Github user dibbhatt commented on a diff in the pull request:
https://github.com/apache/spark/pull/3798#discussion_r23999633
--- Diff:
external/kafka/src/main/scala/org/apache/spark/streaming/kafka/KafkaCluster.scala
---
@@ -0,0 +1,344 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.streaming.kafka
+
+import scala.util.control.NonFatal
+import scala.util.Random
+import scala.collection.mutable.ArrayBuffer
+import java.util.Properties
+import kafka.api._
+import kafka.common.{ErrorMapping, OffsetMetadataAndError,
TopicAndPartition}
+import kafka.consumer.{ConsumerConfig, SimpleConsumer}
+import org.apache.spark.SparkException
+
+/**
+ * Convenience methods for interacting with a Kafka cluster.
+ * @param kafkaParams Kafka <a
href="http://kafka.apache.org/documentation.html#configuration";>
+ * configuration parameters</a>.
+ * Requires "metadata.broker.list" or "bootstrap.servers" to be set with
Kafka broker(s),
+ * NOT zookeeper servers, specified in host1:port1,host2:port2 form
+ */
+private[spark]
+class KafkaCluster(val kafkaParams: Map[String, String]) extends
Serializable {
+ import KafkaCluster.{Err, LeaderOffset}
+
+ val seedBrokers: Array[(String, Int)] =
+ kafkaParams.get("metadata.broker.list")
+ .orElse(kafkaParams.get("bootstrap.servers"))
+ .getOrElse(throw new SparkException("Must specify
metadata.broker.list or bootstrap.servers"))
+ .split(",").map { hp =>
+ val hpa = hp.split(":")
+ (hpa(0), hpa(1).toInt)
+ }
+
+ // ConsumerConfig isn't serializable
+ @transient private var _config: ConsumerConfig = null
+
+ def config: ConsumerConfig = this.synchronized {
+ if (_config == null) {
+ _config = KafkaCluster.consumerConfig(kafkaParams)
+ }
+ _config
+ }
+
+ def connect(host: String, port: Int): SimpleConsumer =
+ new SimpleConsumer(host, port, config.socketTimeoutMs,
+ config.socketReceiveBufferBytes, config.clientId)
+
+ def connectLeader(topic: String, partition: Int): Either[Err,
SimpleConsumer] =
+ findLeader(topic, partition).right.map(hp => connect(hp._1, hp._2))
+
+ // Metadata api
+ // scalastyle:off
+ //
https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-MetadataAPI
+ // scalastyle:on
+
+ def findLeader(topic: String, partition: Int): Either[Err, (String,
Int)] = {
+ val req = TopicMetadataRequest(TopicMetadataRequest.CurrentVersion,
+ 0, config.clientId, Seq(topic))
+ val errs = new Err
+ withBrokers(Random.shuffle(seedBrokers), errs) { consumer =>
+ val resp: TopicMetadataResponse = consumer.send(req)
+ resp.topicsMetadata.find(_.topic == topic).flatMap { tm:
TopicMetadata =>
+ tm.partitionsMetadata.find(_.partitionId == partition)
+ }.foreach { pm: PartitionMetadata =>
+ pm.leader.foreach { leader =>
+ return Right((leader.host, leader.port))
+ }
+ }
+ }
+ Left(errs)
+ }
+
+ def findLeaders(
+ topicAndPartitions: Set[TopicAndPartition]
+ ): Either[Err, Map[TopicAndPartition, (String, Int)]] = {
+ val topics = topicAndPartitions.map(_.topic)
+ val response = getPartitionMetadata(topics).right
+ val answer = response.flatMap { tms: Set[TopicMetadata] =>
+ val leaderMap = tms.flatMap { tm: TopicMetadata =>
+ tm.partitionsMetadata.flatMap { pm: PartitionMetadata =>
+ val tp = TopicAndPartition(tm.topic, pm.partitionId)
+ if (topicAndPartitions(tp)) {
+ pm.leader.map { l =>
+ tp -> (l.host -> l.port)
+ }
+ } else {
+ None
+ }
+ }
+ }.toMap
+
+ if (leaderMap.keys.size == topicAndPartitions.size) {
+ Right(leaderMap)
+ } else {
+ val missing = topicAndPartitions.diff(leaderMap.keySet)
+ val err = new Err
+ err.append(new SparkException(s"Couldn't find leaders for
${missing}"))
+ Left(err)
+ }
+ }
+ answer
+ }
+
+ def getPartitions(topics: Set[String]): Either[Err,
Set[TopicAndPartition]] = {
+ getPartitionMetadata(topics).right.map { r =>
+ r.flatMap { tm: TopicMetadata =>
+ tm.partitionsMetadata.map { pm: PartitionMetadata =>
+ TopicAndPartition(tm.topic, pm.partitionId)
+ }
+ }
+ }
+ }
+
+ def getPartitionMetadata(topics: Set[String]): Either[Err,
Set[TopicMetadata]] = {
+ val req = TopicMetadataRequest(
+ TopicMetadataRequest.CurrentVersion, 0, config.clientId,
topics.toSeq)
+ val errs = new Err
+ withBrokers(Random.shuffle(seedBrokers), errs) { consumer =>
+ val resp: TopicMetadataResponse = consumer.send(req)
+ // error codes here indicate missing / just created topic,
+ // repeating on a different broker wont be useful
+ return Right(resp.topicsMetadata.toSet)
+ }
+ Left(errs)
+ }
+
+ // Leader offset api
+ // scalastyle:off
+ //
https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-OffsetAPI
+ // scalastyle:on
+
+ def getLatestLeaderOffsets(
+ topicAndPartitions: Set[TopicAndPartition]
+ ): Either[Err, Map[TopicAndPartition, LeaderOffset]] =
+ getLeaderOffsets(topicAndPartitions, OffsetRequest.LatestTime)
+
+ def getEarliestLeaderOffsets(
+ topicAndPartitions: Set[TopicAndPartition]
+ ): Either[Err, Map[TopicAndPartition, LeaderOffset]] =
+ getLeaderOffsets(topicAndPartitions, OffsetRequest.EarliestTime)
+
+ def getLeaderOffsets(
+ topicAndPartitions: Set[TopicAndPartition],
+ before: Long
+ ): Either[Err, Map[TopicAndPartition, LeaderOffset]] = {
+ getLeaderOffsets(topicAndPartitions, before, 1).right.map { r =>
+ r.map { kv =>
+ // mapValues isnt serializable, see SI-7005
+ kv._1 -> kv._2.head
+ }
+ }
+ }
+
+ private def flip[K, V](m: Map[K, V]): Map[V, Seq[K]] =
+ m.groupBy(_._2).map { kv =>
+ kv._1 -> kv._2.keys.toSeq
+ }
+
+ def getLeaderOffsets(
+ topicAndPartitions: Set[TopicAndPartition],
+ before: Long,
+ maxNumOffsets: Int
+ ): Either[Err, Map[TopicAndPartition, Seq[LeaderOffset]]] = {
+ findLeaders(topicAndPartitions).right.flatMap { tpToLeader =>
+ val leaderToTp: Map[(String, Int), Seq[TopicAndPartition]] =
flip(tpToLeader)
+ val leaders = leaderToTp.keys
+ var result = Map[TopicAndPartition, Seq[LeaderOffset]]()
+ val errs = new Err
+ withBrokers(leaders, errs) { consumer =>
+ val partitionsToGetOffsets: Seq[TopicAndPartition] =
+ leaderToTp((consumer.host, consumer.port))
+ val reqMap = partitionsToGetOffsets.map { tp: TopicAndPartition =>
+ tp -> PartitionOffsetRequestInfo(before, maxNumOffsets)
+ }.toMap
+ val req = OffsetRequest(reqMap)
+ val resp = consumer.getOffsetsBefore(req)
+ val respMap = resp.partitionErrorAndOffsets
+ partitionsToGetOffsets.foreach { tp: TopicAndPartition =>
+ respMap.get(tp).foreach { por: PartitionOffsetsResponse =>
+ if (por.error == ErrorMapping.NoError) {
+ if (por.offsets.nonEmpty) {
+ result += tp -> por.offsets.map { off =>
+ LeaderOffset(consumer.host, consumer.port, off)
+ }
+ } else {
+ errs.append(new SparkException(
+ s"Empty offsets for ${tp}, is ${before} before log
beginning?"))
+ }
+ } else {
+ errs.append(ErrorMapping.exceptionFor(por.error))
+ }
+ }
+ }
+ if (result.keys.size == topicAndPartitions.size) {
+ return Right(result)
+ }
+ }
+ val missing = topicAndPartitions.diff(result.keySet)
+ errs.append(new SparkException(s"Couldn't find leader offsets for
${missing}"))
+ Left(errs)
+ }
+ }
+
+ // Consumer offset api
+ // scalastyle:off
+ //
https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-OffsetCommit/FetchAPI
+ // scalastyle:on
+
+ def getConsumerOffsets(
+ groupId: String,
+ topicAndPartitions: Set[TopicAndPartition]
+ ): Either[Err, Map[TopicAndPartition, Long]] = {
+ getConsumerOffsetMetadata(groupId, topicAndPartitions).right.map { r =>
--- End diff --
As par Kafka Documentation , these API calls are not fully functional in
releases until Kafka 0.8.1.1. It will be available in the 0.8.2 release. Does
that mean this solution can not work with any earlier version of Kafka ? If
that is case, need to mention in documentation.
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