Awesome
Kafka
Kafka is Go client library for Apache Kafka server, released under MIT license.
Kafka provides minimal abstraction over wire protocol, support for transparent failover and easy to use blocking API.
- godoc generated documentation,
- code examples
Example
Write all messages from stdin to kafka and print all messages from kafka topic to stdout.
package main
import (
"bufio"
"log"
"os"
"strings"
"github.com/optiopay/kafka/v2"
"github.com/optiopay/kafka/v2/proto"
)
const (
topic = "my-messages"
partition = 0
)
var kafkaAddrs = []string{"localhost:9092", "localhost:9093"}
// printConsumed read messages from kafka and print them out
func printConsumed(broker kafka.Client) {
conf := kafka.NewConsumerConf(topic, partition)
conf.StartOffset = kafka.StartOffsetNewest
consumer, err := broker.Consumer(conf)
if err != nil {
log.Fatalf("cannot create kafka consumer for %s:%d: %s", topic, partition, err)
}
for {
msg, err := consumer.Consume()
if err != nil {
if err != kafka.ErrNoData {
log.Printf("cannot consume %q topic message: %s", topic, err)
}
break
}
log.Printf("message %d: %s", msg.Offset, msg.Value)
}
log.Print("consumer quit")
}
// produceStdin read stdin and send every non empty line as message
func produceStdin(broker kafka.Client) {
producer := broker.Producer(kafka.NewProducerConf())
input := bufio.NewReader(os.Stdin)
for {
line, err := input.ReadString('\n')
if err != nil {
log.Fatalf("input error: %s", err)
}
line = strings.TrimSpace(line)
if line == "" {
continue
}
msg := &proto.Message{Value: []byte(line)}
if _, err := producer.Produce(topic, partition, msg); err != nil {
log.Fatalf("cannot produce message to %s:%d: %s", topic, partition, err)
}
}
}
func main() {
conf := kafka.NewBrokerConf("test-client")
conf.AllowTopicCreation = true
// connect to kafka cluster
broker, err := kafka.Dial(kafkaAddrs, conf)
if err != nil {
log.Fatalf("cannot connect to kafka cluster: %s", err)
}
defer broker.Close()
go printConsumed(broker)
produceStdin(broker)
}