fix: improve confluent kafka's global variable access

src/instana/instrumentation/kafka/confluent_kafka_python.py

@@ -17,8 +17,12 @@
     from instana.span.span import InstanaSpan
     from instana.util.traceutils import get_tracer_tuple
 
-    consumer_token = None
-    consumer_span = contextvars.ContextVar("confluent_kafka_consumer_span")
+    consumer_token = contextvars.ContextVar(
+        "confluent_kafka_consumer_token", default=None
+    )
+    consumer_span = contextvars.ContextVar(
+        "confluent_kafka_consumer_span", default=None
+    )
 
     # As confluent_kafka is a wrapper around the C-developed librdkafka
     # (provided automatically via binary wheels), we have to create new classes
@@ -178,24 +182,23 @@ def create_span(
             )  # pragma: no cover
 
     def save_consumer_span_into_context(span: "InstanaSpan") -> None:
-        global consumer_token
         ctx = trace.set_span_in_context(span)
-        consumer_token = context.attach(ctx)
+        token = context.attach(ctx)
+        consumer_token.set(token)
         consumer_span.set(span)
 
     def close_consumer_span(span: "InstanaSpan") -> None:
-        global consumer_token
         if span.is_recording():
             span.end()
             consumer_span.set(None)
-        if consumer_token is not None:
-            context.detach(consumer_token)
-            consumer_token = None
+        token = consumer_token.get(None)
+        if token is not None:
+            context.detach(token)
+            consumer_token.set(None)
 
     def clear_context() -> None:
-        global consumer_token
         context.attach(trace.set_span_in_context(None))
-        consumer_token = None
+        consumer_token.set(None)
         consumer_span.set(None)
 
     def trace_kafka_consume(
@@ -253,6 +256,10 @@ def trace_kafka_poll(
             res = wrapped(*args, **kwargs)
             if res:
                 create_span("poll", res.topic(), res.headers())
+            else:
+                span = consumer_span.get(None)
+                if span is not None:
+                    close_consumer_span(span)
             return res
         except Exception as exc:
             exception = exc

tests/clients/kafka/test_confluent_kafka.py

@@ -709,19 +709,19 @@ def test_save_consumer_span_into_context(self, span: "InstanaSpan") -> None:
         """Test save_consumer_span_into_context function."""
         # Verify initial state
         assert consumer_span.get(None) is None
-        assert confluent_kafka_python.consumer_token is None
+        assert confluent_kafka_python.consumer_token.get(None) is None
 
         # Save span into context
         save_consumer_span_into_context(span)
 
         # Verify token is stored
-        assert confluent_kafka_python.consumer_token is not None
+        assert confluent_kafka_python.consumer_token.get(None) is not None
 
     def test_close_consumer_span_recording_span(self, span: "InstanaSpan") -> None:
         """Test close_consumer_span with a recording span."""
         # Save span into context first
         save_consumer_span_into_context(span)
-        assert confluent_kafka_python.consumer_token is not None
+        assert confluent_kafka_python.consumer_token.get(None) is not None
 
         # Verify span is recording
         assert span.is_recording()
@@ -732,7 +732,7 @@ def test_close_consumer_span_recording_span(self, span: "InstanaSpan") -> None:
         # Verify span was ended and context cleared
         assert not span.is_recording()
         assert consumer_span.get(None) is None
-        assert confluent_kafka_python.consumer_token is None
+        assert confluent_kafka_python.consumer_token.get(None) is None
 
     def test_clear_context(self, span: "InstanaSpan") -> None:
         """Test clear_context function."""
@@ -741,14 +741,14 @@ def test_clear_context(self, span: "InstanaSpan") -> None:
 
         # Verify context has data
         assert consumer_span.get(None) == span
-        assert confluent_kafka_python.consumer_token is not None
+        assert confluent_kafka_python.consumer_token.get(None) is not None
 
         # Clear context
         clear_context()
 
         # Verify all context is cleared
         assert consumer_span.get(None) is None
-        assert confluent_kafka_python.consumer_token is None
+        assert confluent_kafka_python.consumer_token.get(None) is None
 
     def test_trace_kafka_close_exception_handling(self, span: "InstanaSpan") -> None:
         """Test trace_kafka_close handles exceptions and still cleans up spans."""
@@ -757,7 +757,7 @@ def test_trace_kafka_close_exception_handling(self, span: "InstanaSpan") -> None
 
         # Verify span is in context
         assert consumer_span.get(None) == span
-        assert confluent_kafka_python.consumer_token is not None
+        assert confluent_kafka_python.consumer_token.get(None) is not None
 
         # Mock a wrapped function that raises an exception
         mock_wrapped = Mock(side_effect=Exception("Close operation failed"))
@@ -772,7 +772,7 @@ def test_trace_kafka_close_exception_handling(self, span: "InstanaSpan") -> None
 
         # Verify that despite the exception, the span was cleaned up
         assert consumer_span.get(None) is None
-        assert confluent_kafka_python.consumer_token is None
+        assert confluent_kafka_python.consumer_token.get(None) is None
 
         # Verify span was ended
         assert not span.is_recording()