在Storm中将两个螺栓的输出发送到一个螺栓？

Question

将BoltA和BoltB的输出发送到BoltC的最简单方法是什么.我是否必须使用联接或是否有任何更简单的解决方案.A和B具有相同的字段(ts,metric_name,metric_count).

    // KafkaSpout --> LogDecoder
    builder.setBolt(LOGDECODER_BOLT_ID, logdecoderBolt, 10).shuffleGrouping(KAFKA_SPOUT_ID);

    // LogDecoder --> CountBolt
    builder.setBolt(COUNT_BOLT_ID, countBolt, 10).shuffleGrouping(LOGDECODER_BOLT_ID);

    // LogDecoder --> HttpResCodeCountBolt
    builder.setBolt(HTTP_RES_CODE_COUNT_BOLT_ID, http_res_code_count_bolt, 10).shuffleGrouping(LOGDECODER_BOLT_ID);


    # And now I want to send CountBolt and HttpResCodeCountBolt output to Aggregator Bolt.

    // CountBolt --> AggregatwBolt
    builder.setBolt(AGGREGATE_BOLT_ID, aggregateBolt, 5).fieldsGrouping((COUNT_BOLT_ID), new Fields("ts"));

    // HttpResCodeCountBolt --> AggregatwBolt
    builder.setBolt(AGGREGATE_BOLT_ID, aggregateBolt, 5).fieldsGrouping((HTTP_RES_CODE_COUNT_BOLT_ID), new Fields("ts"));

这可能吗 ？

Answer 1

是.只需在fieldsGrouping调用中添加stream-id(下面的"stream1"和"stream2"):

BoltDeclarer bd = builder.setBolt(AGGREGATE_BOLT_ID, aggregateBolt, 5); 
bd.fieldsGrouping((COUNT_BOLT_ID), "stream1",  new Fields("ts"));
bd.fieldsGrouping((HTTP_RES_CODE_COUNT_BOLT_ID), "stream2", new Fields("ts"));

然后在BoltC的execute()方法中,您可以测试以查看元组来自哪个流:

public void execute(Tuple tuple) {

    if ("stream1".equals(tuple.getSourceStreamId())) {
        // this came from stream1
    } else if ("stream2".equals(tuple.getSourceStreamId())) {
        // this came from stream2
    }

由于您知道元组来自哪个流,因此您不需要在两个流上具有相同形状的元组.您只需根据stream-id对元组进行解组.

您还可以检查元组来自哪个组件(因为我输入这个,我认为这可能更适合您的情况)以及发出元组的组件(任务)的实例.