fix(confluent-kafka): populate bootstrap.servers span attributes

KafkaPropertiesExtractor.extract_bootstrap_servers was defined but
never called, so confluent-kafka spans were missing messaging.url,
server.address, and server.port even though the extraction helper
existed for it.

- Capture the config dict in AutoInstrumentedProducer/Consumer and
  surface it on the Proxied{Producer,Consumer} wrappers.
- extract_bootstrap_servers now accepts both the "bootstrap.servers"
  dotted key (confluent-kafka standard) and "bootstrap_servers", and
  safely handles list-valued configs and instances without a config
  attribute.
- wrap_produce / wrap_poll / wrap_consume pull the config and pass
  it through _enrich_span, which sets messaging.url, server.address,
  and server.port (parsing host:port from the first broker).

Closes #4104

Signed-off-by: alliasgher <alliasgher123@gmail.com>

Author: alliasgher

CHANGELOG.md

@@ -11,6 +11,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
+- `opentelemetry-instrumentation-confluent-kafka`: Populate `messaging.url`, `server.address` and `server.port` span attributes from the producer/consumer `bootstrap.servers` config; previously `KafkaPropertiesExtractor.extract_bootstrap_servers` was defined but never called
+  ([#4104](https://github.com/open-telemetry/opentelemetry-python-contrib/issues/4104))
+
 ### Breaking changes
 
 - Drop Python 3.9 support

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

@@ -127,7 +127,27 @@ def instrument_consumer(consumer: Consumer, tracer_provider=None)
 from .version import __version__
 
 
+def _capture_config(args, kwargs):
+    """Return the config dict that was passed to a Producer/Consumer
+    constructor, regardless of whether it was supplied positionally, as
+    ``conf=`` kwarg, or (for Consumer) expanded as **kwargs."""
+    if args and isinstance(args[0], dict):
+        return args[0]
+    conf = kwargs.get("conf")
+    if isinstance(conf, dict):
+        return conf
+    # confluent_kafka.Consumer also supports Consumer(**conf) — in that case
+    # the kwargs themselves are the config.
+    if kwargs:
+        return dict(kwargs)
+    return None
+
+
 class AutoInstrumentedProducer(Producer):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.config = _capture_config(args, kwargs)
+
     # This method is deliberately implemented in order to allow wrapt to wrap this function
     def produce(self, topic, value=None, *args, **kwargs):  # pylint: disable=keyword-arg-before-vararg,useless-super-delegation
         super().produce(topic, value, *args, **kwargs)
@@ -136,6 +156,7 @@ def produce(self, topic, value=None, *args, **kwargs):  # pylint: disable=keywor
 class AutoInstrumentedConsumer(Consumer):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
+        self.config = _capture_config(args, kwargs)
         self._current_consume_span = None
 
     # This method is deliberately implemented in order to allow wrapt to wrap this function
@@ -155,6 +176,10 @@ class ProxiedProducer(Producer):
     def __init__(self, producer: Producer, tracer: Tracer):
         self._producer = producer
         self._tracer = tracer
+        # Surface the wrapped producer's config (if any) so that
+        # KafkaPropertiesExtractor.extract_bootstrap_servers can read it
+        # through this proxy.
+        self.config = getattr(producer, "config", None)
 
     def flush(self, timeout=-1):
         return self._producer.flush(timeout)
@@ -184,6 +209,8 @@ def __init__(self, consumer: Consumer, tracer: Tracer):
         self._tracer = tracer
         self._current_consume_span = None
         self._current_context_token = None
+        # See ProxiedProducer.__init__ for rationale.
+        self.config = getattr(consumer, "config", None)
 
     def close(self, *args, **kwargs):
         return ConfluentKafkaInstrumentor.wrap_close(
@@ -367,10 +394,14 @@ def wrap_produce(func, instance, tracer, args, kwargs):
             topic = KafkaPropertiesExtractor.extract_produce_topic(
                 args, kwargs
             )
+            bootstrap_servers = (
+                KafkaPropertiesExtractor.extract_bootstrap_servers(instance)
+            )
             _enrich_span(
                 span,
                 topic,
                 operation=MessagingOperationTypeValues.RECEIVE,
+                bootstrap_servers=bootstrap_servers,
             )  # Replace
             propagate.inject(
                 headers,
@@ -385,6 +416,9 @@ def wrap_poll(func, instance, tracer, args, kwargs):
 
         record = func(*args, **kwargs)
         if record:
+            bootstrap_servers = (
+                KafkaPropertiesExtractor.extract_bootstrap_servers(instance)
+            )
             with tracer.start_as_current_span(
                 "recv", end_on_exit=True, kind=trace.SpanKind.CONSUMER
             ):
@@ -395,6 +429,7 @@ def wrap_poll(func, instance, tracer, args, kwargs):
                     record.partition(),
                     record.offset(),
                     operation=MessagingOperationTypeValues.PROCESS,
+                    bootstrap_servers=bootstrap_servers,
                 )
             instance._current_context_token = context.attach(
                 trace.set_span_in_context(instance._current_consume_span)
@@ -409,6 +444,9 @@ def wrap_consume(func, instance, tracer, args, kwargs):
 
         records = func(*args, **kwargs)
         if len(records) > 0:
+            bootstrap_servers = (
+                KafkaPropertiesExtractor.extract_bootstrap_servers(instance)
+            )
             with tracer.start_as_current_span(
                 "recv", end_on_exit=True, kind=trace.SpanKind.CONSUMER
             ):
@@ -417,6 +455,7 @@ def wrap_consume(func, instance, tracer, args, kwargs):
                     instance._current_consume_span,
                     records[0].topic(),
                     operation=MessagingOperationTypeValues.PROCESS,
+                    bootstrap_servers=bootstrap_servers,
                 )
             instance._current_context_token = context.attach(
                 trace.set_span_in_context(instance._current_consume_span)

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

@@ -9,6 +9,10 @@
     MESSAGING_SYSTEM,
     MessagingOperationTypeValues,
 )
+from opentelemetry.semconv.attributes.server_attributes import (
+    SERVER_ADDRESS,
+    SERVER_PORT,
+)
 from opentelemetry.semconv.trace import (
     MessagingDestinationKindValues,
     SpanAttributes,
@@ -21,7 +25,17 @@
 class KafkaPropertiesExtractor:
     @staticmethod
     def extract_bootstrap_servers(instance):
-        return instance.config.get("bootstrap_servers")
+        config = getattr(instance, "config", None)
+        if not isinstance(config, dict):
+            return None
+        # confluent-kafka uses the dotted key "bootstrap.servers"; also accept
+        # the python-style "bootstrap_servers" for robustness.
+        servers = config.get("bootstrap.servers") or config.get(
+            "bootstrap_servers"
+        )
+        if isinstance(servers, (list, tuple)):
+            servers = ",".join(str(s) for s in servers)
+        return servers
 
     @staticmethod
     def _extract_argument(key, position, default_value, args, kwargs):
@@ -115,12 +129,37 @@ def _get_links_from_records(records):
     return links
 
 
+def _set_bootstrap_servers_attributes(span, bootstrap_servers):
+    """Populate messaging.url, server.address, server.port from a
+    bootstrap.servers string (e.g. ``host1:9092,host2:9092``)."""
+    if not bootstrap_servers:
+        return
+
+    span.set_attribute(SpanAttributes.MESSAGING_URL, bootstrap_servers)
+
+    first_broker = bootstrap_servers.split(",")[0].strip()
+    if not first_broker:
+        return
+
+    if ":" in first_broker:
+        host, _, port = first_broker.rpartition(":")
+        span.set_attribute(SERVER_ADDRESS, host)
+        try:
+            span.set_attribute(SERVER_PORT, int(port))
+        except ValueError:
+            # Port wasn't numeric; skip rather than emit a bad attribute.
+            _LOG.debug("non-numeric port in bootstrap.servers: %r", port)
+    else:
+        span.set_attribute(SERVER_ADDRESS, first_broker)
+
+
 def _enrich_span(
     span,
     topic,
     partition: Optional[int] = None,
     offset: Optional[int] = None,
     operation: Optional[MessagingOperationTypeValues] = None,
+    bootstrap_servers: Optional[str] = None,
 ):
     if not span.is_recording():
         return
@@ -141,6 +180,8 @@ def _enrich_span(
     else:
         span.set_attribute(SpanAttributes.MESSAGING_TEMP_DESTINATION, True)
 
+    _set_bootstrap_servers_attributes(span, bootstrap_servers)
+
     # https://stackoverflow.com/questions/65935155/identify-and-find-specific-message-in-kafka-topic
     # A message within Kafka is uniquely defined by its topic name, topic partition and offset.
     if partition is not None and offset is not None and topic:

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

@@ -30,6 +30,10 @@
     MESSAGING_OPERATION,
     MESSAGING_SYSTEM,
 )
+from opentelemetry.semconv.attributes.server_attributes import (
+    SERVER_ADDRESS,
+    SERVER_PORT,
+)
 from opentelemetry.semconv.trace import (
     MessagingDestinationKindValues,
     SpanAttributes,
@@ -447,3 +451,53 @@ 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_producer_sets_bootstrap_servers_attributes(self) -> None:
+        instrumentation = ConfluentKafkaInstrumentor()
+        producer = MockedProducer(
+            [],
+            {
+                "bootstrap.servers": "broker-a:9092,broker-b:9093",
+            },
+        )
+
+        producer = instrumentation.instrument_producer(producer)
+        producer.produce(topic="topic-1", key="k", value="v")
+
+        span = self.memory_exporter.get_finished_spans()[0]
+        self.assertEqual(
+            span.attributes[SpanAttributes.MESSAGING_URL],
+            "broker-a:9092,broker-b:9093",
+        )
+        self.assertEqual(span.attributes[SERVER_ADDRESS], "broker-a")
+        self.assertEqual(span.attributes[SERVER_PORT], 9092)
+
+    def test_consumer_sets_bootstrap_servers_attributes(self) -> None:
+        instrumentation = ConfluentKafkaInstrumentor()
+        consumer = MockConsumer(
+            [MockedMessage("topic-1", 0, 0, [])],
+            {
+                "bootstrap.servers": "broker-1:9092",
+                "group.id": "g",
+                "auto.offset.reset": "earliest",
+            },
+        )
+
+        self.memory_exporter.clear()
+        consumer = instrumentation.instrument_consumer(consumer)
+        consumer.poll()
+        # Second (empty) poll ends the in-flight `<topic> process` span so it
+        # shows up in the exporter.
+        consumer.poll()
+
+        process_span = next(
+            s
+            for s in self.memory_exporter.get_finished_spans()
+            if s.name == "topic-1 process"
+        )
+        self.assertEqual(
+            process_span.attributes[SpanAttributes.MESSAGING_URL],
+            "broker-1:9092",
+        )
+        self.assertEqual(process_span.attributes[SERVER_ADDRESS], "broker-1")
+        self.assertEqual(process_span.attributes[SERVER_PORT], 9092)

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

@@ -6,6 +6,7 @@
 class MockConsumer(Consumer):
     def __init__(self, queue, config):
         self._queue = queue
+        self.config = config
         super().__init__(config)
 
     def consume(self, num_messages=1, *args, **kwargs):  # pylint: disable=keyword-arg-before-vararg
@@ -58,6 +59,7 @@ def value(self):
 class MockedProducer(Producer):
     def __init__(self, queue, config):
         self._queue = queue
+        self.config = config
         super().__init__(config)
 
     def produce(self, *args, **kwargs):  # pylint: disable=keyword-arg-before-vararg