加缪-卡夫卡的例子

Question

我的用法是我想把Avro数据从Kafka推到HDFS。加缪似乎是正确的工具，但我无法使它工作。我是加缪的新手，试着让加缪--例子，https://github.com/linkedin/camus

现在我正试着让加缪的例子发挥作用。然而，我仍然面临着一些问题。

用于DummyLogKafkaProducerClient的代码片段

package com.linkedin.camus.example.schemaregistry;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Random;

import kafka.javaapi.producer.Producer;
import kafka.producer.KeyedMessage;
import kafka.producer.ProducerConfig;

import com.linkedin.camus.etl.kafka.coders.KafkaAvroMessageEncoder;
import com.linkedin.camus.example.records.DummyLog;

public class DummyLogKafkaProducerClient {


    public static void main(String[] args) {

        Properties props = new Properties();

        props.put("metadata.broker.list", "localhost:6667");
        // props.put("serializer.class", "kafka.serializer.StringEncoder");
        // props.put("partitioner.class", "example.producer.SimplePartitioner");
        //props.put("request.required.acks", "1");

        ProducerConfig config = new ProducerConfig(props);

        Producer<String, byte[]> producer = new Producer<String, byte[]>(config);

        KafkaAvroMessageEncoder encoder = get_DUMMY_LOG_Encoder();

        for (int i = 0; i < 500; i++) {
            KeyedMessage<String, byte[]> data = new KeyedMessage<String, byte[]>("DUMMY_LOG", encoder.toBytes(getDummyLog()));
            producer.send(data);

        }
    }

    public static DummyLog getDummyLog() {
        Random random = new Random();
        DummyLog dummyLog = DummyLog.newBuilder().build();
        dummyLog.setId(random.nextLong());
        dummyLog.setLogTime(new Date().getTime());
        Map<CharSequence, CharSequence> machoStuff = new HashMap<CharSequence, CharSequence>();
        machoStuff.put("macho1", "abcd");
        machoStuff.put("macho2", "xyz");
        dummyLog.setMuchoStuff(machoStuff);
        return dummyLog;
    }

    public static KafkaAvroMessageEncoder get_DUMMY_LOG_Encoder() {
        KafkaAvroMessageEncoder encoder = new KafkaAvroMessageEncoder("DUMMY_LOG", null);
        Properties props = new Properties();
        props.put(KafkaAvroMessageEncoder.KAFKA_MESSAGE_CODER_SCHEMA_REGISTRY_CLASS, "com.linkedin.camus.example.schemaregistry.DummySchemaRegistry");
        encoder.init(props, "DUMMY_LOG");
        return encoder;

    }
}

我还添加了DummySchemaRegistry的默认no-arg构造函数，因为它提供了实例化异常。

package com.linkedin.camus.example.schemaregistry;

import org.apache.avro.Schema;
import org.apache.hadoop.conf.Configuration;

import com.linkedin.camus.example.records.DummyLog;
import com.linkedin.camus.example.records.DummyLog2;
import com.linkedin.camus.schemaregistry.MemorySchemaRegistry;

/**
 * This is a little dummy registry that just uses a memory-backed schema registry to store two dummy Avro schemas. You
 * can use this with camus.properties
 */
public class DummySchemaRegistry extends MemorySchemaRegistry<Schema> {
    public DummySchemaRegistry(Configuration conf) {
        super();
        super.register("DUMMY_LOG", DummyLog.newBuilder().build().getSchema());
        super.register("DUMMY_LOG_2", DummyLog2.newBuilder().build()
                .getSchema());
    }
    public DummySchemaRegistry() {
        super();
        super.register("DUMMY_LOG", DummyLog.newBuilder().build().getSchema());
        super.register("DUMMY_LOG_2", DummyLog2.newBuilder().build().getSchema());
    }
}

在运行程序后获得的异常跟踪

线程"main“com.linkedin.camus.coders.MessageEncoderException: org.apache.avro.AvroRuntimeException: org.apache.avro.AvroRuntimeException: Field id类型中的异常:LONG pos:0未设置，在com.linkedin.camus.example.schemaregistry.DummyLogKafkaProducerClient.get_DUMMY_LOG_Encoder(DummyLogKafkaProducerClient.java:57) at com.linkedin.camus.example.schemaregistry.DummyLogKafkaProducerClient的com.linkedin.camus.example.schemaregistry.DummyLogKafkaProducerClient.get_DUMMY_LOG_Encoder(DummyLogKafkaProducerClient.java:57)上没有默认值com.linkedin.camus.example.records.DummyLog$Builder.build(DummyLog.java:214) (DummyLogKafkaProducerClient.java:32)由: org.apache.avro.AvroRuntimeException: org.apache.avro.AvroRuntimeException:字段id类型:LONG pos:0未设置并在com.linkedin.camus.example.schemaregistry.DummySchemaRegistry.(DummySchemaRegistry.java:16) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native方法的sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java中没有默认值引起):62)在sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:408) at java.lang.Class.newInstance(Class.java:438) at com.linkedin.camus.etl.kafka.coders.KafkaAvroMessageEncoder.init(KafkaAvroMessageEncoder.java:52) .又有2种原因是: org.apache.avro.AvroRuntimeException: Field id type:LONG pos:0 not set，并且在org没有默认值.apache.avro.data.RecordBuilderBase.defaultValue(RecordBuilderBase.java:151) at com.linkedin.camus.example.records.DummyLog$Builder.build(DummyLog.java:209) .再来9

Answer 1

我想camus希望Avro模式具有默认值。我把我的dummyLog.avsc改成了下面的和重新编译的-

{“命名空间”："com.linkedin.camus.example.records“、”类型“：”记录“、”名称“："DummyLog”、“文档”：“日志中不太重要的内容”、“字段”：{“名称”："id“、”类型“："int”、“默认”：0 }，{“名称”："logTime"，“类型”："int"，“默认”：0}

如果对你有用的话请告诉我。

谢谢，Ambarish

Answer 2

可以默认任何字符串或长字段，如下所示

  {"type":"record","name":"CounterData","namespace":"org.avro.usage.tutorial","fields":[{"name":"word","type":["string","null"]},{"name":"count","type":["long","null"]}]}

Answer 3

Camus并不认为架构会有默认值。我最近用过加缪发现了同样的问题。实际上，它在模式注册表中使用的方式在默认示例中是不正确的。我在加缪代码中做了一些修改，您可以查看https://github.com/chandanbansal/camus，有一些小的更改可以使它工作。他们没有阿夫罗唱片的解码器。我也写过这个。