| /* |
| 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.storm.starter; |
| |
| import java.util.Map; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import org.apache.storm.Config; |
| import org.apache.storm.metric.LoggingMetricsConsumer; |
| import org.apache.storm.starter.bolt.WordCountBolt; |
| import org.apache.storm.starter.spout.RandomSentenceSpout; |
| import org.apache.storm.task.OutputCollector; |
| import org.apache.storm.task.TopologyContext; |
| import org.apache.storm.topology.ConfigurableTopology; |
| import org.apache.storm.topology.IRichBolt; |
| import org.apache.storm.topology.OutputFieldsDeclarer; |
| import org.apache.storm.topology.TopologyBuilder; |
| import org.apache.storm.tuple.Fields; |
| import org.apache.storm.tuple.Tuple; |
| import org.apache.storm.tuple.Values; |
| |
| /** |
| * Some topologies might spawn some threads within bolts to do some work and emit tuples from those threads. |
| * This is a simple wordcount topology example that mimics those use cases and might help us catch possible race conditions. |
| */ |
| public class MultiThreadWordCountTopology extends ConfigurableTopology { |
| public static void main(String[] args) { |
| ConfigurableTopology.start(new MultiThreadWordCountTopology(), args); |
| } |
| |
| @Override |
| protected int run(String[] args) { |
| |
| TopologyBuilder builder = new TopologyBuilder(); |
| |
| builder.setSpout("spout", new RandomSentenceSpout(), 1); |
| builder.setBolt("split", new MultiThreadedSplitSentence(), 1).shuffleGrouping("spout"); |
| builder.setBolt("count", new WordCountBolt(), 1).fieldsGrouping("split", new Fields("word")); |
| |
| //this makes sure there is only one executor per worker, easier to debug |
| //problems involving serialization/deserialization will only happen in inter-worker data transfer |
| conf.put(Config.TOPOLOGY_RAS_ONE_EXECUTOR_PER_WORKER, true); |
| //this involves metricsTick |
| conf.registerMetricsConsumer(LoggingMetricsConsumer.class); |
| |
| conf.setTopologyWorkerMaxHeapSize(128); |
| |
| String topologyName = "multithreaded-word-count"; |
| |
| if (args != null && args.length > 0) { |
| topologyName = args[0]; |
| } |
| return submit(topologyName, conf, builder); |
| } |
| |
| public static class MultiThreadedSplitSentence implements IRichBolt { |
| |
| private OutputCollector collector; |
| private ExecutorService executor; |
| |
| @Override |
| public void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector collector) { |
| this.collector = collector; |
| executor = Executors.newFixedThreadPool(6); |
| //This makes sure metricsTick to be called every 1 second |
| //it makes the race condition between metricsTick and outputCollector easier to happen if any |
| context.registerMetric("dummy-counter", () -> 0, 1); |
| } |
| |
| @Override |
| public void execute(Tuple input) { |
| String str = input.getString(0); |
| String[] splits = str.split("\\s+"); |
| for (String s : splits) { |
| //spawn other threads to do the work and emit |
| Runnable runnableTask = () -> { |
| collector.emit(new Values(s)); |
| }; |
| executor.submit(runnableTask); |
| } |
| } |
| |
| @Override |
| public void declareOutputFields(OutputFieldsDeclarer declarer) { |
| declarer.declare(new Fields("word")); |
| } |
| |
| @Override |
| public Map<String, Object> getComponentConfiguration() { |
| return null; |
| } |
| |
| @Override |
| public void cleanup() { |
| } |
| } |
| } |