"Error registering Avro schema" 尝试将数据流式传输到 Kafka 时

Question

我正在尝试重现 Confluent's official documentation 中的序列化程序示例，并将 avro 格式的数据流式传输到 kafka 主题。

代码如下：

import org.apache.avro.Schema;
import org.apache.avro.generic.GenericData;
import org.apache.avro.generic.GenericRecord;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import java.util.Properties;

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "io.confluent.kafka.serializers.KafkaAvroSerializer");
props.put("value.serializer", "io.confluent.kafka.serializers.KafkaAvroSerializer");
props.put("schema.registry.url", "http://localhost:8081");
KafkaProducer producer = new KafkaProducer(props);

String key = "key1";
String userSchema = "{\"type\":\"record\"," +
                    "\"name\":\"myrecord\"," +
                    "\"fields\":[{\"name\":\"f1\",\"type\":\"string\"}]}";
Schema.Parser parser = new Schema.Parser();
Schema schema = parser.parse(userSchema);
GenericRecord avroRecord = new GenericData.Record(schema);
avroRecord.put("f1", "value1");

ProducerRecord<Object, Object> record = new ProducerRecord<Object, Object>("topic1", key, avroRecord);
try {
  producer.send(record);
} catch(Exception e) {
  e.printStackTrace();
}

但是 producer.send(record); 导致以下错误：

org.apache.kafka.common.errors.SerializationException: Error registering Avro schema: "string"
Caused by: io.confluent.kafka.schemaregistry.client.rest.exceptions.RestClientException: Register schema operation failed while writing to the Kafka store; error code: 50001
    at io.confluent.kafka.schemaregistry.client.rest.RestService.sendHttpRequest(RestService.java:191)
    at io.confluent.kafka.schemaregistry.client.rest.RestService.httpRequest(RestService.java:218)
    at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:307)
    at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:299)
    at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:294)
    at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.registerAndGetId(CachedSchemaRegistryClient.java:61)
    at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.register(CachedSchemaRegistryClient.java:100)
    at io.confluent.kafka.serializers.AbstractKafkaAvroSerializer.serializeImpl(AbstractKafkaAvroSerializer.java:79)
    at io.confluent.kafka.serializers.KafkaAvroSerializer.serialize(KafkaAvroSerializer.java:53)
    at org.apache.kafka.common.serialization.ExtendedSerializer$Wrapper.serialize(ExtendedSerializer.java:65)
    at org.apache.kafka.common.serialization.ExtendedSerializer$Wrapper.serialize(ExtendedSerializer.java:55)
    at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:775)
    at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:760)
    at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:648)
    at com.giorgos.currencies.TestFX.main(TestFX.java:134)

注意我改了

ProducerRecord<Object, Object> record = new ProducerRecord<>("topic1", key, avroRecord);

到

ProducerRecord<Object, Object> record = new ProducerRecord<Object, Object>("topic1", key, avroRecord);

为了处理diamond operator is not supported in -source 1.5错误。

pom.xml 文件的内容如下：

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.giorgos.currencies</groupId>
  <artifactId>giorgos-fx_currencies</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>george-fx_currencies</name>
  <url>http://maven.apache.org</url>

    <repositories>
        <repository>
            <id>apache-repo</id>
            <name>Apache Repository</name>
            <url>https://repository.apache.org/content/repositories/releases</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>confluent</id>
            <url>http://packages.confluent.io/maven/</url>
        </repository>
    </repositories>


    <properties>
        <kafka.version>0.8.2.1</kafka.version>
        <kafka.scala.version>2.10</kafka.scala.version>
        <confluent.version>4.0.0</confluent.version>
        <avro.version>1.7.6</avro.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

   <dependencies>
        <dependency>
            <groupId>org.apache.avro</groupId>
            <artifactId>avro</artifactId>
            <version>${avro.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.avro</groupId>
            <artifactId>avro-maven-plugin</artifactId>
            <version>${avro.version}</version>
        </dependency>
        <dependency>
            <groupId>io.confluent</groupId>
            <artifactId>kafka-avro-serializer</artifactId>
            <version>${confluent.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka-clients</artifactId>
            <version>${kafka.version}</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.avro</groupId>
                <artifactId>avro-maven-plugin</artifactId>
                <version>${avro.version}</version>
                <executions>
                    <execution>
                        <phase>generate-sources</phase>
                        <goals>
                            <goal>schema</goal>
                            <goal>protocol</goal>
                            <goal>idl-protocol</goal>
                        </goals>
                        <configuration>
                            <sourceDirectory>${project.basedir}/src/main/resources/avro</sourceDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <finalName>uber-${project.artifactId}-${project.version}</finalName>
                </configuration>
            </plugin>
        </plugins>
    </build>


</project>

另请注意，mvn package 会导致构建成功且未报告任何错误。 topic1也创建成功，但是由于生产者端流数据失败，消费者没有数据出现。

我用

java -cp target/uber-giorgos-fx_currencies-1.0-SNAPSHOT.jar com.giorgos.currencies.TestFX

到运行代码

Answer 1

我猜你的问题是你的消息键是一个字符串而不是一个 avro 对象。尝试以下生产者属性：

props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "io.confluent.kafka.serializers.KafkaAvroSerializer");

生产者记录到

ProducerRecord<String, Object> record = new ProducerRecord<String, Object>("topic1", key, avroRecord);

希望对您有所帮助

"Error registering Avro schema" 尝试将数据流式传输到 Kafka 时

"Error registering Avro schema" when trying to stream data to Kafka

maven

apache-kafka

avro

confluent-platform