How to use auto - 8 common examples

console.log("Consumes and prints values of messages from a Kafka topic via the REST proxy API wrapper.");
    console.log();
    console.log("Usage: node console_consumer.js [--url ] --topic  [--group ] [--message-limit ] [--from-beginning] [--format ]");
    process.exit(help ? 0 : 1);
}

if (consumerGroup === undefined)
    consumerGroup = "console-consumer-" + Math.round(Math.random() * 100000);

var kafka = new KafkaRest({"url": api_url});
var consumed = 0;
var consumerConfig = {
    "format": format
};
if (fromBeginning) {
    consumerConfig['auto.offset.reset'] = 'smallest';
}
kafka.consumer(consumerGroup).join(consumerConfig, function(err, consumer_instance) {
    if (err) return console.log("Failed to create instance in consumer group: " + err);

    console.log("Consumer instance initialized: " + consumer_instance.toString());
    var stream = consumer_instance.subscribe(topicName);
    stream.on('data', function(msgs) {
        for(var i = 0; i < msgs.length; i++) {
            if (format == "binary") {
                // Messages keys (if available) and values are decoded from base64 into Buffers. You'll need to decode based
                // on whatever serialization format you used. By default here, we just try to decode to text.
                console.log(msgs[i].value.toString('utf8'));
                // Also available: msgs[i].key, msgs[i].partition
            } else {
                console.log(JSON.stringify(msgs[i].value));
            }

var binary = (format == "binary");

if (consumerGroup === undefined)
    consumerGroup = "tweet-trending-consumer-" + Math.round(Math.random() * 100000);

var kafka = new KafkaRest({"url": api_url});
var consumer_instance;
// How often to report the top 10
var report_period = 10000;
// How much to discount the current weights for each report_period
var period_discount_rate = .99;

var consumerConfig = { "format" : format };
if (fromBeginning) {
    consumerConfig['auto.offset.reset'] = 'smallest';
}
kafka.consumer(consumerGroup).join(consumerConfig, function(err, ci) {
    if (err) return console.log("Failed to create instance in consumer group: " + err);
    consumer_instance = ci;
    var stream = consumer_instance.subscribe(topicName);
    stream.on('data', function(msgs) {
        for(var i = 0; i < msgs.length; i++) {
            var tweet = (binary ? JSON.parse(msgs[i].value.toString('utf8')) : msgs[i].value);
            processTweet(tweet);
        }
    });
    stream.on('error', function(err) {
        console.log("Consumer instance reported an error: " + err);
        shutdown();
    });

_initConsumer() {
        const consumerParams = {
            'metadata.broker.list': this._kafkaHosts,
            'group.id': this._groupId,
            'enable.auto.commit': this._autoCommit,
            'offset_commit_cb': this._onOffsetCommit.bind(this),
        };
        if (this._fromOffset !== undefined) {
            consumerParams['auto.offset.reset'] = this._fromOffset;
        }
        if (this._fetchMaxBytes !== undefined) {
            consumerParams['fetch.message.max.bytes'] = this._fetchMaxBytes;
        }
        this._consumer = new kafka.KafkaConsumer(consumerParams);
        this._consumer.connect();
        return this._consumer.once('ready', () => {
            this._consumerReady = true;
            this._checkIfReady();
        });
    }

constructor(conf: any, topicConf: any = {}, options: Options = {}) {
    this.dying = false
    this.dead = false
    this.topics = []
    conf['auto.commit.interval.ms'] =
      conf['auto.commit.interval.ms'] || DEFAULT_AUTO_COMMIT_INTERVAL

    if (!conf['rebalance_cb']) {
      conf['rebalance_cb'] = (err: any, assignment: any) => {
        if (err.code === ErrorCode.ERR__ASSIGN_PARTITIONS) {
          this.consumer.assign(assignment)
          let rebalanceLog = 'consumer rebalance : '
          for (const assign of assignment) {
            rebalanceLog += `{topic ${assign.topic}, partition: ${assign.partition}} `
          }
          this.logger.info(rebalanceLog)
        } else if (err.code === ErrorCode.ERR__REVOKE_PARTITIONS) {
          this.consumer.unassign()
        } else {
          this.logger.error(err)
        }

constructor(conf: any, topicConf: any = {}, options: Options = {}) {
    this.dying = false
    this.dead = false
    this.topics = []
    conf['auto.commit.interval.ms'] =
      conf['auto.commit.interval.ms'] || DEFAULT_AUTO_COMMIT_INTERVAL

    if (!conf['rebalance_cb']) {
      conf['rebalance_cb'] = (err: any, assignment: any) => {
        if (err.code === ErrorCode.ERR__ASSIGN_PARTITIONS) {
          this.consumer.assign(assignment)
          let rebalanceLog = 'consumer rebalance : '
          for (const assign of assignment) {
            rebalanceLog += `{topic ${assign.topic}, partition: ${assign.partition}} `
          }
          this.logger.info(rebalanceLog)
        } else if (err.code === ErrorCode.ERR__REVOKE_PARTITIONS) {
          this.consumer.unassign()
        } else {
          this.logger.error(err)
        }
      }