Exemple #1
0
func (*Sample) produceSample() string {
	return fmt.Sprintf(`
public class KafkaProducer {
    private final Producer<String, String> producer;
    public final static String TOPIC = "TEST-TOPIC";
 
    private KafkaProducer(){
        Properties props = new Properties();
        props.put("%s", "k10101a.mycorp.kfk.com:10101,k10101b.mycorp.kfk.com:10101");
        props.put("producer.type", "sync"); // sync | async
        props.put("serializer.class", "kafka.serializer.StringEncoder");
        props.put("key.serializer.class", "kafka.serializer.StringEncoder");

		// batch related
        props.put("batch.num.messages", 200);      // by default 200
        props.put("queue.buffering.max.ms", 5000); // by default 5s
 
        // %s
        // 0, means that the producer never waits for an acknowledgement from the broker
        // 1, means that the producer gets an acknowledgement after the leader replica has received the data
        //-1, means that the producer gets an acknowledgement after all in-sync replicas have received the data
        props.put("%s", "1"); // 1 is enough in most cases
 
        producer = new Producer<String, String>(new ProducerConfig(props));
    }
 
    void produce() {
        int messageNo = 1000;
        final int COUNT = 10000;
 
        while (messageNo < COUNT) {
            String key = String.valueOf(messageNo);
            String data = "hello kafka message " + key;
            producer.send(new KeyedMessage<String, String>(TOPIC, key, data));
            messageNo ++;
        }
    }
 
    public static void main(String[] args) {
        new KafkaProducer().produce();
    }
}
        `,
		color.Cyan("metadata.broker.list"),
		color.Cyan("request.required.acks"),
		color.Cyan("request.required.acks"))
}
Exemple #2
0
func (*Sample) offsetCommitFetchSample() string {
	return fmt.Sprintf(`
KafkaConsumer<K, V> consumer = new KafkaConsumer<K, V>(properties);
...
TopicPartition p0 = new TopicPartition("topic1", 0);
TopicPartition p1 = new TopicPartition("topic1", 1);
%s

Map<TopicPartition, Long> offsets = new LinkedHashMap<TopicPartition, Long>();
offsets.Put(p0, 123L);
offsets.Put(p1, 4564L);

%s
consumer.commit(offsets, CommitType.SYNC);

%s
long committedOffset = consumer.committed(p1);
        `,
		color.Cyan("consumer.subscribe(p0, p1);"),
		color.Cyan("// commit offsets"),
		color.Cyan("//fetch offsets"))
}
Exemple #3
0
func (this *Kateway) Run(args []string) (exitCode int) {
	cmdFlags := flag.NewFlagSet("kateway", flag.ContinueOnError)
	cmdFlags.Usage = func() { this.Ui.Output(this.Help()) }
	cmdFlags.StringVar(&this.zone, "z", "", "")
	cmdFlags.BoolVar(&this.configMode, "cf", false, "")
	cmdFlags.StringVar(&this.id, "id", "", "")
	cmdFlags.BoolVar(&this.install, "i", false, "")
	cmdFlags.BoolVar(&this.longFmt, "l", false, "")
	cmdFlags.StringVar(&this.configOption, "option", "", "")
	cmdFlags.BoolVar(&this.versionOnly, "ver", false, "")
	cmdFlags.BoolVar(&this.flameGraph, "flame", false, "")
	cmdFlags.StringVar(&this.logLevel, "loglevel", "", "")
	cmdFlags.StringVar(&this.visualLog, "visualog", "", "")
	cmdFlags.BoolVar(&this.showZkNodes, "zk", false, "")
	cmdFlags.BoolVar(&this.checkup, "checkup", false, "")
	cmdFlags.BoolVar(&this.benchmark, "bench", false, "")
	cmdFlags.StringVar(&this.benchmarkMaster, "master", "", "")
	cmdFlags.BoolVar(&this.pub, "pub", false, "")
	cmdFlags.BoolVar(&this.sub, "sub", false, "")
	cmdFlags.BoolVar(&this.benchmarkAsync, "async", false, "")
	cmdFlags.BoolVar(&this.curl, "curl", false, "")
	if err := cmdFlags.Parse(args); err != nil {
		return 2
	}

	if this.benchmark {
		if validateArgs(this, this.Ui).
			require("-z").
			requireAdminRights("-z").
			invalid(args) {
			return 2
		}

		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		zone := ctx.Zone(zkzone.Name())
		this.benchApp = zone.SmokeApp
		this.benchSecret = zone.SmokeSecret
		this.benchTopic = zone.SmokeTopic
		this.benchVer = zone.SmokeTopicVersion
		this.benchPubEndpoint = zone.PubEndpoint
		if this.id != "" {
			kws, err := zkzone.KatewayInfos()
			swallow(err)
			for _, kw := range kws {
				if kw.Id == this.id {
					this.benchPubEndpoint = kw.PubAddr
					break
				}
			}
		}
		this.benchId = fmt.Sprintf("%s-%s", ctx.Hostname(), strings.Replace(uuid.New(), "-", "", -1))
		this.runBenchmark(zkzone)
		return
	}

	if this.flameGraph {
		if validateArgs(this, this.Ui).
			require("-z", "-id").
			requireAdminRights("-z").
			invalid(args) {
			return 2
		}

		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		this.generateFlameGraph(zkzone)
		return
	}

	if this.visualLog != "" {
		this.doVisualize()
		return
	}

	if this.pub {
		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		this.runPub(zkzone)
		return
	}

	if this.sub {
		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		this.runSub(zkzone)
		return
	}

	if this.install {
		if validateArgs(this, this.Ui).
			require("-z").
			invalid(args) {
			return 2
		}

		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		this.installGuide(zkzone)
		return
	}

	if this.configOption != "" {
		this.configMode = true
	}

	if this.configMode {
		if validateArgs(this, this.Ui).
			require("-z").
			requireAdminRights("-z").
			invalid(args) {
			return 2
		}

		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		if this.logLevel != "" {
			if this.id != "" {
				kw := zkzone.KatewayInfoById(this.id)
				if kw == nil {
					panic(fmt.Sprintf("kateway %s invalid entry found in zk", this.id))
				}

				this.callKateway(kw, "PUT", fmt.Sprintf("v1/log/%s", this.logLevel))
			} else {
				// apply on all kateways
				kws, _ := zkzone.KatewayInfos()
				for _, kw := range kws {
					this.callKateway(kw, "PUT", fmt.Sprintf("v1/log/%s", this.logLevel))
				}
			}
		}

		if this.configOption != "" {
			parts := strings.SplitN(this.configOption, "=", 2)
			if len(parts) != 2 {
				this.Ui.Error("usage: key=value")
				return
			}
			k, v := parts[0], parts[1]
			if this.id != "" {
				kw := zkzone.KatewayInfoById(this.id)
				if kw == nil {
					panic(fmt.Sprintf("kateway %s invalid entry found in zk", this.id))
				}

				this.callKateway(kw, "PUT", fmt.Sprintf("v1/options/%s/%s", k, v))
			} else {
				// apply on all kateways
				kws, _ := zkzone.KatewayInfos()
				for _, kw := range kws {
					this.callKateway(kw, "PUT", fmt.Sprintf("v1/options/%s/%s", k, v))
				}
			}
		}

		return
	}

	if this.checkup {
		if this.zone == "" {
			forAllSortedZones(func(zkzone *zk.ZkZone) {
				this.runCheckup(zkzone)
			})

			return
		}

		zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
		this.runCheckup(zkzone)
		return
	}

	if this.showZkNodes {
		this.Ui.Output(fmt.Sprintf(`%s pubsub manager db dsn
%s job db cluster config
%s turn off webhook dir`,
			color.Green("%-50s", zk.KatewayMysqlPath),
			color.Green("%-50s", zk.PubsubJobConfig),
			color.Green("%-50s", zk.PubsubWebhooksOff)))
		return
	}

	// display mode
	lines := make([]string, 0)
	header := "Zone|Id|Ip|Pprof|Build|Cpu|Heap|Obj|Go|P/S|hhIn/hhOut|Uptime"
	lines = append(lines, header)
	forSortedZones(func(zkzone *zk.ZkZone) {
		if this.zone != "" && zkzone.Name() != this.zone {
			return
		}

		if !this.versionOnly {
			mysqlDsn, err := zkzone.KatewayMysqlDsn()
			if err != nil {
				this.Ui.Warn(fmt.Sprintf("kateway[%s] mysql DSN not set on zk yet", zkzone.Name()))
				this.Ui.Output(fmt.Sprintf("e,g. %s -> pubsub:pubsub@tcp(10.77.135.217:10010)/pubsub?charset=utf8&timeout=10s",
					zk.KatewayMysqlPath))
			} else {
				this.Ui.Output(fmt.Sprintf("zone[%s] manager db: %s",
					color.Cyan(zkzone.Name()), mysqlDsn))
			}
		}

		kateways, err := zkzone.KatewayInfos()
		if err != nil {
			if err == zklib.ErrNoNode {
				this.Ui.Output("no kateway running")
				return
			} else {
				swallow(err)
			}

		}

		for _, kw := range kateways {
			if this.id != "" && this.id != kw.Id {
				continue
			}

			statusMap, _ := this.getKatewayStatusMap(kw.ManAddr)
			logLevel, _ := statusMap["loglevel"].(string)
			heapSize, _ := statusMap["heap"].(string)
			heapObjs, _ := statusMap["objects"].(string)
			pubConn, _ := statusMap["pubconn"].(string)
			hhAppendN, _ := statusMap["hh_appends"].(string)
			hhDeliverN, _ := statusMap["hh_delivers"].(string)
			subConn, _ := statusMap["subconn"].(string)
			goN, _ := statusMap["goroutines"].(string)

			if this.versionOnly {
				pprofAddr := kw.DebugAddr
				if len(pprofAddr) > 0 && pprofAddr[0] == ':' {
					pprofAddr = kw.Ip + pprofAddr
				}
				pprofAddr = fmt.Sprintf("%s/debug/pprof/", pprofAddr)
				lines = append(lines, fmt.Sprintf("%s|%s|%s|%s|%s/%s|%s|%s|%s|%s|%s/%s|%s/%s|%s",
					zkzone.Name(),
					kw.Id, kw.Ip,
					pprofAddr, kw.Build, kw.BuiltAt,
					kw.Cpu,
					heapSize, heapObjs,
					goN,
					pubConn, subConn, hhAppendN, hhDeliverN,
					gofmt.PrettySince(kw.Ctime)))
				continue
			}

			this.Ui.Info(fmt.Sprintf("id:%-2s host:%s cpu:%-2s up:%s",
				kw.Id, kw.Host, kw.Cpu,
				gofmt.PrettySince(kw.Ctime)))
			this.Ui.Output(fmt.Sprintf("    ver: %s\n   arch: %s\n  build: %s\n  built: %s\n    log: %s\n    pub: %s\n    sub: %s\n    man: %s\n    dbg: %s",
				kw.Ver,
				kw.Arch,
				color.Red(kw.Build),
				kw.BuiltAt,
				logLevel,
				kw.PubAddr,
				kw.SubAddr,
				kw.ManAddr,
				kw.DebugAddr,
			))

			if this.longFmt {
				this.Ui.Output("    full status:")
				this.Ui.Output(this.getKatewayStatus(kw.ManAddr))
			}

		}

	})

	if this.versionOnly && len(lines) > 1 {
		fmt.Println(columnize.SimpleFormat(lines))
	}

	return
}
Exemple #4
0
func (this *Host) diagnose() {
	clusters := make([]string, 0)
	leadingTopics := make(map[string][]int32) // topic:partitionID
	msgs := make(map[string]int64)

	// check if it is registered
	zkzone := zk.NewZkZone(zk.DefaultConfig(this.zone, ctx.ZoneZkAddrs(this.zone)))
	zkzone.ForSortedBrokers(func(cluster string, liveBrokers map[string]*zk.BrokerZnode) {
		zkcluster := zkzone.NewCluster(cluster)

		for _, broker := range liveBrokers {
			if broker.Host != this.host {
				continue
			}

			this.Ui.Output(broker.String())

			clusters = append(clusters, cluster)

			kfk, err := sarama.NewClient([]string{broker.Addr()}, saramaConfig())
			if err != nil {
				this.Ui.Error(err.Error())
				continue
			}

			topics, err := kfk.Topics()
			swallow(err)
			for _, topic := range topics {
				partions, err := kfk.WritablePartitions(topic)
				swallow(err)
				for _, partitionID := range partions {
					leader, err := kfk.Leader(topic, partitionID)
					swallow(err)
					host, _, err := net.SplitHostPort(leader.Addr())
					swallow(err)
					if host != this.host {
						continue
					}

					latestOffset, err := kfk.GetOffset(topic, partitionID, sarama.OffsetNewest)
					swallow(err)
					oldestOffset, err := kfk.GetOffset(topic, partitionID, sarama.OffsetOldest)
					swallow(err)

					msgs[topic] += (latestOffset - oldestOffset)
					if _, present := leadingTopics[topic]; !present {
						leadingTopics[topic] = make([]int32, 0)
					}
					leadingTopics[topic] = append(leadingTopics[topic], partitionID)
				}
			}

			kfk.Close()
		}

		registeredBrokers := zkcluster.RegisteredInfo().Roster
		for _, b := range registeredBrokers {
			if b.Host == this.host {
				this.Ui.Output(fmt.Sprintf("registered in cluster: %s", cluster))
			}
		}
	})

	this.Ui.Output(color.Cyan("clusters\n%s", strings.Repeat("-", 80)))
	for _, c := range clusters {
		this.Ui.Output(c)
	}

	this.Ui.Output(color.Cyan("clusters\n%s", strings.Repeat("-", 80)))
	for t, ps := range leadingTopics {
		this.Ui.Output(fmt.Sprintf("%35s M:%-10d P:%+v", t, msgs[t], ps))
	}
}
Exemple #5
0
func (this *Checkup) Run(args []string) (exitCode int) {
	var cmd cli.Command
	if false {
		this.Ui.Output(color.Cyan("checking zookeepeer\n%s", strings.Repeat("-", 80)))
		cmd = &Zookeeper{
			Ui:  this.Ui,
			Cmd: this.Cmd,
		}
		cmd.Run(append(args, "-c", "srvr"))
		this.Ui.Output("")
	}

	this.Ui.Output(color.Cyan("ping all brokers\n%s", strings.Repeat("-", 80)))
	cmd = &Ping{
		Ui:  this.Ui,
		Cmd: this.Cmd,
	}
	cmd.Run(append(args, "-p"))
	this.Ui.Output("")

	this.Ui.Output(color.Cyan("checking registered brokers are alive\n%s", strings.Repeat("-", 80)))
	cmd = &Clusters{
		Ui:  this.Ui,
		Cmd: this.Cmd,
	}
	cmd.Run(append(args, "-verify"))
	this.Ui.Output("")

	this.Ui.Output(color.Cyan("checking offline brokers\n%s", strings.Repeat("-", 80)))
	cmd = &Brokers{
		Ui:  this.Ui,
		Cmd: this.Cmd,
	}
	cmd.Run(append(args, "-stale"))
	this.Ui.Output("")

	this.Ui.Output(color.Cyan("checking under replicated brokers\n%s", strings.Repeat("-", 80)))
	cmd = &UnderReplicated{
		Ui:  this.Ui,
		Cmd: this.Cmd,
	}
	cmd.Run(args)
	this.Ui.Output("")

	this.Ui.Output(color.Cyan("checking kguard\n%s", strings.Repeat("-", 80)))
	cmd = &Kguard{
		Ui:  this.Ui,
		Cmd: this.Cmd,
	}
	cmd.Run(args)
	this.Ui.Output("")

	this.Ui.Output(color.Cyan("checking problematic lag consumers\n%s", strings.Repeat("-", 80)))
	cmd = &Lags{
		Ui:  this.Ui,
		Cmd: this.Cmd,
	}
	cmd.Run(append(args, "-p"))

	this.Ui.Output("")
	this.Ui.Output("Did you find something wrong?")

	return
}
Exemple #6
0
func (this *Topics) displayTopicsOfCluster(zkcluster *zk.ZkCluster) {
	echoBuffer := func(lines []string) {
		for _, l := range lines {
			this.Ui.Output(l)
		}
	}

	linesInTopicMode := make([]string, 0)
	if this.verbose {
		linesInTopicMode = this.echoOrBuffer(zkcluster.Name(), linesInTopicMode)
	}

	// get all alive brokers within this cluster
	brokers := zkcluster.Brokers()
	if len(brokers) == 0 {
		linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%4s%s", " ",
			color.Red("%s empty brokers", zkcluster.Name())), linesInTopicMode)
		echoBuffer(linesInTopicMode)
		return
	}

	if this.verbose {
		sortedBrokerIds := make([]string, 0, len(brokers))
		for brokerId, _ := range brokers {
			sortedBrokerIds = append(sortedBrokerIds, brokerId)
		}
		sort.Strings(sortedBrokerIds)
		for _, brokerId := range sortedBrokerIds {
			if this.ipInNumber {
				linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%4s%s %s", " ",
					color.Green(brokerId), brokers[brokerId]), linesInTopicMode)
			} else {
				linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%4s%s %s", " ",
					color.Green(brokerId), brokers[brokerId].NamedString()), linesInTopicMode)
			}

		}
	}

	kfk, err := sarama.NewClient(zkcluster.BrokerList(), saramaConfig())
	if err != nil {
		if this.verbose {
			linesInTopicMode = this.echoOrBuffer(color.Yellow("%5s%+v %s", " ",
				zkcluster.BrokerList(), err.Error()), linesInTopicMode)
		}

		return
	}
	defer kfk.Close()

	topics, err := kfk.Topics()
	swallow(err)
	if len(topics) == 0 {
		if this.topicPattern == "" && this.verbose {
			linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%5s%s", " ",
				color.Magenta("no topics")), linesInTopicMode)
			echoBuffer(linesInTopicMode)
		}

		return
	}

	sortedTopics := make([]string, 0, len(topics))
	for _, t := range topics {
		sortedTopics = append(sortedTopics, t)
	}
	sort.Strings(sortedTopics)

	topicsCtime := zkcluster.TopicsCtime()
	hasTopicMatched := false
	for _, topic := range sortedTopics {
		if !patternMatched(topic, this.topicPattern) {
			continue
		}

		if this.since > 0 && time.Since(topicsCtime[topic]) > this.since {
			continue
		}

		this.topicN++

		hasTopicMatched = true
		if this.verbose {
			linesInTopicMode = this.echoOrBuffer(strings.Repeat(" ", 4)+color.Cyan(topic), linesInTopicMode)
		}

		// get partitions and check if some dead
		alivePartitions, err := kfk.WritablePartitions(topic)
		swallow(err)
		partions, err := kfk.Partitions(topic)
		swallow(err)
		if len(alivePartitions) != len(partions) {
			linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%30s %s %s P: %s/%+v",
				zkcluster.Name(), color.Cyan("%-50s", topic), color.Red("partial dead"), color.Green("%+v", alivePartitions), partions), linesInTopicMode)
		}

		replicas, err := kfk.Replicas(topic, partions[0])
		if err != nil {
			this.Ui.Error(fmt.Sprintf("%s/%d %v", topic, partions[0], err))
		}

		this.partitionN += len(partions)
		if !this.verbose {
			linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%30s %s %3dP %dR %s",
				zkcluster.Name(),
				color.Cyan("%-50s", topic),
				len(partions), len(replicas),
				gofmt.PrettySince(topicsCtime[topic])), linesInTopicMode)
			continue
		}

		for _, partitionID := range alivePartitions {
			leader, err := kfk.Leader(topic, partitionID)
			swallow(err)

			replicas, err := kfk.Replicas(topic, partitionID)
			if err != nil {
				this.Ui.Error(fmt.Sprintf("%s/%d %v", topic, partitionID, err))
			}

			isr, isrMtime, partitionCtime := zkcluster.Isr(topic, partitionID)
			isrMtimeSince := gofmt.PrettySince(isrMtime)
			if time.Since(isrMtime).Hours() < 24 {
				// ever out of sync last 24h
				isrMtimeSince = color.Magenta(isrMtimeSince)
			}

			underReplicated := false
			if len(isr) != len(replicas) {
				underReplicated = true
			}

			latestOffset, err := kfk.GetOffset(topic, partitionID,
				sarama.OffsetNewest)
			swallow(err)

			oldestOffset, err := kfk.GetOffset(topic, partitionID,
				sarama.OffsetOldest)
			swallow(err)

			if this.count > 0 && (latestOffset-oldestOffset) < this.count {
				continue
			}

			this.totalMsgs += latestOffset - oldestOffset
			this.totalOffsets += latestOffset
			if !underReplicated {
				linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%8d Leader:%s Replicas:%+v Isr:%+v Offset:%16s - %-16s Num:%-15s %s-%s",
					partitionID,
					color.Green("%d", leader.ID()), replicas, isr,
					gofmt.Comma(oldestOffset), gofmt.Comma(latestOffset), gofmt.Comma(latestOffset-oldestOffset),
					gofmt.PrettySince(partitionCtime), isrMtimeSince), linesInTopicMode)
			} else {
				// use red for alert
				linesInTopicMode = this.echoOrBuffer(fmt.Sprintf("%8d Leader:%s Replicas:%+v Isr:%s Offset:%16s - %-16s Num:%-15s %s-%s",
					partitionID,
					color.Green("%d", leader.ID()), replicas, color.Red("%+v", isr),
					gofmt.Comma(oldestOffset), gofmt.Comma(latestOffset), gofmt.Comma(latestOffset-oldestOffset),
					gofmt.PrettySince(partitionCtime), isrMtimeSince), linesInTopicMode)
			}
		}
	}

	if this.topicPattern != "" {
		if hasTopicMatched {
			echoBuffer(linesInTopicMode)
		}

	} else {
		echoBuffer(linesInTopicMode)
	}
}
Exemple #7
0
func (*Sample) consumeSample() string {
	return fmt.Sprintf(`
public class KafkaConsumer {
    private final ConsumerConnector consumer;

    private KafkaConsumer() {
        Properties props = new Properties();
        props.put("%s", "zk2181a.wdds.zk.com:2181,zk2181b.wdds.zk.com:2181,zk2181c.wdds.zk.com:2181/kafka");
        props.put("%s", "group1");
        props.put("zookeeper.session.timeout.ms", "4000");
        props.put("zookeeper.sync.time.ms", "200");
        props.put("auto.commit.interval.ms", "60000");   // 1m
        //props.put("auto.offset.reset", "smallest");    // largest | smallest
        props.put("serializer.class", "kafka.serializer.StringEncoder");
        ConsumerConfig config = new ConsumerConfig(props);

        consumer = kafka.consumer.Consumer.createJavaConsumerConnector(config);
    }

    public void shutdown() {
        if (consumer != null) {
            consumer.shutdown();
        }
   }

    void consume(String topic, int %s) {
        // %s
        // %s
        // %s
        Runtime.getRuntime().addShutdownHook(new Thread() {
            public void run() {
                consumer.shutdown();
            }
        });

        Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
        topicCountMap.put(topic, %s);

        StringDecoder keyDecoder = new StringDecoder(new VerifiableProperties());
        StringDecoder valueDecoder = new StringDecoder(new VerifiableProperties());

        Map<String, List<KafkaStream<String, String>>> consumerMap = 
                consumer.createMessageStreams(topicCountMap, keyDecoder, valueDecoder);
        KafkaStream<String, String> stream = consumerMap.get(topic).get(0);
        ConsumerIterator<String, String> it = stream.iterator();
        while (it.hasNext()) {
            // consumer.commitOffsets(); // manually commit offsets
            System.out.println(it.next().message());
        }
    }

    public static void main(String[] args) {
        new KafkaConsumer().consume();
    }
}   
        `,
		color.Cyan("zookeeper.connect"),
		color.Cyan("group.id"),
		color.Green("threads"),
		color.Red("VERY important!"),
		color.Red("graceful shutdown the consumer group to commit consumed offset"),
		color.Red("avoid consuming duplicated message when restarting the same consumer group"),
		color.Green("threads"))
}