fix #4278: proxy all methods in ProxiedProducer/Consumer

Remove Producer/Consumer inheritance from
ProxiedProducer and ProxiedConsumer. Add
__getattr__ to delegate undefined methods
to the wrapped client, fixing segfaults on
calls like list_topics() or assignment().

Add regression tests to verify delegation
of undefined methods on both proxy classes.

Author: JMGalvao

CHANGELOG.md

@@ -18,6 +18,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- `opentelemetry-instrumentation-confluent-kafka`: Fix `ProxiedProducer` and `ProxiedConsumer` not delegating methods to the underlying producer/consumer instances
+  ([#4278](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4278))
 - Fix intermittent `Core Contrib Test` CI failures caused by GitHub git CDN SHA propagation lag by installing core packages from the already-checked-out local copy instead of a second git clone
   ([#4305](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4305))
 

instrumentation/opentelemetry-instrumentation-confluent-kafka/src/opentelemetry/instrumentation/confluent_kafka/__init__.py

@@ -151,7 +151,7 @@ def close(self):  # pylint: disable=useless-super-delegation
         return super().close()
 
 
-class ProxiedProducer(Producer):
+class ProxiedProducer:
     def __init__(self, producer: Producer, tracer: Tracer):
         self._producer = producer
         self._tracer = tracer
@@ -177,8 +177,11 @@ def produce(self, topic, value=None, *args, **kwargs):  # pylint: disable=keywor
     def original_producer(self):
         return self._producer
 
+    def __getattr__(self, name):
+        return getattr(self._producer, name)
 
-class ProxiedConsumer(Consumer):
+
+class ProxiedConsumer:
     def __init__(self, consumer: Consumer, tracer: Tracer):
         self._consumer = consumer
         self._tracer = tracer
@@ -224,6 +227,9 @@ def subscribe(self, topics, on_assign=lambda *args: None, *args, **kwargs):  # p
     def original_consumer(self):
         return self._consumer
 
+    def __getattr__(self, name):
+        return getattr(self._consumer, name)
+
 
 class ConfluentKafkaInstrumentor(BaseInstrumentor):
     """An instrumentor for confluent kafka module

instrumentation/opentelemetry-instrumentation-confluent-kafka/tests/test_instrumentation.py

@@ -373,3 +373,45 @@ def test_producer_flush(self) -> None:
         span_list = self.memory_exporter.get_finished_spans()
         self._assert_span_count(span_list, 1)
         self._assert_topic(span_list[0], "topic-1")
+
+    def test_proxied_producer_delegates_undefined_methods(
+        self,
+    ) -> None:
+        """Regression test for #4278: methods not defined on
+        ProxiedProducer must delegate to the underlying
+        producer instead of hitting an uninitialized handle."""
+        instrumentation = ConfluentKafkaInstrumentor()
+        message_queue = []
+
+        producer = MockedProducer(
+            message_queue,
+            {
+                "bootstrap.servers": "localhost:29092",
+            },
+        )
+
+        proxied = instrumentation.instrument_producer(producer)
+        self.assertEqual(proxied.list_topics(), "producer_topics")
+
+    def test_proxied_consumer_delegates_undefined_methods(
+        self,
+    ) -> None:
+        """Regression test for #4278: methods not defined on
+        ProxiedConsumer must delegate to the underlying
+        consumer instead of hitting an uninitialized handle."""
+        instrumentation = ConfluentKafkaInstrumentor()
+
+        consumer = MockConsumer(
+            [],
+            {
+                "bootstrap.servers": "localhost:29092",
+                "group.id": "mygroup",
+                "auto.offset.reset": "earliest",
+            },
+        )
+
+        proxied = instrumentation.instrument_consumer(consumer)
+        self.assertEqual(
+            proxied.list_topics(), "consumer_topics"
+        )
+        self.assertEqual(proxied.assignment(), [])

instrumentation/opentelemetry-instrumentation-confluent-kafka/tests/utils.py

@@ -18,6 +18,12 @@ def poll(self, timeout=None):
             return self._queue.pop(0)
         return None
 
+    def list_topics(self, topic=None, timeout=-1):
+        return "consumer_topics"
+
+    def assignment(self):
+        return []
+
 
 class MockedMessage:
     def __init__(
@@ -77,3 +83,6 @@ def poll(self, *args, **kwargs):
 
     def flush(self, *args, **kwargs):
         return len(self._queue)
+
+    def list_topics(self, topic=None, timeout=-1):
+        return "producer_topics"