flink:如何使用相同的streamexecutionenvironment读取多个kafka集群

klr1opcd  于 2021-06-25  发布在  Flink
关注(0)|答案(1)|浏览(529)

我想从Flink的多个Kafka星团中读取数据。
但结果是,Kafka的漫画只读第一部Kafka的作品。
我能够读取两个Kafka集群只有当我有两个Kafka分别流,这不是我想要的。
是否可以将多个源连接到单个读卡器。
样本代码

public class KafkaReader<T> implements Reader<T>{

private StreamExecutionEnvironment executionEnvironment ;

public StreamExecutionEnvironment getExecutionEnvironment(Properties properties){
    executionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment();
    executionEnvironment.setRestartStrategy( RestartStrategies.fixedDelayRestart(3, 1500));

    executionEnvironment.enableCheckpointing(
            Integer.parseInt(properties.getProperty(Constants.SSE_CHECKPOINT_INTERVAL,"5000")), CheckpointingMode.EXACTLY_ONCE);
    executionEnvironment.getCheckpointConfig().setCheckpointTimeout(60000);
    //executionEnvironment.getCheckpointConfig().setMaxConcurrentCheckpoints(1);
    //try {
    //  executionEnvironment.setStateBackend(new FsStateBackend(new Path(Constants.SSE_CHECKPOINT_PATH)));
        // The RocksDBStateBackend or The FsStateBackend
    //} catch (IOException e) {
        // LOGGER.error("Exception during initialization of stateBackend in execution environment"+e.getMessage());
    }

    return executionEnvironment;
}
public DataStream<T> readFromMultiKafka(Properties properties_k1, Properties properties_k2 ,DeserializationSchema<T> deserializationSchema) {

    DataStream<T> kafkaMessageStream = executionEnvironment.addSource(new FlinkKafkaConsumer08<T>( 
            properties_k1.getProperty(Constants.TOPIC),deserializationSchema, 
            properties_k1));
    executionEnvironment.addSource(new FlinkKafkaConsumer08<T>( 
            properties_k2.getProperty(Constants.TOPIC),deserializationSchema, 
            properties_k2));

    return kafkaMessageStream;
}

public DataStream<T> readFromKafka(Properties properties,DeserializationSchema<T> deserializationSchema) {

    DataStream<T> kafkaMessageStream = executionEnvironment.addSource(new FlinkKafkaConsumer08<T>( 
            properties.getProperty(Constants.TOPIC),deserializationSchema, 
            properties));

    return kafkaMessageStream;
}

}
我的电话:

public static void main( String[] args ) throws Exception
{
    Properties pk1 = new Properties();
    pk1.setProperty(Constants.TOPIC, "flink_test");
    pk1.setProperty("zookeeper.connect", "localhost:2181");
    pk1.setProperty("group.id", "1");
    pk1.setProperty("bootstrap.servers", "localhost:9092");
    Properties pk2 = new Properties();
    pk2.setProperty(Constants.TOPIC, "flink_test");
    pk2.setProperty("zookeeper.connect", "localhost:2182");
    pk2.setProperty("group.id", "1");
    pk2.setProperty("bootstrap.servers", "localhost:9093");

    Reader<String> reader = new KafkaReader<String>();
    //Do not work

    StreamExecutionEnvironment environment = reader.getExecutionEnvironment(pk1);
    DataStream<String> dataStream1 = reader.readFromMultiKafka(pk1,pk2,new SimpleStringSchema());
    DataStream<ImpressionObject> transform = new TsvTransformer().transform(dataStream);

    transform.print();      

  //Works:

    StreamExecutionEnvironment environment = reader.getExecutionEnvironment(pk1);
    DataStream<String> dataStream1 = reader.readFromKafka(pk1, new SimpleStringSchema());
    DataStream<String> dataStream2 = reader.readFromKafka(pk2, new SimpleStringSchema());

    DataStream<Tuple2<String, Integer>> transform1 = dataStream1.flatMap(new LineSplitter()).keyBy(0)
    .timeWindow(Time.seconds(5)).sum(1).setParallelism(5);
    DataStream<Tuple2<String, Integer>> transform2 = dataStream2.flatMap(new LineSplitter()).keyBy(0)
            .timeWindow(Time.seconds(5)).sum(1).setParallelism(5);

    transform1.print();     
    transform2.print();     

    environment.execute("Kafka Reader");
}
62o28rlo

62o28rlo1#

为了解决这个问题,我建议您为每个集群创建flinkkafkaconsumer的单独示例(这是您已经在做的),然后合并结果流:

StreamExecutionEnvironment environment = reader.getExecutionEnvironment(pk1);
DataStream<String> dataStream1 = reader.readFromKafka(pk1, new SimpleStringSchema());
DataStream<String> dataStream2 = reader.readFromKafka(pk2, new SimpleStringSchema());
DataStream<String> finalStream = dataStream1.union(dataStream2);

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