Configuration Sample Code
@ApplicationScoped
public class ElasticSearchConfiguration {
private static ElasticsearchClient client;
private static synchronized void connectElasticSearchCluster() {
if (Objects.nonNull(client)) {
return;
}
final CredentialsProvider credentialsProvider =
new BasicCredentialsProvider();
credentialsProvider.setCredentials(AuthScope.ANY,
new UsernamePasswordCredentials(ELASTIC_USER, ELASTIC_PASSWORD));
RestClientBuilder builder = RestClient.builder(initializeHttpHost())
.setHttpClientConfigCallback(httpClientBuilder -> httpClientBuilder
.setDefaultCredentialsProvider(credentialsProvider));
// init RestClient only once
RestClient restClient = builder.build();
ElasticsearchTransport transport = new RestClientTransport(
restClient, new JacksonJsonpMapper());
client = new ElasticsearchClient(transport);
}
private static HttpHost[] initializeHttpHost() {
List<String> hosts = Splitter.on(",").splitToList(ELASTIC_CLUSTER_HOST);
List<HttpHost> result = Lists.newArrayList();
hosts.forEach(item -> {
HttpHost httpHost = HttpHost.create(item);
result.add(httpHost);
});
return result.toArray(new HttpHost[hosts.size()]);
}
public ElasticsearchClient openConnection() {
if (Objects.isNull(client) && ENABLE_ELASTIC) {
connectElasticSearchCluster();
}
return client;
}
}
Usage Sample Code
@ApplicationScoped
public class SearchService {
@Inject
private ElasticSearchConfiguration elasticSearchConfiguration;
private List<Long> paginationQuery(List<String> queryIndexNames, Query query) {
ElasticsearchClient elasticsearchClient = elasticSearchConfiguration.openConnection();
SearchResponse<TestDocument> searchResponse = elasticsearchClient.search(builder.build(), TestDocument.class);
...
return new ArrayList<>();
}
}
According to the official documentation
The RestClient class is thread-safe and ideally has the same lifecycle as the application that uses it
So I think RestClient should be singleton.for the same reason, I think Java API clients, such as ElasticsearchClient, should also be singleton.
When the application shut down, I want to close the ElasticsearchClient, I found that there is no close method, only the client._transport().close() method; should I use this method? Or should I make RestClient also a static property and use RestClient.close() method, if so, doesn't ElasticsearchClient need to be closed?
:+1