Make it possible to skip logging before the actual call

python/nav/util.py

@@ -535,3 +535,18 @@ def resource_bytes(package, filename):
     """
     ref = resource_files(package) / filename
     return ref.read_bytes()
+
+
+def check_log_level(logger, loglevel):
+    """
+    Check that the level of the logger is equal to or below loglevel
+
+    Use before possibly expensive logging operations, like calling logging in
+    a loop or building an expensive object that will be logged and thrown away.
+
+    Avoid this classic mistake:
+
+        logger.info("%s", expensive_function())
+    """
+    level = logger.getEffectiveLevel()
+    return level <= loglevel

python/nav/web/auth/remote_user.py

@@ -20,10 +20,13 @@
 from os.path import join
 import secrets
 
+from django.conf import settings
+
 from nav.auditlog.models import LogEntry
 from nav.config import NAVConfigParser
 from nav.models.profiles import Account
 from nav.web.auth.utils import set_account
+from nav.util import check_log_level
 
 
 __all__ = []
@@ -178,6 +181,10 @@ def get_username(request):
     if not request:
         return None
 
+    if settings.DEBUG or check_log_level(_logger, logging.DEBUG):
+        for metakey, value in request.META.items():
+            if metakey[0] == metakey[0].upper():
+                _logger.debug('%s: %s', metakey, value)
     workaround = 'none'
     try:
         workaround_config = _config.get('remote-user', 'workaround')

tests/unittests/util_test.py

@@ -0,0 +1,17 @@
+import logging
+
+import pytest
+
+from nav.util import check_log_level
+
+
+class TestCheckLogLevel:
+    def test_actual_loglevel_above_input_should_return_false(self, *_):
+        logger = logging.getLogger()
+        logger.setLevel(logging.INFO)
+        assert check_log_level(logger, logging.DEBUG) is False
+
+    def test_actual_loglevel_below_input_should_return_true(self, *_):
+        logger = logging.getLogger()
+        logger.setLevel(logging.INFO)
+        assert check_log_level(logger, logging.WARNING)