# coding: utf-8
import errno
import glob
import os
import re
from subprocess import STDOUT, CalledProcessError, check_output
from typing import Dict
# Used both for config and some state like available_versions cache
# mainly because it's easier to put it in cagefs as a single dir
# We have symlink to that dir in /etc
# for ease of use the selector config and avoiding problem with cagefs
CONFIG_DIR = "/usr/share/l.v.e-manager/cl.python"
ALT_NAMES = "alt-python"
# It's also used to construct base_dir:
ALT_PYTHON_PREFIX = "/opt/alt/python"
class PythonError(Exception):
"""Top level error class for admin's part of Python selector"""
pass
class PythonConfigError(PythonError):
"""Generic error class for PythonConfig"""
pass
def create_config_dirs():
try:
os.makedirs(CONFIG_DIR)
except OSError as e:
if e.errno != errno.EEXIST: # ignore only "File exists" error
raise
def is_major_version(ver):
"""Return True if specified MAJOR version is valid for processing"""
if not isinstance(ver, str):
return False
if not re.match(r"^\d+\.\d+$", ver):
return False
return True
def scan_python_versions() -> Dict[str, Dict[str, str]]:
"""
Search CloudLinux Python interpreters and return information about them.
Returns:
Dictionary mapping major Python versions (e.g., "2.7", "3.9") to
dictionaries containing the full version and root path.
"""
result = {}
for alt_python_folder in glob.glob(f"{ALT_PYTHON_PREFIX}*"):
# Extract the folder name without path (e.g., "python27")
folder_name = os.path.basename(alt_python_folder)
# Extract version digits from folder name
version_digits = "".join(filter(str.isdigit, folder_name))
# Skip paths without at least 2 digits in the version - for them the version can't be determined
# Primary example is alt-python-internal, see CLOS-3346
if len(version_digits) < 2:
continue
# Format version as major.minor (e.g., "2.7" from "27")
major_minor_version = f"{version_digits[0]}.{version_digits[1:]}"
# Construct path to Python binary using os.path.join for cross-platform compatibility
python_bin = os.path.join(alt_python_folder, "bin", f"python{major_minor_version}")
if not os.path.isfile(python_bin):
continue
try:
# Get full Python version string
full_version_output = check_output([python_bin, "-V"], text=True, stderr=STDOUT)
# Extract version number from output like "Python 3.9.10"
parts = full_version_output.strip().split()
if len(parts) >= 2:
full_ver = parts[1]
result[major_minor_version] = {
"full_version": full_ver,
"root_path": alt_python_folder,
}
except CalledProcessError:
# Skip this interpreter if there's an error running it
continue
return result
__all__ = (
"CONFIG_DIR",
"ALT_NAMES",
"ALT_PYTHON_PREFIX",
"PythonError",
"PythonConfigError",
"create_config_dirs",
"is_major_version",
"scan_python_versions",
)
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