diff --git a/doc/users/next_whats_new/loggers.rst b/doc/users/next_whats_new/loggers.rst
new file mode 100644
index 000000000000..0c64998c6e3d
--- /dev/null
+++ b/doc/users/next_whats_new/loggers.rst
@@ -0,0 +1,10 @@
+``set_loglevel`` can opt-out of manipulating logging handlers
+-------------------------------------------------------------
+
+It is now possible to configure the logging level of the Matplotilb standard
+library logger without also implicitly installing a handler via both
+`matplotlib.set_loglevel` and `matplotlib.pyplot.set_loglevel` ::
+
+ mpl.set_loglevel('debug', ensure_handler=False)
+ # or
+ plt.set_loglevel('debug', ensure_handler=False)
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 50033b212a93..3b4f9aa76876 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -230,27 +230,43 @@ def _ensure_handler():
return handler
-def set_loglevel(level):
+def set_loglevel(level, *, ensure_handler=True):
"""
- Set Matplotlib's root logger and root logger handler level, creating
- the handler if it does not exist yet.
+ Configure Matplotlib's logging levels.
+
+ Matplotlib uses the standard library `logging` framework under the root
+ logger 'matplotlib'. This is a helper function to:
+
+ - set Matplotlib's root logger level
+ - optionally set the root logger handler's level, creating the handler
+ if it does not exist yet
Typically, one should call ``set_loglevel("info")`` or
``set_loglevel("debug")`` to get additional debugging information.
+ Users or applications that are installing their own logging handlers
+ may want to directly manipulate ``logging.getLogger('matplotlib')`` rather
+ than use this function.
+
Parameters
----------
level : {"notset", "debug", "info", "warning", "error", "critical"}
The log level of the handler.
+ ensure_handler : bool
+ If True will ensure that there is a `logging.StreamHandler` added to
+ the matplotlib root logger and that its level matches the logger level.
+
Notes
-----
The first time this function is called, an additional handler is attached
to Matplotlib's root handler; this handler is reused every time and this
function simply manipulates the logger and handler's level.
+
"""
_log.setLevel(level.upper())
- _ensure_handler().setLevel(level.upper())
+ if ensure_handler:
+ _ensure_handler().setLevel(level.upper())
def _logged_cached(fmt, func=None):
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