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# Copyright: (c) 2021, Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
from __future__ import annotations
import os
import pathlib
import subprocess
import sys
import typing as t
from ansible.module_utils.common.text.converters import to_bytes
from ansible.module_utils._internal._ansiballz import _respawn
_ANSIBLE_PARENT_PATH = pathlib.Path(__file__).parents[3]
def has_respawned():
return hasattr(sys.modules['__main__'], '_respawned')
def respawn_module(interpreter_path) -> t.NoReturn:
"""
Respawn the currently-running Ansible Python module under the specified Python interpreter.
Ansible modules that require libraries that are typically available only under well-known interpreters
(eg, ``apt``, ``dnf``) can use bespoke logic to determine the libraries they need are not
available, then call `respawn_module` to re-execute the current module under a different interpreter
and exit the current process when the new subprocess has completed. The respawned process inherits only
stdout/stderr from the current process.
Only a single respawn is allowed. ``respawn_module`` will fail on nested respawns. Modules are encouraged
to call `has_respawned()` to defensively guide behavior before calling ``respawn_module``, and to ensure
that the target interpreter exists, as ``respawn_module`` will not fail gracefully.
:arg interpreter_path: path to a Python interpreter to respawn the current module
"""
if has_respawned():
raise Exception('module has already been respawned')
# FUTURE: we need a safe way to log that a respawn has occurred for forensic/debug purposes
payload = _respawn.create_payload()
stdin_read, stdin_write = os.pipe()
os.write(stdin_write, to_bytes(payload))
os.close(stdin_write)
rc = subprocess.call([interpreter_path, '--'], stdin=stdin_read)
sys.exit(rc) # pylint: disable=ansible-bad-function
def probe_interpreters_for_module(interpreter_paths, module_name):
"""
Probes a supplied list of Python interpreters, returning the first one capable of
importing the named module. This is useful when attempting to locate a "system
Python" where OS-packaged utility modules are located.
:arg interpreter_paths: iterable of paths to Python interpreters. The paths will be probed
in order, and the first path that exists and can successfully import the named module will
be returned (or ``None`` if probing fails for all supplied paths).
:arg module_name: fully-qualified Python module name to probe for (for example, ``selinux``)
"""
PYTHONPATH = os.getenv('PYTHONPATH', '')
env = os.environ.copy()
env.update({
'PYTHONPATH': f'{_ANSIBLE_PARENT_PATH}:{PYTHONPATH}'.rstrip(': ')
})
for interpreter_path in interpreter_paths:
if not os.path.exists(interpreter_path):
continue
try:
rc = subprocess.call(
[
interpreter_path,
'-c',
f'import {module_name}, ansible.module_utils.basic',
],
env=env,
)
if rc == 0:
return interpreter_path
except Exception:
continue
return None
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