Spring Actuator + Kafka Streams - 将 kafka 流状态添加到健康检查端点

Question

我有一个使用 apache kafka-streams 的 Spring Boot 应用程序。我不使用弹簧云流。我添加了执行器健康检查端点。我在application.yml 中这样配置它：

management:
  health.db.enabled: false
  endpoints.web:
    base-path:
    path-mapping.health: /

当引发运行时异常并且我的流已停止，如日志所示，但运行状况检查状态为 UP。

2019-09-17 13:16:31.522 INFO 1 --- [ Thread-5] org.apache.kafka.streams.KafkaStreams : stream-client [lpp-model-stream-7e6e8fea-fcad-4033-92a4-5ede50de6e17] Streams client stopped completely

如何将 kafka 流状态绑定到健康检查端点？

我的 pom.xml：

  <dependencies>
            <dependency>
                <groupId>org.springframework.kafka</groupId>
                <artifactId>spring-kafka</artifactId>
            </dependency>
            <dependency>
                <groupId>org.apache.kafka</groupId>
                <artifactId>kafka-streams</artifactId>
            </dependency>
            <dependency>
                <groupId>data-wizards</groupId>
                <artifactId>lpp-common-avro</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
            <dependency>
                <groupId>io.confluent</groupId>
                <artifactId>kafka-streams-avro-serde</artifactId>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>com.google.code.gson</groupId>
                <artifactId>gson</artifactId>
            </dependency>
            <dependency>
                <groupId>io.vavr</groupId>
                <artifactId>vavr</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

链接到我创建流的代码：https://gist.github.com/solveretur/fc4fdd6c7663dc4d58fe72d48029f9c3

Answer 1

健康信息是从实现应用程序上下文中配置的 HealthIndicator 接口的所有 bean 收集的。

您可以创建一个自定义 HealthIndicator，您可以使用它来报告 Kafka Streams 错误。

如下创建您的 HealthIndicator 单例 bean

@Component
public class MyHealthIndicator implements HealthIndicator {
    private Exception caughtException = null;
    // Any other information you want to store.
    @Override
    public Health health() {

        if (caughtException == null) {
            return Health
                .up()
                .withDetail("status", "Kafka Streams Running")
                .build();
        }
        else {
            return Health
                .down()
                .withDetail("status", "Not Available")
                .withDetail("error", caughtException.getMessage())
                .build();
        }
    }
    public void setException(Exception caughtException) {
        this.caughtException = caughtException;
    }
}

然后你可以在你使用 Kafka Streams 的地方自动装配这个 bean，你可以如下设置异常。

public class MyApp {
    @Autowire
    private MyHealthIndicator healthIndicator; // You can also use constructor injection instead. 

    // Rest of the code


    public void init() {
        // Streams initialization code here
        streams.setUncaughtExceptionHandler((Thread thread, Throwable throwable) -> {
            healthIndicator.setException(new Exception(throwable));
        });
    }

}

我希望这会有所帮助，但如果没有，请提供一个 Minimal, Verifiable, Reproducible 示例，有人可以使用该示例

Answer 2

KafkaStreams 维护内存中 State，它可以映射到 Actuator 的健康状态。状态可能是以下之一：CREATED、ERROR、NOT_RUNNING、PENDING_SHUTDOWN、REBALANCING、RUNNING - 它们是不言自明的。有关状态转换，请参阅文档https://kafka.apache.org/11/javadoc/org/apache/kafka/streams/KafkaStreams.State.html

如果您正在寻找一个完整的示例，您可以使用以下示例并根据您的需要对其进行更新（例如，您可能不会将 CREATED 视为状态 UP）。确保在应用程序上下文中有一个 KafkaStreams 类型的 bean。

//Note that class name prefix before `HealthIndicator` will be camel-cased
//and used as a health component name, `kafkaStreams` here
@Component
public class KafkaStreamsHealthIndicator implements HealthIndicator {

    //if you have multiple instances, inject as Map<String, KafkaStreams>
    //Spring will map KafkaStreams instances by bean names present in context
    //so you can provide status details for each stream by name
    @Autowired
    private KafkaStreams kafkaStreams; 

    @Override
    public Health health() {
        State kafkaStreamsState = kafkaStreams.state();

        // CREATED, RUNNING or REBALANCING
        if (kafkaStreamsState == State.CREATED || kafkaStreamsState.isRunning()) {
            //set details if you need one
            return Health.up().build();
        }

        // ERROR, NOT_RUNNING, PENDING_SHUTDOWN, 
        return Health.down().withDetail("state", kafkaStreamsState.name()).build();
    }
}

然后健康端点将显示如下：

{
    "status": "UP",
    "kafkaStreams": {
        "status": "DOWN",
        "details": {  //not included if "UP"
            "state": "NOT_RUNNING"
        }
    }
}