minor changes

Author: ohmayr

google/api_core/client_logging.py

@@ -37,16 +37,24 @@
 #         return json.dumps(log_obj)
 
 
-def setup_logging(log_level="CRITICAL", namespace="google"):
-    if not logging.getLogger().hasHandlers():
+def setup_logging(log_level, namespace="google"):
+    
+    # NOTE: A logger with namespace="google" is only configured if all of the below conditions hold true:
+    # - A root logger is not configured.
+    # - N/A: A logger with namespace="google" is not already configured (This statement is removed.)
+    # - GOOGLE_SDK_PYTHON_LOGGING_LEVEL is set.
+    if not logging.getLogger().hasHandlers() and log_level:
 
         # define a module for our repositories
         logger = logging.getLogger(namespace)
-        logger.setLevel(log_level)
+        try:
+            logger.setLevel(log_level)
+        except ValueError:
+            logger.setLevel("WARNING")
+            logger.warning(f"Configured log level `{log_level}` is incorrect. Defaulting to WARNING.")
 
         # Default settings
         console_handler = logging.StreamHandler()
-        console_handler.setLevel(log_level)
         formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
         console_handler.setFormatter(formatter)
         logger.addHandler(console_handler)