support topic as kwarg

Author: nozik

Diff for: CHANGELOG.md

@@ -22,6 +22,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#903](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/903))
 - `opentelemetry-instrumentation-falcon` Safer patching mechanism
   ([#895](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/895))
+- `opentelemetry-instrumentation-kafka-python` Fix topic extraction
+  ([#949](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/949))
 
 ## [1.9.1-0.28b1](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.9.1-0.28b1) - 2022-01-29
 

Diff for: instrumentation/opentelemetry-instrumentation-kafka-python/src/opentelemetry/instrumentation/kafka/utils.py

@@ -25,11 +25,11 @@ def _extract_argument(key, position, default_value, args, kwargs):
         return kwargs.get(key, default_value)
 
     @staticmethod
-    def extract_send_topic(args):
+    def extract_send_topic(args, kwargs):
         """extract topic from `send` method arguments in KafkaProducer class"""
-        if len(args) > 0:
-            return args[0]
-        return "unknown"
+        return KafkaPropertiesExtractor._extract_argument(
+            "topic", 0, "unknown", args, kwargs
+        )
 
     @staticmethod
     def extract_send_value(args, kwargs):
@@ -56,7 +56,7 @@ def extract_send_headers(args, kwargs):
     def extract_send_partition(instance, args, kwargs):
         """extract partition `send` method arguments, using the `_partition` method in KafkaProducer class"""
         try:
-            topic = KafkaPropertiesExtractor.extract_send_topic(args)
+            topic = KafkaPropertiesExtractor.extract_send_topic(args, kwargs)
             key = KafkaPropertiesExtractor.extract_send_key(args, kwargs)
             value = KafkaPropertiesExtractor.extract_send_value(args, kwargs)
             partition = KafkaPropertiesExtractor._extract_argument(
@@ -145,7 +145,7 @@ def _traced_send(func, instance, args, kwargs):
             headers = []
             kwargs["headers"] = headers
 
-        topic = KafkaPropertiesExtractor.extract_send_topic(args)
+        topic = KafkaPropertiesExtractor.extract_send_topic(args, kwargs)
         bootstrap_servers = KafkaPropertiesExtractor.extract_bootstrap_servers(
             instance
         )

Diff for: instrumentation/opentelemetry-instrumentation-kafka-python/tests/test_utils.py

@@ -19,6 +19,14 @@ def setUp(self) -> None:
         self.headers = []
         self.kwargs = {"partition": 0, "headers": self.headers}
 
+    def test_wrap_send_with_topic_as_arg(self):
+        self.wrap_send_helper(self.args, self.kwargs)
+
+    def test_wrap_send_with_topic_as_kwarg(self):
+        kwargs = self.kwargs.copy()
+        kwargs['topic'] = self.topic_name
+        self.wrap_send_helper([], kwargs)
+
     @mock.patch(
         "opentelemetry.instrumentation.kafka.utils.KafkaPropertiesExtractor.extract_bootstrap_servers"
     )
@@ -28,8 +36,10 @@ def setUp(self) -> None:
     @mock.patch("opentelemetry.instrumentation.kafka.utils._enrich_span")
     @mock.patch("opentelemetry.trace.set_span_in_context")
     @mock.patch("opentelemetry.propagate.inject")
-    def test_wrap_send(
+    def wrap_send_helper(
         self,
+        send_args: [str],
+        send_kwargs: dict,
         inject: mock.MagicMock,
         set_span_in_context: mock.MagicMock,
         enrich_span: mock.MagicMock,
@@ -44,12 +54,12 @@ def test_wrap_send(
 
         wrapped_send = _wrap_send(tracer, produce_hook)
         retval = wrapped_send(
-            original_send_callback, kafka_producer, self.args, self.kwargs
+            original_send_callback, kafka_producer, send_args, send_kwargs
         )
 
         extract_bootstrap_servers.assert_called_once_with(kafka_producer)
         extract_send_partition.assert_called_once_with(
-            kafka_producer, self.args, self.kwargs
+            kafka_producer, send_args, send_kwargs
         )
         tracer.start_as_current_span.assert_called_once_with(
             expected_span_name, kind=SpanKind.PRODUCER
@@ -69,10 +79,10 @@ def test_wrap_send(
             self.headers, context=context, setter=_kafka_setter
         )
 
-        produce_hook.assert_called_once_with(span, self.args, self.kwargs)
+        produce_hook.assert_called_once_with(span, send_args, send_kwargs)
 
         original_send_callback.assert_called_once_with(
-            *self.args, **self.kwargs
+            *send_args, **send_kwargs
         )
         self.assertEqual(retval, original_send_callback.return_value)