org.apache.spark.streaming.kafka

Class KafkaUtils

Object

org.apache.spark.streaming.kafka.KafkaUtils

public class KafkaUtils
extends Object

Constructor Summary

Constructors

Constructor and Description
KafkaUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> JavaInputDStream<R>	createDirectStream(JavaStreamingContext jssc, Class<K> keyClass, Class<V> valueClass, Class<KD> keyDecoderClass, Class<VD> valueDecoderClass, Class<R> recordClass, java.util.Map<String,String> kafkaParams, java.util.Map<kafka.common.TopicAndPartition,Long> fromOffsets, Function<kafka.message.MessageAndMetadata<K,V>,R> messageHandler) Create an input stream that directly pulls messages from Kafka Brokers without using any receiver.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> JavaPairInputDStream<K,V>	createDirectStream(JavaStreamingContext jssc, Class<K> keyClass, Class<V> valueClass, Class<KD> keyDecoderClass, Class<VD> valueDecoderClass, java.util.Map<String,String> kafkaParams, java.util.Set<String> topics) Create an input stream that directly pulls messages from Kafka Brokers without using any receiver.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> InputDStream<R>	createDirectStream(StreamingContext ssc, scala.collection.immutable.Map<String,String> kafkaParams, scala.collection.immutable.Map<kafka.common.TopicAndPartition,Object> fromOffsets, scala.Function1<kafka.message.MessageAndMetadata<K,V>,R> messageHandler, scala.reflect.ClassTag<K> evidence$14, scala.reflect.ClassTag<V> evidence$15, scala.reflect.ClassTag<KD> evidence$16, scala.reflect.ClassTag<VD> evidence$17, scala.reflect.ClassTag<R> evidence$18) Create an input stream that directly pulls messages from Kafka Brokers without using any receiver.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> InputDStream<scala.Tuple2<K,V>>	createDirectStream(StreamingContext ssc, scala.collection.immutable.Map<String,String> kafkaParams, scala.collection.immutable.Set<String> topics, scala.reflect.ClassTag<K> evidence$19, scala.reflect.ClassTag<V> evidence$20, scala.reflect.ClassTag<KD> evidence$21, scala.reflect.ClassTag<VD> evidence$22) Create an input stream that directly pulls messages from Kafka Brokers without using any receiver.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> JavaRDD<R>	createRDD(JavaSparkContext jsc, Class<K> keyClass, Class<V> valueClass, Class<KD> keyDecoderClass, Class<VD> valueDecoderClass, Class<R> recordClass, java.util.Map<String,String> kafkaParams, OffsetRange[] offsetRanges, java.util.Map<kafka.common.TopicAndPartition,Broker> leaders, Function<kafka.message.MessageAndMetadata<K,V>,R> messageHandler) Create a RDD from Kafka using offset ranges for each topic and partition.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> JavaPairRDD<K,V>	createRDD(JavaSparkContext jsc, Class<K> keyClass, Class<V> valueClass, Class<KD> keyDecoderClass, Class<VD> valueDecoderClass, java.util.Map<String,String> kafkaParams, OffsetRange[] offsetRanges) Create a RDD from Kafka using offset ranges for each topic and partition.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> RDD<scala.Tuple2<K,V>>	createRDD(SparkContext sc, scala.collection.immutable.Map<String,String> kafkaParams, OffsetRange[] offsetRanges, scala.reflect.ClassTag<K> evidence$5, scala.reflect.ClassTag<V> evidence$6, scala.reflect.ClassTag<KD> evidence$7, scala.reflect.ClassTag<VD> evidence$8) Create a RDD from Kafka using offset ranges for each topic and partition.
static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> RDD<R>	createRDD(SparkContext sc, scala.collection.immutable.Map<String,String> kafkaParams, OffsetRange[] offsetRanges, scala.collection.immutable.Map<kafka.common.TopicAndPartition,Broker> leaders, scala.Function1<kafka.message.MessageAndMetadata<K,V>,R> messageHandler, scala.reflect.ClassTag<K> evidence$9, scala.reflect.ClassTag<V> evidence$10, scala.reflect.ClassTag<KD> evidence$11, scala.reflect.ClassTag<VD> evidence$12, scala.reflect.ClassTag<R> evidence$13) Create a RDD from Kafka using offset ranges for each topic and partition.
static <K,V,U extends kafka.serializer.Decoder<?>,T extends kafka.serializer.Decoder<?>> JavaPairReceiverInputDStream<K,V>	createStream(JavaStreamingContext jssc, Class<K> keyTypeClass, Class<V> valueTypeClass, Class<U> keyDecoderClass, Class<T> valueDecoderClass, java.util.Map<String,String> kafkaParams, java.util.Map<String,Integer> topics, StorageLevel storageLevel) Create an input stream that pulls messages from Kafka Brokers.
static JavaPairReceiverInputDStream<String,String>	createStream(JavaStreamingContext jssc, String zkQuorum, String groupId, java.util.Map<String,Integer> topics) Create an input stream that pulls messages from Kafka Brokers.
static JavaPairReceiverInputDStream<String,String>	createStream(JavaStreamingContext jssc, String zkQuorum, String groupId, java.util.Map<String,Integer> topics, StorageLevel storageLevel) Create an input stream that pulls messages from Kafka Brokers.
static <K,V,U extends kafka.serializer.Decoder<?>,T extends kafka.serializer.Decoder<?>> ReceiverInputDStream<scala.Tuple2<K,V>>	createStream(StreamingContext ssc, scala.collection.immutable.Map<String,String> kafkaParams, scala.collection.immutable.Map<String,Object> topics, StorageLevel storageLevel, scala.reflect.ClassTag<K> evidence$1, scala.reflect.ClassTag<V> evidence$2, scala.reflect.ClassTag<U> evidence$3, scala.reflect.ClassTag<T> evidence$4) Create an input stream that pulls messages from Kafka Brokers.
static ReceiverInputDStream<scala.Tuple2<String,String>>	createStream(StreamingContext ssc, String zkQuorum, String groupId, scala.collection.immutable.Map<String,Object> topics, StorageLevel storageLevel) Create an input stream that pulls messages from Kafka Brokers.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KafkaUtils

public KafkaUtils()

Method Detail

createStream

public static ReceiverInputDStream<scala.Tuple2<String,String>> createStream(StreamingContext ssc,
                                                             String zkQuorum,
                                                             String groupId,
                                                             scala.collection.immutable.Map<String,Object> topics,
                                                             StorageLevel storageLevel)

Create an input stream that pulls messages from Kafka Brokers.

Parameters:

ssc - StreamingContext object

zkQuorum - Zookeeper quorum (hostname:port,hostname:port,..)

groupId - The group id for this consumer

topics - Map of (topic_name -> numPartitions) to consume. Each partition is consumed in its own thread

storageLevel - Storage level to use for storing the received objects (default: StorageLevel.MEMORY_AND_DISK_SER_2)

Returns:

DStream of (Kafka message key, Kafka message value)

createStream

public static <K,V,U extends kafka.serializer.Decoder<?>,T extends kafka.serializer.Decoder<?>> ReceiverInputDStream<scala.Tuple2<K,V>> createStream(StreamingContext ssc,
                                                                                                                                     scala.collection.immutable.Map<String,String> kafkaParams,
                                                                                                                                     scala.collection.immutable.Map<String,Object> topics,
                                                                                                                                     StorageLevel storageLevel,
                                                                                                                                     scala.reflect.ClassTag<K> evidence$1,
                                                                                                                                     scala.reflect.ClassTag<V> evidence$2,
                                                                                                                                     scala.reflect.ClassTag<U> evidence$3,
                                                                                                                                     scala.reflect.ClassTag<T> evidence$4)

Create an input stream that pulls messages from Kafka Brokers.

Parameters:

ssc - StreamingContext object

kafkaParams - Map of kafka configuration parameters, see http://kafka.apache.org/08/configuration.html

topics - Map of (topic_name -> numPartitions) to consume. Each partition is consumed in its own thread.

storageLevel - Storage level to use for storing the received objects

evidence$1 - (undocumented)

evidence$2 - (undocumented)

evidence$3 - (undocumented)

evidence$4 - (undocumented)

Returns:

DStream of (Kafka message key, Kafka message value)

createStream

public static JavaPairReceiverInputDStream<String,String> createStream(JavaStreamingContext jssc,
                                                       String zkQuorum,
                                                       String groupId,
                                                       java.util.Map<String,Integer> topics)

Create an input stream that pulls messages from Kafka Brokers. Storage level of the data will be the default StorageLevel.MEMORY_AND_DISK_SER_2.

Parameters:

jssc - JavaStreamingContext object

zkQuorum - Zookeeper quorum (hostname:port,hostname:port,..)

groupId - The group id for this consumer

topics - Map of (topic_name -> numPartitions) to consume. Each partition is consumed in its own thread

Returns:

DStream of (Kafka message key, Kafka message value)

createStream

public static JavaPairReceiverInputDStream<String,String> createStream(JavaStreamingContext jssc,
                                                       String zkQuorum,
                                                       String groupId,
                                                       java.util.Map<String,Integer> topics,
                                                       StorageLevel storageLevel)

Create an input stream that pulls messages from Kafka Brokers.

Parameters:

jssc - JavaStreamingContext object

zkQuorum - Zookeeper quorum (hostname:port,hostname:port,..).

groupId - The group id for this consumer.

topics - Map of (topic_name -> numPartitions) to consume. Each partition is consumed in its own thread.

storageLevel - RDD storage level.

Returns:

DStream of (Kafka message key, Kafka message value)

createStream

public static <K,V,U extends kafka.serializer.Decoder<?>,T extends kafka.serializer.Decoder<?>> JavaPairReceiverInputDStream<K,V> createStream(JavaStreamingContext jssc,
                                                                                                                               Class<K> keyTypeClass,
                                                                                                                               Class<V> valueTypeClass,
                                                                                                                               Class<U> keyDecoderClass,
                                                                                                                               Class<T> valueDecoderClass,
                                                                                                                               java.util.Map<String,String> kafkaParams,
                                                                                                                               java.util.Map<String,Integer> topics,
                                                                                                                               StorageLevel storageLevel)

Create an input stream that pulls messages from Kafka Brokers.

Parameters:

jssc - JavaStreamingContext object

keyTypeClass - Key type of DStream

valueTypeClass - value type of Dstream

keyDecoderClass - Type of kafka key decoder

valueDecoderClass - Type of kafka value decoder

kafkaParams - Map of kafka configuration parameters, see http://kafka.apache.org/08/configuration.html

topics - Map of (topic_name -> numPartitions) to consume. Each partition is consumed in its own thread

storageLevel - RDD storage level.

Returns:

DStream of (Kafka message key, Kafka message value)

createRDD

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> RDD<scala.Tuple2<K,V>> createRDD(SparkContext sc,
                                                                                                                   scala.collection.immutable.Map<String,String> kafkaParams,
                                                                                                                   OffsetRange[] offsetRanges,
                                                                                                                   scala.reflect.ClassTag<K> evidence$5,
                                                                                                                   scala.reflect.ClassTag<V> evidence$6,
                                                                                                                   scala.reflect.ClassTag<KD> evidence$7,
                                                                                                                   scala.reflect.ClassTag<VD> evidence$8)

Create a RDD from Kafka using offset ranges for each topic and partition.

Parameters:

sc - SparkContext object

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers) specified in host1:port1,host2:port2 form.

offsetRanges - Each OffsetRange in the batch corresponds to a range of offsets for a given Kafka topic/partition

evidence$5 - (undocumented)

evidence$6 - (undocumented)

evidence$7 - (undocumented)

evidence$8 - (undocumented)

Returns:

RDD of (Kafka message key, Kafka message value)

createRDD

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> RDD<R> createRDD(SparkContext sc,
                                                                                                     scala.collection.immutable.Map<String,String> kafkaParams,
                                                                                                     OffsetRange[] offsetRanges,
                                                                                                     scala.collection.immutable.Map<kafka.common.TopicAndPartition,Broker> leaders,
                                                                                                     scala.Function1<kafka.message.MessageAndMetadata<K,V>,R> messageHandler,
                                                                                                     scala.reflect.ClassTag<K> evidence$9,
                                                                                                     scala.reflect.ClassTag<V> evidence$10,
                                                                                                     scala.reflect.ClassTag<KD> evidence$11,
                                                                                                     scala.reflect.ClassTag<VD> evidence$12,
                                                                                                     scala.reflect.ClassTag<R> evidence$13)

Create a RDD from Kafka using offset ranges for each topic and partition. This allows you specify the Kafka leader to connect to (to optimize fetching) and access the message as well as the metadata.

Parameters:

sc - SparkContext object

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers) specified in host1:port1,host2:port2 form.

offsetRanges - Each OffsetRange in the batch corresponds to a range of offsets for a given Kafka topic/partition

leaders - Kafka brokers for each TopicAndPartition in offsetRanges. May be an empty map, in which case leaders will be looked up on the driver.

messageHandler - Function for translating each message and metadata into the desired type

evidence$9 - (undocumented)

evidence$10 - (undocumented)

evidence$11 - (undocumented)

evidence$12 - (undocumented)

evidence$13 - (undocumented)

Returns:

RDD of R

createRDD

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> JavaPairRDD<K,V> createRDD(JavaSparkContext jsc,
                                                                                                             Class<K> keyClass,
                                                                                                             Class<V> valueClass,
                                                                                                             Class<KD> keyDecoderClass,
                                                                                                             Class<VD> valueDecoderClass,
                                                                                                             java.util.Map<String,String> kafkaParams,
                                                                                                             OffsetRange[] offsetRanges)

Create a RDD from Kafka using offset ranges for each topic and partition.

Parameters:

jsc - JavaSparkContext object

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers) specified in host1:port1,host2:port2 form.

offsetRanges - Each OffsetRange in the batch corresponds to a range of offsets for a given Kafka topic/partition

keyClass - type of Kafka message key

valueClass - type of Kafka message value

keyDecoderClass - type of Kafka message key decoder

valueDecoderClass - type of Kafka message value decoder

Returns:

RDD of (Kafka message key, Kafka message value)

createRDD

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> JavaRDD<R> createRDD(JavaSparkContext jsc,
                                                                                                         Class<K> keyClass,
                                                                                                         Class<V> valueClass,
                                                                                                         Class<KD> keyDecoderClass,
                                                                                                         Class<VD> valueDecoderClass,
                                                                                                         Class<R> recordClass,
                                                                                                         java.util.Map<String,String> kafkaParams,
                                                                                                         OffsetRange[] offsetRanges,
                                                                                                         java.util.Map<kafka.common.TopicAndPartition,Broker> leaders,
                                                                                                         Function<kafka.message.MessageAndMetadata<K,V>,R> messageHandler)

Create a RDD from Kafka using offset ranges for each topic and partition. This allows you specify the Kafka leader to connect to (to optimize fetching) and access the message as well as the metadata.

Parameters:

jsc - JavaSparkContext object

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers) specified in host1:port1,host2:port2 form.

offsetRanges - Each OffsetRange in the batch corresponds to a range of offsets for a given Kafka topic/partition

leaders - Kafka brokers for each TopicAndPartition in offsetRanges. May be an empty map, in which case leaders will be looked up on the driver.

messageHandler - Function for translating each message and metadata into the desired type

keyClass - (undocumented)

valueClass - (undocumented)

keyDecoderClass - (undocumented)

valueDecoderClass - (undocumented)

recordClass - (undocumented)

Returns:

RDD of R

createDirectStream

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> InputDStream<R> createDirectStream(StreamingContext ssc,
                                                                                                                       scala.collection.immutable.Map<String,String> kafkaParams,
                                                                                                                       scala.collection.immutable.Map<kafka.common.TopicAndPartition,Object> fromOffsets,
                                                                                                                       scala.Function1<kafka.message.MessageAndMetadata<K,V>,R> messageHandler,
                                                                                                                       scala.reflect.ClassTag<K> evidence$14,
                                                                                                                       scala.reflect.ClassTag<V> evidence$15,
                                                                                                                       scala.reflect.ClassTag<KD> evidence$16,
                                                                                                                       scala.reflect.ClassTag<VD> evidence$17,
                                                                                                                       scala.reflect.ClassTag<R> evidence$18)

Create an input stream that directly pulls messages from Kafka Brokers without using any receiver. This stream can guarantee that each message from Kafka is included in transformations exactly once (see points below).

Points to note: - No receivers: This stream does not use any receiver. It directly queries Kafka - Offsets: This does not use Zookeeper to store offsets. The consumed offsets are tracked by the stream itself. For interoperability with Kafka monitoring tools that depend on Zookeeper, you have to update Kafka/Zookeeper yourself from the streaming application. You can access the offsets used in each batch from the generated RDDs (see HasOffsetRanges). - Failure Recovery: To recover from driver failures, you have to enable checkpointing in the StreamingContext. The information on consumed offset can be recovered from the checkpoint. See the programming guide for details (constraints, etc.). - End-to-end semantics: This stream ensures that every records is effectively received and transformed exactly once, but gives no guarantees on whether the transformed data are outputted exactly once. For end-to-end exactly-once semantics, you have to either ensure that the output operation is idempotent, or use transactions to output records atomically. See the programming guide for more details.

Parameters:

ssc - StreamingContext object

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers) specified in host1:port1,host2:port2 form.

fromOffsets - Per-topic/partition Kafka offsets defining the (inclusive) starting point of the stream

messageHandler - Function for translating each message and metadata into the desired type

evidence$14 - (undocumented)

evidence$15 - (undocumented)

evidence$16 - (undocumented)

evidence$17 - (undocumented)

evidence$18 - (undocumented)

Returns:

DStream of R

createDirectStream

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> InputDStream<scala.Tuple2<K,V>> createDirectStream(StreamingContext ssc,
                                                                                                                                     scala.collection.immutable.Map<String,String> kafkaParams,
                                                                                                                                     scala.collection.immutable.Set<String> topics,
                                                                                                                                     scala.reflect.ClassTag<K> evidence$19,
                                                                                                                                     scala.reflect.ClassTag<V> evidence$20,
                                                                                                                                     scala.reflect.ClassTag<KD> evidence$21,
                                                                                                                                     scala.reflect.ClassTag<VD> evidence$22)

Create an input stream that directly pulls messages from Kafka Brokers without using any receiver. This stream can guarantee that each message from Kafka is included in transformations exactly once (see points below).

Points to note: - No receivers: This stream does not use any receiver. It directly queries Kafka - Offsets: This does not use Zookeeper to store offsets. The consumed offsets are tracked by the stream itself. For interoperability with Kafka monitoring tools that depend on Zookeeper, you have to update Kafka/Zookeeper yourself from the streaming application. You can access the offsets used in each batch from the generated RDDs (see HasOffsetRanges). - Failure Recovery: To recover from driver failures, you have to enable checkpointing in the StreamingContext. The information on consumed offset can be recovered from the checkpoint. See the programming guide for details (constraints, etc.). - End-to-end semantics: This stream ensures that every records is effectively received and transformed exactly once, but gives no guarantees on whether the transformed data are outputted exactly once. For end-to-end exactly-once semantics, you have to either ensure that the output operation is idempotent, or use transactions to output records atomically. See the programming guide for more details.

Parameters:

ssc - StreamingContext object

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers), specified in host1:port1,host2:port2 form. If not starting from a checkpoint, "auto.offset.reset" may be set to "largest" or "smallest" to determine where the stream starts (defaults to "largest")

topics - Names of the topics to consume

evidence$19 - (undocumented)

evidence$20 - (undocumented)

evidence$21 - (undocumented)

evidence$22 - (undocumented)

Returns:

DStream of (Kafka message key, Kafka message value)

createDirectStream

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>,R> JavaInputDStream<R> createDirectStream(JavaStreamingContext jssc,
                                                                                                                           Class<K> keyClass,
                                                                                                                           Class<V> valueClass,
                                                                                                                           Class<KD> keyDecoderClass,
                                                                                                                           Class<VD> valueDecoderClass,
                                                                                                                           Class<R> recordClass,
                                                                                                                           java.util.Map<String,String> kafkaParams,
                                                                                                                           java.util.Map<kafka.common.TopicAndPartition,Long> fromOffsets,
                                                                                                                           Function<kafka.message.MessageAndMetadata<K,V>,R> messageHandler)

Create an input stream that directly pulls messages from Kafka Brokers without using any receiver. This stream can guarantee that each message from Kafka is included in transformations exactly once (see points below).

Points to note: - No receivers: This stream does not use any receiver. It directly queries Kafka - Offsets: This does not use Zookeeper to store offsets. The consumed offsets are tracked by the stream itself. For interoperability with Kafka monitoring tools that depend on Zookeeper, you have to update Kafka/Zookeeper yourself from the streaming application. You can access the offsets used in each batch from the generated RDDs (see HasOffsetRanges). - Failure Recovery: To recover from driver failures, you have to enable checkpointing in the StreamingContext. The information on consumed offset can be recovered from the checkpoint. See the programming guide for details (constraints, etc.). - End-to-end semantics: This stream ensures that every records is effectively received and transformed exactly once, but gives no guarantees on whether the transformed data are outputted exactly once. For end-to-end exactly-once semantics, you have to either ensure that the output operation is idempotent, or use transactions to output records atomically. See the programming guide for more details.

Parameters:

jssc - JavaStreamingContext object

keyClass - Class of the keys in the Kafka records

valueClass - Class of the values in the Kafka records

keyDecoderClass - Class of the key decoder

valueDecoderClass - Class of the value decoder

recordClass - Class of the records in DStream

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers), specified in host1:port1,host2:port2 form.

fromOffsets - Per-topic/partition Kafka offsets defining the (inclusive) starting point of the stream

messageHandler - Function for translating each message and metadata into the desired type

Returns:

DStream of R

createDirectStream

public static <K,V,KD extends kafka.serializer.Decoder<K>,VD extends kafka.serializer.Decoder<V>> JavaPairInputDStream<K,V> createDirectStream(JavaStreamingContext jssc,
                                                                                                                               Class<K> keyClass,
                                                                                                                               Class<V> valueClass,
                                                                                                                               Class<KD> keyDecoderClass,
                                                                                                                               Class<VD> valueDecoderClass,
                                                                                                                               java.util.Map<String,String> kafkaParams,
                                                                                                                               java.util.Set<String> topics)

Create an input stream that directly pulls messages from Kafka Brokers without using any receiver. This stream can guarantee that each message from Kafka is included in transformations exactly once (see points below).

Points to note: - No receivers: This stream does not use any receiver. It directly queries Kafka - Offsets: This does not use Zookeeper to store offsets. The consumed offsets are tracked by the stream itself. For interoperability with Kafka monitoring tools that depend on Zookeeper, you have to update Kafka/Zookeeper yourself from the streaming application. You can access the offsets used in each batch from the generated RDDs (see HasOffsetRanges). - Failure Recovery: To recover from driver failures, you have to enable checkpointing in the StreamingContext. The information on consumed offset can be recovered from the checkpoint. See the programming guide for details (constraints, etc.). - End-to-end semantics: This stream ensures that every records is effectively received and transformed exactly once, but gives no guarantees on whether the transformed data are outputted exactly once. For end-to-end exactly-once semantics, you have to either ensure that the output operation is idempotent, or use transactions to output records atomically. See the programming guide for more details.

Parameters:

jssc - JavaStreamingContext object

keyClass - Class of the keys in the Kafka records

valueClass - Class of the values in the Kafka records

keyDecoderClass - Class of the key decoder

valueDecoderClass - Class type of the value decoder

kafkaParams - Kafka configuration parameters. Requires "metadata.broker.list" or "bootstrap.servers" to be set with Kafka broker(s) (NOT zookeeper servers), specified in host1:port1,host2:port2 form. If not starting from a checkpoint, "auto.offset.reset" may be set to "largest" or "smallest" to determine where the stream starts (defaults to "largest")

topics - Names of the topics to consume

Returns:

DStream of (Kafka message key, Kafka message value)