feat(misc): primitive parsing from environment variables

autotest/test_misc.py

@@ -14,6 +14,9 @@
     get_packages,
     has_package,
     has_pkg,
+    parse_bool,
+    parse_float,
+    parse_int,
     set_dir,
     set_env,
     timed,
@@ -280,3 +283,59 @@ def sleep1dec():
     cap = capfd.readouterr()
     print(cap.out)
     assert re.match(r"sleep1dec took \d+\.\d+ ms", cap.out)
+
+
+def test_parse_bool_default():
+    assert parse_bool("TEST_VALUE", default=True)
+
+
+def test_parse_int_default():
+    assert parse_int("TEST_VALUE", default=2) == 2
+
+
+def test_parse_float_default():
+    assert parse_float("TEST_VALUE", default=1.1) == 1.1
+
+
+@pytest.mark.parametrize(
+    "value, expected",
+    [
+        ("true", True),
+        ("True", True),
+        ("TRUE", True),
+        ("false", False),
+        ("False", False),
+        ("FALSE", False),
+        ("", None),
+        ("garbage", None),
+        (1, None),
+        (1.0, None),
+    ],
+)
+def test_parse_bool(value, expected):
+    with set_env(TEST_VALUE=str(value)):
+        assert parse_bool("TEST_VALUE") == expected
+
+
+@pytest.mark.parametrize(
+    "value, expected",
+    [("1", 1), ("1.", 1), ("1.0", 1), ("1.9", 1), ("", None), ("true", None)],
+)
+def test_parse_int(value, expected):
+    with set_env(TEST_VALUE=str(value)):
+        assert parse_int("TEST_VALUE") == expected
+
+
+@pytest.mark.parametrize(
+    "value, expected",
+    [
+        ("1", 1.0),
+        ("", None),
+        ("1.", 1.0),
+        ("1.0", 1.0),
+        ("1.11", 1.11),
+    ],
+)
+def test_parse_float(value, expected):
+    with set_env(TEST_VALUE=str(value)):
+        assert parse_float("TEST_VALUE") == expected

modflow_devtools/misc.py

@@ -2,6 +2,7 @@
 import socket
 import sys
 import traceback
+from ast import literal_eval
 from contextlib import contextmanager
 from functools import wraps
 from importlib import metadata
@@ -31,39 +32,6 @@ def set_dir(path: PathLike):
         print(f"Returned to previous directory: {origin}")
 
 
-@contextmanager
-def set_env(*remove, **update):
-    """
-    Temporarily updates the ``os.environ`` dictionary in-place.
-
-    Referenced from https://stackoverflow.com/a/34333710/6514033.
-
-    The ``os.environ`` dictionary is updated in-place so that the modification
-    is sure to work in all situations.
-
-    :param remove: Environment variables to remove.
-    :param update: Dictionary of environment variables and values to add/update.
-    """
-    env = environ
-    update = update or {}
-    remove = remove or []
-
-    # List of environment variables being updated or removed.
-    stomped = (set(update.keys()) | set(remove)) & set(env.keys())
-    # Environment variables and values to restore on exit.
-    update_after = {k: env[k] for k in stomped}
-    # Environment variables and values to remove on exit.
-    remove_after = frozenset(k for k in update if k not in env)
-
-    try:
-        env.update(update)
-        [env.pop(k, None) for k in remove]
-        yield
-    finally:
-        env.update(update_after)
-        [env.pop(k) for k in remove_after]
-
-
 class add_sys_path:
     """
     Context manager to add temporarily to the system path.
@@ -486,3 +454,72 @@ def call():
         return res
 
     return _timed
+
+
+def parse_bool(name: str, default: Optional[bool] = None) -> Optional[bool]:
+    """Try to parse a boolean from the environment variable with the given name,
+    return None or an optional default value if it doesn't exist or parsing fails."""
+    try:
+        v = literal_eval(environ.get(name).lower().title())
+    except:
+        return default
+    if isinstance(v, bool):
+        return v
+    return None
+
+
+def parse_int(name: str, default: Optional[int] = None) -> Optional[int]:
+    """Try to parse an integer from the environment variable with the given name,
+    return None or an optional default value if it doesn't exist or parsing fails."""
+    try:
+        v = literal_eval(environ.get(name))
+    except:
+        return default
+    if isinstance(v, (int, float)):
+        return int(v)
+    return None
+
+
+def parse_float(name: str, default: Optional[float] = None) -> Optional[float]:
+    """Try to parse a float from the environment variable with the given name,
+    return None or an optional default value if it doesn't exist or parsing fails."""
+    try:
+        v = literal_eval(environ.get(name))
+    except:
+        return default
+    if isinstance(v, (int, float)):
+        return float(v)
+    return None
+
+
+@contextmanager
+def set_env(*remove, **update):
+    """
+    Temporarily updates the ``os.environ`` dictionary in-place.
+
+    Referenced from https://stackoverflow.com/a/34333710/6514033.
+
+    The ``os.environ`` dictionary is updated in-place so that the modification
+    is sure to work in all situations.
+
+    :param remove: Environment variables to remove.
+    :param update: Dictionary of environment variables and values to add/update.
+    """
+    env = environ
+    update = update or {}
+    remove = remove or []
+
+    # List of environment variables being updated or removed.
+    stomped = (set(update.keys()) | set(remove)) & set(env.keys())
+    # Environment variables and values to restore on exit.
+    update_after = {k: env[k] for k in stomped}
+    # Environment variables and values to remove on exit.
+    remove_after = frozenset(k for k in update if k not in env)
+
+    try:
+        env.update(update)
+        [env.pop(k, None) for k in remove]
+        yield
+    finally:
+        env.update(update_after)
+        [env.pop(k) for k in remove_after]