Only log DB queries when enabled

docs/deployment/@relengapi/config.rst

@@ -28,7 +28,9 @@ This is effective for development, but certainly not for production.
 The database for the relengapi core is named ``relengapi``.
 Other blueprints may require additional URIs.
 
-If you ever need to see what SQLAlchemy is doing with the connection pool, it is useful to enable the logging. To do that make sure you have the ``SQLALCHEMY_DB_LOG`` is flag to set to True.
+If you ever need to see what SQLAlchemy is doing with the connection pool, it is useful to enable verbose query logging.
+To do so, set ``SQLALCHEMY_DB_LOG = True``.
+Note that this output is *very* verbose and may severely impact site performance.
 
 .. _Deployment-Authentication:
 

relengapi/lib/db.py

@@ -21,9 +21,7 @@
 from sqlalchemy.pool import Pool
 
 
-# db logging
 logger = logging.getLogger(__name__)
-logging.basicConfig()
 
 
 class _QueryProperty(object):
@@ -84,9 +82,12 @@ def _get_db_config(self, dbname):
 
     @synchronized(threading.Lock())
     def engine(self, dbname):
-        # Get the log level for db logs
-        if self.app.config.get('SQLALCHEMY_DB_LOG'):
-            logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)
+        # Set the log level for db logs
+        sqla_logger = logging.getLogger('sqlalchemy.engine')
+        if self.app.config.get('SQLALCHEMY_DB_LOG', False):
+            sqla_logger.setLevel(logging.INFO)
+        else:
+            sqla_logger.setLevel(logging.WARNING)
 
         if dbname not in self._engines:
             uri = self._get_db_config(dbname)

settings_example.py

@@ -15,9 +15,8 @@
 # configuration is present, is to use '*.db' files in the directory containing
 # the RelengAPI source code.
 
-# set the flag True for logging SQLAlchemy engine activities
-# default it is set to True
-SQLALCHEMY_DB_LOG = True
+# set to True to log SQLAlchemy engine activities (very verbose!)
+# SQLALCHEMY_DB_LOG = False
 
 # ===== Authentication and Authorization =====