Bring back Elasticsearch RestClient auto-configuration

Prior to this commit, Spring Boot would only auto-configure the
`RestHighLevelClient` and `RestClientBuilder` if the
`RestHighLevelClient` was present. This was done in 1d73d4e.

This commit brings back the exposing of the `RestClient` bean in when
exposing the `RestHighLevelClient` or when the `RestHighLevelClient`
is not present. It allows for using the auto-configuration and its
customizers of the `RestClientBuilder` in a similar way as it is done
for the `RestTemplateBuilder` and the `WebClient.Builder`.

The presence of the `elasticsearch-rest-high-level-client` module is
now optional. This opens the door for potentially adding support for
the new Elasticsearch Java Client[1] that is based on the same
`RestClient`.

The health contributor and its configuration has also been updated to
only depend on the low-level RestClient.

See gh-28496

[1] https://github.com/elastic/elasticsearch-java

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticSearchRestHealthContributorAutoConfiguration.java

@@ -44,14 +44,13 @@
 @ConditionalOnClass(org.elasticsearch.client.RestHighLevelClient.class)
 @ConditionalOnBean(org.elasticsearch.client.RestHighLevelClient.class)
 @ConditionalOnEnabledHealthIndicator("elasticsearch")
-public class ElasticSearchRestHealthContributorAutoConfiguration extends
-		CompositeHealthContributorConfiguration<ElasticsearchRestHealthIndicator, org.elasticsearch.client.RestHighLevelClient> {
+public class ElasticSearchRestHealthContributorAutoConfiguration
+		extends CompositeHealthContributorConfiguration<ElasticsearchRestHealthIndicator, RestClient> {
 
 	@Bean
 	@ConditionalOnMissingBean(name = { "elasticsearchHealthIndicator", "elasticsearchHealthContributor" })
-	public HealthContributor elasticsearchHealthContributor(
-			Map<String, org.elasticsearch.client.RestHighLevelClient> clients) {
+	public HealthContributor elasticsearchHealthContributor(Map<String, RestClient> clients) {
 		return createContributor(clients);
 	}
 
-}
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticSearchRestHealthContributorConfigurations.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2012-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.elasticsearch;
+
+import java.util.Map;
+
+import org.elasticsearch.client.RestClient;
+
+import org.springframework.boot.actuate.autoconfigure.health.CompositeHealthContributorConfiguration;
+import org.springframework.boot.actuate.elasticsearch.ElasticsearchRestClientHealthIndicator;
+import org.springframework.boot.actuate.health.HealthContributor;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Elasticsearch rest client health contributor configurations.
+ *
+ * @author Filip Hrisafov
+ */
+class ElasticSearchRestHealthContributorConfigurations {
+
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass(org.elasticsearch.client.RestHighLevelClient.class)
+	@ConditionalOnBean(org.elasticsearch.client.RestHighLevelClient.class)
+	@Deprecated
+	static class RestHighLevelClientHealthContributorConfiguration extends
+			CompositeHealthContributorConfiguration<org.springframework.boot.actuate.elasticsearch.ElasticsearchRestHealthIndicator, org.elasticsearch.client.RestHighLevelClient> {
+
+		@Bean
+		@ConditionalOnMissingBean(name = { "elasticsearchHealthIndicator", "elasticsearchHealthContributor" })
+		HealthContributor elasticsearchHealthContributor(
+				Map<String, org.elasticsearch.client.RestHighLevelClient> clients) {
+			return createContributor(clients);
+		}
+
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnBean(RestClient.class)
+	@ConditionalOnMissingBean(org.elasticsearch.client.RestHighLevelClient.class)
+	static class RestClientHealthContributorConfiguration
+			extends CompositeHealthContributorConfiguration<ElasticsearchRestClientHealthIndicator, RestClient> {
+
+		@Bean
+		@ConditionalOnMissingBean(name = { "elasticsearchHealthIndicator", "elasticsearchHealthContributor" })
+		HealthContributor elasticsearchHealthContributor(Map<String, RestClient> clients) {
+			return createContributor(clients);
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticsearchReactiveHealthContributorAutoConfigurationTests.java

@@ -50,6 +50,7 @@ void runShouldCreateIndicator() {
 	}
 
 	@Test
+	@SuppressWarnings("deprecation")
 	void runWithRegularIndicatorShouldOnlyCreateReactiveIndicator() {
 		this.contextRunner
 				.withConfiguration(AutoConfigurations.of(ElasticSearchRestHealthContributorAutoConfiguration.class))

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/elasticsearch/ElasticsearchRestHealthContributorAutoConfigurationTests.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.elasticsearch;
+
+import org.elasticsearch.client.RestClient;
+import org.elasticsearch.client.RestClientBuilder;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.autoconfigure.health.HealthContributorAutoConfiguration;
+import org.springframework.boot.actuate.elasticsearch.ElasticsearchRestClientHealthIndicator;
+import org.springframework.boot.actuate.elasticsearch.ElasticsearchRestHealthIndicator;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.elasticsearch.ElasticsearchRestClientAutoConfiguration;
+import org.springframework.boot.test.context.FilteredClassLoader;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ElasticsearchRestClientAutoConfiguration}.
+ *
+ * @author Filip Hrisafov
+ */
+class ElasticsearchRestHealthContributorAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(ElasticsearchRestClientAutoConfiguration.class,
+					ElasticSearchRestHealthContributorAutoConfiguration.class,
+					HealthContributorAutoConfiguration.class));
+
+	@Test
+	@SuppressWarnings("deprecation")
+	void runShouldCreateIndicator() {
+		this.contextRunner.run((context) -> assertThat(context).hasSingleBean(ElasticsearchRestHealthIndicator.class)
+				.hasBean("elasticsearchHealthContributor"));
+	}
+
+	@Test
+	void runWithoutRestHighLevelClientAndWithoutRestClientShouldNotCreateIndicator() {
+		this.contextRunner
+				.withClassLoader(
+						new FilteredClassLoader(org.elasticsearch.client.RestHighLevelClient.class, RestClient.class))
+				.run((context) -> assertThat(context).doesNotHaveBean(ElasticsearchRestClientHealthIndicator.class)
+						.doesNotHaveBean("elasticsearchHealthContributor"));
+	}
+
+	@Test
+	@SuppressWarnings("deprecation")
+	void runWithoutRestHighLevelClientAndWithRestClientShouldCreateIndicator() {
+		this.contextRunner.withUserConfiguration(CustomRestClientConfiguration.class)
+				.run((context) -> assertThat(context).hasSingleBean(ElasticsearchRestClientHealthIndicator.class)
+						.doesNotHaveBean(ElasticsearchRestHealthIndicator.class)
+						.hasBean("elasticsearchHealthContributor"));
+	}
+
+	@Test
+	@SuppressWarnings("deprecation")
+	void runWithRestHighLevelClientAndWithRestClientShouldCreateIndicator() {
+		this.contextRunner.withUserConfiguration(CustomRestHighClientConfiguration.class)
+				.run((context) -> assertThat(context).hasSingleBean(ElasticsearchRestClientHealthIndicator.class)
+						.hasBean("elasticsearchHealthContributor"));
+	}
+
+	@Test
+	void runWhenDisabledShouldNotCreateIndicator() {
+		this.contextRunner.withPropertyValues("management.health.elasticsearch.enabled:false")
+				.run((context) -> assertThat(context).doesNotHaveBean(ElasticsearchRestClientHealthIndicator.class)
+						.doesNotHaveBean("elasticsearchHealthContributor"));
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class CustomRestClientConfiguration {
+
+		@Bean
+		RestClient customRestClient(RestClientBuilder builder) {
+			return builder.build();
+		}
+
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@SuppressWarnings("deprecation")
+	static class CustomRestHighClientConfiguration {
+
+		@Bean
+		org.elasticsearch.client.RestHighLevelClient customRestHighClient(RestClientBuilder builder) {
+			return new org.elasticsearch.client.RestHighLevelClient(builder);
+		}
+
+		@Bean
+		RestClient customClient(org.elasticsearch.client.RestHighLevelClient restHighLevelClient) {
+			return restHighLevelClient.getLowLevelClient();
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/elasticsearch/ElasticsearchRestClientHealthIndicator.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.elasticsearch;
+
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import org.apache.http.HttpStatus;
+import org.apache.http.StatusLine;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
+import org.elasticsearch.client.RestClient;
+
+import org.springframework.boot.actuate.health.AbstractHealthIndicator;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.json.JsonParser;
+import org.springframework.boot.json.JsonParserFactory;
+import org.springframework.util.StreamUtils;
+
+/**
+ * {@link HealthIndicator} for an Elasticsearch cluster using a {@link RestClient}.
+ *
+ * @author Artsiom Yudovin
+ * @author Brian Clozel
+ * @author Filip Hrisafov
+ * @since 2.7
+ */
+public class ElasticsearchRestClientHealthIndicator extends AbstractHealthIndicator {
+
+	private static final String RED_STATUS = "red";
+
+	private final RestClient client;
+
+	private final JsonParser jsonParser;
+
+	public ElasticsearchRestClientHealthIndicator(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);
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/elasticsearch/ElasticsearchRestHealthIndicator.java

@@ -16,22 +16,9 @@
 
 package org.springframework.boot.actuate.elasticsearch;
 
-import java.io.InputStream;
-import java.nio.charset.StandardCharsets;
-import java.util.Map;
-
-import org.apache.http.HttpStatus;
-import org.apache.http.StatusLine;
-import org.elasticsearch.client.Request;
-import org.elasticsearch.client.Response;
 import org.elasticsearch.client.RestClient;
 
-import org.springframework.boot.actuate.health.AbstractHealthIndicator;
-import org.springframework.boot.actuate.health.Health;
 import org.springframework.boot.actuate.health.HealthIndicator;
-import org.springframework.boot.json.JsonParser;
-import org.springframework.boot.json.JsonParserFactory;
-import org.springframework.util.StreamUtils;
 
 /**
  * {@link HealthIndicator} for an Elasticsearch cluster using a {@link RestClient}.
@@ -40,51 +27,19 @@
  * @author Brian Clozel
  * @author Filip Hrisafov
  * @since 2.1.1
+ * @deprecated since 2.7.0 for removal in 2.9.0 in favor of
+ * {@link ElasticsearchRestClientHealthIndicator}
  */
-public class ElasticsearchRestHealthIndicator extends AbstractHealthIndicator {
-
-	private static final String RED_STATUS = "red";
-
-	private final RestClient client;
-
-	private final JsonParser jsonParser;
+@Deprecated
+public class ElasticsearchRestHealthIndicator extends ElasticsearchRestClientHealthIndicator {
 
 	@SuppressWarnings("deprecation")
 	public ElasticsearchRestHealthIndicator(org.elasticsearch.client.RestHighLevelClient client) {
 		this(client.getLowLevelClient());
 	}
 
 	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);
+		super(client);
 	}
 
 }