# A utility library for getting information about a Python executable.

#

# This may be used as a script.

__all__ = [

'get_python_id',

'get_python_info',

'inspect_python_install',

]

import hashlib

import json

import os

import subprocess

import sys

def get_python_id(python=sys.executable, *, prefix=None):

"""Return a unique (str) identifier for the given Python executable."""

if not python or isinstance(python, str):

info = get_python_info(python or sys.executable)

else:

info = python

python = info['executable']

data = [

# "executable" represents the install location

# (and build, to an extent).

info['executable'],

# sys.version encodes version, git info, build_date, and build_tool.

info['version_str'],

info['implementation_name'],

'.'.join(str(v) for v in info['implementation_version']),

str(info['api_version']),

info['magic_number'],

]

# XXX Add git info if a dev build.

h = hashlib.sha256()

for value in data:

h.update(value.encode('utf-8'))

# XXX Also include the sorted output of "python -m pip freeze"?

py_id = h.hexdigest()

# XXX Return the whole string?

py_id = py_id[:12]

if prefix:

if prefix is True:

major, minor = info['version_info'][:2]

py_id = f'{info["implementation_name"]}{major}.{minor}-{py_id}'

else:

py_id = prefix + py_id

return py_id

def get_python_info(python=sys.executable):

if not python or python == sys.executable:

return _get_raw_info()

try:

text = subprocess.check_output(

[python, __file__],

universal_newlines=True,

)

except subprocess.CalledProcessError:

raise Exception(f'could not get info for {python}')

return json.loads(text)

def inspect_python_install(python=sys.executable):

if isinstance(python, str):

info = get_python_info(python)

else:

info = python

return _inspect_python_install(**info)

#######################################

# internal implementation

try:

PLATLIBDIR = sys.platlibdir

except AttributeError:

PLATLIBDIR = 'lib'

STDLIB_DIR = os.path.dirname(os.__file__)

try:

from importlib.util import MAGIC_NUMBER

except ImportError:

import _imp

MAGIC_NUMBER = _imp.get_magic()

def _inspect_python_install(executable, prefix, base_prefix,

platlibdir, stdlib_dir,

version_info, platform, implementation_name,

**_ignored):

is_venv = prefix != base_prefix

if os.path.basename(stdlib_dir) == 'Lib':

base_executable = os.path.join(os.path.dirname(stdlib_dir), 'python')

if not os.path.exists(base_executable):

raise NotImplementedError(base_executable)

is_dev = True

else:

major, minor = version_info[:2]

python = f'python{major}.{minor}'

if is_venv:

if '.' in os.path.basename(executable):

ext = executable.rpartition('.')[2]

python_exe = f'{python}.{ext}'

else:

python_exe = python

expected = os.path.join(base_prefix, platlibdir, python)

if stdlib_dir == expected:

bindir = os.path.basename(os.path.dirname(executable))

base_executable = os.path.join(base_prefix, bindir, python_exe)

else:

# XXX This is good enough for now.

base_executable = executable

#raise NotImplementedError(stdlib_dir)

elif implementation_name == 'cpython':

if platform == 'win32':

expected = os.path.join(prefix, platlibdir)

else:

expected = os.path.join(prefix, platlibdir, python)

if stdlib_dir == expected:

base_executable = executable

else:

raise NotImplementedError(stdlib_dir)

else:

base_executable = executable

is_dev = False

return base_executable, is_dev, is_venv

def _get_raw_info():

return {

'executable': sys.executable,

'version_str': sys.version,

'version_info': tuple(sys.version_info),

'hexversion': sys.hexversion,

'api_version': sys.api_version,

'magic_number': MAGIC_NUMBER.hex(),

'implementation_name': sys.implementation.name.lower(),

'implementation_version': tuple(sys.implementation.version),

'platform': sys.platform,

'prefix': sys.prefix,

'exec_prefix': sys.exec_prefix,

'base_prefix': sys.base_prefix,

'base_exec_prefix': sys.base_exec_prefix,

'platlibdir': PLATLIBDIR,

'stdlib_dir': STDLIB_DIR,

# XXX Also include the build options (e.g. configure flags)?

}

#######################################

# use as a script

if __name__ == '__main__':

info = _get_raw_info()

json.dump(info, sys.stdout, indent=4)

print()