Add utilities to get info from Python environments

Most of these functions were added to Spyder first but we need to have
them here now.

spyder_kernels/utils/pythonenv.py

@@ -0,0 +1,75 @@
+# -*- coding: utf-8 -*-
+# -----------------------------------------------------------------------------
+# Copyright (c) 2009- Spyder Kernels Contributors
+#
+# Licensed under the terms of the MIT License
+# (see spyder_kernels/__init__.py for details)
+# -----------------------------------------------------------------------------
+
+"""Utilities to get information about Python environments."""
+
+# Standard library imports
+import os
+from pathlib import Path
+
+
+def add_quotes(path):
+    """Return quotes if needed for spaces on path."""
+    quotes = '"' if ' ' in path and '"' not in path else ''
+    return '{quotes}{path}{quotes}'.format(quotes=quotes, path=path)
+
+
+def get_conda_env_path(pyexec, quote=False):
+    """
+    Return the full path to the conda environment from a given python
+    executable.
+
+    If `quote` is True, then quotes are added if spaces are found in the path.
+    """
+    pyexec = pyexec.replace('\\', '/')
+    if os.name == 'nt':
+        conda_env = os.path.dirname(pyexec)
+    else:
+        conda_env = os.path.dirname(os.path.dirname(pyexec))
+
+    if quote:
+        conda_env = add_quotes(conda_env)
+
+    return conda_env
+
+
+def is_conda_env(prefix=None, pyexec=None):
+    """Check if prefix or python executable are in a conda environment."""
+    if pyexec is not None:
+        pyexec = pyexec.replace('\\', '/')
+
+    if (prefix is None and pyexec is None) or (prefix and pyexec):
+        raise ValueError('Only `prefix` or `pyexec` should be provided!')
+
+    if pyexec and prefix is None:
+        prefix = get_conda_env_path(pyexec).replace('\\', '/')
+
+    return os.path.exists(os.path.join(prefix, 'conda-meta'))
+
+
+def is_pyenv_env(pyexec):
+    """Check if a python executable is a Pyenv environment."""
+    path = Path(pyexec)
+    return "pyenv" in path.parts[:-1]
+
+
+def get_env_dir(interpreter, only_dir=False):
+    """Get the environment directory from the interpreter executable."""
+    path = Path(interpreter)
+
+    if os.name == 'nt':
+        # This is enough for Conda and Pyenv envs
+        env_dir = path.parent
+
+        # This is necessary for envs created with `python -m venv`
+        if env_dir.parts[-1].lower() == "scripts":
+            env_dir = path.parents[1]
+    else:
+        env_dir = path.parents[1]
+
+    return env_dir.parts[-1] if only_dir else str(env_dir)

spyder_kernels/utils/tests/test_pythonenv.py

@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+# -----------------------------------------------------------------------------
+# Copyright (c) 2009- Spyder Kernels Contributors
+#
+# Licensed under the terms of the MIT License
+# (see spyder_kernels/__init__.py for details)
+# -----------------------------------------------------------------------------
+
+"""
+Tests for utilities in the pythonenv module
+"""
+
+# Standard library imports
+import os
+
+# Third-party imports
+import pytest
+
+# Local imports
+from spyder_kernels.utils.pythonenv import (
+    add_quotes,
+    get_conda_env_path,
+    get_env_dir,
+)
+
+
+if os.name == 'nt':
+    TEST_PYEXEC = 'c:/miniconda/envs/foobar/python.exe'
+else:
+    TEST_PYEXEC = '/miniconda/envs/foobar/bin/python'
+
+
+def test_add_quotes():
+    output = add_quotes('/some path/with spaces')
+    assert output == '"/some path/with spaces"'
+
+    output = add_quotes('/some-path/with-no-spaces')
+    assert output == '/some-path/with-no-spaces'
+
+
+def test_get_conda_env_path():
+    output = get_conda_env_path(TEST_PYEXEC)
+    if os.name == 'nt':
+        assert output == 'c:/miniconda/envs/foobar'
+    else:
+        assert output == '/miniconda/envs/foobar'
+
+
+def test_get_env_dir():
+    output_dir = get_env_dir(TEST_PYEXEC, only_dir=False)
+    if os.name == "nt":
+        assert output_dir == 'c:\\miniconda\\envs\\foobar'
+    else:
+        assert output_dir == '/miniconda/envs/foobar'
+
+    output = get_env_dir(TEST_PYEXEC, only_dir=True)
+    assert output == "foobar"
+
+    if os.name == "nt":
+        venv_pyexec = 'C:\\Miniconda3\\envs\\foobar\\Scripts\\python.exe'
+        output = get_env_dir(venv_pyexec, only_dir=True)
+        assert output == "foobar"
+
+
+if __name__ == "__main__":
+    pytest.main()