[ConfluentKafkaInstrumentor] Not all methods are supported by returned proxy objects

[zilinjak]

Describe your environment

• Python: 3.9.25
• OS: macOS Darwin 25.3.0 (also reproducible on Linux)
• confluent-kafka: 2.6.1
• opentelemetry-instrumentation-confluent-kafka: 0.60b1
• opentelemetry-api: 1.29.0
• opentelemetry-sdk: 1.29.0

What happened?

Calling list_topics() or assignment() on a ProxiedProducer or ProxiedConsumer returned by ConfluentKafkaInstrumentor().instrument_producer() / instrument_consumer() causes a segmentation fault or error RuntimeError: Consumer closed.

Reproducer:

from confluent_kafka import Producer
from opentelemetry.instrumentation.confluent_kafka import ConfluentKafkaInstrumentor

# Create and instrument producer
p = Producer({'bootstrap.servers': 'localhost:9092'})
p_instrumented = ConfluentKafkaInstrumentor().instrument_producer(p)

# This causes a segfault
topics = p_instrumented.list_topics(timeout=5)

Note:
There may be more methods missing in the proxy object. And I propose that the Proxy class should proxy all method calls on the actual confluent Kafka client when not defined in the proxy class.

Steps to Reproduce

Start kafka using docker and run following code:

from confluent_kafka import Producer
from opentelemetry.instrumentation.confluent_kafka import ConfluentKafkaInstrumentor

# Create and instrument producer
p = Producer({'bootstrap.servers': 'localhost:9092'})
p_instrumented = ConfluentKafkaInstrumentor().instrument_producer(p)

# This causes a segfault
topics = p_instrumented.list_topics(timeout=5)

Expected Result

The app does not crash.

Actual Result

segmentation fault or error RuntimeError: Consumer closed when calling list_topics()

Additional context

No response

Would you like to implement a fix?

None

Tip

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[xrmx]

And I propose that the Proxy class should proxy all method calls on the actual confluent Kafka client when not defined in the proxy class.

I think this is what the code is doing right now since the Proxy classes are inheriting the Producer and Consumer classes. If there's any issue I think it is in the methods we are overriding.

I think is kinda a duplicate of #4270, in the sense that fixing that may fix this one too.

[JMGalvao]

Hi! I was able to successfully reproduce the bug described in this issue on my local environment using the steps provided. When calling list_topics() on the instrumented producer returned by ConfluentKafkaInstrumentor().instrument_producer(), the process crashes with a segmentation fault (exit code 139), which matches the behavior reported here.

I’m interested in working on fixing this issue!
Would it be possible for me to be assigned to this issue?

Thank you!