Disable Logging panel when DEBUG is set to False to prevent memory leaks

debug_toolbar/panels/logging.py

@@ -6,6 +6,7 @@
     import threading
 except ImportError:
     threading = None
+from django.conf import settings
 from django.utils.translation import ungettext, ugettext_lazy as _
 from debug_toolbar.panels import Panel
 from debug_toolbar.utils import ThreadCollector
@@ -15,13 +16,33 @@
 
 class LogCollector(ThreadCollector):
 
+    def __init__(self):
+        ThreadCollector.__init__(self)
+        self.enabled = False
+
     def collect(self, item, thread=None):
         # Avoid logging SQL queries since they are already in the SQL panel
         # TODO: Make this check whether SQL panel is enabled
         if item.get('channel', '') == 'django.db.backends':
             return
         super(LogCollector, self).collect(item, thread)
 
+    def enable_logging(self):
+        """
+        Enable logging if it has not already been enabled and DEBUG is True.
+        """
+        if self.enabled:
+            return
+
+        # Check to make sure DEBUG is enabled to prevent silent memory leaks.
+        if settings.DEBUG:
+            # We don't use enable/disable_instrumentation because logging is global.
+            # We can't add thread-local logging handlers. Hopefully logging is cheap.
+            logging_handler = ThreadTrackingHandler(collector)
+            logging.root.setLevel(logging.NOTSET)
+            logging.root.addHandler(logging_handler)
+            self.enabled = True
+
 
 class ThreadTrackingHandler(logging.Handler):
     def __init__(self, collector):
@@ -45,13 +66,8 @@ def emit(self, record):
         self.collector.collect(record)
 
 
-# We don't use enable/disable_instrumentation because logging is global.
-# We can't add thread-local logging handlers. Hopefully logging is cheap.
-
 collector = LogCollector()
-logging_handler = ThreadTrackingHandler(collector)
-logging.root.setLevel(logging.NOTSET)
-logging.root.addHandler(logging_handler)
+collector.enable_logging()
 
 
 class LoggingPanel(Panel):

docs/changes.rst

@@ -11,6 +11,7 @@ New features
 
 * The SQL panel colors queries depending on the stack level.
 * The Profiler panel allows configuring the maximum depth.
+* The Logging panel will not attempt to collect data when DEBUG is False.
 
 Bugfixes
 ~~~~~~~~

tests/panels/test_logging.py

@@ -4,16 +4,21 @@
 
 from debug_toolbar.panels.logging import (
     collector, MESSAGE_IF_STRING_REPRESENTATION_INVALID)
+from django.test.utils import override_settings
 
 from ..base import BaseTestCase
 
 
+@override_settings(DEBUG=True)
 class LoggingPanelTestCase(BaseTestCase):
 
     def setUp(self):
         super(LoggingPanelTestCase, self).setUp()
         self.panel = self.toolbar.get_panel_by_id('LoggingPanel')
         self.logger = logging.getLogger(__name__)
+        # DEBUG may be set to False initially, preventing the default tracking
+        # from executing. Force an enable here to ensure that logging is activated.
+        collector.enable_logging()
         collector.clear_collection()
 
     def test_happy_case(self):