Read the data from specific partition of topic in Kafka broker via Spark Streaming

Question

I am new to Spark an apology for asking such a question. I have a use case where I want to read a data from a specific partition of a topic with the help of Spark Streaming. I am using Spark Java API to do all the stuff.

I have created a topic named test with replication factor 2 and 5 partitions. Hopefully with the help of spark streaming Kafka integration guide, I am able to do all the things like creating a JavaStreamingContext object, creating a direct stream to Kafka broker and able to read all the message from all partition.

But still my use case does not fulfill, I have to read only messages of a particular partition of a topic in Kafka broker instead of all messages from all partition.

Answer 1

You should be able to read specific partition from specific offset using following code.

Map<TopicAndPartition, Long> consumerOffsets = new HashMap<TopicAndPartition, Long>();
TopicAndPartition p1 = new TopicAndPartition("yourtopic","yourpartition");
consumerOffsets.put(p1,offset);

JavaInputDStream<String>  messages = KafkaUtils.createDirectStream(
        jssc, 
        String.class, 
        String.class,
        StringDecoder.class, 
        StringDecoder.class, 
        String.class,
        kafkaParams,
        consumerOffsetsLong,
        new Function<MessageAndMetadata<String, String>, String>() {
            public String call(MessageAndMetadata<String, String> msgAndMeta) throws Exception {
                return msgAndMeta.message();
            }
        }
);