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Go Dcp Kafka

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Go implementation of the Kafka Connect Couchbase.

Go Dcp Kafka streams documents from Couchbase Database Change Protocol (DCP) and publishes Kafka events in near real-time.

Features

  • Less resource usage and higher throughput(see Benchmarks).
  • Custom Kafka key and headers implementation(see Example).
  • Sending multiple Kafka events for a DCP event(see Example).
  • Handling different DCP events such as expiration, deletion and mutation(see Example).
  • Kafka compression support(Gzip, Snappy, Lz4, Zstd).
  • Kafka producer acknowledges support(fire-and-forget, wait for the leader, wait for the full ISR).
  • Metadata can be saved to Couchbase or Kafka.
  • Managing batch configurations such as maximum batch size, batch bytes, batch ticker durations.
  • Scale up and down by custom membership algorithms(Couchbase, KubernetesHa, Kubernetes StatefulSet or Static, see examples).
  • Easily manageable configurations.

Benchmarks

The benchmark was made with the 1,001,006 Couchbase document, because it is possible to more clearly observe the difference in the batch structure between the two packages. Default configurations for Java Kafka Connect Couchbase used for both connectors.

Package Time to Process Events Average CPU Usage(Core) Average Memory Usage
Go Dcp Kafka(1.20) 12s 0.383 428MB
Java Kafka Connect Couchbase(JDK11) 19s 1.5 932MB

Example

Struct Config

func mapper(event couchbase.Event) []message.KafkaMessage {
	// return nil if you wish to discard the event
	return []message.KafkaMessage{
		{
			Headers: nil,
			Key:     event.Key,
			Value:   event.Value,
		},
	}
}

func main() {
	c, err := dcpkafka.NewConnector(&config.Connector{
		Dcp: dcpConfig.Dcp{
			Hosts:      []string{"localhost:8091"},
			Username:   "user",
			Password:   "password",
			BucketName: "dcp-test",
			Dcp: dcpConfig.ExternalDcp{
				Group: dcpConfig.DCPGroup{
					Name: "groupName",
					Membership: dcpConfig.DCPGroupMembership{
						RebalanceDelay: 3 * time.Second,
					},
				},
			},
			Metadata: dcpConfig.Metadata{
				Config: map[string]string{
					"bucket":     "checkpoint-bucket-name",
					"scope":      "_default",
					"collection": "_default",
				},
				Type: "couchbase",
			},
			Debug: true},
		Kafka: config.Kafka{
			CollectionTopicMapping: map[string]string{"_default": "topic"},
			Brokers:                []string{"localhost:9092"},
		},
	}, mapper)
	if err != nil {
		panic(err)
	}

	defer c.Close()
	c.Start()
}

File Config

File Config

Configuration

Dcp Configuration

Check out on go-dcp

Kafka Specific Configuration

Variable Type Required Default Description
kafka.collectionTopicMapping map[string]string yes Defines which Couchbase collection events will be sent to which topic,:warning: If topic information is entered in the mapper, it will OVERWRITE this config.
kafka.brokers []string yes Broker ip and port information
kafka.producerBatchSize integer no 2000 Maximum message count for batch, if exceed flush will be triggered.
kafka.producerBatchBytes 64 bit integer no 10mb Maximum size(byte) for batch, if exceed flush will be triggered. 10mb is default.
kafka.producerMaxAttempts int no math.MaxInt Limit on how many attempts will be made to deliver a message.
kafka.producerBatchTickerDuration time.Duration no 10s Batch is being flushed automatically at specific time intervals for long waiting messages in batch.
kafka.readTimeout time.Duration no 30s segmentio/kafka-go - Timeout for read operations
kafka.writeTimeout time.Duration no 30s segmentio/kafka-go - Timeout for write operations
kafka.compression integer no 0 Compression can be used if message size is large, CPU usage may be affected. 0=None, 1=Gzip, 2=Snappy, 3=Lz4, 4=Zstd
kafka.balancer string no Hash Define balancer strategy. Available fields: Hash, LeastBytes, RoundRobin, ReferenceHash, CRC32Balancer, Murmur2Balancer.
kafka.requiredAcks integer no 1 segmentio/kafka-go - Number of acknowledges from partition replicas required before receiving a response to a produce request. 0=fire-and-forget, do not wait for acknowledgements from the, 1=wait for the leader to acknowledge the writes, -1=wait for the full ISR to acknowledge the writes
kafka.secureConnection bool no false Enable secure Kafka.
kafka.rootCAPath string no *not set Define root CA path.
kafka.interCAPath string no *not set Define inter CA path.
kafka.scramUsername string no *not set Define scram username.
kafka.scramPassword string no *not set Define scram password.
kafka.metadataTTL time.Duration no 60s TTL for the metadata cached by segmentio, increase it to reduce network requests. For more detail please check docs.
kafka.metadataTopics []string no Topic names for the metadata cached by segmentio, define topics here that the connector may produce. In large Kafka clusters, this will reduce memory usage. For more detail please check docs.
kafka.clientID string no Unique identifier that the transport communicates to the brokers when it sends requests. For more detail please check docs.
kafka.allowAutoTopicCreation bool no false Create topic if missing. For more detail please check docs.

Kafka Metadata Configuration(Use it if you want to store the checkpoint data in Kafka)

Variable Type Description
metadata.type string Metadata storing types. kafka,file or couchbase.
metadata.readOnly bool Set this for debugging state purposes.
metadata.config map[string]string Set key-values of config. topic,partition,replicationFactor for kafka type

Exposed metrics

Metric Name Description Labels Value Type
cbgo_kafka_connector_latency_ms_current Time to adding to the batch. N/A Gauge
cbgo_kafka_connector_batch_produce_latency_ms_current Time to produce messages in the batch. N/A Gauge

You can also use all DCP-related metrics explained here. All DCP-related metrics are automatically injected. It means you don't need to do anything.

Breaking Changes

Date taking effect Date announced Change How to check
November 11, 2023 November 11, 2023 Creating connector via builder Compile project

Grafana Metric Dashboard

Grafana & Prometheus Example

Contributing

Go Dcp Kafka is always open for direct contributions. For more information please check our Contribution Guideline document.

License

Released under the MIT License.