
# Rebuild the working_set based on the new sys.path.
pkg_resources._initialize_master_working_set()
class MachSiteManager:
"""Represents the activate-able "import scope" Mach needs
Whether running independently, using the system packages, or automatically managing
dependencies with "pip install", this class provides an easy handle to verify
that the "site" is up-to-date (whether than means that system packages don't
collide with vendored packages, or that the on-disk virtualenv needs rebuilding).
Note that, this is a *virtual* site: an on-disk Python virtualenv
is only created if there will be "pip installs" into the Mach site.
"""
def __init__(
self,
topsrcdir: str,
virtualenv_root: Optional[str],
requirements: MachEnvRequirements,
original_python: "ExternalPythonSite",
site_packages_source: SitePackagesSource,
):
"""
Args:
topsrcdir: The path to the Firefox repo
virtualenv_root: The path to the the associated Mach virtualenv,
if any
requirements: The requirements associated with the Mach site, parsed from
the file at python/sites/mach.txt
original_python: The external Python site that was used to invoke Mach.
If Mach invocations are nested, then "original_python" refers to
Python site that was used to start Mach first.
Usually the system Python, such as /usr/bin/python3.
site_packages_source: Where the Mach site will import its pip-installed
dependencies from
"""
self._topsrcdir = topsrcdir
self._site_packages_source = site_packages_source
self._requirements = requirements
self._virtualenv_root = virtualenv_root
self._metadata = MozSiteMetadata(
sys.hexversion,
"mach",
site_packages_source,
original_python,
self._virtualenv_root,
)
@classmethod
def from_environment(cls, topsrcdir: str, get_state_dir: Callable[[], str]):
"""
Args:
topsrcdir: The path to the Firefox repo
get_state_dir: A function that resolves the path to the checkout-scoped
state_dir, generally ~/.mozbuild/srcdirs/<checkout-based-dir>/
"""
requirements = resolve_requirements(topsrcdir, "mach")
# Mach needs to operate in environments in which no pip packages are installed
# yet, and the system isn't guaranteed to have the packages we need. For example,
# "./mach bootstrap" can't have any dependencies.
# So, all external dependencies of Mach's must be optional.
assert (
not requirements.pypi_requirements
), "Mach pip package requirements must be optional."
# external_python is the Python interpreter that invoked Mach for this process.
external_python = ExternalPythonSite(sys.executable)
# original_python is the first Python interpreter that invoked the top-level
# Mach process. This is different from "external_python" when there's nested
# Mach invocations.
active_metadata = MozSiteMetadata.from_runtime()
if active_metadata:
original_python = active_metadata.original_python
else:
original_python = external_python
source = SitePackagesSource.for_mach()
virtualenv_root = (
_mach_virtualenv_root(get_state_dir())
if source == SitePackagesSource.VENV
else None
)
return cls(
topsrcdir,
virtualenv_root,
requirements,
original_python,
source,
)
def _up_to_date(self):
if self._site_packages_source == SitePackagesSource.NONE:
return SiteUpToDateResult(True)
elif self._site_packages_source == SitePackagesSource.SYSTEM:
_assert_pip_check(
self._topsrcdir, self._sys_path(), "mach", self._requirements
)
return SiteUpToDateResult(True)
elif self._site_packages_source == SitePackagesSource.VENV:
environment = self._virtualenv()
return _is_venv_up_to_date(
self._topsrcdir,
environment,
self._pthfile_lines(environment),
self._requirements,
self._metadata,
)
def ensure(self, *, force=False):
result = self._up_to_date()
if force or not result.is_up_to_date:
if Path(sys.prefix) == Path(self._metadata.prefix):
# If the Mach virtualenv is already activated, then the changes caused
# by rebuilding the virtualenv won't take effect until the next time
# Mach is used, which can lead to confusing one-off errors.
# Instead, request that the user resolve the out-of-date situation,
# *then* come back and run the intended command.
raise VirtualenvOutOfDateException(result.reason)
self._build()
def attempt_populate_optional_packages(self):
if self._site_packages_source != SitePackagesSource.VENV:
pass
self._virtualenv().install_optional_packages(
self._requirements.pypi_optional_requirements
)
def activate(self):
assert not MozSiteMetadata.current
self.ensure()
with self._metadata.update_current_site(
self._virtualenv().python_path
if self._site_packages_source == SitePackagesSource.VENV
else sys.executable,
):
# Reset the sys.path to insulate ourselves from the environment.
# This should be safe to do, since activation of the Mach site happens so
# early in the Mach lifecycle that no packages should have been imported
# from external sources yet.
sys.path = self._sys_path()
if self._site_packages_source == SitePackagesSource.VENV:
# Activate the Mach virtualenv in the current Python context. This
# automatically adds the virtualenv's "site-packages" to our scope, in
# addition to our first-party/vendored modules since they're specified
# in the "mach.pth" file.
activate_virtualenv(self._virtualenv())
def _build(self):
if self._site_packages_source != SitePackagesSource.VENV:
# The Mach virtualenv doesn't have a physical virtualenv on-disk if it won't
# be "pip install"-ing. So, there's no build work to do.
return
environment = self._virtualenv()
_create_venv_with_pthfile(
self._topsrcdir,
environment,
self._pthfile_lines(environment),
True,
self._requirements,
self._metadata,
)
def _sys_path(self):
if self._site_packages_source == SitePackagesSource.SYSTEM:
stdlib_paths, system_site_paths = self._metadata.original_python.sys_path()
return [
*stdlib_paths,
*self._requirements.pths_as_absolute(self._topsrcdir),
*system_site_paths,
]
elif self._site_packages_source == SitePackagesSource.NONE:
stdlib_paths = self._metadata.original_python.sys_path_stdlib()
return [
*stdlib_paths,
*self._requirements.pths_as_absolute(self._topsrcdir),
]
elif self._site_packages_source == SitePackagesSource.VENV:
stdlib_paths = self._metadata.original_python.sys_path_stdlib()
return [
*stdlib_paths,
# self._requirements will be added as part of the virtualenv activation.
]
def _pthfile_lines(self, environment):
return [
# Prioritize vendored and first-party modules first.
*self._requirements.pths_as_absolute(self._topsrcdir),
# Then, include the virtualenv's site-packages.
*_deprioritize_venv_packages(
environment, self._site_packages_source == SitePackagesSource.VENV
),
]
def _virtualenv(self):
assert self._site_packages_source == SitePackagesSource.VENV
return PythonVirtualenv(self._metadata.prefix)
class CommandSiteManager:
"""Activate sites and ad-hoc-install pip packages
Provides tools to ensure that a command's scope will have expected, compatible
packages. Manages prioritization of the import scope, and ensures consistency
regardless of how a virtualenv is used (whether via in-process activation, or when
used standalone to invoke a script).
A few notes:
* The command environment always inherits Mach's import scope. This is because
"unloading" packages in Python is error-prone, so in-process activations will always
carry Mach's dependencies along with it. Accordingly, compatibility between each
command environment and the Mach environment must be maintained
* Unlike the Mach environment, command environments *always* have an associated
physical virtualenv on-disk. This is because some commands invoke child Python
processes, and that child process should have the same import scope.
"""
def __init__(
self,
topsrcdir: str,
mach_virtualenv_root: Optional[str],
virtualenv_root: str,
site_name: str,
active_metadata: MozSiteMetadata,
populate_virtualenv: bool,
requirements: MachEnvRequirements,
):
"""
Args:
topsrcdir: The path to the Firefox repo
mach_virtualenv_root: The path to the Mach virtualenv, if any
virtualenv_root: The path to the virtualenv associated with this site
site_name: The name of this site, such as "build"
active_metadata: The currently-active moz-managed site
populate_virtualenv: True if packages should be installed to the on-disk
virtualenv with "pip". False if the virtualenv should only include
sys.path modifications, and all 3rd-party packages should be imported from
Mach's site packages source.
requirements: The requirements associated with this site, parsed from
the file at python/sites/<site_name>.txt
"""
self._topsrcdir = topsrcdir
self._mach_virtualenv_root = mach_virtualenv_root
self.virtualenv_root = virtualenv_root
self._site_name = site_name
self._virtualenv = PythonVirtualenv(self.virtualenv_root)
self.python_path = self._virtualenv.python_path
self.bin_path = self._virtualenv.bin_path
self._populate_virtualenv = populate_virtualenv
self._mach_site_packages_source = active_metadata.mach_site_packages_source
self._requirements = requirements
self._metadata = MozSiteMetadata(
sys.hexversion,
site_name,
active_metadata.mach_site_packages_source,
active_metadata.original_python,
virtualenv_root,
)
@classmethod
def from_environment(
cls,
topsrcdir: str,
get_state_dir: Callable[[], Optional[str]],
site_name: str,
command_virtualenvs_dir: str,
):
"""
Args:
topsrcdir: The path to the Firefox repo
get_state_dir: A function that resolves the path to the checkout-scoped
state_dir, generally ~/.mozbuild/srcdirs/<checkout-based-dir>/
site_name: The name of this site, such as "build"
command_virtualenvs_dir: The location under which this site's virtualenv
should be created
"""
active_metadata = MozSiteMetadata.from_runtime()
assert (
active_metadata
), "A Mach-managed site must be active before doing work with command sites"
mach_site_packages_source = active_metadata.mach_site_packages_source
pip_restricted_site = site_name in PIP_NETWORK_INSTALL_RESTRICTED_VIRTUALENVS
if (
not pip_restricted_site
and mach_site_packages_source == SitePackagesSource.SYSTEM
):
# Sites that aren't pip-network-install-restricted are likely going to be
# incompatible with the system. Besides, this use case shouldn't exist, since
# using the system packages is supposed to only be needed to lower risk of
# important processes like building Firefox.
raise Exception(
'Cannot use MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE="system" for any '
f"sites other than {PIP_NETWORK_INSTALL_RESTRICTED_VIRTUALENVS}. The "
f'current attempted site is "{site_name}".'
)
mach_virtualenv_root = (
_mach_virtualenv_root(get_state_dir())
if mach_site_packages_source == SitePackagesSource.VENV
else None
)
populate_virtualenv = (
mach_site_packages_source == SitePackagesSource.VENV
or not pip_restricted_site
)
return cls(
topsrcdir,
mach_virtualenv_root,
os.path.join(command_virtualenvs_dir, site_name),
site_name,
active_metadata,
populate_virtualenv,
resolve_requirements(topsrcdir, site_name),
)
def ensure(self):
"""Ensure that this virtualenv is built, up-to-date, and ready for use
If using a virtualenv Python binary directly, it's useful to call this function
first to ensure that the virtualenv doesn't have obsolete references or packages.
"""
result = self._up_to_date()
if not result.is_up_to_date:
active_site = MozSiteMetadata.from_runtime()
if active_site.site_name == self._site_name:
print(result.reason, file=sys.stderr)
raise Exception(
f'The "{self._site_name}" site is out-of-date, even though it has '
f"already been activated. Was it modified while this Mach process "
f"was running?"
)
_create_venv_with_pthfile(
self._topsrcdir,
self._virtualenv,
self._pthfile_lines(),
self._populate_virtualenv,
self._requirements,
self._metadata,
)
def activate(self):
"""Activate this site in the current Python context.
If you run a random Python script and wish to "activate" the
site, you can simply instantiate an instance of this class
and call .activate() to make the virtualenv active.
"""
active_site = MozSiteMetadata.from_runtime()
site_is_already_active = active_site.site_name == self._site_name
if (
active_site.site_name not in ("mach", "common")
and not site_is_already_active
):
raise Exception(
f'Activating from one command site ("{active_site.site_name}") to '
f'another ("{self._site_name}") is not allowed, because they may '
"be incompatible."
)
self.ensure()
if site_is_already_active:
return
with self._metadata.update_current_site(self._virtualenv.python_path):
activate_virtualenv(self._virtualenv)
def install_pip_package(self, package):
"""Install a package via pip.
The supplied package is specified using a pip requirement specifier.
e.g. 'foo' or 'foo==1.0'.
If the package is already installed, this is a no-op.
"""
if Path(sys.prefix) == Path(self.virtualenv_root):
# If we're already running in this interpreter, we can optimize in
# the case that the package requirement is already satisfied.
from pip._internal.req.constructors import install_req_from_line
req = install_req_from_line(package)
req.check_if_exists(use_user_site=False)
if req.satisfied_by is not None:
return
self._virtualenv.pip_install_with_constraints([package])
def install_pip_requirements(self, path, require_hashes=True, quiet=False):
"""Install a pip requirements.txt file.
The supplied path is a text file containing pip requirement
specifiers.
If require_hashes is True, each specifier must contain the
expected hash of the downloaded package. See:
"""
if not os.path.isabs(path):
path = os.path.join(self._topsrcdir, path)
args = ["--requirement", path]
if require_hashes:
args.append("--require-hashes")
install_result = self._virtualenv.pip_install(
args,
check=not quiet,
stdout=subprocess.PIPE if quiet else None,
)
if install_result.returncode:
print(install_result.stdout)
raise InstallPipRequirementsException(
f'Failed to install "{path}" into the "{self._site_name}" site.'
)
check_result = subprocess.run(
[self.python_path, "-m", "pip", "check"],
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
universal_newlines=True,
)
if check_result.returncode:
if quiet:
# If "quiet" was specified, then the "pip install" output wasn't printed
# earlier, and was buffered instead. Print that buffer so that debugging
# the "pip check" failure is easier.
print(install_result.stdout)
subprocess.check_call(
[self.python_path, "-m", "pip", "list", "-v"], stdout=sys.stderr
)
print(check_result.stdout, file=sys.stderr)
raise InstallPipRequirementsException(
f'As part of validation after installing "{path}" into the '
f'"{self._site_name}" site, the site appears to contain installed '
"packages that are incompatible with each other."
)
def _pthfile_lines(self):
"""Generate the prioritized import scope to encode in the venv's pthfile
The import priority looks like this:
1. Mach's vendored/first-party modules
2. Mach's site-package source (the Mach virtualenv, the system Python, or neither)
3. The command's vendored/first-party modules
4. The command's site-package source (either the virtualenv or the system Python,
if it's not already added)
Note that, when using the system Python, it may either be prioritized before or
after the command's vendored/first-party modules. This is a symptom of us
attempting to avoid conflicting with the system packages.
For example, there's at least one job in CI that operates with an ancient
environment with a bunch of old packages, many of whom conflict with our vendored
packages. However, the specific command that we're running for the job doesn't
need any of the system's packages, so we're safe to insulate ourselves.
Mach doesn't know the command being run when it's preparing its import scope,
so it has to be defensive. Therefore:
1. If Mach needs a system package: system packages are higher priority.
2. If Mach doesn't need a system package, but the current command does: system
packages are still be in the list, albeit at a lower priority.
"""
# Prioritize Mach's vendored and first-party modules first.
lines = resolve_requirements(self._topsrcdir, "mach").pths_as_absolute(
self._topsrcdir
)
mach_site_packages_source = self._mach_site_packages_source
if mach_site_packages_source == SitePackagesSource.SYSTEM:
# When Mach is using the system environment, add it next.
_, system_site_paths = self._metadata.original_python.sys_path()
lines.extend(system_site_paths)
elif mach_site_packages_source == SitePackagesSource.VENV:
# When Mach is using its on-disk virtualenv, add its site-packages directory.
assert self._mach_virtualenv_root
lines.extend(
PythonVirtualenv(self._mach_virtualenv_root).site_packages_dirs()
)
# Add this command's vendored and first-party modules.
lines.extend(self._requirements.pths_as_absolute(self._topsrcdir))
# Finally, ensure that pip-installed packages are the lowest-priority
# source to import from.
lines.extend(
_deprioritize_venv_packages(self._virtualenv, self._populate_virtualenv)
)
# Note that an on-disk virtualenv is always created for commands, even if they
# are using the system as their site-packages source. This is to support use
# cases where a fresh Python process must be created, but it also must have
# access to <site>'s 1st- and 3rd-party packages.
return lines
def _up_to_date(self):
pthfile_lines = self._pthfile_lines()
if self._mach_site_packages_source == SitePackagesSource.SYSTEM:
_assert_pip_check(
self._topsrcdir,
pthfile_lines,
self._site_name,
self._requirements if not self._populate_virtualenv else None,
)
return _is_venv_up_to_date(
self._topsrcdir,
self._virtualenv,
pthfile_lines,
self._requirements,
self._metadata,
)
class PythonVirtualenv:
"""Calculates paths of interest for general python virtual environments"""
def __init__(self, prefix):
is_windows = sys.platform == "cygwin" or (
sys.platform == "win32" and os.sep == "\\"
)
if is_windows:
self.bin_path = os.path.join(prefix, "Scripts")
self.python_path = os.path.join(self.bin_path, "python.exe")
else:
self.bin_path = os.path.join(prefix, "bin")
self.python_path = os.path.join(self.bin_path, "python")
self.prefix = prefix
@functools.lru_cache(maxsize=None)
def resolve_sysconfig_packages_path(self, sysconfig_path):
# macOS uses a different default sysconfig scheme based on whether it's using the
# system Python or running in a virtualenv.
# Manually define the scheme (following the implementation in
# "sysconfig._get_default_scheme()") so that we're always following the
# code path for a virtualenv directory structure.
if os.name == "posix":
scheme = "posix_prefix"
else:
scheme = os.name
sysconfig_paths = sysconfig.get_paths(scheme)
data_path = Path(sysconfig_paths["data"])
path = Path(sysconfig_paths[sysconfig_path])
relative_path = path.relative_to(data_path)
# Path to virtualenv's "site-packages" directory for provided sysconfig path
return os.path.normpath(Path(self.prefix) / relative_path)
def site_packages_dirs(self):
dirs = []
if sys.platform.startswith("win"):
dirs.append(os.path.normpath(self.prefix))
purelib = self.resolve_sysconfig_packages_path("purelib")
platlib = self.resolve_sysconfig_packages_path("platlib")
dirs.append(purelib)
if platlib != purelib:
dirs.append(platlib)
return dirs
def pip_install_with_constraints(self, pip_args):
"""Create a pip constraints file or existing packages
When pip installing an incompatible package, pip will follow through with
the install but raise a warning afterwards.
To defend our environment from breakage, we run "pip install" but add all
existing packages to a "constraints file". This ensures that conflicts are
raised as errors up-front, and the virtual environment doesn't have conflicting
packages installed.
Note: pip_args is expected to contain either the requested package or
requirements file.
"""
existing_packages = self._resolve_installed_packages()
with tempfile.TemporaryDirectory() as tempdir:
constraints_path = os.path.join(tempdir, "site-constraints.txt")
with open(constraints_path, "w") as file:
file.write(
"\n".join(
[
f"{name}=={version}"
for name, version in existing_packages.items()
]
)
)
return self.pip_install(["--constraint", constraints_path] + pip_args)
def pip_install(self, pip_install_args, **kwargs):
# setuptools will use the architecture of the running Python instance when
# building packages. However, it's possible for the Xcode Python to be a universal
# binary (x86_64 and arm64) without the associated macOS SDK supporting arm64,
# thereby causing a build failure. To avoid this, we explicitly influence the
# build to only target a single architecture - our current architecture.
kwargs.setdefault("env", os.environ.copy()).setdefault(
"ARCHFLAGS", "-arch {}".format(platform.machine())
)
kwargs.setdefault("check", True)
kwargs.setdefault("stderr", subprocess.STDOUT)
kwargs.setdefault("universal_newlines", True)
# It's tempting to call pip natively via pip.main(). However,
# the current Python interpreter may not be the virtualenv python.
# This will confuse pip and cause the package to attempt to install
# against the executing interpreter. By creating a new process, we
# force the virtualenv's interpreter to be used and all is well.
# It /might/ be possible to cheat and set sys.executable to
# self.python_path. However, this seems more risk than it's worth.
return subprocess.run(
[self.python_path, "-m", "pip", "install"] + pip_install_args,
**kwargs,
)
def install_optional_packages(self, optional_requirements):
for requirement in optional_requirements:
try:
self.pip_install_with_constraints([str(requirement.requirement)])
except subprocess.CalledProcessError:
print(
f"Could not install {requirement.requirement.name}, so "
f"{requirement.repercussion}. Continuing."
)
def _resolve_installed_packages(self):
return _resolve_installed_packages(self.python_path)
class RequirementsValidationResult:
def __init__(self):
self._package_discrepancies = []
self.has_all_packages = True
self.provides_any_package = False
def add_discrepancy(self, requirement, found):
self._package_discrepancies.append((requirement, found))
self.has_all_packages = False
def report(self):
lines = []
for requirement, found in self._package_discrepancies:
if found:
error = f'Installed with unexpected version "{found}"'
else:
error = "Not installed"
lines.append(f"{requirement}: {error}")
return "\n".join(lines)
@classmethod
def from_packages(cls, packages, requirements):
result = cls()
for pkg in requirements.pypi_requirements:
installed_version = packages.get(pkg.requirement.name)
if not installed_version or not pkg.requirement.specifier.contains(
installed_version
):
result.add_discrepancy(pkg.requirement, installed_version)
elif installed_version:
result.provides_any_package = True
for pkg in requirements.pypi_optional_requirements:
installed_version = packages.get(pkg.requirement.name)
if installed_version and not pkg.requirement.specifier.contains(
installed_version
):
result.add_discrepancy(pkg.requirement, installed_version)
elif installed_version:
result.provides_any_package = True
return result
class ExternalPythonSite:
"""Represents the Python site that is executing Mach
The external Python site could be a virtualenv (created by venv or virtualenv) or
the system Python itself, so we can't make any significant assumptions on its
structure.
"""
def __init__(self, python_executable):
self._prefix = os.path.dirname(os.path.dirname(python_executable))
self.python_path = python_executable
@functools.lru_cache(maxsize=None)
def sys_path(self):
"""Return lists of sys.path entries: one for standard library, one for the site
These two lists are calculated at the same time so that we can interpret them
in a single Python subprocess, as running a whole Python instance is
very expensive in the context of Mach initialization.
"""
env = {
k: v
for k, v in os.environ.items()
# Don't include items injected by IDEs into the system path.
if k not in ("PYTHONPATH", "PYDEVD_LOAD_VALUES_ASYNC")
}
stdlib = subprocess.Popen(
[
self.python_path,
# Don't "import site" right away, so we can split the standard library
# paths from the site paths.
"-S",
"-c",
"import sys; from collections import OrderedDict; "
# Skip the first item in the sys.path, as it's the working directory
# of the invoked script (so, in this case, "").
# Use list(OrderectDict...) to de-dupe items, such as when using
# pyenv on Linux.
"print(list(OrderedDict.fromkeys(sys.path[1:])))",
],
universal_newlines=True,
env=env,
stdout=subprocess.PIPE,
)
system = subprocess.Popen(
[
self.python_path,
"-c",
"import os; import sys; import site; "
"packages = site.getsitepackages(); "
# Only add the "user site packages" if not in a virtualenv (which is
# identified by the prefix == base_prefix check
"packages.insert(0, site.getusersitepackages()) if "
" sys.prefix == sys.base_prefix else None; "
# When a Python instance launches, it only adds each
# "site.getsitepackages()" entry if it exists on the file system.
# Replicate that behaviour to get a more accurate list of system paths.
"packages = [p for p in packages if os.path.exists(p)]; "
"print(packages)",
],
universal_newlines=True,
env=env,
stdout=subprocess.PIPE,
)
# Run python processes in parallel - they take roughly the same time, so this
# cuts this functions run time in half.
stdlib_out, _ = stdlib.communicate()
system_out, _ = system.communicate()
assert stdlib.returncode == 0
assert system.returncode == 0
stdlib = ast.literal_eval(stdlib_out)
system = ast.literal_eval(system_out)
# On Windows, some paths are both part of the default sys.path *and* are included
# in the "site packages" list. Keep the "stdlib" one, and remove the dupe from
# the "system packages" list.
system = [path for path in system if path not in stdlib]
return stdlib, system
def sys_path_stdlib(self):
"""Return list of default sys.path entries for the standard library"""
stdlib, _ = self.sys_path()
return stdlib
@functools.lru_cache(maxsize=None)
def resolve_requirements(topsrcdir, site_name):
manifest_path = os.path.join(topsrcdir, "python", "sites", f"{site_name}.txt")
if not os.path.exists(manifest_path):
raise Exception(
f'The current command is using the "{site_name}" '
"site. However, that site is missing its associated "
f'requirements definition file at "{manifest_path}".'
)
thunderbird_dir = os.path.join(topsrcdir, "comm")
is_thunderbird = os.path.exists(thunderbird_dir) and bool(
os.listdir(thunderbird_dir)
)
try:
return MachEnvRequirements.from_requirements_definition(
topsrcdir,
is_thunderbird,
site_name not in PIP_NETWORK_INSTALL_RESTRICTED_VIRTUALENVS,
manifest_path,
)
except UnexpectedFlexibleRequirementException as e:
raise Exception(
f'The "{site_name}" site does not have all pypi packages pinned '
f'in the format "package==version" (found "{e.raw_requirement}").\n'
f"Only the {PIP_NETWORK_INSTALL_RESTRICTED_VIRTUALENVS} sites are "
"allowed to have unpinned packages."
)
def _virtualenv_py_path(topsrcdir):
return os.path.join(
topsrcdir, "third_party", "python", "virtualenv", "virtualenv.py"
)
def _resolve_installed_packages(python_executable):
pip_json = subprocess.check_output(
[
python_executable,
"-m",
"pip",
"list",
"--format",
"json",
"--disable-pip-version-check",
],
universal_newlines=True,
)
installed_packages = json.loads(pip_json)
return {package["name"]: package["version"] for package in installed_packages}
def _assert_pip_check(topsrcdir, pthfile_lines, virtualenv_name, requirements):
"""Check if the provided pthfile lines have a package incompatibility
If there's an incompatibility, raise an exception and allow it to bubble up since
it will require user intervention to resolve.
If requirements aren't provided (such as when Mach is using SYSTEM, but the command
site is using VENV), then skip the "pthfile satisfies requirements" step.
"""
if os.environ.get(
f"MACH_SYSTEM_ASSERTED_COMPATIBLE_WITH_{virtualenv_name.upper()}_SITE", None
):
# Don't re-assert compatibility against the system python within Mach subshells.
return
print(
'Running "pip check" to verify compatibility between the system Python and the '
f'"{virtualenv_name}" site.'
)
with tempfile.TemporaryDirectory() as check_env_path:
# Pip detects packages on the "sys.path" that have a ".dist-info" or
# a ".egg-info" directory. The majority of our Python dependencies are
# vendored as extracted wheels or sdists, so they are automatically picked up.
# This gives us sufficient confidence to do a `pip check` with both vendored
# packages + system packages in scope, and trust the results.
# Note: rather than just running the system pip with a modified "sys.path",
# we create a new virtualenv that has our pinned pip version, so that
# we get consistent results (there's been lots of pip resolver behaviour
# changes recently).
subprocess.check_call(
[
sys.executable,
_virtualenv_py_path(topsrcdir),
"--no-download",
check_env_path,
],
stdout=subprocess.DEVNULL,
)
check_env = PythonVirtualenv(check_env_path)
with open(
os.path.join(
os.path.join(check_env.resolve_sysconfig_packages_path("platlib")),
PTH_FILENAME,
),
"w",
) as f:
f.write("\n".join(pthfile_lines))
pip = [check_env.python_path, "-m", "pip"]
if requirements:
packages = _resolve_installed_packages(check_env.python_path)
validation_result = RequirementsValidationResult.from_packages(
packages, requirements
)
if not validation_result.has_all_packages:
subprocess.check_call(pip + ["list", "-v"], stdout=sys.stderr)
print(validation_result.report(), file=sys.stderr)
raise Exception(
f'The "{virtualenv_name}" site is not compatible with the installed '
"system Python packages."
)
check_result = subprocess.run(
pip + ["check"],
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
universal_newlines=True,
)
if check_result.returncode:
subprocess.check_call(pip + ["list", "-v"], stdout=sys.stderr)
print(check_result.stdout, file=sys.stderr)
raise Exception(
'According to "pip check", the current Python '
"environment has package-compatibility issues."
)
os.environ[
f"MACH_SYSTEM_ASSERTED_COMPATIBLE_WITH_{virtualenv_name.upper()}_SITE"
] = "1"
def _deprioritize_venv_packages(virtualenv, populate_virtualenv):
# Virtualenvs implicitly add some "site packages" to the sys.path upon being
# activated. However, Mach generally wants to prioritize the existing sys.path
# (such as vendored packages) over packages installed to virtualenvs.
# So, this function moves the virtualenv's site-packages to the bottom of the sys.path
# at activation-time.
return [
line
for site_packages_dir in virtualenv.site_packages_dirs()
# repr(...) is needed to ensure Windows path backslashes aren't mistaken for
# escape sequences.
# Additionally, when removing the existing "site-packages" folder's entry, we have
# to do it in a case-insensitive way because, on Windows:
# * Python adds it as <venv>/lib/site-packages
# * While sysconfig tells us it's <venv>/Lib/site-packages
# * (note: on-disk, it's capitalized, so sysconfig is slightly more accurate).
for line in filter(
None,
(
"import sys; sys.path = [p for p in sys.path if "
f"p.lower() != {repr(site_packages_dir)}.lower()]",
f"import sys; sys.path.append({repr(site_packages_dir)})"
if populate_virtualenv
else None,
),
)
]
def _create_venv_with_pthfile(
topsrcdir,
target_venv,
pthfile_lines,
populate_with_pip,
requirements,
metadata,
):
virtualenv_root = target_venv.prefix
if os.path.exists(virtualenv_root):
shutil.rmtree(virtualenv_root)
os.makedirs(virtualenv_root)
metadata.write(is_finalized=False)
subprocess.check_call(
[
metadata.original_python.python_path,
_virtualenv_py_path(topsrcdir),
# pip, setuptools and wheel are vendored and inserted into the virtualenv
# scope automatically, so "virtualenv" doesn't need to seed it.
"--no-seed",
virtualenv_root,
]
)
platlib_site_packages_dir = target_venv.resolve_sysconfig_packages_path("platlib")
pthfile_contents = "\n".join(pthfile_lines)
with open(os.path.join(platlib_site_packages_dir, PTH_FILENAME), "w") as f:
f.write(pthfile_contents)
if populate_with_pip:
for requirement in requirements.pypi_requirements:
target_venv.pip_install([str(requirement.requirement)])
target_venv.install_optional_packages(requirements.pypi_optional_requirements)
metadata.write(is_finalized=True)
def _is_venv_up_to_date(
topsrcdir,
target_venv,
expected_pthfile_lines,
requirements,
expected_metadata,
):
if not os.path.exists(target_venv.prefix):
return SiteUpToDateResult(False, f'"{target_venv.prefix}" does not exist')
# Modifications to any of the following files mean the virtualenv should be
# rebuilt:
# * The `virtualenv` package
# * Any of our requirements manifest files
virtualenv_package = os.path.join(
topsrcdir,
"third_party",
"python",
"virtualenv",
"virtualenv",
"version.py",
)
deps = [virtualenv_package] + requirements.requirements_paths
metadata_mtime = os.path.getmtime(
os.path.join(target_venv.prefix, METADATA_FILENAME)
)
for dep_file in deps:
if os.path.getmtime(dep_file) > metadata_mtime:
return SiteUpToDateResult(
False, f'"{dep_file}" has changed since the virtualenv was created'
)
try:
existing_metadata = MozSiteMetadata.from_path(target_venv.prefix)
except MozSiteMetadataOutOfDateError as e:
# The metadata is missing required fields, so must be out-of-date.
return SiteUpToDateResult(False, str(e))
if existing_metadata != expected_metadata:
# The metadata doesn't exist or some fields have different values.
return SiteUpToDateResult(
False,
f"The existing metadata on-disk ({vars(existing_metadata)}) does not match "
f"the expected metadata ({vars(expected_metadata)}",
)
platlib_site_packages_dir = target_venv.resolve_sysconfig_packages_path("platlib")
pthfile_path = os.path.join(platlib_site_packages_dir, PTH_FILENAME)
try:
with open(pthfile_path) as file:
current_pthfile_contents = file.read().strip()
except FileNotFoundError:
return SiteUpToDateResult(False, f'No pthfile found at "{pthfile_path}"')
expected_pthfile_contents = "\n".join(expected_pthfile_lines)
if current_pthfile_contents != expected_pthfile_contents:
return SiteUpToDateResult(
False,
f'The pthfile at "{pthfile_path}" does not match the expected value.\n'
f"# --- on-disk pthfile: ---\n"
f"{current_pthfile_contents}\n"
f"# --- expected pthfile contents ---\n"
f"{expected_pthfile_contents}\n"
f"# ---",
)
return SiteUpToDateResult(True)
def activate_virtualenv(virtualenv: PythonVirtualenv):
os.environ["PATH"] = os.pathsep.join(
[virtualenv.bin_path] + os.environ.get("PATH", "").split(os.pathsep)
)
os.environ["VIRTUAL_ENV"] = virtualenv.prefix
for path in virtualenv.site_packages_dirs():
site.addsitedir(os.path.realpath(path))
sys.prefix = virtualenv.prefix
def _mach_virtualenv_root(checkout_scoped_state_dir):
workspace = os.environ.get("WORKSPACE")
if os.environ.get("MOZ_AUTOMATION") and workspace:
# In CI, put Mach virtualenv in the $WORKSPACE dir, which should be cleaned
# between jobs.
return os.path.join(workspace, "mach_virtualenv")
return os.path.join(checkout_scoped_state_dir, "_virtualenvs", "mach")