Refactored Kafka src and ch code to reuse same consumer group handler code

[slinkydeveloper]

Replaces #551
Fixes knative/eventing#944
Fixes #552

Proposed Changes

• Removed sarama-cluster lib
• Refactored Kafka channel and source to share same code for handling incoming kafka messages
• Now kafka source commit the offset when the message is malformed

Release Note

consumerMode property in kafka broker config-map is no longer supported
sarama now uses v2 apis

[knative-prow-robot]

Hi @slinkydeveloper. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[matzew]

/ok-to-test

[matzew]

/retest

[matzew]

@slinkydeveloper

to the dispatcher_test.go file, please add:

func TestNewDispatcher(t *testing.T) {

	args := &KafkaDispatcherArgs{
		ClientID:     "kafka-ch-dispatcher",
		Brokers:      []string{"127.0.0.1:9092"},
		TopicFunc:    utils.TopicName,
		Logger:       nil,
	}
	_, err := NewDispatcher(args)
	if err == nil {
		t.Errorf("Expected error want %s, got %s", "message receiver is not set", err)
	}
}

[matzew]

/test pull-knative-eventing-contrib-go-coverage

[matzew]

/lgtm
/approve

[matzew]

/lgtm

[matzew]

/approve

[slinkydeveloper]

/assign @n3wscott

[grantr]

/lgtm

Added a few minor comments, but they are optional and can be addressed in a future PR.

[n3wscott]

/approve

[slinkydeveloper]

/retest

[grantr]

Looks like Go is complaining about data races in ConsumerFactory tests

[slinkydeveloper]

My bad, in sarama documentation it says that if kafkaConfig.Consumer.Return.Errors is true, then the consumer errors are notified directly through the channel. I suppose we can just comment the error when we call consumerGroup.Consume

[knative-metrics-robot]

The following is the coverage report on pkg/.
Say /test pull-knative-eventing-contrib-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
kafka/channel/pkg/dispatcher/dispatcher.go	68.1%	69.7%	1.6
kafka/common/pkg/kafka/consumer_factory.go	Do not exist	100.0%
kafka/common/pkg/kafka/consumer_handler.go	Do not exist	100.0%
kafka/source/pkg/adapter/adapter.go	41.2%	69.2%	28.0

[matzew]

/lgtm
/approve

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: grantr, matzew, n3wscott, slinkydeveloper

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