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我有一个用 kafka 探索 spring 的示例项目（在这里找到）。我有一个订阅主题my-test-topic-upstream的听众，它只会丢失消息和密钥并将其发布到另一个主题my-test-topic-downstream。我试过这是本地 kafka （docker-compose文件在那里），它可以工作。

现在我正在尝试使用嵌入式 kafka 服务器为此编写测试。在测试中，我有一个嵌入式服务器正在启动（TestContext.java），它应该在测试之前启动（覆盖 junit beforeAll）。

private static EmbeddedKafkaBroker kafka() {
    EmbeddedKafkaBroker kafkaEmbedded =
        new EmbeddedKafkaBroker(
            3,
            false,
            1,
            "my-test-topic-upstream", "my-test-topic-downstream");
    Map<String, String> brokerProperties = new HashMap<>();
    brokerProperties.put("default.replication.factor", "1");
    brokerProperties.put("offsets.topic.replication.factor", "1");
    brokerProperties.put("group.initial.rebalance.delay.ms", "3000");
    kafkaEmbedded.brokerProperties(brokerProperties);
    try {
      kafkaEmbedded.afterPropertiesSet();
    } catch (Exception e) {
      throw new RuntimeException(e);
    }

    return kafkaEmbedded;
  }

然后我创建一个生产者（TickProducer）并向我希望我的听众能够消费的主题发布一条消息。

public TickProducer(String brokers) {
    Properties props = new Properties();
    props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokers);
    props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
    props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());

    producer = new KafkaProducer<>(props);
  }

  public RecordMetadata publishTick(String brand)
          throws ExecutionException, InterruptedException {
    return publish(TOPIC, brand, Instant.now().toString());
  }

  private RecordMetadata publish(String topic, String key, String value)
      throws ExecutionException, InterruptedException {
    final RecordMetadata recordMetadata;
    recordMetadata = producer.send(new ProducerRecord<>(topic, key, value)).get();
    producer.flush();
    return recordMetadata;
  }

我看到以下日志消息继续记录。

11:32:35.745 [main] WARN  o.apache.kafka.clients.NetworkClient - [Consumer clientId=consumer-1, groupId=my-test-group] Connection to node -1 could not be established. Broker may not be available.

最后失败了

11:36:52.774 [main] ERROR o.s.boot.SpringApplication - Application run failed
org.springframework.context.ApplicationContextException: Failed to start bean 'org.springframework.kafka.config.internalKafkaListenerEndpointRegistry'; nested exception is org.apache.kafka.common.errors.TimeoutException: Timeout expired while fetching topic metadata

这里有什么提示吗？

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1 回答 1

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查看 INFO 日志ConsumerConfig以查看他尝试连接的位置（将其与 比较ProducerConfig）。我怀疑您没有更新 spring bootbootstrap-servers属性以指向嵌入式代理。

看

/**
 * Set the system property with this name to the list of broker addresses.
 * @param brokerListProperty the brokerListProperty to set
 * @return this broker.
 * @since 2.3
 */
public EmbeddedKafkaBroker brokerListProperty(String brokerListProperty) {
    this.brokerListProperty = brokerListProperty;
    return this;
}

将其设置为spring.kafka.bootstrap-serverswhich 随后将被使用而不是SPRING_EMBEDDED_KAFKA_BROKERS.

顺便说一句，使用@EmbeddedKafka注释通常比自己实例化服务器更容易。

于 2020-03-10T13:05:18.890 回答