storm從0.9.0開始，增加了指標統計框架，用來收集應用程序的特定指標，並將其輸出到外部系統。
本文中採用的監聽類是LoggingMetricsConsumer，統計指標值將輸出到metric.log日誌文件中。
當然也可以自定義監聽類，只需要實現IMetricsConsumer接口即可，這些類可以在代碼裏註冊（registerMetricsConsumer），也可以在 storm.yaml配置文件中註冊：
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topology.metrics.consumer.register:
- class: "backtype.storm.metrics.LoggingMetricsConsumer"
parallelism.hint: 1
- class: "org.mycompany.MyMetricsConsumer"
parallelism.hint: 1
argument:
- endpoint: "metrics-collector.mycompany.org"
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下面簡單修改storm-starter包中的例子，統計三個指標：
1、每5秒統計execute方法的調用次數
2、每1分鐘統計每個單詞的出現次數
3、每1分鐘統計所有出現的單詞的平均長度
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public class ExclamationTopology {
public static class ExclamationBolt extends BaseRichBolt {
OutputCollector _collector;
//定義指標統計對象
transient CountMetric _countMetric;
transient MultiCountMetric _wordCountMetric;
transient ReducedMetric _wordLengthMeanMetric;
@Override
public void prepare(Map conf, TopologyContext context, OutputCollector collector) {
_collector = collector;
initMetrics(context);
}
@Override
public void execute(Tuple tuple) {
_collector.emit(tuple, new Values(tuple.getString(0) + "!!!"));
_collector.ack(tuple);
updateMetrics(tuple.getString(0));
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("word"));
}
//初始化計數器
void initMetrics(TopologyContext context)
{
_countMetric = new CountMetric();
_wordCountMetric = new MultiCountMetric();
_wordLengthMeanMetric = new ReducedMetric(new MeanReducer());
context.registerMetric("execute_count", _countMetric, 5);
context.registerMetric("word_count", _wordCountMetric, 60);
context.registerMetric("word_length", _wordLengthMeanMetric, 60);
}
//更新計數器
void updateMetrics(String word)
{
_countMetric.incr();
_wordCountMetric.scope(word).incr();
_wordLengthMeanMetric.update(word.length());
}
}
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);
//輸出統計指標值到日誌文件中
conf.registerMetricsConsumer(LoggingMetricsConsumer.class, 2);
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();
}
}
}
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統計結果的獲取與清空（源碼）：
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***********************************************************
CountMetric
***********************************************************
public Object getValueAndReset() {
long ret = _value;
_value = 0;
return ret;
}
***********************************************************
MultiCountMetric
***********************************************************
public Object getValueAndReset() {
Map ret = new HashMap();
for(Map.Entry<String, CountMetric> e : _value.entrySet()) {
ret.put(e.getKey(), e.getValue().getValueAndReset());
}
return ret;
}
***********************************************************
ReducedMetric
***********************************************************
public Object getValueAndReset() {
Object ret = _reducer.extractResult(_accumulator);
_accumulator = _reducer.init();
return ret;
}
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Storm UI界面：
metric日誌內容節選——
某一臺機器上的日誌：
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2014-04-01 00:57:38,855 64645 1396339058 ubuntu:6703 8:exclaim1 execute_count 776
2014-04-01 00:58:03,855 89645 1396339083 ubuntu:6703 8:exclaim1 execute_count 66
2014-04-01 01:01:38,878 304668 1396339298 ubuntu:6703 8:exclaim1 word_count {bertels=172, jackson=152, nathan=155, mike=155, golda=155}
2014-04-01 01:01:38,878 304668 1396339298 ubuntu:6703 8:exclaim1 word_length 5.821292775665399
2014-04-01 01:03:38,878 424668 1396339418 ubuntu:6703 8:exclaim1 word_count {bertels=161, jackson=156, nathan=151, mike=158, golda=163}
2014-04-01 01:03:38,878 424668 1396339418 ubuntu:6703 8:exclaim1 word_length 5.79467680608365
2014-04-01 01:03:48,937 434727 1396339428 ubuntu:6703 8:exclaim1 execute_count 65
2014-04-01 01:03:58,935 444725 1396339438 ubuntu:6703 8:exclaim1 execute_count 65
2014-04-01 01:05:38,879 544669 1396339538 ubuntu:6703 8:exclaim1 word_count {bertels=165, jackson=167, nathan=144, mike=146, golda=165}
2014-04-01 01:05:38,879 544669 1396339538 ubuntu:6703 8:exclaim1 word_length 5.841168996188056
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另一臺機器上的日誌：
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2014-04-01 00:57:00,934 12756 1396339020 ubuntu:6703 7:exclaim1 execute_count 95
2014-04-01 00:57:00,958 12780 1396339020 ubuntu:6702 9:exclaim2 execute_count 95
2014-04-01 00:57:00,959 12781 1396339020 ubuntu:6703 10:exclaim2 execute_count 94
2014-04-01 00:57:05,927 17749 1396339025 ubuntu:6702 6:exclaim1 execute_count 97
2014-04-01 00:57:10,948 22770 1396339030 ubuntu:6702 9:exclaim2 execute_count 99
2014-04-01 00:57:15,931 27753 1396339035 ubuntu:6703 7:exclaim1 execute_count 100
2014-04-01 00:58:55,949 127771 1396339135 ubuntu:6702 9:exclaim2 word_length 8.829391891891891
2014-04-01 00:58:55,963 127785 1396339135 ubuntu:6703 10:exclaim2 word_count {bertels!!!=250, golda!!!=216, jackson!!!=237, nathan!!!=231, mike!!!=250}
2014-04-01 00:58:55,963 127785 1396339135 ubuntu:6703 10:exclaim2 word_length 8.806587837837839
2014-04-01 00:59:55,918 187740 1396339195 ubuntu:6702 6:exclaim1 word_count {bertels=256, jackson=248, nathan=234, mike=224, golda=219}
2014-04-01 00:59:55,995 187817 1396339195 ubuntu:6703 10:exclaim2 execute_count 98
2014-04-01 01:00:00,994 192816 1396339200 ubuntu:6702 9:exclaim2 execute_count 98
2014-04-01 01:00:05,966 197788 1396339205 ubuntu:6703 7:exclaim1 execute_count 99
2014-04-01 01:00:55,949 247771 1396339255 ubuntu:6702 9:exclaim2 word_count {bertels!!!=248, golda!!!=233, jackson!!!=220, nathan!!!=241, mike!!!=240}
2014-04-01 01:00:55,965 247787 1396339255 ubuntu:6703 10:exclaim2 word_count {bertels!!!=258, golda!!!=240, jackson!!!=214, nathan!!!=258, mike!!!=215}
2014-04-01 01:00:55,965 247787 1396339255 ubuntu:6703 10:exclaim2 word_length 8.832911392405064
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