Storm入門示例

　　開發Storm的第一步就是設計Topology，爲了方便開發者入門，首先咱們設計一個簡答的例子，該例子的主要的功能就是把每一個單詞的後面加上Hello，World後綴，而後再打印輸出，整個例子的Topology圖以下：

　　整個Topology分爲三部分：

　　TestWordSpout:數據源，負責發送words

　　ExclamationBolt:負責把每一個單詞後面加上後綴

　　PrintBolt:負責把單詞打印輸出

代碼實現：

1.使用IDEA建立maven過程，添加Maven依賴

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.ysl</groupId>
    <artifactId>storm</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/storm/storm -->
        <dependency>
            <groupId>org.apache.storm</groupId>
            <artifactId>storm-core</artifactId>
            <version>0.9.4</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <mainClass>com.ysl.WordsTopology</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

TestWordSpout：

package com.ysl.spouts;

import backtype.storm.spout.SpoutOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichSpout;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;
import backtype.storm.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;
import java.util.Random;

public class TestWordSpout extends BaseRichSpout{

    private static Logger logger = LoggerFactory.getLogger(TestWordSpout.class);
    private SpoutOutputCollector collector = null;

    public void open(Map map, TopologyContext topologyContext, SpoutOutputCollector spoutOutputCollector) {
        this.collector = spoutOutputCollector;
    }

    public void nextTuple() {
        Utils.sleep(1000);
        final String[] words = new String[]{"fdfs","fdfs","ffsdfs"};
        final Random random = new Random();
        final String word = words[random.nextInt(words.length)];
        collector.emit(new Values(word));
    }

    public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {
        outputFieldsDeclarer.declare(new Fields("word"));
    }
}

ExclamationBolt:

package com.ysl.bolts;

import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;

public class ExclamationBolt extends BaseRichBolt{

    private static Logger logger = LoggerFactory.getLogger(ExclamationBolt.class);

    private OutputCollector collector = null;

    public void prepare(Map map, TopologyContext topologyContext, OutputCollector outputCollector) {
        this.collector = outputCollector;
    }

    public void execute(Tuple tuple) {
        this.collector.emit(tuple,new Values(tuple.getString(0)+"!!!"));
        this.collector.ack(tuple);
    }

    public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {
        outputFieldsDeclarer.declare(new Fields("word"));
    }
}

PrintBolt:

package com.ysl.bolts;

import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Tuple;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;

public class PrintBolt extends BaseRichBolt{

    private static Logger logger = LoggerFactory.getLogger(PrintBolt.class);

    private OutputCollector collector = null;

    public void prepare(Map map, TopologyContext topologyContext, OutputCollector outputCollector) {
        this.collector = outputCollector;
    }

    public void execute(Tuple tuple) {
        logger.info(tuple.getString(0) + ".......");
        this.collector.ack(tuple);
    }

    public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {

    }
}

WordsTopology:

package com.ysl;

import backtype.storm.Config;
import backtype.storm.LocalCluster;
import backtype.storm.StormSubmitter;
import backtype.storm.generated.AlreadyAliveException;
import backtype.storm.generated.InvalidTopologyException;
import backtype.storm.topology.TopologyBuilder;
import backtype.storm.utils.Utils;
import com.ysl.bolts.ExclamationBolt;
import com.ysl.bolts.PrintBolt;
import com.ysl.spouts.TestWordSpout;

public class WordsTopology {
    public static void main(String[] args) throws AlreadyAliveException, InvalidTopologyException {
        TopologyBuilder topologyBuilder = new TopologyBuilder();
        topologyBuilder.setSpout("word",new TestWordSpout(),1);
        topologyBuilder.setBolt("exclaim",new ExclamationBolt(),1).shuffleGrouping("word");
        topologyBuilder.setBolt("print",new PrintBolt(),1).shuffleGrouping("exclaim");
        Config config = new Config();
        config.setDebug(true);
        if(args != null && args.length > 0){
            config.setNumWorkers(3);
            StormSubmitter.submitTopologyWithProgressBar(args[0],config,topologyBuilder.createTopology());
        }else{
            LocalCluster localCluster = new LocalCluster();
            localCluster.submitTopology("test",config,topologyBuilder.createTopology());
            Utils.sleep(30000);
            localCluster.killTopology("test");
            localCluster.shutdown();
        }
    }
}

2.打包運行

　　使用maven打包應用程序，命令以下：

mvn clean install

　　storm的運行方式有兩種：一是本地運行，適合調試和開發，本身直接在IDEA中執行main函數運行便可，本地模式的代碼中有設置睡眠時間，到時間後主動kill topoloyg

　　二是遠程集羣模式運行：集羣模式須要先建立一個包含程序代碼以及代碼所依賴的依賴包的jar包（有關storm的jar包不用包括， 這些jar包會在工做節點上自動被添加到classpath裏面去)。若是使用maven, 那麼插件:Maven Assembly Plugin能夠幫你打包，詳細見上述maven的設置。

　　遠程運行要使用storm的命令提交topology到storm集羣：

storm jar /home/workspace/storm/target/storm-1.0-SNAPSHOT.jar com.ysl.WordsTopology testfrfr

執行上面的命令後，出現下面的日誌，表示執行成功：

346  [main] INFO  backtype.storm.StormSubmitter - Jar not uploaded to master yet. Submitting jar...
351  [main] INFO  backtype.storm.StormSubmitter - Uploading topology jar /home/workspace/storm/target/storm-1.0-SNAPSHOT.jar to assigned location: storm-local/nimbus/inbox/stormjar-89514681-2477-44c2-8924-7907d16e3ba1.jar
Start uploading file '/home/workspace/storm/target/storm-1.0-SNAPSHOT.jar' to 'storm-local/nimbus/inbox/stormjar-89514681-2477-44c2-8924-7907d16e3ba1.jar' (6196 bytes)
[==================================================] 6196 / 6196
File '/home/workspace/storm/target/storm-1.0-SNAPSHOT.jar' uploaded to 'storm-local/nimbus/inbox/stormjar-89514681-2477-44c2-8924-7907d16e3ba1.jar' (6196 bytes)
363  [main] INFO  backtype.storm.StormSubmitter - Successfully uploaded topology jar to assigned location: storm-local/nimbus/inbox/stormjar-89514681-2477-44c2-8924-7907d16e3ba1.jar
363  [main] INFO  backtype.storm.StormSubmitter - Submitting topology testfrfr in distributed mode with conf {"topology.workers":3,"topology.debug":true}
448  [main] INFO  backtype.storm.StormSubmitter - Finished submitting topology:

終止一個topology

要終止一個topology, 執行:

storm kill {stormname}

其中{stormname}是提交topology給storm集羣的時候指定的名字。

storm不會立刻終止topology。相反，它會先終止全部的spout，讓它們再也不發射任何新的tuple， storm會等Config.TOPOLOGY_MESSAGE_TIMEOUT_SECS秒以後才殺掉全部的工做進程。這會給topology足夠的時 間來完成全部咱們執行storm kill命令的時候還沒完成的tuple。