[core] improving Pin and configuration implementation

Author: Emanuele Palazzetti

ddtrace/pin.py

@@ -119,7 +119,7 @@ def onto(self, obj, send=True):
             pin_name = _DD_PIN_PROXY_NAME if isinstance(obj, wrapt.ObjectProxy) else _DD_PIN_NAME
 
             # set the target reference; any get_from, clones and retarget the new PIN
-            self._target = obj
+            self._target = id(obj)
             return setattr(obj, pin_name, self)
         except AttributeError:
             log.debug("can't pin onto object. skipping", exc_info=True)
@@ -130,6 +130,12 @@ def clone(self, service=None, app=None, app_type=None, tags=None, tracer=None):
         if not tags and self.tags:
             tags = self.tags.copy()
 
+        # we use a copy instead of a deepcopy because we expect configurations
+        # to have only a root level dictionary without nested objects. Using
+        # deepcopy introduces a big overhead:
+        #
+        # copy: 0.00654911994934082
+        # deepcopy: 0.2787208557128906
         config = self._config.copy()
 
         return Pin(

ddtrace/settings.py

@@ -1,5 +1,12 @@
+import logging
+
 from copy import deepcopy
 
+from .pin import Pin
+
+
+log = logging.getLogger(__name__)
+
 
 class ConfigException(Exception):
     """Configuration exception when an integration that is not available
@@ -34,6 +41,7 @@ def get_from(self, obj):
         """
         pin = Pin.get_from(obj)
         if pin is None:
+            log.debug('No configuration found for %s', obj)
             return {}
 
         return pin._config