Allow make_filtering_bound_logger to receive a str for level

fixes #665

CHANGELOG.md

@@ -38,6 +38,8 @@ You can find our backwards-compatibility policy [here](https://github.com/hynek/
 - `structlog.stdlib.recreate_defaults()` now also adds `structlog.stdlib.PositionalArgumentsFormatter`.
   In default native mode, this is done by the loggers at the edge.
 
+- `structlog.make_filtering_bound_logger()` now also accepts a string for *min_level*.
+
 
 ## Fixed
 

src/structlog/_native.py

@@ -22,6 +22,7 @@
     ERROR,
     INFO,
     LEVEL_TO_NAME,
+    NAME_TO_LEVEL,
     NOTSET,
     WARNING,
 )
@@ -70,7 +71,9 @@ async def aexception(
     return runner
 
 
-def make_filtering_bound_logger(min_level: int) -> type[FilteringBoundLogger]:
+def make_filtering_bound_logger(
+    min_level: int | str,
+) -> type[FilteringBoundLogger]:
     """
     Create a new `FilteringBoundLogger` that only logs *min_level* or higher.
 
@@ -103,12 +106,19 @@ def make_filtering_bound_logger(min_level: int) -> type[FilteringBoundLogger]:
             <https://docs.python.org/3/library/logging.html#levels>`_ for
             possible values.
 
+            If you pass a string, it must be one of: ``critical``, ``error``,
+            ``warning``, ``info``, ``debug``, ``notset`` (upper/lower case
+            doesn't matter).
+
     .. versionadded:: 20.2.0
     .. versionchanged:: 21.1.0 The returned loggers are now pickleable.
     .. versionadded:: 20.1.0 The ``log()`` method.
     .. versionadded:: 22.2.0
        Async variants ``alog()``, ``adebug()``, ``ainfo()``, and so forth.
+    .. versionchanged:: 25.1.0 *min_level* can now be a string.
     """
+    if isinstance(min_level, str):
+        min_level = NAME_TO_LEVEL[min_level.lower()]
 
     return LEVEL_TO_FILTERING_LOGGER[min_level]
 

tests/test_log_levels.py

@@ -10,6 +10,7 @@
 
 from structlog import make_filtering_bound_logger
 from structlog._log_levels import LEVEL_TO_NAME
+from structlog._native import _nop
 from structlog.contextvars import (
     bind_contextvars,
     clear_contextvars,
@@ -314,3 +315,12 @@ def test_log_percent(self, bl, cl):
         bl.info("hey %! %%!")
 
         assert [("info", (), {"event": "hey %! %%!"})] == cl.calls
+
+    def test_log_level_str(self):
+        """
+        *min_level* can be a string and the case doesn't matter.
+        """
+        bl = make_filtering_bound_logger("wArNiNg")
+
+        assert bl.warning is not _nop
+        assert bl.info is _nop