add possibility to instrument mutiple engines

Author: hemma

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

@@ -73,9 +73,6 @@ class SQLAlchemyInstrumentor(BaseInstrumentor):
     See `BaseInstrumentor`
     """
 
-    def __new__(cls, *args, **kwargs):
-        return object.__new__(cls, *args, **kwargs)
-
     def instrumentation_dependencies(self) -> Collection[str]:
         return _instruments
 
@@ -86,6 +83,7 @@ def _instrument(self, **kwargs):
         Args:
             **kwargs: Optional arguments
                 ``engine``: a SQLAlchemy engine instance
+                ``engines``: a list of SQLAlchemy engine instances
                 ``tracer_provider``: a TracerProvider, defaults to global
 
         Returns:
@@ -111,6 +109,12 @@ def _instrument(self, **kwargs):
                 kwargs.get("engine"),
                 kwargs.get("enable_commenter", False),
             )
+        if kwargs.get("engines") is not None and isinstance(kwargs.get("engines"), list):
+            return [EngineTracer(
+                _get_tracer(tracer_provider),
+                engine,
+                kwargs.get("enable_commenter", False),) for engine in kwargs.get("engines")]
+
         return None
 
     def _uninstrument(self, **kwargs):

instrumentation/opentelemetry-instrumentation-sqlalchemy/tests/test_sqlalchemy.py

@@ -55,16 +55,12 @@ def test_instrument_two_engines(self):
         engine_2 = create_engine("sqlite:///:memory:")
 
         SQLAlchemyInstrumentor().instrument(
-            engine=engine_1,
+            engines=[engine_1, engine_2],
             tracer_provider=self.tracer_provider,
         )
+
         cnx_1 = engine_1.connect()
         cnx_1.execute("SELECT	1 + 1;").fetchall()
-
-        SQLAlchemyInstrumentor().instrument(
-            engine=engine_2,
-            tracer_provider=self.tracer_provider,
-        )
         cnx_2 = engine_2.connect()
         cnx_2.execute("SELECT	1 + 1;").fetchall()