Issue with Topic Creation Using ReplicaAssignments in xk6-kafka

[vereshchagin-d]

Hi!

Environment:

• Kafka 3.7.0 running in Kubernetes
• Docker image: mostafamoradian/xk6-kafka:0.28.0

Description:
I'm encountering an issue when trying to create a topic with replicaAssignments. Below is the code snippet used:

connection.createTopic({
  topic: "my-topic", 
  numPartitions: -1, // Also tried declaring only `topic` and `replicaAssignments`
  replicationFactor: -1, //
  replicaAssignments: [{partition: 0, replicas: [0,1,2]}]
});

The error message I receive is:

time="2024-11-22T11:23:47Z" level=error msg="Failed to create topic., OriginalError: [42] Invalid Request: this most likely occurs because of a request being malformed by the client library or the message was sent to an incompatible broker, se the broker logs for more details" error="Failed to create topic., OriginalError: [42] Invalid Request: this most likely occurs because of a request being malformed by the client library or the message was sent to an incompatible broker, se the broker logs for more details"

Observations:
Upon checking the code, I noticed that in this section of the source code, default values for NumPartitions and ReplicationFactor are set to 1 if they are <= 0.

        if topicConfig.NumPartitions <= 0 {
		topicConfig.NumPartitions = 1
	}

	if topicConfig.ReplicationFactor <= 0 {
		topicConfig.ReplicationFactor = 1
	}

This behavior seems incorrect when using replicaAssignments since NumPartitions and ReplicationFactor should be inferred from the replicaAssignments field according to the Kafka protocol.

References:

• Kafka Go tests: Example test with replicaAssignments
• Kafka protocol documentation: Topic creation protocol

Suggested Fix:
The library should allow NumPartitions and ReplicationFactor to remain unset or explicitly -1 when replicaAssignments is provided. This would align the behavior with Kafka’s protocol and similar libraries.

[vereshchagin-d]

Hi @mostafa,

Thank you for your work on the xk6-kafka project—it’s been incredibly useful for our Kafka-related testing needs.

I’ve encountered an issue when trying to create a topic with replicaAssignments and have provided a detailed report [above/in this issue]. It seems like the library sets default values for NumPartitions and ReplicationFactor even when replicaAssignments is provided, which contradicts Kafka’s protocol.

Would you be able to take a look when you have time? I’ve included links to relevant Kafka documentation and test cases from kafka-go library to help clarify the context.

Let me know if there’s any additional information I can provide or steps I can take to assist. Thanks again for maintaining this project!

Best regards,
Dmitriy

[mostafa]

Hey @vereshchagin-d,

Looks like a bug. Would you please create a PR to fix this?

[vereshchagin-d]

Hey @mostafa,

I'm currently swamped with work and won't be able to address this issue in the next few weeks. I'll circle back to it as soon as I have some bandwidth.

Thanks for understanding!