Spring Elasticsearch Clients

Spring Elasticsearch Clients

Spring data Elasticsearch operates upon an Elasticsearch client that is connected to a single Elasticsearch node or a cluster. Although the Elasticsearch Client can be used to work with the cluster, applications using Spring Data Elasticsearch normally use the higher level abstractions of Elasticsearch Operations and Elasticsearch Repositories.

Transport Client

static class Config {

  @Bean
  Client client() {
  Settings settings = Settings.builder()
    .put("cluster.name", "elasticsearch")   
      .build();
  TransportClient client = new PreBuiltTransportClient(settings);
    client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1")
      , 9300));                               
    return client;
  }
}

// ...

IndexRequest request = new IndexRequest("spring-data", "elasticsearch", randomID())
 .source(someObject)
 .setRefreshPolicy(IMMEDIATE);

High Level REST Client

The Java High Level REST Client now is the default client of Elasticsearch, it provides a straight forward replacement for the TransportClient as it accepts and returns the very same request/response objects and therefore depends on the Elasticsearch core project. Asynchronous calls are operated upon a client managed thread pool and require a callback to be notified when the request is done.

import org.springframework.beans.factory.annotation.Autowired;@Configuration

static class Config {

  @Bean

  RestHighLevelClient client() {

    ClientConfiguration clientConfiguration = ClientConfiguration.builder() 

      .connectedTo("localhost:9200", "localhost:9201")

      .build();

    return RestClients.create(clientConfiguration).rest();                  

  }

}

// ...

  @Autowired

  RestHighLevelClient highLevelClient;

  RestClient lowLevelClient = highLevelClient.lowLevelClient();             

// ...

IndexRequest request = new IndexRequest("spring-data", "elasticsearch", randomID())

  .source(singletonMap("feature", "high-level-rest-client"))

  .setRefreshPolicy(IMMEDIATE);

IndexResponse response = highLevelClient.index(request);

Reactive Client

The ReactiveElasticsearchClient is a non official driver based on WebClient. It uses the request/response objects provided by the Elasticsearch core project. Calls are directly operated on the reactive stack, not wrapping async (thread pool bound) responses into reactive types.

static class Config {

  @Bean

  ReactiveElasticsearchClient client() {

    ClientConfiguration clientConfiguration = ClientConfiguration.builder()   

      .connectedTo("localhost:9200", "localhost:9291")

      .withWebClientConfigurer(webClient -> {                                 

        ExchangeStrategies exchangeStrategies = ExchangeStrategies.builder()

            .codecs(configurer -> configurer.defaultCodecs()

                .maxInMemorySize(-1))

            .build();

        return webClient.mutate().exchangeStrategies(exchangeStrategies).build();

       })

      .build();

    return ReactiveRestClients.create(clientConfiguration);

  }

}

// ...

Mono<IndexResponse> response = client.index(request ->

  request.index("spring-data")

    .type("elasticsearch")

    .id(randomID())

    .source(singletonMap("feature", "reactive-client"))

    .setRefreshPolicy(IMMEDIATE);

);

Client Configuration

Client behavior can be changed via the ClientConfiguration that allows to set options for SSL, connect and socket timeouts.

// optional if Basic Auhtentication is needed

HttpHeaders defaultHeaders = new HttpHeaders();

defaultHeaders.setBasicAuth(USER_NAME, USER_PASS);                      

ClientConfiguration clientConfiguration = ClientConfiguration.builder()

  .connectedTo("localhost:9200", "localhost:9291")                      

  .withConnectTimeout(Duration.ofSeconds(5))                            

  .withSocketTimeout(Duration.ofSeconds(3))                             

  .useSsl()                                                             

  .withDefaultHeaders(defaultHeaders)                                   

  .withBasicAuth(username, password)                                    

  . // ... other options

  .build();