Storm starter - Overview

Storm的starter例子, 都给的很有诚意, 不光是例子, 而是可以直接使用在实际的场景里面.  并且提高一些很有用的tool, 比如SlidingWindowCounter, TimeCacheMap  所以starter可以说是提高了基于storm编程的框架, 值得认真研究一下...

 

ExclamationTopology, 基本的Topology

没有什么特别的地方, 标准的例子

/** * This is a basic example of a Storm topology. */ public class ExclamationTopology { public static class ExclamationBolt extends BaseRichBolt { OutputCollector _collector; @Override public void prepare(Map conf, TopologyContext context, OutputCollector collector) { _collector = collector; } @Override public void execute(Tuple tuple) { _collector.emit(tuple, new Values(tuple.getString(0) + "!!!")); _collector.ack(tuple); } @Override public void declareOutputFields(OutputFieldsDeclarer declarer) { declarer.declare(new Fields("word")); } } public static void main(String[] args) throws Exception { TopologyBuilder builder = new TopologyBuilder(); builder.setSpout("word", new TestWordSpout(), 10); builder.setBolt("exclaim1", new ExclamationBolt(), 3) .shuffleGrouping("word"); builder.setBolt("exclaim2", new ExclamationBolt(), 2) .shuffleGrouping("exclaim1"); Config conf = new Config(); conf.setDebug(true); if(args!=null && args.length > 0) { conf.setNumWorkers(3); StormSubmitter.submitTopology(args[0], conf, builder.createTopology()); } else { LocalCluster cluster = new LocalCluster(); cluster.submitTopology("test", conf, builder.createTopology()); Utils.sleep(10000); cluster.killTopology("test"); cluster.shutdown(); } } }

 

RollingTopWords

实现了TopN和滑动窗口功能  这个例子的Bolt实现的很有指导意义, Storm starter - RollingTopWords

 

SingleJoinExample

通过TimeCacheMap, 实现基于memory的join, Storm starter - SingleJoinExample

 

BasicDRPCTopology, ReachTopology

关于DRPC的例子, 参考Twitter Storm – DRPC

 

TransactionalGlobalCount, TransactionalWords

Transactional Topology, Storm - Transactional-topologies

TransactionalGlobalCount比较简单, 看看TransactionalWords  在对word计数的基础上, 加上word count分布统计信息

public static Map<String, CountValue> COUNT_DATABASE = new HashMap<String, CountValue>(); public static Map<Integer, BucketValue> BUCKET_DATABASE = new HashMap<Integer, BucketValue>(); 使用Count_Database来记录word的计数  使用Bucket_Database来记录word计数的分布, 比如, 出现0~9次的word有多少, 10~20的word有多少  public static class KeyedCountUpdater extends BaseTransactionalBolt implements ICommitter

对于KeyedCountUpdater和前面的简单例子没有啥大区别, 在execute时对word进行count, 在finishBatch时, 直接commit到Count_Database  输出, new Fields("id", "key", "count", "prev-count"), 其他都好理解, 为啥需要prev-count? 因为在更新Bucket_Database, 需要知道该word的bucket是否发生迁移, 所以必须知道之前的count

 

Bucketize, 根据count/BUCKET_SIZE, 算出应该属于哪个bucket  如果新的word, 直接在某bucket +1  如果word的bucket发生变化, 在新的bucket +1, 旧的bucket –1  如果没有变化, 不需要输出

public static class Bucketize extends BaseBasicBolt { @Override public void execute(Tuple tuple, BasicOutputCollector collector) { TransactionAttempt attempt = (TransactionAttempt) tuple.getValue(0); int curr = tuple.getInteger(2); Integer prev = tuple.getInteger(3); int currBucket = curr / BUCKET_SIZE; Integer prevBucket = null; if(prev!=null) { prevBucket = prev / BUCKET_SIZE; } if(prevBucket==null) { collector.emit(new Values(attempt, currBucket, 1)); } else if(currBucket != prevBucket) { collector.emit(new Values(attempt, currBucket, 1)); collector.emit(new Values(attempt, prevBucket, -1)); } } @Override public void declareOutputFields(OutputFieldsDeclarer declarer) { declarer.declare(new Fields("attempt", "bucket", "delta")); } } BucketCountUpdater, 也就是将上面的bucket的更新, 更新到Bucket_Database 

Topology定义如下,

MemoryTransactionalSpout spout = new MemoryTransactionalSpout(DATA, new Fields("word"), PARTITION_TAKE_PER_BATCH); TransactionalTopologyBuilder builder = new TransactionalTopologyBuilder("top-n-words", "spout", spout, 2); builder.setBolt("count", new KeyedCountUpdater(), 5) .fieldsGrouping("spout", new Fields("word")); builder.setBolt("bucketize", new Bucketize()) .noneGrouping("count"); builder.setBolt("buckets", new BucketCountUpdater(), 5) .fieldsGrouping("bucketize", new Fields("bucket"));

 

WordCountTopology, 多语言的支持

Storm 多语言支持

分别使用ShellBolt和BaseBasicBolt来声明使用python和Java实现的Blot

public static class SplitSentence extends ShellBolt implements IRichBolt { public SplitSentence() { super("python", "splitsentence.py"); } @Override public void declareOutputFields(OutputFieldsDeclarer declarer) { declarer.declare(new Fields("word")); } @Override public Map<String, Object> getComponentConfiguration() { return null; } } public static class WordCount extends BaseBasicBolt { Map<String, Integer> counts = new HashMap<String, Integer>(); @Override public void execute(Tuple tuple, BasicOutputCollector collector) { String word = tuple.getString(0); Integer count = counts.get(word); if(count==null) count = 0; count++; counts.put(word, count); collector.emit(new Values(word, count)); } @Override public void declareOutputFields(OutputFieldsDeclarer declarer) { declarer.declare(new Fields("word", "count")); } }

在定义Topology的时候, 可以直接将ShellBolt和BaseBasicBolt混合使用, 非常方便

TopologyBuilder builder = new TopologyBuilder(); builder.setSpout("spout", new RandomSentenceSpout(), 5); builder.setBolt("split", new SplitSentence(), 8) .shuffleGrouping("spout"); builder.setBolt("count", new WordCount(), 12) .fieldsGrouping("split", new Fields("word")); 本文章摘自博客园，原文发布日期：2013-05-24 相关资源：敏捷开发V1.0.pptx