I am trying out an simple reactive-kafka program which reads and writes to Kafka. It starts up but does nothing even when I am publishing messages to the input topic.
implicit val system = ActorSystem("main")
implicit val materializer = ActorMaterializer()
val kafkaUrl: String = "localhost:9092"
val producerSettings = ProducerSettings(system, new ByteArraySerializer, new StringSerializer)
.withBootstrapServers(kafkaUrl)
val consumerSettings = ConsumerSettings(system, new ByteArrayDeserializer, new StringDeserializer,
Set("inputTopic"))
.withBootstrapServers(kafkaUrl)
.withGroupId("group1")
.withProperty(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest")
val flow: RunnableGraph[Control] = Consumer.committableSource(consumerSettings.withClientId("client1"))
.map { msg =>
println("msg = " + msg)
Producer.Message(new ProducerRecord[Array[Byte], String]("test.topic2", msg.value), msg.committableOffset)
}
.to(Producer.commitableSink(producerSettings))
flow.run()
It just stays there forever. Any tips on debugging why this is not working?
Related
I am trying to count the number of words in the text and save result to the Cassandra database.
Producer reads the data from the file and sends it to kafka. Consumer uses spark streaming to read and process the date,and then sends the result of the calculations to the table.
My producer looks like this:
object ProducerPlayground extends App {
val topicName = "test"
private def createProducer: Properties = {
val producerProperties = new Properties()
producerProperties.setProperty(
ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,
"localhost:9092"
)
producerProperties.setProperty(
ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG,
classOf[IntegerSerializer].getName
)
producerProperties.setProperty(
ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,
classOf[StringSerializer].getName
)
producerProperties
}
val producer = new KafkaProducer[Int, String](createProducer)
val source = Source.fromFile("G:\\text.txt", "UTF-8")
val lines = source.getLines()
var key = 0
for (line <- lines) {
producer.send(new ProducerRecord[Int, String](topicName, key, line))
key += 1
}
source.close()
producer.flush()
}
Consumer looks like this:
object BatchLayer {
def main(args: Array[String]) {
val brokers = "localhost:9092"
val topics = "test"
val groupId = "groupId-1"
val sparkConf = new SparkConf()
.setAppName("BatchLayer")
.setMaster("local[*]")
val ssc = new StreamingContext(sparkConf, Seconds(3))
val sc = ssc.sparkContext
sc.setLogLevel("OFF")
val topicsSet = topics.split(",").toSet
val kafkaParams = Map[String, Object](
ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG -> brokers,
ConsumerConfig.GROUP_ID_CONFIG -> groupId,
ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG -> classOf[StringDeserializer],
ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG -> classOf[StringDeserializer],
ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG -> "false"
)
val stream =
KafkaUtils.createDirectStream[String, String](
ssc,
LocationStrategies.PreferConsistent,
ConsumerStrategies.Subscribe[String, String](topicsSet, kafkaParams)
)
val cass = CassandraConnector(sparkConf)
cass.withSessionDo { session =>
session.execute(
s"CREATE KEYSPACE IF NOT EXISTS batch_layer WITH REPLICATION = {'class': 'SimpleStrategy', 'replication_factor': 1 }"
)
session.execute(s"CREATE TABLE IF NOT EXISTS batch_layer.test (key VARCHAR PRIMARY KEY, value INT)")
session.execute(s"TRUNCATE batch_layer.test")
}
stream
.map(v => v.value())
.flatMap(x => x.split(" "))
.filter(x => !x.contains(Array('\n', '\t')))
.map(x => (x, 1))
.reduceByKey(_ + _)
.saveToCassandra("batch_layer", "test", SomeColumns("key", "value"))
ssc.start()
ssc.awaitTermination()
}
}
After starting producer, the program stops working with this error. What did I do wrong ?
It makes very little sense to use legacy streaming in 2021st - it's very cumbersome to use, and you also need to track offsets for Kafka, etc. It's better to use Structured Streaming instead - it will track offsets for your through the checkpoints, you will work with high-level Dataset APIs, etc.
In your case code could look as following (didn't test, but it's adopted from this working example):
val streamingInputDF = spark.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "localhost:9092")
.option("subscribe", "test")
.load()
val wordsCountsDF = streamingInputDF.selectExpr("CAST(value AS STRING) as value")
.selectExpr("split(value, '\\w+', -1) as words")
.selectExpr("explode(words) as word")
.filter("word != ''")
.groupBy($"word")
.count()
.select($"word", $"count")
// create table ...
val query = wordsCountsDF.writeStream
.outputMode(OutputMode.Update)
.format("org.apache.spark.sql.cassandra")
.option("checkpointLocation", "path_to_checkpoint)
.option("keyspace", "test")
.option("table", "<table_name>")
.start()
query.awaitTermination()
P.S. In your example, most probable error is that you're trying to use .saveToCassandra directly on DStream - it doesn't work this way.
I am using flink-1.4.2 with scala and I want to consume multiple data stream sources of Kafka. I have used union function of combine them but I am able to use one kafka source.
def main(args: Array[String]) {
val kProps = new Properties()
kProps.setProperty("bootstrap.servers", "kafka01.prod.com:9092")
kProps.setProperty("group.id", "test_cg")
kProps.setProperty("enable.auto.commit", "true")
kProps.setProperty("auto.offset.reset", "latest")
val kProps2 = new Properties()
kProps2.setProperty("bootstrap.servers", "kafka04.prod.com:9092")
kProps2.setProperty("group.id", "test_cg_2")
kProps2.setProperty("enable.auto.commit", "true")
kProps2.setProperty("auto.offset.reset", "latest")
val sink = new BucketingSink[SimpleKafkaOutputMsg]("s3://some-bucket/")
sink.setBucketer(new DateTimeBucketer[SimpleKafkaOutputMsg]("yyyy-MM-dd-HH"))
sink.setWriter(new StringWriter[SimpleKafkaOutputMsg])
sink.setBatchSize(350 * 1024 * 1024) // 350 MB
sink.setPendingPrefix("file-")
sink.setPendingSuffix(".csv")
val env = StreamExecutionEnvironment.getExecutionEnvironment
env.setStreamTimeCharacteristic(TimeCharacteristic.ProcessingTime)
env.setParallelism(9)
env.setStateBackend(new RocksDBStateBackend("file:///tmp/flink/checkpoints", false))
val topics = List("ROUNDTRIP1")
val inpStream1 = env.addSource(new FlinkKafkaConsumer011(topics.asJava, new IndexedSectorMessagDes(), kProps))
val topics2 = List("ROUNDTRIP2")
val inpStream2 = env.addSource(new FlinkKafkaConsumer011(topics2.asJava, new IndexedSectorMessagDes(), kProps2))
val inpStream = inpStream1.union(inpStream2)
.filter(new InvalidFlightsFilterFunction())
.map(attachUID(_))
.assignTimestampsAndWatermarks(new IngestionTimeExtractor[IndexedSectorMessage]())
val intStream = inpStream.flatMap { s => flattenFlights(s) }
intStream.keyBy(getFlightKey _).process(new KeyedWindowTimeMedianFunction()).addSink(sink)
env.execute("Scala WindowExample Example")`
I am trying to write a streaming application that both reads from and writes to Kafka. I currently have this but I have to toString my tuple class.
object StreamingJob {
def main(args: Array[String]) {
// set up the streaming execution environment
val env = StreamExecutionEnvironment.getExecutionEnvironment
val properties = new Properties()
properties.setProperty("bootstrap.servers", "localhost:9092")
properties.setProperty("zookeeper.connect", "localhost:2181")
properties.setProperty("group.id", "test")
val consumer = env.addSource(new FlinkKafkaConsumer08[String]("topic", new SimpleStringSchema(), properties))
val counts = consumer.flatMap { _.toLowerCase.split("\\W+") filter { _.nonEmpty } }
.map { (_, 1) }
.keyBy(0)
.timeWindow(Time.seconds(5))
.sum(1)
val producer = new FlinkKafkaProducer08[String](
"localhost:9092",
"my-topic",
new SimpleStringSchema())
counts.map(_.toString()).addSink(producer)
env.execute("Window Stream WordCount")
env.execute("Flink Streaming Scala API Skeleton")
}
}
The closest I could get to getting this working was the following but the FlinkKafkaProducer08 refuses to accept the type parameter as part of the constructor.
val producer = new FlinkKafkaProducer08[(String, Int)](
"localhost:9092",
"my-topic",
new TypeSerializerOutputFormat[(String, Int)])
counts.addSink(producer)
I am wondering if there is a way to write the tuples directly to my Kafka sink.
You need a class approximately like this that serializes your tuples:
private class SerSchema extends SerializationSchema[Tuple2[String, Int]] {
override def serialize(tuple2: Tuple2[String, Int]): Array[Byte] = ...
}
I am running spark with the local[8] configuration. The input is a kafka stream with 8 brokers. But as seen in the system monitor, it isn't parallel enough, it seems that about only one node is running. The input to the kafka streamer is about 1.6GB big, so it should process much faster.
system monitor
Kafka Producer:
import java.io.{BufferedReader, FileReader}
import java.util
import java.util.{Collections, Properties}
import logparser.LogEvent
import org.apache.hadoop.conf.Configuration
import org.apache.kafka.clients.producer.{KafkaProducer, Producer, ProducerRecord}
import org.apache.kafka.common.serialization.StringDeserializer
object sparkStreaming{
private val NUMBER_OF_LINES = 100000000
val brokers ="localhost:9092,localhost:9093,localhost:9094,localhost:9095,localhost:9096,localhost:9097,localhost:9098,localhost:9099"
val topicName = "log-1"
val fileName = "data/HDFS.log"
val producer = getProducer()
// no hdfs , read from text file.
def produce(): Unit = {
try { //1. Get the instance of Configuration
val configuration = new Configuration
val fr = new FileReader(fileName)
val br = new BufferedReader(fr)
var line = ""
line = br.readLine
var count = 1
//while (line != null){
while ( {
line != null && count < NUMBER_OF_LINES
}) {
System.out.println("Sending batch " + count + " " + line)
producer.send(new ProducerRecord[String, LogEvent](topicName, new LogEvent(count,line,System.currentTimeMillis())))
line = br.readLine
count = count + 1
}
producer.close()
System.out.println("Producer exited successfully for " + fileName)
} catch {
case e: Exception =>
System.out.println("Exception while producing for " + fileName)
System.out.println(e)
}
}
private def getProducer() : KafkaProducer[String,LogEvent] = { // create instance for properties to access producer configs
val props = new Properties
//Assign localhost id
props.put("bootstrap.servers", brokers)
props.put("auto.create.topics.enable", "true")
//Set acknowledgements for producer requests.
props.put("acks", "all")
//If the request fails, the producer can automatically retry,
props.put("retries", "100")
//Specify buffer size in config
props.put("batch.size", "16384")
//Reduce the no of requests less than 0
props.put("linger.ms", "1")
//The buffer.memory controls the total amount of memory available to the producer for buffering.
props.put("buffer.memory", "33554432")
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer")
props.put("value.serializer", "logparser.LogEventSerializer")
props.put("topic.metadata.refresh.interval.ms", "1")
val producer = new KafkaProducer[String, LogEvent](props)
producer
}
def sendBackToKafka(logEvent: LogEvent): Unit ={
producer.send(new ProducerRecord[String, LogEvent] ("times",logEvent))
}
def main (args: Array[String]): Unit = {
println("Starting to produce");
this.produce();
}
}
Consumer:
package logparser
import java.io._
import java.util.Properties
import kafka.serializer.StringDecoder
import org.apache.kafka.clients.producer.{KafkaProducer, ProducerRecord}
import org.apache.kafka.common.serialization.StringDeserializer
import org.apache.spark.SparkConf
import org.apache.spark.rdd.RDD
import org.apache.spark.streaming._
import org.apache.spark.streaming.kafka010._
object consumer {
var tFromKafkaToSpark: Long = 0
var tParsing : Long = 0
val startTime = System.currentTimeMillis()
val CPUNumber = 8
val pw = new PrintWriter(new FileOutputStream("data/Streaming"+CPUNumber+"config2x.txt",false))
pw.write("Writing Started")
def printstarttime(): Unit ={
pw.print("StartTime : " + System.currentTimeMillis())
}
def printendtime(): Unit ={
pw.print("EndTime : " + System.currentTimeMillis());
}
val producer = getProducer()
private def getProducer() : KafkaProducer[String,TimeList] = { // create instance for properties to access producer configs
val props = new Properties
val brokers ="localhost:9090,"
//Assign localhost id
props.put("bootstrap.servers", brokers)
props.put("auto.create.topics.enable", "true")
//Set acknowledgements for producer requests.
props.put("acks", "all")
//If the request fails, the producer can automatically retry,
props.put("retries", "100")
//Specify buffer size in config
props.put("batch.size", "16384")
//Reduce the no of requests less than 0
props.put("linger.ms", "1")
//The buffer.memory controls the total amount of memory available to the producer for buffering.
props.put("buffer.memory", "33554432")
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer")
props.put("value.serializer", "logparser.TimeListSerializer")
props.put("topic.metadata.refresh.interval.ms", "1")
val producer = new KafkaProducer[String, TimeList](props)
producer
}
def sendBackToKafka(timeList: TimeList): Unit ={
producer.send(new ProducerRecord[String, TimeList]("times",timeList))
}
def main(args: Array[String]) {
val topics = "log-1"
//val Array(brokers, ) = Array("localhost:9092","log-1")
val brokers = "localhost:9092"
// Create context with 2 second batch interval
val sparkConf = new SparkConf().setAppName("DirectKafkaWordCount").setMaster("local[" + CPUNumber + "]")
val ssc = new StreamingContext(sparkConf, Seconds(1))
// Create direct kafka stream with brokers and topics
val topicsSet = topics.split(",").toSet
var kafkaParams = Map[String, AnyRef]("metadata.broker.list" -> brokers)
kafkaParams = kafkaParams + ("bootstrap.servers" -> "localhost:9092,localhost:9093,localhost:9094,localhost:9095,localhost:9096,localhost:9097,localhost:9098,localhost:9099")
kafkaParams = kafkaParams + ("auto.offset.reset"-> "latest")
kafkaParams = kafkaParams + ("group.id" -> "test-consumer-group")
kafkaParams = kafkaParams + ("key.deserializer" -> classOf[StringDeserializer])
kafkaParams = kafkaParams + ("value.deserializer"-> "logparser.LogEventDeserializer")
//kafkaParams.put("zookeeper.connect", "192.168.101.165:2181");
kafkaParams = kafkaParams + ("enable.auto.commit"-> "true")
kafkaParams = kafkaParams + ("auto.commit.interval.ms"-> "1000")
kafkaParams = kafkaParams + ("session.timeout.ms"-> "20000")
kafkaParams = kafkaParams + ("metadata.max.age.ms"-> "1000")
val messages = KafkaUtils.createDirectStream[String, LogEvent](
ssc,
LocationStrategies.PreferConsistent,
ConsumerStrategies.Subscribe[String, LogEvent](topicsSet, kafkaParams))
var started = false
val lines = messages.map(_.value)
val lineswTime = lines.map(event =>
{
event.addNextEventTime(System.currentTimeMillis())
event
}
)
lineswTime.foreachRDD(a => a.foreach(e => println(e.getTimeList)))
val logLines = lineswTime.map(
(event) => {
//println(event.getLogline.stringMessages.toString)
event.setLogLine(event.getContent)
println("Got event with id = " + event.getId)
event.addNextEventTime(System.currentTimeMillis())
println(event.getLogline.stringMessages.toString)
event
}
)
//logLines.foreachRDD(a => a.foreach(e => println(e.getTimeList + e.getLogline.stringMessages.toString)))
val x = logLines.map(le => {
le.addNextEventTime(System.currentTimeMillis())
sendBackToKafka(new TimeList(le.getTimeList))
le
})
x.foreachRDD(a => a.foreach(e => println(e.getTimeList)))
//logLines.map(ll => ll.addNextEventTime(System.currentTimeMillis()))
println("--------------***///*****-------------------")
//logLines.print(10)
/*
val words = lines.flatMap(_.split(" "))
val wordCounts = words.map(x => (x, 1L)).reduceByKey(_ + _)
wordCounts.print()
*/
// Start the computation
ssc.start()
ssc.awaitTermination()
ssc.stop(false)
pw.close()
}
}
There's a piece of information missing in your problem statement: how many partitions does your input topic log-1 have?
My guess is that such topic have less than 8 partitions.
The parallelism of Spark Streaming (in case of a Kafka source) is tied (modulo re-partitioning) to the number of total Kafka partitions it consumes (i.e. the RDDs' partitions are taken from the Kafka partitions).
If, as I suspect, your input topic only has a few partitions, for each micro-batch Spark Streaming will task only an equal amount of nodes with the computation. All the other nodes will sit idling.
The fact that you see all the node working in an almost round-robin fashion is due to the fact that Spark do not always choose the same node for processing data for the same partition, but it actually actively mix things up.
In order to have a better idea on what's happening I'd need to see some statistics from the Spark UI Streaming page.
Given the information you provided so far however, the insufficient Kafka partitioning would be my best bet for this behaviour.
Everything consuming from Kafka is limited by the number of partitions your topic(s) has. One consumer per partition. How much do you have ?
Although Spark can redistribute the work, it's not recommended as you might be spending more time exchanging information between executors than actually processing it.
I am getting below error in spark-streaming application, i am using kafka for input stream. When i was doing with socket, it was working fine. But when i changed to kafka it's giving error. Anyone has idea why it's throwing error, do i need to change my batch time and check pointing time?
ERROR StreamingContext: Error starting the context, marking it as stopped
java.lang.StackOverflowError
My program:
def main(args: Array[String]): Unit = {
// Function to create and setup a new StreamingContext
def functionToCreateContext(): StreamingContext = {
val conf = new SparkConf().setAppName("HBaseStream")
val sc = new SparkContext(conf)
// create a StreamingContext, the main entry point for all streaming functionality
val ssc = new StreamingContext(sc, Seconds(5))
val brokers = args(0)
val topics= args(1)
val topicsSet = topics.split(",").toSet
val kafkaParams = Map[String, String]("metadata.broker.list" -> brokers)
val messages = KafkaUtils.createDirectStream[String, String, StringDecoder, StringDecoder](
ssc, kafkaParams, topicsSet)
val inputStream = messages.map(_._2)
// val inputStream = ssc.socketTextStream(args(0), args(1).toInt)
ssc.checkpoint(checkpointDirectory)
inputStream.print(1)
val parsedStream = inputStream
.map(line => {
val splitLines = line.split(",")
(splitLines(1), splitLines.slice(2, splitLines.length).map((_.trim.toLong)))
})
import breeze.linalg.{DenseVector => BDV}
import scala.util.Try
val state: DStream[(String, Array[Long])] = parsedStream.updateStateByKey(
(current: Seq[Array[Long]], prev: Option[Array[Long]]) => {
prev.map(_ +: current).orElse(Some(current))
.flatMap(as => Try(as.map(BDV(_)).reduce(_ + _).toArray).toOption)
})
state.checkpoint(Duration(10000))
state.foreachRDD(rdd => rdd.foreach(Blaher.blah))
ssc
}
// Get StreamingContext from checkpoint data or create a new one
val context = StreamingContext.getOrCreate(checkpointDirectory, functionToCreateContext _)
}
}
Try to delete the checkpoint directory.
I'm not sure but it seems that your streaming context fails to restore from the checkpoints.
anyway, it worked for me.