聊聊springboot elasticsearch healthIndicator

序

本文主要研究一下springboot elasticsearch healthIndicator

ElasticsearchHealthIndicatorProperties

spring-boot-actuator-autoconfigure-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticsearchHealthIndicatorProperties.java

@ConfigurationProperties(prefix = "management.health.elasticsearch",
        ignoreUnknownFields = false)
public class ElasticsearchHealthIndicatorProperties {

    /**
     * Comma-separated index names.
     */
    private List<String> indices = new ArrayList<>();

    /**
     * Time to wait for a response from the cluster.
     */
    private Duration responseTimeout = Duration.ofMillis(100);

    public List<String> getIndices() {
        return this.indices;
    }

    public void setIndices(List<String> indices) {
        this.indices = indices;
    }

    public Duration getResponseTimeout() {
        return this.responseTimeout;
    }

    public void setResponseTimeout(Duration responseTimeout) {
        this.responseTimeout = responseTimeout;
    }

}

• ElasticsearchHealthIndicatorProperties提供了indices，responseTimeout两个配置项

ElasticSearchClientHealthIndicatorAutoConfiguration

spring-boot-actuator-autoconfigure-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticSearchClientHealthIndicatorAutoConfiguration.java

@Configuration
@ConditionalOnClass(Client.class)
@ConditionalOnBean(Client.class)
@ConditionalOnEnabledHealthIndicator("elasticsearch")
@AutoConfigureBefore(HealthIndicatorAutoConfiguration.class)
@AutoConfigureAfter(ElasticsearchAutoConfiguration.class)
@EnableConfigurationProperties(ElasticsearchHealthIndicatorProperties.class)
public class ElasticSearchClientHealthIndicatorAutoConfiguration extends
        CompositeHealthIndicatorConfiguration<ElasticsearchHealthIndicator, Client> {

    private final Map<String, Client> clients;

    private final ElasticsearchHealthIndicatorProperties properties;

    public ElasticSearchClientHealthIndicatorAutoConfiguration(
            Map<String, Client> clients,
            ElasticsearchHealthIndicatorProperties properties) {
        this.clients = clients;
        this.properties = properties;
    }

    @Bean
    @ConditionalOnMissingBean(name = "elasticsearchHealthIndicator")
    public HealthIndicator elasticsearchHealthIndicator() {
        return createHealthIndicator(this.clients);
    }

    @Override
    protected ElasticsearchHealthIndicator createHealthIndicator(Client client) {
        Duration responseTimeout = this.properties.getResponseTimeout();
        return new ElasticsearchHealthIndicator(client,
                (responseTimeout != null) ? responseTimeout.toMillis() : 100,
                this.properties.getIndices());
    }

}

• ElasticSearchClientHealthIndicatorAutoConfiguration创建的是ElasticsearchHealthIndicator(elasticsearch)，它是通过org.elasticsearch.client.Client去检测的

ElasticsearchHealthIndicator

spring-boot-actuator-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/elasticsearch/ElasticsearchHealthIndicator.java

public class ElasticsearchHealthIndicator extends AbstractHealthIndicator {

    private static final String[] ALL_INDICES = { "_all" };

    private final Client client;

    private final String[] indices;

    private final long responseTimeout;

    /**
     * Create a new {@link ElasticsearchHealthIndicator} instance.
     * @param client the Elasticsearch client
     * @param responseTimeout the request timeout in milliseconds
     * @param indices the indices to check
     */
    public ElasticsearchHealthIndicator(Client client, long responseTimeout,
            List<String> indices) {
        this(client, responseTimeout,
                (indices != null) ? StringUtils.toStringArray(indices) : null);
    }

    /**
     * Create a new {@link ElasticsearchHealthIndicator} instance.
     * @param client the Elasticsearch client
     * @param responseTimeout the request timeout in milliseconds
     * @param indices the indices to check
     */
    public ElasticsearchHealthIndicator(Client client, long responseTimeout,
            String... indices) {
        super("Elasticsearch health check failed");
        this.client = client;
        this.responseTimeout = responseTimeout;
        this.indices = indices;
    }

    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        ClusterHealthRequest request = Requests.clusterHealthRequest(
                ObjectUtils.isEmpty(this.indices) ? ALL_INDICES : this.indices);
        ClusterHealthResponse response = this.client.admin().cluster().health(request)
                .actionGet(this.responseTimeout);
        switch (response.getStatus()) {
        case GREEN:
        case YELLOW:
            builder.up();
            break;
        case RED:
        default:
            builder.down();
            break;
        }
        builder.withDetail("clusterName", response.getClusterName());
        builder.withDetail("numberOfNodes", response.getNumberOfNodes());
        builder.withDetail("numberOfDataNodes", response.getNumberOfDataNodes());
        builder.withDetail("activePrimaryShards", response.getActivePrimaryShards());
        builder.withDetail("activeShards", response.getActiveShards());
        builder.withDetail("relocatingShards", response.getRelocatingShards());
        builder.withDetail("initializingShards", response.getInitializingShards());
        builder.withDetail("unassignedShards", response.getUnassignedShards());
    }

}

• ElasticsearchHealthIndicator继承了AbstractHealthIndicator，这里如果不指定indices的话，默认是ALL_INDICES(_all)；doHealthCheck方法使用client.admin().cluster().health(request)来进行请求，之后根据ClusterHealthResponse的状态来决定是up还是down，如果是GREEN或YELLOW则返回Status.UP，如果是RED则返回Status.DOWN

ElasticSearchRestHealthIndicatorAutoConfiguration

spring-boot-actuator-autoconfigure-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticSearchRestHealthIndicatorAutoConfiguration.java

@Configuration
@ConditionalOnClass(RestClient.class)
@ConditionalOnBean(RestClient.class)
@ConditionalOnEnabledHealthIndicator("elasticsearch")
@AutoConfigureBefore(HealthIndicatorAutoConfiguration.class)
@AutoConfigureAfter({ RestClientAutoConfiguration.class,
        ElasticSearchClientHealthIndicatorAutoConfiguration.class })
public class ElasticSearchRestHealthIndicatorAutoConfiguration extends
        CompositeHealthIndicatorConfiguration<ElasticsearchRestHealthIndicator, RestClient> {

    private final Map<String, RestClient> clients;

    public ElasticSearchRestHealthIndicatorAutoConfiguration(
            Map<String, RestClient> clients) {
        this.clients = clients;
    }

    @Bean
    @ConditionalOnMissingBean(name = "elasticsearchRestHealthIndicator")
    public HealthIndicator elasticsearchRestHealthIndicator() {
        return createHealthIndicator(this.clients);
    }

    @Override
    protected ElasticsearchRestHealthIndicator createHealthIndicator(RestClient client) {
        return new ElasticsearchRestHealthIndicator(client);
    }

}

• ElasticSearchRestHealthIndicatorAutoConfiguration创建的是ElasticsearchRestHealthIndicator(elasticsearchRest)，它是通过org.elasticsearch.client.RestClient去检测的

ElasticsearchRestHealthIndicator

spring-boot-actuator-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/elasticsearch/ElasticsearchRestHealthIndicator.java

public class ElasticsearchRestHealthIndicator extends AbstractHealthIndicator {

    private static final String RED_STATUS = "red";

    private final RestClient client;

    private final JsonParser jsonParser;

    public ElasticsearchRestHealthIndicator(RestClient client) {
        super("Elasticsearch health check failed");
        this.client = client;
        this.jsonParser = JsonParserFactory.getJsonParser();
    }

    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        Response response = this.client
                .performRequest(new Request("GET", "/_cluster/health/"));
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() != HttpStatus.SC_OK) {
            builder.down();
            builder.withDetail("statusCode", statusLine.getStatusCode());
            builder.withDetail("reasonPhrase", statusLine.getReasonPhrase());
            return;
        }
        try (InputStream inputStream = response.getEntity().getContent()) {
            doHealthCheck(builder,
                    StreamUtils.copyToString(inputStream, StandardCharsets.UTF_8));
        }
    }

    private void doHealthCheck(Health.Builder builder, String json) {
        Map<String, Object> response = this.jsonParser.parseMap(json);
        String status = (String) response.get("status");
        if (RED_STATUS.equals(status)) {
            builder.outOfService();
        }
        else {
            builder.up();
        }
        builder.withDetails(response);
    }

}

• ElasticsearchRestHealthIndicator继承了AbstractHealthIndicator，构造器通过JsonParserFactory.getJsonParser()创建了JsonParser
• doHealthCheck方法通过RestClient.performRequest(new Request("GET", "/_cluster/health/"))进行请求，如果http response status code不是HttpStatus.SC_OK，直接返回Status.DOWN；如果是HttpStatus.SC_OK再进一步解析json判断
• 私有的doHealthCheck方法通过jsonParser.parseMap(json)解析返回json为Map，然后取status字段，如果是red则返回Status.OUT_OF_SERVICE，否则返回Status.UP

GET /_cluster/health/在http response status code为200的情况下返回的结构实例如下：

{
  "cluster_name" : "docker-cluster",
  "status" : "yellow",
  "timed_out" : false,
  "number_of_nodes" : 1,
  "number_of_data_nodes" : 1,
  "active_primary_shards" : 8,
  "active_shards" : 8,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 6,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 57.14285714285714
}

ElasticSearchJestHealthIndicatorAutoConfiguration

spring-boot-actuator-autoconfigure-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticSearchJestHealthIndicatorAutoConfiguration.java

@Configuration
@ConditionalOnClass(JestClient.class)
@ConditionalOnBean(JestClient.class)
@ConditionalOnEnabledHealthIndicator("elasticsearch")
@AutoConfigureBefore(HealthIndicatorAutoConfiguration.class)
@AutoConfigureAfter({ JestAutoConfiguration.class,
        ElasticSearchClientHealthIndicatorAutoConfiguration.class })
public class ElasticSearchJestHealthIndicatorAutoConfiguration extends
        CompositeHealthIndicatorConfiguration<ElasticsearchJestHealthIndicator, JestClient> {

    private final Map<String, JestClient> clients;

    public ElasticSearchJestHealthIndicatorAutoConfiguration(
            Map<String, JestClient> clients) {
        this.clients = clients;
    }

    @Bean
    @ConditionalOnMissingBean(name = "elasticsearchHealthIndicator")
    public HealthIndicator elasticsearchHealthIndicator() {
        return createHealthIndicator(this.clients);
    }

    @Override
    protected ElasticsearchJestHealthIndicator createHealthIndicator(JestClient client) {
        return new ElasticsearchJestHealthIndicator(client);
    }

}

• ElasticSearchJestHealthIndicatorAutoConfiguration创建的是ElasticsearchJestHealthIndicator(elasticsearch)，它是通过io.searchbox.client.JestClient去检测的

ElasticsearchJestHealthIndicator

spring-boot-actuator-2.1.4.RELEASE-sources.jar!/org/springframework/boot/actuate/elasticsearch/ElasticsearchJestHealthIndicator.java

public class ElasticsearchJestHealthIndicator extends AbstractHealthIndicator {

    private final JestClient jestClient;

    private final JsonParser jsonParser = JsonParserFactory.getJsonParser();

    public ElasticsearchJestHealthIndicator(JestClient jestClient) {
        super("Elasticsearch health check failed");
        this.jestClient = jestClient;
    }

    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        JestResult healthResult = this.jestClient
                .execute(new io.searchbox.cluster.Health.Builder().build());
        if (healthResult.getResponseCode() != 200 || !healthResult.isSucceeded()) {
            builder.down();
            builder.withDetail("statusCode", healthResult.getResponseCode());
        }
        else {
            Map<String, Object> response = this.jsonParser
                    .parseMap(healthResult.getJsonString());
            String status = (String) response.get("status");
            if (status.equals(io.searchbox.cluster.Health.Status.RED.getKey())) {
                builder.outOfService();
            }
            else {
                builder.up();
            }
            builder.withDetails(response);
        }
    }

}

• ElasticsearchJestHealthIndicator继承了AbstractHealthIndicator，构造器通过接收JestClient
• doHealthCheck方法通过jestClient.execute(new io.searchbox.cluster.Health.Builder().build())进行请求，如果http response status code不是200，或者healthResult.isSucceeded()不是true则直接返回Status.DOWN
• 如果http response status code是200且healthResult.isSucceeded()为true则再进一步通过jsonParser.parseMap(json)解析返回json为Map，然后取status字段，如果是io.searchbox.cluster.Health.Status.RED.getKey()则返回Status.OUT_OF_SERVICE，否则返回Status.UP

小结

• springboot提供了三个elasticsearch的healthIndicator配置，分别是ElasticSearchClientHealthIndicatorAutoConfiguration、ElasticSearchRestHealthIndicatorAutoConfiguration、ElasticSearchJestHealthIndicatorAutoConfiguration
• ElasticSearchClientHealthIndicatorAutoConfiguration创建的是ElasticsearchHealthIndicator(elasticsearch)，它是通过org.elasticsearch.client.Client去检测的
• ElasticSearchRestHealthIndicatorAutoConfiguration创建的是ElasticsearchRestHealthIndicator(elasticsearchRest)，它是通过org.elasticsearch.client.RestClient去检测的
• ElasticSearchJestHealthIndicatorAutoConfiguration创建的是ElasticsearchJestHealthIndicator(elasticsearch)，它是通过io.searchbox.client.JestClient去检测的
• ElasticsearchHealthIndicatorProperties提供了indices，responseTimeout两个配置项，对于使用org.elasticsearch.client.Client的如果没有配置应用使用的indices，则使用ALL_INDICES(_all)去请求；而使用org.elasticsearch.client.RestClient或io.searchbox.client.JestClient的它们请求的是/_cluster/health/这个接口

doc

• spring-boot-actuator-autoconfigure module