spring boot的健康检查HealthIndicators实战

目录

• springboot 健康检查HealthIndicators
• springboot health indicator原理及其使用
• 作用
• 自动配置的Health Indicator
• 分组
• 如何管理Health Indicator
• RedisHealthIndicator源码解析
• 自定义Indicator

springboot 健康检查HealthIndicators

想提供自定义健康信息，你可以注册实现了HealthIndicator接口的Spring beans。

你需要提供一个health()方法的实现，并返回一个Health响应。

Health响应需要包含一个status和可选的用于展示的详情。

import org.springframework.boot.actuate.health.HealthIndicator;
import org.springframework.stereotype.Component;
@Component
public class MyHealth implements HealthIndicator {
@Override
public Health health() {
int errorCode = check(); // perform some specific health check
if (errorCode != 0) {
return Health.down().withDetail("Error Code", errorCode).build();
} r
eturn Health.up().build();
}
}

除了Spring Boot预定义的Status类型，Health也可以返回一个代表新的系统状态的自定义Status。

在这种情况下，需要提供一个HealthAggregator接口的自定义实现，或使用management.health.status.order属性配置默认的实现。

例如，假设一个新的，代码为FATAL的Status被用于你的一个HealthIndicator实现中。 为了配置严重程度， 你需要将下面的配

置添加到application属性文件中：

management.health.status.order: DOWN, OUT_OF_SERVICE, UNKNOWN, UP

如果使用HTTP访问health端点， 你可能想要注册自定义的status， 并使用HealthMvcEndpoint进行映射。 例如， 你可以将

FATAL映射为HttpStatus.SERVICE_UNAVAILABLE。

springboot health indicator原理及其使用

作用

sping boot health 可以通过暴露的接口来提供系统及其系统组件是否可用。默认通过/health来访问。返回结果如下：

{
  "status": "UP",
  "discoveryComposite": {
    "description": "Spring Cloud Eureka Discovery Client",
    "status": "UP",
    "discoveryClient": {
      "description": "Spring Cloud Eureka Discovery Client",
      "status": "UP",
      "services": [
        "..."
      ]
    },
    "eureka": {
      "description": "Remote status from Eureka server",
      "status": "UP",
      "applications": {
        "AOMS-MOBILE": 1,
        "DATA-EXCHANGE": 1,
        "CLOUD-GATEWAY": 2,
        "AOMS": 1,
        "AOMS-AIIS": 0,
        "AOMS-EUREKA": 2
      }
    }
  },
  "diskSpace": {
    "status": "UP",
    "total": 313759301632,
    "free": 291947081728,
    "threshold": 10485760
  },
  "refreshScope": {
    "status": "UP"
  },
  "hystrix": {
    "status": "UP"
  }
}

状态说明：

• UNKNOWN：未知状态，映射HTTP状态码为503
• UP：正常，映射HTTP状态码为200
• DOWN：失败，映射HTTP状态码为503
• OUT_OF_SERVICE：不能对外提供服务，但是服务正常。映射HTTP状态码为200

注意：UNKNOWN，DOWN，OUT_OF_SERVICE在为微服务环境下会导致注册中心中的实例也为down状态，请根据具体的业务来正确使用状态值。

自动配置的Health Indicator

自动配置的HealthIndicator主要有以下内容：

Key Name Description cassandra CassandraDriverHealthIndicator Checks that a Cassandra database is up. couchbase CouchbaseHealthIndicator Checks that a Couchbase cluster is up. datasource DataSourceHealthIndicator Checks that a connection to DataSource can be obtained. diskspace DiskSpaceHealthIndicator Checks for low disk space. elasticsearch ElasticsearchRestHealthIndicator Checks that an Elasticsearch cluster is up. hazelcast HazelcastHealthIndicator Checks that a Hazelcast server is up. influxdb InfluxDbHealthIndicator Checks that an InfluxDB server is up. jms JmsHealthIndicator Checks that a JMS broker is up. ldap LdapHealthIndicator Checks that an LDAP server is up. mail MailHealthIndicator Checks that a mail server is up. mongo MongoHealthIndicator Checks that a Mongo database is up. neo4j Neo4jHealthIndicator Checks that a Neo4j database is up. ping PingHealthIndicator Always responds with UP. rabbit RabbitHealthIndicator Checks that a Rabbit server is up. redis RedisHealthIndicator Checks that a Redis server is up. solr SolrHealthIndicator Checks that a Solr server is up.

分组

可以通过一个别名来启用一组指标的访问。配置的格式如下：

management.endpoint.health.group.<name>
//demo:
management.endpoint.health.group.mysys.include=db,redis,mail
management.endpoint.health.group.custom.exclude=rabbit

如何管理Health Indicator

开启

可以通过management.health.key.enabled来启用key对应的indicator。例如：

management.health.db.enabled=true

关闭

management.health.db.enabled=false

RedisHealthIndicator源码解析

下面，通过RedisHealthIndicator源码来为什么可以这么写。

代码结构

自动配置的health indicator有HealthIndicator和HealthIndicatorAutoConfiguration两部分组成。

HealthIndicator所在包在org.springframework.boot.actuate，

HealthIndicatorAutoConfiguration所在包在org.springframework.boot.actuate.autoconfigure下

//RedisHealthIndicator.java
public class RedisHealthIndicator extends AbstractHealthIndicator {
	static final String VERSION = "version";
	static final String REDIS_VERSION = "redis_version";
	private final RedisConnectionFactory redisConnectionFactory;
	public RedisHealthIndicator(RedisConnectionFactory connectionFactory) {
		super("Redis health check failed");
		Assert.notNull(connectionFactory, "ConnectionFactory must not be null");
		this.redisConnectionFactory = connectionFactory;
	}
	@Override
	protected void doHealthCheck(Health.Builder builder) throws Exception {
		RedisConnection connection = RedisConnectionUtils
				.getConnection(this.redisConnectionFactory);
		try {
			if (connection instanceof RedisClusterConnection) {
				ClusterInfo clusterInfo = ((RedisClusterConnection) connection)
						.clusterGetClusterInfo();
				builder.up().withDetail("cluster_size", clusterInfo.getClusterSize())
						.withDetail("slots_up", clusterInfo.getSlotsOk())
						.withDetail("slots_fail", clusterInfo.getSlotsFail());
			}
			else {
				Properties info = connection.info();
				builder.up().withDetail(VERSION, info.getProperty(REDIS_VERSION));
			}
		}
		finally {
			RedisConnectionUtils.releaseConnection(connection,
					this.redisConnectionFactory);
		}
	}
}

主要实现doHealthCheck方法来实现具体的判断逻辑。注意，操作完成后在finally中释放资源。

在父类AbstractHealthIndicator中，对doHealthCheck进行了try catch,如果出现异常，则返回Down状态。

 //AbstractHealthIndicator.java
 @Override
 public final Health health() {
  Health.Builder builder = new Health.Builder();
  try {
   doHealthCheck(builder);
  }
  catch (Exception ex) {
   if (this.logger.isWarnEnabled()) {
    String message = this.healthCheckFailedMessage.apply(ex);
    this.logger.warn(StringUtils.hasText(message) ? message : DEFAULT_MESSAGE,
      ex);
   }
   builder.down(ex);
  }
  return builder.build();
 }

RedisHealthIndicatorAutoConfiguration完成RedisHealthIndicator的自动配置

@Configuration
@ConditionalOnClass(RedisConnectionFactory.class)
@ConditionalOnBean(RedisConnectionFactory.class)
@ConditionalOnEnabledHealthIndicator("redis")
@AutoConfigureBefore(HealthIndicatorAutoConfiguration.class)
@AutoConfigureAfter({ RedisAutoConfiguration.class,
  RedisReactiveHealthIndicatorAutoConfiguration.class })
public class RedisHealthIndicatorAutoConfiguration extends
  CompositeHealthIndicatorConfiguration<RedisHealthIndicator, RedisConnectionFactory> {
 private final Map<String, RedisConnectionFactory> redisConnectionFactories;
 public RedisHealthIndicatorAutoConfiguration(
   Map<String, RedisConnectionFactory> redisConnectionFactories) {
  this.redisConnectionFactories = redisConnectionFactories;
 }
 @Bean
 @ConditionalOnMissingBean(name = "redisHealthIndicator")
 public HealthIndicator redisHealthIndicator() {
  return createHealthIndicator(this.redisConnectionFactories);
 }
}

重点说明ConditionalOnEnabledHealthIndicator:如果management.health..enabled为true,则生效。

CompositeHealthIndicatorConfiguration 中会通过HealthIndicatorRegistry注册创建的HealthIndicator

自定义Indicator

@Component
@ConditionalOnProperty(name="spring.dfs.http.send-url")
@Slf4j
public class DfsHealthIndicator implements HealthIndicator {
    @Value("${spring.dfs.http.send-url}")
    private String dsfSendUrl;
    @Override
    public Health health() {
        log.debug("正在检查dfs配置项...");
        log.debug("dfs 请求地址：{}",dsfSendUrl);
        Health.Builder up = Health.up().withDetail("url", dsfSendUrl);
        try {
            HttpUtils.telnet(StringUtils.getIpFromUrl(dsfSendUrl),StringUtils.getPortFromUrl(dsfSendUrl));
            return up.build();
        } catch (IOException e) {
            e.printStackTrace();
            log.error("DFS配置项错误或网络超时");
            return up.withException(e).build();
        }
    }
}

返回值：

{
    "dfs": {
    "status": "UP",
    "url": "10.254.131.197:8088",
    "error": "java.net.ConnectException: Connection refused (Connection refused)"
    }
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持自由互联。