Class: KafkaUtils

NOTE: This currently only works on Kafka key/values which are Strings 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.