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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;}}
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• 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 extendsCompositeHealthIndicatorConfiguration<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);}@Overrideprotected ElasticsearchHealthIndicator createHealthIndicator(Client client) {Duration responseTimeout = this.properties.getResponseTimeout();return new ElasticsearchHealthIndicator(client,(responseTimeout != null) ? responseTimeout.toMillis() : 100,this.properties.getIndices());}}
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• 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;}@Overrideprotected 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());}}
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• 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 extendsCompositeHealthIndicatorConfiguration<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);}@Overrideprotected ElasticsearchRestHealthIndicator createHealthIndicator(RestClient client) {return new ElasticsearchRestHealthIndicator(client);}}
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• 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();}@Overrideprotected 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);}}
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• 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
}
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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 extendsCompositeHealthIndicatorConfiguration<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);}@Overrideprotected ElasticsearchJestHealthIndicator createHealthIndicator(JestClient client) {return new ElasticsearchJestHealthIndicator(client);}}
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• 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;}@Overrideprotected 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);}}}
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• 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