Expose GSSAPI Service name configuration of Kafka Scaler

[ArunYogesh]

The current GSSAPI configuration for Kafka scaler has a hard coded service name. The service name can be different in some Kafka configurations, hence exposing it to be configurable.

Checklist

• Changelog has been updated and is aligned with our changelog requirements
• Commits are signed with Developer Certificate of Origin (DCO - learn more)

Fixes #5474

[JorTurFer]

Thanks for the contribution!
We need to parse the value from triggerMetadata because currently serviceName is always "" . A unit test to cover this would be nice too.
Last but not least, we have to open another PR to docs repo adding the info: https://github.com/kedacore/keda-docs/blob/main/content/docs/2.14/scalers/apache-kafka.md

[ArunYogesh]

Thank you for the hint, I have now updated the code to read from the base configuration. I believe it should be part of the auth params and not trigger Metadata, since it is a Kerberos configuration? Please correct me if my understanding is incorrect. As per your request, I have raised a separate pull request for the documentation .

[JorTurFer]

Could you solve DCO check please?

[JorTurFer]

/run-e2e kafka
Update: You can check the progress here

[ArunYogesh]

Could you solve DCO check please?

Sorry, Done.

[JorTurFer]

/run-e2e kafka
Update: You can check the progress here

[JorTurFer]

@dttung2905 @zroubalik , WDYT?

[dttung2905]

Hi @ArunYogesh , thanks for the PR. Overall I think its a good change. I have a few nits:

• Could you help to make changes to https://github.com/kedacore/keda/blob/main/pkg/scalers/apache_kafka_scaler.go too ? We currently support 2 kafka version (kafka_scaler using sarama library and apache_kafka_scaler using kafka-go)
• Could you help to add some tests for it too, probably in this ?

  keda/pkg/scalers/kafka_scaler_test.go

  Line 331 in cdbcb9f

  func getBrokerTestBase(t *testing.T, meta kafkaMetadata, testData parseKafkaMetadataTestData, err error) {

  . Please help to make similar changes to apache_kafka_scaler too
• We also need to update the doc for it as well.

[JorTurFer]

I guess that we can continue with the current implementation without adding the support to the experimental, as after the last community call we plan to deprecate and remove the experimental one. WDYT @zroubalik @tomkerkhove @dttung2905 ?

For me, once the tests' requirement is done we can merge this if you agree

[JorTurFer]

LGTM!

[JorTurFer]

/run-e2e kafka
Update: You can check the progress here

[JorTurFer]

Thanks for the contribution!

[hayscoder]

Thank you all!