Add additional_ignores to StackInfoRenderer

Fixes #396

CHANGELOG.rst

@@ -39,6 +39,8 @@ Changes:
 - Overloaded the ``bind``, ``unbind``, ``try_unbind`` and ``new`` methods in the ``FilteringBoundLogger`` `Protocol <https://docs.python.org/3/library/typing.html#typing.Protocol>`_.
   This makes it easier to use objects of type ``FilteringBoundLogger`` in a typed context.
   `#392 <https://github.com/hynek/structlog/pull/392>`_
+- ``structlog.processors.StackInfoRenderer`` now has an *additional_ignores* parameter that allows you to filter out your own logging layer.
+  `#396 <https://github.com/hynek/structlog/issues/396>`_
 
 
 ----

src/structlog/processors.py

@@ -526,20 +526,32 @@ class StackInfoRenderer:
     Add stack information with key ``stack`` if ``stack_info`` is `True`.
 
     Useful when you want to attach a stack dump to a log entry without
-    involving an exception.
+    involving an exception and works analogously to the *stack_info* argument
+    of the Python standard library logging.
 
-    It works analogously to the *stack_info* argument of the Python 3 standard
-    library logging.
+    :param additional_ignores: By default, stack frames coming from
+        ``structlog`` are ignored. With this argument you can add additional
+        names that are ignored, before the stack starts being rendered. They
+        are matched using ``startswith()``, so they don't have to match
+        exactly. The names are used to find the first relevant name, therefore
+        once a frame is found that doesn't start with ``structlog`` or one of
+        *additional_ignores*, **no filtering** is applied to subsequent frames.
 
     .. versionadded:: 0.4.0
+    .. versionadded:: 22.1.0  *additional_ignores*
     """
 
+    __slots__ = ["_additional_ignores"]
+
+    def __init__(self, additional_ignores: Optional[List[str]] = None) -> None:
+        self._additional_ignores = additional_ignores
+
     def __call__(
         self, logger: WrappedLogger, name: str, event_dict: EventDict
     ) -> EventDict:
         if event_dict.pop("stack_info", None):
             event_dict["stack"] = _format_stack(
-                _find_first_app_frame_and_name()[0]
+                _find_first_app_frame_and_name(self._additional_ignores)[0]
             )
 
         return event_dict

tests/test_generic.py

@@ -51,12 +51,10 @@ def test_proxies_anything(self):
         assert "log", "foo" == b.log("foo")
         assert "gol", "bar" == b.gol("bar")
 
-    @pytest.mark.parametrize("proto", range(pickle.HIGHEST_PROTOCOL + 1))
+    @pytest.mark.parametrize("proto", range(3, pickle.HIGHEST_PROTOCOL + 1))
     def test_pickle(self, proto):
         """
         Can be pickled and unpickled.
-
-        Works only on Python 3: TypeError: can't pickle instancemethod objects
         """
         b = BoundLogger(
             ReturnLogger(),

tests/test_processors.py

@@ -708,6 +708,18 @@ def test_renders_correct_stack(self, sir):
 
         assert 'ed = sir(None, None, {"stack_info": True})' in ed["stack"]
 
+    def test_additional_ignores(self):
+        """
+        Filtering of names works.
+        """
+        sir = StackInfoRenderer(["tests.additional_frame"])
+
+        ed = additional_frame(
+            functools.partial(sir, None, None, {"stack_info": True})
+        )
+
+        assert "additional_frame.py" not in ed["stack"]
+
 
 class TestFigureOutExcInfo:
     @pytest.mark.parametrize("true_value", [True, 1, 1.1])