Add support to disabled kubernetes health indicator (#450)

Currently, `KubernetesHealthIndicator` bean missed
`ConditionalOnEnabledHealthIndicator` annotation. This commit introduces
this annotation which allow to enable or disable via configuration
properties `management.health.kubernetes.enabled`.

Fixes gh-449

spring-cloud-kubernetes-core/pom.xml

@@ -51,7 +51,7 @@
 		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
-			<artifactId>spring-boot-actuator</artifactId>
+			<artifactId>spring-boot-actuator-autoconfigure</artifactId>
 			<optional>true</optional>
 		</dependency>
 		<dependency>

spring-cloud-kubernetes-core/src/main/java/org/springframework/cloud/kubernetes/KubernetesAutoConfiguration.java

@@ -25,6 +25,7 @@ import io.fabric8.kubernetes.client.KubernetesClient;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.boot.actuate.autoconfigure.health.ConditionalOnEnabledHealthIndicator;
 import org.springframework.boot.actuate.health.HealthIndicator;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -37,6 +38,7 @@ import org.springframework.context.annotation.Configuration;
  * Auto configuration for Kubernetes.
  *
  * @author Ioannis Canellos
+ * @author Eddú Meléndez
  */
 @Configuration
 @ConditionalOnProperty(value = "spring.cloud.kubernetes.enabled", matchIfMissing = true)
@@ -158,6 +160,7 @@ public class KubernetesAutoConfiguration {
 	protected static class KubernetesActuatorConfiguration {
 
 		@Bean
+		@ConditionalOnEnabledHealthIndicator("kubernetes")
 		public KubernetesHealthIndicator kubernetesHealthIndicator(PodUtils podUtils) {
 			return new KubernetesHealthIndicator(podUtils);
 		}

spring-cloud-kubernetes-core/src/test/java/org/springframework/cloud/kubernetes/HealthIndicatorDisabledTest.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2013-2019 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.cloud.kubernetes;
+
+import io.fabric8.kubernetes.client.Config;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.fabric8.kubernetes.server.mock.KubernetesServer;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.kubernetes.example.App;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.not;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = App.class, properties = {
+		"management.health.kubernetes.enabled=false" })
+public class HealthIndicatorDisabledTest {
+
+	@ClassRule
+	public static KubernetesServer server = new KubernetesServer();
+
+	private static KubernetesClient mockClient;
+
+	@Autowired
+	private WebTestClient webClient;
+
+	@Value("${local.server.port}")
+	private int port;
+
+	@BeforeClass
+	public static void setUpBeforeClass() {
+		mockClient = server.getClient();
+
+		// Configure the kubernetes master url to point to the mock server
+		System.setProperty(Config.KUBERNETES_MASTER_SYSTEM_PROPERTY,
+				mockClient.getConfiguration().getMasterUrl());
+		System.setProperty(Config.KUBERNETES_TRUST_CERT_SYSTEM_PROPERTY, "true");
+		System.setProperty(Config.KUBERNETES_AUTH_TRYKUBECONFIG_SYSTEM_PROPERTY, "false");
+		System.setProperty(Config.KUBERNETES_AUTH_TRYSERVICEACCOUNT_SYSTEM_PROPERTY,
+				"false");
+		System.setProperty(Config.KUBERNETES_NAMESPACE_SYSTEM_PROPERTY, "test");
+	}
+
+	@Test
+	public void healthEndpointShouldContainKubernetes() {
+		this.webClient.get().uri("http://localhost:{port}/actuator/health", this.port)
+				.accept(MediaType.APPLICATION_JSON).exchange().expectStatus().isOk()
+				.expectBody(String.class).value(not(containsString("kubernetes")));
+	}
+
+}