KafkaChannel doesn't respect the scope annotation when creating the topic

[aliok]

ORIGINAL ISSUE: knative/eventing-contrib#1189

Describe the bug
When eventing.knative.dev/scope: namespace annotation is available on a channel, KafkaChannel should create the topic in the Kafka cluster that's specified in the config-kafka configmap within the same namespace.
But the topic is created in the Kafka cluster that's specified in the Knative system's knative-eventing/config-kafka configmap.

Expected behavior
Topic should be created in the correct Kafka instance.

To Reproduce

• Create a Kafka cluster in kafka namespace
• Use that cluster in Knative eventing system's knative-eventing/config-kafka configmap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: config-kafka
  namespace: knative-eventing
data:
  bootstrapServers: my-cluster-kafka-bootstrap.kafka:9092

• Create a Kafka cluster in foo namespace
• Use that cluster in foo's knative-eventing/config-kafka configmap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: config-kafka
  namespace: foo
data:
  bootstrapServers: my-cluster-kafka-bootstrap.foo:9092

• Create a channel in foo, with the namespace scope annotation:

apiVersion: messaging.knative.dev/v1alpha1
kind: KafkaChannel
metadata:
  name: my-kafka-channel
  namespace: foo
  annotations:
    eventing.knative.dev/scope: namespace
spec:
  numPartitions: 1
  replicationFactor: 1

• Topic is created in the first Kafka cluster

Knative release version
I reproduced the issue on 0.13, but it is valid in 0.14 too

Additional context
Creating namespace-scoped dispatchers : https://github.com/knative/eventing-contrib/blob/release-0.14/kafka/channel/README.md

Code refs:

• This is the place where the system Kafka config is read: https://github.com/knative/eventing-contrib/blob/25ab82d6a7319e16440ba6550055c2ae6f046605/kafka/channel/pkg/reconciler/controller/controller.go#L90
• It is passed from here to there, until it is used in the topic creation: https://github.com/knative/eventing-contrib/blob/25ab82d6a7319e16440ba6550055c2ae6f046605/kafka/channel/pkg/reconciler/controller/kafkachannel.go#L176
• scope reading happens after the topic creation using the system namespace

[aliok]

Related #126

[ssandanshi]

This bug fix would be greatly appreciated.

[Vkrish-Nimmagadda]

Hello KN Enthusiasts,
Can someone please help if this bug if fixed ? We are using KNative for one of our releases and this is blocking us as we are not able to create a Topic. It would be great if there is a workaround till the fix. We have the latest version fo Knative-eventing (0.24.1). Any quick help is appreciated.

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[aliok]

/remove-lifecycle stale

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[pierDipi]

/remove-lifecycle stale
/triage accepted