piggy-back changes already done in Fabric8PodUtils (#787)

* fix

* move to assertj

spring-cloud-kubernetes-client-autoconfig/pom.xml

@@ -48,6 +48,11 @@
 			<artifactId>spring-boot-starter-web</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.mockito</groupId>
+			<artifactId>mockito-inline</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 </project>

spring-cloud-kubernetes-client-autoconfig/src/main/java/org/springframework/cloud/kubernetes/client/KubernetesClientPodUtils.java

@@ -25,8 +25,10 @@ import io.kubernetes.client.util.Config;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.cloud.kubernetes.commons.EnvReader;
 import org.springframework.cloud.kubernetes.commons.LazilyInstantiate;
 import org.springframework.cloud.kubernetes.commons.PodUtils;
+import org.springframework.util.StringUtils;
 
 /**
  * @author Ryan Baxter
@@ -38,15 +40,22 @@ public class KubernetesClientPodUtils implements PodUtils<V1Pod> {
 	 */
 	public static final String HOSTNAME = "HOSTNAME";
 
+	/**
+	 * KUBERNETES_SERVICE_HOST environment variable name.
+	 */
+	public static final String KUBERNETES_SERVICE_HOST = "KUBERNETES_SERVICE_HOST";
+
 	private static final Log LOG = LogFactory.getLog(KubernetesClientPodUtils.class);
 
 	private final CoreV1Api client;
 
 	private final String hostName;
 
-	private Supplier<V1Pod> current;
+	private final Supplier<V1Pod> current;
 
-	private String namespace;
+	private final String namespace;
+
+	private final String serviceHost;
 
 	public KubernetesClientPodUtils(CoreV1Api client, String namespace) {
 		if (client == null) {
@@ -54,14 +63,15 @@ public class KubernetesClientPodUtils implements PodUtils<V1Pod> {
 		}
 
 		this.client = client;
-		this.hostName = System.getenv(HOSTNAME);
-		this.current = LazilyInstantiate.using(() -> internalGetPod());
+		this.hostName = EnvReader.getEnv(HOSTNAME);
+		this.serviceHost = EnvReader.getEnv(KUBERNETES_SERVICE_HOST);
+		this.current = LazilyInstantiate.using(this::internalGetPod);
 		this.namespace = namespace;
 	}
 
 	@Override
 	public Supplier<V1Pod> currentPod() {
-		return this.current;
+		return current;
 	}
 
 	@Override
@@ -69,30 +79,35 @@ public class KubernetesClientPodUtils implements PodUtils<V1Pod> {
 		return currentPod().get() != null;
 	}
 
-	private synchronized V1Pod internalGetPod() {
+	private V1Pod internalGetPod() {
 		try {
-			LOG.info("Getting pod internal");
-			if (isServiceAccountFound() && isHostNameEnvVarPresent()) {
-				return this.client.readNamespacedPod(this.hostName, namespace, null, null, null);
-			}
-			else {
-				return null;
+			if (isServiceHostEnvVarPresent() && isHostNameEnvVarPresent() && isServiceAccountFound()) {
+				return client.readNamespacedPod(hostName, namespace, null, null, null);
 			}
 		}
 		catch (Throwable t) {
-			LOG.warn("Failed to get pod with name:[" + this.hostName + "]. You should look into this if things aren't"
+			LOG.warn("Failed to get pod with name:[" + hostName + "]. You should look into this if things aren't"
 					+ " working as you expect. Are you missing serviceaccount permissions?", t);
-			return null;
 		}
+		return null;
+	}
+
+	private boolean isServiceHostEnvVarPresent() {
+		return StringUtils.hasLength(serviceHost);
 	}
 
 	private boolean isHostNameEnvVarPresent() {
-		return this.hostName != null && !this.hostName.isEmpty();
+		return StringUtils.hasLength(hostName);
 	}
 
 	private boolean isServiceAccountFound() {
-		return Paths.get(Config.SERVICEACCOUNT_TOKEN_PATH).toFile().exists()
-				&& Paths.get(Config.SERVICEACCOUNT_CA_PATH).toFile().exists();
+		boolean serviceAccountPathPresent = Paths.get(Config.SERVICEACCOUNT_TOKEN_PATH).toFile().exists();
+		if (!serviceAccountPathPresent) {
+			// https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/
+			LOG.warn("serviceaccount path not present, did you disable it via 'automountServiceAccountToken : false'?"
+					+ " Major functionalities will not work without that property being set");
+		}
+		return serviceAccountPathPresent && Paths.get(Config.SERVICEACCOUNT_CA_PATH).toFile().exists();
 	}
 
 }

spring-cloud-kubernetes-client-autoconfig/src/test/java/org/springframework/cloud/kubernetes/client/KubernetesClientPodUtilsTests.java

@@ -0,0 +1,174 @@
+/*
+ * Copyright 2013-2021 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.client;
+
+import java.io.File;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.function.Supplier;
+
+import io.kubernetes.client.openapi.ApiException;
+import io.kubernetes.client.openapi.apis.CoreV1Api;
+import io.kubernetes.client.openapi.models.V1Pod;
+import io.kubernetes.client.util.Config;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+import org.mockito.Mockito;
+
+import org.springframework.cloud.kubernetes.commons.EnvReader;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * @author wind57
+ */
+public class KubernetesClientPodUtilsTests {
+
+	private static final String KUBERNETES_SERVICE_HOST = KubernetesClientPodUtils.KUBERNETES_SERVICE_HOST;
+
+	private static final String HOSTNAME = KubernetesClientPodUtils.HOSTNAME;
+
+	private static final String SERVICE_ACCOUNT_TOKEN_PATH = Config.SERVICEACCOUNT_TOKEN_PATH;
+
+	private static final String SERVICE_ACCOUNT_CERT_PATH = Config.SERVICEACCOUNT_CA_PATH;
+
+	private static final String POD_HOSTNAME = "pod-hostname";
+
+	private static final String HOST = "10.1.1.1";
+
+	private static final V1Pod POD = new V1Pod();
+
+	private final CoreV1Api client = Mockito.mock(CoreV1Api.class);
+
+	private final Path tokenPath = Mockito.mock(Path.class);
+
+	private final File tokenFile = Mockito.mock(File.class);
+
+	private final Path certPath = Mockito.mock(Path.class);
+
+	private final File certFile = Mockito.mock(File.class);
+
+	private MockedStatic<EnvReader> envReader;
+
+	private MockedStatic<Paths> paths;
+
+	@BeforeEach
+	public void before() {
+		envReader = Mockito.mockStatic(EnvReader.class);
+		paths = Mockito.mockStatic(Paths.class);
+	}
+
+	@AfterEach
+	public void after() {
+		envReader.close();
+		paths.close();
+	}
+
+	@Test
+	public void constructorThrowsIllegalArgumentExceptionWhenKubeClientIsNull() {
+		assertThatThrownBy(() -> new KubernetesClientPodUtils(null, "namespace"))
+				.isInstanceOf(IllegalArgumentException.class)
+				.hasMessage("Must provide an instance of KubernetesClient");
+	}
+
+	@Test
+	public void serviceHostNotPresent() {
+		mockHost(null);
+
+		KubernetesClientPodUtils util = new KubernetesClientPodUtils(client, "namespace");
+		Supplier<V1Pod> sup = util.currentPod();
+		assertSupplierAndClient(sup, util);
+	}
+
+	@Test
+	public void hostNameNotPresent() {
+		mockHost(HOST);
+		mockHostname(null);
+
+		KubernetesClientPodUtils util = new KubernetesClientPodUtils(client, "namespace");
+		Supplier<V1Pod> sup = util.currentPod();
+		assertSupplierAndClient(sup, util);
+	}
+
+	@Test
+	public void serviceAccountPathNotPresent() {
+		mockTokenPath(false);
+		mockHostname(HOST);
+
+		KubernetesClientPodUtils util = new KubernetesClientPodUtils(client, "namespace");
+		Supplier<V1Pod> sup = util.currentPod();
+		assertSupplierAndClient(sup, util);
+	}
+
+	@Test
+	public void serviceAccountCertPathNotPresent() {
+		mockTokenPath(true);
+		mockCertPath(false);
+		mockHostname(HOST);
+
+		KubernetesClientPodUtils util = new KubernetesClientPodUtils(client, "namespace");
+		Supplier<V1Pod> sup = util.currentPod();
+		assertSupplierAndClient(sup, util);
+	}
+
+	@Test
+	public void allPresent() throws ApiException {
+		mockTokenPath(true);
+		mockCertPath(true);
+		mockHost(HOST);
+		mockHostname(POD_HOSTNAME);
+		mockPodResult();
+
+		KubernetesClientPodUtils util = new KubernetesClientPodUtils(client, "namespace");
+		Supplier<V1Pod> sup = util.currentPod();
+		assertThat(sup.get()).isNotNull();
+		assertThat(util.isInsideKubernetes()).isTrue();
+	}
+
+	private void assertSupplierAndClient(Supplier<V1Pod> sup, KubernetesClientPodUtils util) {
+		assertThat(sup.get()).isNull();
+		assertThat(util.isInsideKubernetes()).isFalse();
+	}
+
+	private void mockHost(String host) {
+		envReader.when(() -> EnvReader.getEnv(KUBERNETES_SERVICE_HOST)).thenReturn(host);
+	}
+
+	private void mockHostname(String name) {
+		envReader.when(() -> EnvReader.getEnv(HOSTNAME)).thenReturn(name);
+	}
+
+	private void mockTokenPath(boolean result) {
+		Mockito.when(tokenPath.toFile()).thenReturn(tokenFile);
+		Mockito.when(tokenFile.exists()).thenReturn(result);
+		paths.when(() -> Paths.get(SERVICE_ACCOUNT_TOKEN_PATH)).thenReturn(tokenPath);
+	}
+
+	private void mockCertPath(boolean result) {
+		Mockito.when(certPath.toFile()).thenReturn(certFile);
+		Mockito.when(certFile.exists()).thenReturn(result);
+		paths.when(() -> Paths.get(SERVICE_ACCOUNT_CERT_PATH)).thenReturn(certPath);
+	}
+
+	private void mockPodResult() throws ApiException {
+		Mockito.when(client.readNamespacedPod(POD_HOSTNAME, "namespace", null, null, null)).thenReturn(POD);
+	}
+
+}