Disable load balancer auto-config when Kubernetes disabled (#653)

When "spring.cloud.kubernetes.enabled=false", the Spring Cloud LoadBalancer auto-configuration will not be loaded.

Fixes gh-612

spring-cloud-kubernetes-loadbalancer/src/main/java/org/springframework/cloud/kubernetes/loadbalancer/KubernetesLoadBalancerAutoConfiguration.java

@@ -18,6 +18,7 @@ package org.springframework.cloud.kubernetes.loadbalancer;
 
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.cloud.kubernetes.commons.ConditionalOnKubernetesEnabled;
 import org.springframework.cloud.kubernetes.discovery.KubernetesDiscoveryProperties;
 import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClients;
 import org.springframework.context.annotation.Bean;
@@ -30,6 +31,7 @@ import org.springframework.context.annotation.Configuration;
  */
 @Configuration(proxyBeanMethods = false)
 @EnableConfigurationProperties(KubernetesLoadBalancerProperties.class)
+@ConditionalOnKubernetesEnabled
 @ConditionalOnProperty(value = "spring.cloud.kubernetes.loadbalancer.enabled", matchIfMissing = true)
 @LoadBalancerClients(defaultConfiguration = KubernetesLoadBalancerClientConfiguration.class)
 public class KubernetesLoadBalancerAutoConfiguration {

spring-cloud-kubernetes-loadbalancer/src/test/java/org/springframework/cloud/kubernetes/loadbalancer/KubernetesLoadBalancerAutoConfigurationTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2013-2020 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.cloud.kubernetes.loadbalancer;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.cloud.kubernetes.discovery.KubernetesDiscoveryProperties;
+import org.springframework.context.ConfigurableApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Thomas Vitale
+ */
+class KubernetesLoadBalancerAutoConfigurationTests {
+
+	private ConfigurableApplicationContext context;
+
+	@AfterEach
+	public void close() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	void kubernetesLoadBalancerWhenKubernetesDisabledAndLoadBalancerDisabled() {
+		setup("spring.cloud.kubernetes.enabled=false", "spring.cloud.kubernetes.loadbalancer.enabled=false");
+		assertThat(this.context.getBeanNamesForType(KubernetesServiceInstanceMapper.class)).isEmpty();
+	}
+
+	@Test
+	void kubernetesLoadBalancerWhenKubernetesDisabledAndLoadBalancerEnabled() {
+		setup("spring.cloud.kubernetes.enabled=false", "spring.cloud.kubernetes.loadbalancer.enabled=true");
+		assertThat(this.context.getBeanNamesForType(KubernetesServiceInstanceMapper.class)).isEmpty();
+	}
+
+	@Test
+	void kubernetesLoadBalancerWhenKubernetesEnabledAndLoadBalancerEnabled() {
+		setup("spring.cloud.kubernetes.enabled=true", "spring.cloud.kubernetes.loadbalancer.enabled=true");
+		assertThat(this.context.getBeanNamesForType(KubernetesServiceInstanceMapper.class)).hasSize(1);
+	}
+
+	@Test
+	void kubernetesLoadBalancerWhenKubernetesEnabledAndLoadBalancerDisabled() {
+		setup("spring.cloud.kubernetes.enabled=true", "spring.cloud.kubernetes.loadbalancer.enabled=false");
+		assertThat(this.context.getBeanNamesForType(KubernetesServiceInstanceMapper.class)).isEmpty();
+	}
+
+	@Test
+	void kubernetesLoadBalancerWhenDefaultProperties() {
+		setup();
+		assertThat(this.context.getBeanNamesForType(KubernetesServiceInstanceMapper.class)).hasSize(1);
+	}
+
+	private void setup(String... env) {
+		this.context = new SpringApplicationBuilder(KubernetesLoadBalancerAutoConfiguration.class,
+				KubernetesDiscoveryProperties.class).web(org.springframework.boot.WebApplicationType.NONE)
+						.properties(env).run();
+	}
+}