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ASF GitHub Bot updated STORM-3598: ---------------------------------- Labels: pull-request-available (was: ) > Storm UI visualization throws NullPointerException > -------------------------------------------------- > > Key: STORM-3598 > URL: https://issues.apache.org/jira/browse/STORM-3598 > Project: Apache Storm > Issue Type: Bug > Affects Versions: 2.0.0, 2.1.0 > Reporter: Ethan Li > Assignee: Ethan Li > Priority: Major > Labels: pull-request-available > > We encountered an issue with visualization on UI. > > {code:java} > 2020-03-09 19:59:01.756 o.a.s.d.u.r.StormApiResource qtp1919834117-167291 > [ERROR] Failure getting topology visualization > java.lang.NullPointerException: null > at > org.apache.storm.stats.StatsUtil.mergeWithAddPair(StatsUtil.java:1855) > ~[storm-server-2.2.0.y.jar:2.2.0.y] > at > org.apache.storm.stats.StatsUtil.expandAveragesSeq(StatsUtil.java:2308) > ~[storm-server-2.2.0.y.jar:2.2.0.y] > at > org.apache.storm.stats.StatsUtil.aggregateAverages(StatsUtil.java:832) > ~[storm-server-2.2.0.y.jar:2.2.0.y] > at > org.apache.storm.stats.StatsUtil.aggregateBoltStats(StatsUtil.java:731) > ~[storm-server-2.2.0.y.jar:2.2.0.y] > at > org.apache.storm.stats.StatsUtil.boltStreamsStats(StatsUtil.java:900) > ~[storm-server-2.2.0.y.jar:2.2.0.y] > at > org.apache.storm.daemon.ui.UIHelpers.getVisualizationData(UIHelpers.java:1939) > ~[storm-webapp-2.2.0.y.jar:2.2.0.y] > at > org.apache.storm.daemon.ui.resources.StormApiResource.getTopologyVisualization(StormApiResource.java:423) > ~[storm-webapp-2.2.0.y.jar:2.2.0.y] > {code} > This is a bug in the code. > https://github.com/apache/storm/blob/master/storm-server/src/main/java/org/apache/storm/stats/StatsUtil.java#L1846-L1858 > {code:java} > for (K kk : mm1.keySet()) { > List seq1 = mm1.get(kk); > List seq2 = mm2.get(kk); > List sums = new ArrayList(); > for (int i = 0; i < seq1.size(); i++) { > if (seq1.get(i) instanceof Long) { > sums.add(((Number) seq1.get(i)).longValue() + > ((Number) seq2.get(i)).longValue()); > } else { > sums.add(((Number) seq1.get(i)).doubleValue() + > ((Number) seq2.get(i)).doubleValue()); > } > } > tmp.put(kk, sums); > } > {code} > It assume mm1 and mm2 always have the same key, which is not true. > And it can be reproduced by my example code: > {code:java} > public class WordCountTopology extends ConfigurableTopology { > private static final Logger LOG = > LoggerFactory.getLogger(WordCountTopology.class); > public static void main(String[] args) { > ConfigurableTopology.start(new WordCountTopology(), args); > } > protected int run(String[] args) { > TopologyBuilder builder = new TopologyBuilder(); > builder.setSpout("spout1", new RandomSpout(1), 1); > builder.setSpout("spout2", new RandomSpout(2), 1); > builder.setBolt("bolt", new RandomBolt(), 2).directGrouping("spout1", > "stream1") > .directGrouping("spout2", "stream2"); > String topologyName = "word-count"; > conf.setNumWorkers(3); > if (args != null && args.length > 0) { > topologyName = args[0]; > } > return submit(topologyName, conf, builder); > } > static class RandomSpout extends BaseRichSpout { > String stream; > int id; > public RandomSpout(int id) { > this.id = id; > stream = "stream" + id; > } > int taskId = 0; > SpoutOutputCollector collector; > public void open(Map<String, Object> conf, TopologyContext context, > SpoutOutputCollector collector) { > taskId = context.getThisTaskId(); > this.collector = collector; > } > /** > * Different spout send tuples to different bolt via different stream. > */ > public void nextTuple() { > LOG.info("emitting {}", id); > if (id == 1) { > Values val = new Values("test a sentence"); > collector.emitDirect(2, stream, val, val); > } else { > Values val = new Values("test 2 sentence"); > collector.emitDirect(3, stream, val, val); > } > try { > Thread.sleep(1000); > } catch (InterruptedException e) { > e.printStackTrace(); > } > } > public void declareOutputFields(OutputFieldsDeclarer declarer) { > declarer.declareStream(stream, new Fields("word")); > } > } > static class RandomBolt extends BaseBasicBolt { > public void execute(Tuple input, BasicOutputCollector collector) { > LOG.info("executing:" + input.getSourceComponent()); > } > public void declareOutputFields(OutputFieldsDeclarer declarer) { > } > } > } > {code} > In this example, one of the bolt will only receive data from stream1 and > another bolt will only receive data from stream2. So in the map, > {code:java} > List seq1 = mm1.get(kk); > List seq2 = mm2.get(kk); > {code} > seq1 is null if kk is stream1, seq2 is null if kk is stream2. > > We have other places aggregating executor stats without this problem because > it's using different code > https://github.com/apache/storm/blob/master/storm-server/src/main/java/org/apache/storm/stats/StatsUtil.java#L502-L513 > and this problem has been taken cared of. -- This message was sent by Atlassian Jira (v8.3.4#803005)