import os

import shutil

import subprocess

import functools

import typing as T

from pathlib import Path

Pathlike = T.Union[str, Path]

@functools.lru_cache()

def wsl_available() -> bool:

"""

heuristic to detect if Windows Subsystem for Linux is available.

Uses presence of /etc/os-release in the WSL image to say Linux is there.

This is a de facto file standard across Linux distros.

"""

has_wsl = False

if os.name == "nt" and shutil.which("wsl"):

has_wsl = wsl_file_exist("/etc/os-release")

return has_wsl

def wsl_file_exist(file: Pathlike) -> bool:

"""

path is specified as if in WSL

NOT //wsl$/Ubuntu/etc/os-release

but /etc/os-release

"""

if os.name != "nt":

return False

try:

return subprocess.run(["wsl", "test", "-f", str(file)], timeout=10).returncode == 0

except subprocess.TimeoutExpired:

return False