From 90d3850177bfcba8a9149beb0b78bc50f088e682 Mon Sep 17 00:00:00 2001
From: Georgios Andrianakis <geoand@gmail.com>
Date: Mon, 8 Oct 2018 15:20:36 +0300
Subject: [PATCH] Polish discovery client

---
 .../discovery/KubernetesDiscoveryClient.java  | 80 +++++--------------
 1 file changed, 18 insertions(+), 62 deletions(-)

diff --git a/spring-cloud-kubernetes-discovery/src/main/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClient.java b/spring-cloud-kubernetes-discovery/src/main/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClient.java
index b9eac58d..589a460f 100644
--- a/spring-cloud-kubernetes-discovery/src/main/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClient.java
+++ b/spring-cloud-kubernetes-discovery/src/main/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClient.java
@@ -16,23 +16,19 @@
  */
 package org.springframework.cloud.kubernetes.discovery;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.function.Predicate;
-import java.util.stream.Collectors;
-
 import io.fabric8.kubernetes.api.model.EndpointAddress;
 import io.fabric8.kubernetes.api.model.EndpointSubset;
 import io.fabric8.kubernetes.api.model.Endpoints;
 import io.fabric8.kubernetes.api.model.Service;
 import io.fabric8.kubernetes.client.KubernetesClient;
-import io.fabric8.kubernetes.client.utils.Utils;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
-import org.springframework.cloud.client.DefaultServiceInstance;
 import org.springframework.cloud.client.ServiceInstance;
 import org.springframework.cloud.client.discovery.DiscoveryClient;
 import org.springframework.expression.Expression;
@@ -43,7 +39,6 @@ import org.springframework.util.Assert;
 public class KubernetesDiscoveryClient implements DiscoveryClient {
 
 	private static final Log log = LogFactory.getLog(KubernetesDiscoveryClient.class);
-	private static final String HOSTNAME = "HOSTNAME";
 
 	private KubernetesClient client;
 	private final KubernetesDiscoveryProperties properties;
@@ -73,63 +68,16 @@ public class KubernetesDiscoveryClient implements DiscoveryClient {
 		return "Kubernetes Discovery Client";
 	}
 
-	public ServiceInstance getLocalServiceInstance() {
-		String serviceName = properties.getServiceName();
-		String podName = System.getenv(HOSTNAME);
-		ServiceInstance defaultInstance = new DefaultServiceInstance(serviceName,
-				"localhost",
-				8080,
-				false);
-
-		Endpoints endpoints = client.endpoints().withName(serviceName).get();
-		Optional<Service> service = Optional.ofNullable(client.services().withName(serviceName).get());
-		final Map<String, String> labels;
-		if (service.isPresent()) {
-			labels = service.get().getMetadata().getLabels();
-		} else {
-			labels = null;
-		}
-		if (Utils.isNullOrEmpty(podName) || endpoints == null) {
-			return defaultInstance;
-		}
-		try {
-			List<EndpointSubset> subsets = endpoints.getSubsets();
-
-			if (subsets != null) {
-				for (EndpointSubset s : subsets) {
-					List<EndpointAddress> addresses = s.getAddresses();
-					for (EndpointAddress a : addresses) {
-						return new KubernetesServiceInstance(serviceName,
-								a,
-								s.getPorts().stream().findFirst().orElseThrow(IllegalStateException::new),
-								labels,
-								false);
-					}
-				}
-			}
-			return defaultInstance;
-
-		} catch (Throwable t) {
-			return defaultInstance;
-		}
-	}
-
 	@Override
 	public List<ServiceInstance> getInstances(String serviceId) {
 		Assert.notNull(serviceId,
 				"[Assertion failed] - the object argument must be null");
-		Optional<Service> service = Optional.ofNullable(client.services().withName(serviceId).get());
-		final Map<String, String> labels;
-		if (service.isPresent()) {
-			labels = service.get().getMetadata().getLabels();
-		} else {
-			labels = null;
-		}
+		final Map<String, String> labels = getLabels(serviceId);
 
-		Optional<Endpoints> endpoints = Optional.ofNullable(client.endpoints().withName(serviceId).get());
-		List<EndpointSubset> subsets = endpoints.get().getSubsets();
+		Endpoints endpoints = client.endpoints().withName(serviceId).get();
+		List<EndpointSubset> subsets = null != endpoints ? endpoints.getSubsets() : new ArrayList<>();
 		List<ServiceInstance> instances = new ArrayList<>();
-		if (subsets != null) {
+		if (!subsets.isEmpty()) {
 			for (EndpointSubset s : subsets) {
 				List<EndpointAddress> addresses = s.getAddresses();
 				for (EndpointAddress a : addresses) {
@@ -145,6 +93,14 @@ public class KubernetesDiscoveryClient implements DiscoveryClient {
 		return instances;
 	}
 
+	private Map<String, String> getLabels(String serviceName) {
+		final Service service = client.services().withName(serviceName).get();
+		if (service != null) {
+			return service.getMetadata().getLabels();
+		}
+		return Collections.emptyMap();
+	}
+
 	@Override
 	public List<String> getServices() {
 		String spelExpression = properties.getFilter();