Examples

examples/consumergroup/README.md

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+# Consumergroup example
+
+This example shows you how to use the Sarama consumer group consumer. The example simply starts consuming the given Kafka topics and logs the consumed messages.
+
+```bash
+$ go run main.go -brokers="127.0.0.1:9092" -topics="sarama" -group="example"
+```

examples/consumergroup/go.mod

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+module github.com/Shopify/sarama/examples/consumer
+
+replace github.com/Shopify/sarama => ../../
+
+require github.com/Shopify/sarama v0.0.0-00010101000000-000000000000

examples/consumergroup/go.sum

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+github.com/DataDog/zstd v1.3.5 h1:DtpNbljikUepEPD16hD4LvIcmhnhdLTiW/5pHgbmp14=
+github.com/DataDog/zstd v1.3.5/go.mod h1:1jcaCB/ufaK+sKp1NBhlGmpz41jOoPQ35bpF36t7BBo=
+github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/eapache/go-resiliency v1.1.0 h1:1NtRmCAqadE2FN4ZcN6g90TP3uk8cg9rn9eNK2197aU=
+github.com/eapache/go-resiliency v1.1.0/go.mod h1:kFI+JgMyC7bLPUVY133qvEBtVayf5mFgVsvEsIPBvNs=
+github.com/eapache/go-xerial-snappy v0.0.0-20180814174437-776d5712da21 h1:YEetp8/yCZMuEPMUDHG0CW/brkkEp8mzqk2+ODEitlw=
+github.com/eapache/go-xerial-snappy v0.0.0-20180814174437-776d5712da21/go.mod h1:+020luEh2TKB4/GOp8oxxtq0Daoen/Cii55CzbTV6DU=
+github.com/eapache/queue v1.1.0 h1:YOEu7KNc61ntiQlcEeUIoDTJ2o8mQznoNvUhiigpIqc=
+github.com/eapache/queue v1.1.0/go.mod h1:6eCeP0CKFpHLu8blIFXhExK/dRa7WDZfr6jVFPTqq+I=
+github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db h1:woRePGFeVFfLKN/pOkfl+p/TAqKOfFu+7KPlMVpok/w=
+github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/pierrec/lz4 v2.0.5+incompatible h1:2xWsjqPFWcplujydGg4WmhC/6fZqK42wMM8aXeqhl0I=
+github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
+github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a h1:9ZKAASQSHhDYGoxY8uLVpewe1GDZ2vu2Tr/vTdVAkFQ=
+github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=

examples/consumergroup/main.go

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+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+
+	"github.com/Shopify/sarama"
+)
+
+// Sarma configuration options
+var (
+	brokers = ""
+	version = ""
+	group   = ""
+	topics  = ""
+	oldest  = true
+	verbose = false
+)
+
+func init() {
+	flag.StringVar(&brokers, "brokers", "", "Kafka bootstrap brokers to connect to, as a comma separated list")
+	flag.StringVar(&group, "group", "", "Kafka consumer group definition")
+	flag.StringVar(&version, "version", "2.1.1", "Kafka cluster version")
+	flag.StringVar(&topics, "topics", "", "Kafka topics to be consumed, as a comma seperated list")
+	flag.BoolVar(&oldest, "oldest", true, "Kafka consumer consume initial ofset from oldest")
+	flag.BoolVar(&verbose, "verbose", false, "Sarama logging")
+	flag.Parse()
+
+	if len(brokers) == 0 {
+		panic("no Kafka bootstrap brokers defined, please set the -brokers flag")
+	}
+
+	if len(topics) == 0 {
+		panic("no topics given to be consumed, please set the -topics flag")
+	}
+
+	if len(group) == 0 {
+		panic("no Kafka consumer group defined, please set the -group flag")
+	}
+}
+
+func main() {
+	log.Println("Starting a new Sarama consumer")
+
+	if verbose {
+		sarama.Logger = log.New(os.Stdout, "[sarama] ", log.LstdFlags)
+	}
+
+	version, err := sarama.ParseKafkaVersion(version)
+	if err != nil {
+		panic(err)
+	}
+
+	/**
+	 * Construct a new Sarama configuration.
+	 * The Kafka cluster version has to be defined before the consumer/producer is initialized.
+	 */
+	config := sarama.NewConfig()
+	config.Version = version
+
+	if oldest {
+		config.Consumer.Offsets.Initial = sarama.OffsetOldest
+	}
+
+	/**
+	 * Setup a new Sarama consumer group
+	 */
+	consumer := Consumer{
+		ready: make(chan bool, 0),
+	}
+
+	ctx := context.Background()
+	client, err := sarama.NewConsumerGroup(strings.Split(brokers, ","), group, config)
+	if err != nil {
+		panic(err)
+	}
+
+	go func() {
+		for {
+			err := client.Consume(ctx, strings.Split(topics, ","), &consumer)
+			if err != nil {
+				panic(err)
+			}
+		}
+	}()
+
+	<-consumer.ready // Await till the consumer has been set up
+	log.Println("Sarama consumer up and running!...")
+
+	sigterm := make(chan os.Signal, 1)
+	signal.Notify(sigterm, syscall.SIGINT, syscall.SIGTERM)
+
+	<-sigterm // Await a sigterm signal before safely closing the consumer
+
+	err = client.Close()
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Consumer represents a Sarama consumer group consumer
+type Consumer struct {
+	ready chan bool
+}
+
+// Setup is run at the beginning of a new session, before ConsumeClaim
+func (consumer *Consumer) Setup(sarama.ConsumerGroupSession) error {
+	// Mark the consumer as ready
+	close(consumer.ready)
+	return nil
+}
+
+// Cleanup is run at the end of a session, once all ConsumeClaim goroutines have exited
+func (consumer *Consumer) Cleanup(sarama.ConsumerGroupSession) error {
+	return nil
+}
+
+// ConsumeClaim must start a consumer loop of ConsumerGroupClaim's Messages().
+func (consumer *Consumer) ConsumeClaim(session sarama.ConsumerGroupSession, claim sarama.ConsumerGroupClaim) error {
+	for message := range claim.Messages() {
+		log.Printf("Message claimed: value = %s, timestamp = %v, topic = %s", string(message.Value), message.Timestamp, message.Topic)
+		session.MarkMessage(message, "")
+	}
+
+	return nil
+}