Polish "Make Kubernetes detection slightly more efficient"

See gh-19002

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/cloud/CloudPlatform.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -16,8 +16,6 @@
 
 package org.springframework.boot.cloud;
 
-import java.io.File;
-
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.Environment;
@@ -75,22 +73,16 @@ public enum CloudPlatform {
 	 */
 	KUBERNETES {
 
-		private static final String SERVICE_HOST_SUFFIX = "_SERVICE_HOST";
-
-		private static final String SERVICE_PORT_SUFFIX = "_SERVICE_PORT";
-
-		private static final String SECRET_LOCATION = "/var/run/secrets/kubernetes.io";
-
 		private static final String KUBERNETES_SERVICE_HOST = "KUBERNETES_SERVICE_HOST";
 
 		private static final String KUBERNETES_SERVICE_PORT = "KUBERNETES_SERVICE_PORT";
 
+		private static final String SERVICE_HOST_SUFFIX = "_SERVICE_HOST";
+
+		private static final String SERVICE_PORT_SUFFIX = "_SERVICE_PORT";
+
 		@Override
 		public boolean isActive(Environment environment) {
-			if (environment.containsProperty(KUBERNETES_SERVICE_HOST)
-					|| environment.containsProperty(KUBERNETES_SERVICE_PORT) || isSecretLocationExists()) {
-				return true;
-			}
 			if (environment instanceof ConfigurableEnvironment) {
 				return isActive((ConfigurableEnvironment) environment);
 			}
@@ -100,9 +92,15 @@ public enum CloudPlatform {
 		private boolean isActive(ConfigurableEnvironment environment) {
 			PropertySource<?> environmentPropertySource = environment.getPropertySources()
 					.get(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME);
+			if (environmentPropertySource != null) {
+				if (environmentPropertySource.containsProperty(KUBERNETES_SERVICE_HOST)
+						&& environmentPropertySource.containsProperty(KUBERNETES_SERVICE_PORT)) {
+					return true;
+				}
 				if (environmentPropertySource instanceof EnumerablePropertySource) {
 					return isActive((EnumerablePropertySource<?>) environmentPropertySource);
 				}
+			}
 			return false;
 		}
 
@@ -119,11 +117,6 @@ public enum CloudPlatform {
 			return false;
 		}
 
-		private boolean isSecretLocationExists() {
-			File file = new File(SECRET_LOCATION);
-			return file.exists() && file.isDirectory();
-		}
-
 	};
 
 	/**

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/cloud/CloudPlatformTests.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * 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.
@@ -16,7 +16,6 @@
 
 package org.springframework.boot.cloud;
 
-import java.io.File;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
@@ -85,28 +84,38 @@ class CloudPlatformTests {
 	}
 
 	@Test
-	void getActiveWhenHasServiceHostAndServicePortShouldReturnKubernetes() {
-		MockEnvironment environment = new MockEnvironment();
-		Map<String, Object> source = new HashMap<>();
-		source.put("EXAMPLE_SERVICE_HOST", "---");
-		source.put("EXAMPLE_SERVICE_PORT", "8080");
-		PropertySource<?> propertySource = new SystemEnvironmentPropertySource(
-				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, source);
-		environment.getPropertySources().addFirst(propertySource);
+	void getActiveWhenHasKubernetesServiceHostAndPortShouldReturnKubernetes() {
+		Map<String, Object> envVars = new HashMap<>();
+		envVars.put("KUBERNETES_SERVICE_HOST", "---");
+		envVars.put("KUBERNETES_SERVICE_PORT", "8080");
+		Environment environment = getEnvironmentWithEnvVariables(envVars);
 		CloudPlatform platform = CloudPlatform.getActive(environment);
 		assertThat(platform).isEqualTo(CloudPlatform.KUBERNETES);
 		assertThat(platform.isActive(environment)).isTrue();
 	}
 
 	@Test
-	void getActiveWhenHasKubernetesHostAndPortShouldReturnKubernetes() {
-		MockEnvironment environment = new MockEnvironment();
-		Map<String, Object> source = new HashMap<>();
-		source.put("KUBERNETES_SERVICE_HOST", "---");
-		source.put("KUBERNETES_SERVICE_PORT", "8080");
-		PropertySource<?> propertySource = new SystemEnvironmentPropertySource(
-				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, source);
-		environment.getPropertySources().addFirst(propertySource);
+	void getActiveWhenHasKubernetesServiceHostAndNoKubernetesServicePortShouldNotReturnKubernetes() {
+		Environment environment = getEnvironmentWithEnvVariables(
+				Collections.singletonMap("KUBERNETES_SERVICE_HOST", "---"));
+		CloudPlatform platform = CloudPlatform.getActive(environment);
+		assertThat(platform).isNull();
+	}
+
+	@Test
+	void getActiveWhenHasKubernetesServicePortAndNoKubernetesServiceHostShouldNotReturnKubernetes() {
+		Environment environment = getEnvironmentWithEnvVariables(
+				Collections.singletonMap("KUBERNETES_SERVICE_PORT", "8080"));
+		CloudPlatform platform = CloudPlatform.getActive(environment);
+		assertThat(platform).isNull();
+	}
+
+	@Test
+	void getActiveWhenHasServiceHostAndServicePortShouldReturnKubernetes() {
+		Map<String, Object> envVars = new HashMap<>();
+		envVars.put("EXAMPLE_SERVICE_HOST", "---");
+		envVars.put("EXAMPLE_SERVICE_PORT", "8080");
+		Environment environment = getEnvironmentWithEnvVariables(envVars);
 		CloudPlatform platform = CloudPlatform.getActive(environment);
 		assertThat(platform).isEqualTo(CloudPlatform.KUBERNETES);
 		assertThat(platform.isActive(environment)).isTrue();
@@ -114,16 +123,18 @@ class CloudPlatformTests {
 
 	@Test
 	void getActiveWhenHasServiceHostAndNoServicePortShouldNotReturnKubernetes() {
-		MockEnvironment environment = new MockEnvironment();
-		PropertySource<?> propertySource = new SystemEnvironmentPropertySource(
-				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
+		Environment environment = getEnvironmentWithEnvVariables(
 				Collections.singletonMap("EXAMPLE_SERVICE_HOST", "---"));
-		environment.getPropertySources().addFirst(propertySource);
 		CloudPlatform platform = CloudPlatform.getActive(environment);
-		File path = new File("/var/run/secrets/kubernetes.io");
-		if (!path.exists() && !path.isDirectory()) {
 		assertThat(platform).isNull();
 	}
+
+	private Environment getEnvironmentWithEnvVariables(Map<String, Object> environmentVariables) {
+		MockEnvironment environment = new MockEnvironment();
+		PropertySource<?> propertySource = new SystemEnvironmentPropertySource(
+				StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, environmentVariables);
+		environment.getPropertySources().addFirst(propertySource);
+		return environment;
 	}
 
 }