Fix psycopg2 instrument_connection

Author: tammy-baylis-swi

instrumentation/opentelemetry-instrumentation-psycopg2/src/opentelemetry/instrumentation/psycopg2/__init__.py

@@ -106,18 +106,19 @@
 from typing import Collection
 
 import psycopg2
+import wrapt
 from psycopg2.extensions import (
     cursor as pg_cursor,  # pylint: disable=no-name-in-module
 )
 from psycopg2.sql import Composed  # pylint: disable=no-name-in-module
 
+from opentelemetry import trace as trace_api
 from opentelemetry.instrumentation import dbapi
 from opentelemetry.instrumentation.instrumentor import BaseInstrumentor
 from opentelemetry.instrumentation.psycopg2.package import _instruments
 from opentelemetry.instrumentation.psycopg2.version import __version__
 
 _logger = logging.getLogger(__name__)
-_OTEL_CURSOR_FACTORY_KEY = "_otel_orig_cursor_factory"
 
 
 class Psycopg2Instrumentor(BaseInstrumentor):
@@ -130,6 +131,8 @@ class Psycopg2Instrumentor(BaseInstrumentor):
 
     _DATABASE_SYSTEM = "postgresql"
 
+    _otel_cursor_factory = None
+
     def instrumentation_dependencies(self) -> Collection[str]:
         return _instruments
 
@@ -158,32 +161,40 @@ def _uninstrument(self, **kwargs):
         dbapi.unwrap_connect(psycopg2, "connect")
 
     # TODO(owais): check if core dbapi can do this for all dbapi implementations e.g, pymysql and mysql
-    @staticmethod
-    def instrument_connection(connection, tracer_provider=None):
-        if not hasattr(connection, "_is_instrumented_by_opentelemetry"):
-            connection._is_instrumented_by_opentelemetry = False
-
-        if not connection._is_instrumented_by_opentelemetry:
-            setattr(
-                connection, _OTEL_CURSOR_FACTORY_KEY, connection.cursor_factory
-            )
-            connection.cursor_factory = _new_cursor_factory(
-                tracer_provider=tracer_provider
-            )
-            connection._is_instrumented_by_opentelemetry = True
-        else:
+    def instrument_connection(
+        self,
+        connection,
+        tracer_provider: typing.Optional[trace_api.TracerProvider] = None,
+        enable_commenter: bool = False,
+        commenter_options: dict = None,
+    ):
+        if isinstance(connection, wrapt.ObjectProxy):
+            # The connection is already instrumented from wrapt.wrap_function_wrapper
+            # of the psycopg2 module's `connect` method by DB-API `wrap_connect`,
+            # so the Psycopg2Instrumentor is marked as instrumenting.
             _logger.warning(
                 "Attempting to instrument Psycopg connection while already instrumented"
             )
+            self._is_instrumented_by_opentelemetry = True
+            return connection
+
+        # Save cursor_factory at instrumentor level because
+        # psycopg2 connection type does not allow arbitrary attrs
+        self._otel_cursor_factory = connection.cursor_factory
+        connection.cursor_factory = _new_cursor_factory(
+            base_factory=connection.cursor_factory,
+            tracer_provider=tracer_provider,
+            enable_commenter=enable_commenter,
+            commenter_options=commenter_options,
+        )
+        self._is_instrumented_by_opentelemetry = True
+
         return connection
 
     # TODO(owais): check if core dbapi can do this for all dbapi implementations e.g, pymysql and mysql
-    @staticmethod
-    def uninstrument_connection(connection):
-        connection.cursor_factory = getattr(
-            connection, _OTEL_CURSOR_FACTORY_KEY, None
-        )
-
+    def uninstrument_connection(self, connection):
+        self._is_instrumented_by_opentelemetry = False
+        connection.cursor_factory = self._otel_cursor_factory
         return connection
 
 
@@ -231,14 +242,23 @@ def get_statement(self, cursor, args):
         return statement
 
 
-def _new_cursor_factory(db_api=None, base_factory=None, tracer_provider=None):
+def _new_cursor_factory(
+    db_api: dbapi.DatabaseApiIntegration = None,
+    base_factory: pg_cursor = None,
+    tracer_provider: typing.Optional[trace_api.TracerProvider] = None,
+    enable_commenter: bool = False,
+    commenter_options: dict = None,
+):
     if not db_api:
         db_api = DatabaseApiIntegration(
             __name__,
             Psycopg2Instrumentor._DATABASE_SYSTEM,
             connection_attributes=Psycopg2Instrumentor._CONNECTION_ATTRIBUTES,
             version=__version__,
             tracer_provider=tracer_provider,
+            enable_commenter=enable_commenter,
+            commenter_options=commenter_options,
+            connect_module=psycopg2,
         )
 
     base_factory = base_factory or pg_cursor