feat: Add poll instrumentation for kafka-python.

Signed-off-by: Paulo Vital <paulo.vital@ibm.com>

Author: pvital

src/instana/instrumentation/kafka/kafka_python.py

@@ -85,6 +85,45 @@ def trace_kafka_consume(
             else:
                 return res
 
+    @wrapt.patch_function_wrapper("kafka", "KafkaConsumer.poll")
+    def trace_kafka_poll(
+        wrapped: Callable[..., "kafka.KafkaConsumer.poll"],
+        instance: "kafka.KafkaConsumer",
+        args: Tuple[int, str, Tuple[Any, ...]],
+        kwargs: Dict[str, Any],
+    ) -> Dict[str, Any]:
+        if tracing_is_off():
+            return wrapped(*args, **kwargs)
+
+        tracer, parent_span, _ = get_tracer_tuple()
+
+        # The KafkaConsumer.consume() from the kafka-python-ng call the
+        # KafkaConsumer.poll() internally, so we do not consider it here.
+        if parent_span and parent_span.name == "kafka-consumer":
+            return wrapped(*args, **kwargs)
+
+        parent_context = (
+            parent_span.get_span_context()
+            if parent_span
+            else tracer.extract(
+                Format.KAFKA_HEADERS, {}, disable_w3c_trace_context=True
+            )
+        )
+
+        with tracer.start_as_current_span(
+            "kafka-consumer", span_context=parent_context, kind=SpanKind.CONSUMER
+        ) as span:
+            topic = list(instance.subscription())[0]
+            span.set_attribute("kafka.service", topic)
+            span.set_attribute("kafka.access", "poll")
+
+            try:
+                res = wrapped(*args, **kwargs)
+            except Exception as exc:
+                span.record_exception(exc)
+            else:
+                return res
+
     logger.debug("Instrumenting Kafka (kafka-python)")
 except ImportError:
     pass

tests/clients/kafka/test_kafka_python.py

@@ -81,8 +81,6 @@ def test_trace_kafka_python_send(self) -> None:
         assert kafka_span.data["kafka"]["access"] == "send"
 
     def test_trace_kafka_python_consume(self) -> None:
-        agent.options.allow_exit_as_root = False
-
         # Produce some events
         self.producer.send(testenv["kafka_topic"], b"raw_bytes1")
         self.producer.send(testenv["kafka_topic"], b"raw_bytes2")
@@ -125,9 +123,48 @@ def test_trace_kafka_python_consume(self) -> None:
         assert kafka_span.data["kafka"]["service"] == testenv["kafka_topic"]
         assert kafka_span.data["kafka"]["access"] == "consume"
 
-    def test_trace_kafka_python_error(self) -> None:
-        agent.options.allow_exit_as_root = False
+    def test_trace_kafka_python_poll(self) -> None:
+        # Produce some events
+        self.producer.send(testenv["kafka_topic"], b"raw_bytes1")
+        self.producer.send(testenv["kafka_topic"], b"raw_bytes2")
+        self.producer.flush()
+
+        # Consume the events
+        consumer = KafkaConsumer(
+            testenv["kafka_topic"],
+            bootstrap_servers=testenv["kafka_bootstrap_servers"],
+            auto_offset_reset="earliest",  # consume earliest available messages
+            enable_auto_commit=False,  # do not auto-commit offsets
+            consumer_timeout_ms=1000,
+        )
+
+        with tracer.start_as_current_span("test"):
+            msg = consumer.poll()  # noqa: F841
+
+        consumer.close()
 
+        spans = self.recorder.queued_spans()
+        assert len(spans) == 2
+
+        kafka_span = spans[0]
+        test_span = spans[1]
+
+        # Same traceId
+        assert test_span.t == kafka_span.t
+
+        # Parent relationships
+        assert kafka_span.p == test_span.s
+
+        # Error logging
+        assert not test_span.ec
+        assert not kafka_span.ec
+
+        assert kafka_span.n == "kafka"
+        assert kafka_span.k == SpanKind.SERVER
+        assert kafka_span.data["kafka"]["service"] == testenv["kafka_topic"]
+        assert kafka_span.data["kafka"]["access"] == "poll"
+
+    def test_trace_kafka_python_error(self) -> None:
         # Consume the events
         consumer = KafkaConsumer(
             "inexistent_kafka_topic",