cliutil: Add is_main_script function.

conservancy_beancount/cliutil.py

@@ -18,6 +18,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>."""
 
 import argparse
 import enum
+import inspect
 import logging
 import operator
 import os
@@ -133,6 +134,11 @@ def add_version_argument(parser: argparse.ArgumentParser) -> argparse.Action:
         help="Show program version and license information",
     )
 
+def is_main_script() -> bool:
+    """Return true if the caller is the "main" program."""
+    stack = inspect.stack(context=False)
+    return len(stack) <= 3 and stack[-1].function.startswith('<')
+
 def setup_logger(logger: Union[str, logging.Logger]='',
                  loglevel: int=logging.INFO,
                  stream: TextIO=sys.stderr,

tests/test_cliutil.py

@@ -91,6 +91,9 @@ def test_excepthook_traceback(caplog):
     assert caplog.records
     assert caplog.records[-1].message == ''.join(traceback.format_exception(*args))
 
+def test_is_main_script():
+    assert not cliutil.is_main_script()
+
 @pytest.mark.parametrize('arg,expected', [
     ('debug', logging.DEBUG),
     ('info', logging.INFO),