def setup_python()

in configure.py [0:0]
51 lines of code
11 McCabe index (conditional complexity)

def setup_python(environ_cp):
  """Setup python related env variables."""
  # Get PYTHON_BIN_PATH, default is the current running python.
  default_python_bin_path = sys.executable
  ask_python_bin_path = (
      'Please specify the location of python. [Enter to use the default: {}]: '
  ).format(default_python_bin_path)
  while True:
    python_bin_path = get_from_env_or_user_or_default(
        environ_cp,
        'PYTHON_BIN_PATH',
        ask_python_bin_path,
        default_python_bin_path,
    )
    # Check if the path is valid
    if os.path.isfile(python_bin_path) and os.access(python_bin_path, os.X_OK):
      break
    elif not os.path.exists(python_bin_path):
      print('Invalid python path: {} cannot be found.'.format(python_bin_path))
    else:
      print(
          '{} is not executable.  Is it the python binary?'.format(
              python_bin_path
          )
      )
    environ_cp['PYTHON_BIN_PATH'] = ''

  # Get PYTHON_LIB_PATH
  python_lib_path = environ_cp.get('PYTHON_LIB_PATH')
  if not python_lib_path:
    python_lib_paths = get_python_path(environ_cp, python_bin_path)
    if environ_cp.get('USE_DEFAULT_PYTHON_LIB_PATH') == '1':
      python_lib_path = python_lib_paths[0]
    else:
      print(
          'Found possible Python library paths:\n  %s'
          % '\n  '.join(python_lib_paths)
      )
      default_python_lib_path = python_lib_paths[0]
      python_lib_path = get_input(
          'Please input the desired Python library path to use.  '
          'Enter to use the default: [{}]\n'.format(python_lib_paths[0])
      )
      if not python_lib_path:
        python_lib_path = default_python_lib_path
    environ_cp['PYTHON_LIB_PATH'] = python_lib_path

  # Set-up env variables used by python_configure.bzl
  write_action_env('PYTHON_BIN_PATH', python_bin_path)
  write_action_env('PYTHON_LIB_PATH', python_lib_path)
  write_to_bazelrc('build --python_path="{}"'.format(python_bin_path))
  environ_cp['PYTHON_BIN_PATH'] = python_bin_path

  # If choosen python_lib_path is from a path specified in the PYTHONPATH
  # variable, need to tell bazel to include PYTHONPATH
  if environ_cp.get('PYTHONPATH'):
    python_paths = environ_cp.get('PYTHONPATH').split(':')
    if python_lib_path in python_paths:
      write_action_env('PYTHONPATH', environ_cp.get('PYTHONPATH'))

  # Write tools/python_bin_path.sh
  with open(_PYTHON_BIN_PATH, 'a') as f:
    f.write('export PYTHON_BIN_PATH="{}"'.format(python_bin_path))