Make the source of Service Metadata configurable (#270)

Make service metadata configurable, so that users can tune it
however they see fit. Specifically we add:

* Add flag to enable/disable addition of labels to metadata
(default: true)
* Add optional prefix to label keys (default none)
* Add flag to enable/disable addition of annotation to metadata
(default: true)
* Add optional prefix to annotation keys (default none)

Fixes: gh-260

spring-cloud-kubernetes-discovery/src/main/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClient.java

@@ -23,6 +23,7 @@ import io.fabric8.kubernetes.api.model.Service;
 import io.fabric8.kubernetes.client.KubernetesClient;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Predicate;
@@ -35,6 +36,7 @@ import org.springframework.expression.Expression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.expression.spel.support.SimpleEvaluationContext;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 public class KubernetesDiscoveryClient implements DiscoveryClient {
 
@@ -72,19 +74,35 @@ public class KubernetesDiscoveryClient implements DiscoveryClient {
 	public List<ServiceInstance> getInstances(String serviceId) {
 		Assert.notNull(serviceId,
 				"[Assertion failed] - the object argument must be null");
-		final Map<String, String> labels = getLabels(serviceId);
 
 		Endpoints endpoints = client.endpoints().withName(serviceId).get();
 		List<EndpointSubset> subsets = null != endpoints ? endpoints.getSubsets() : new ArrayList<>();
 		List<ServiceInstance> instances = new ArrayList<>();
 		if (!subsets.isEmpty()) {
+
+			final Service service = client.services().withName(serviceId).get();
+
+			final Map<String, String> metadata = new HashMap<>();
+			if(properties.isEnabledAdditionOfLabelsAsMetadata()) {
+				metadata.putAll(
+					getMapWithPrefixedKeys(
+						service.getMetadata().getLabels(), properties.getLabelKeysPrefix())
+				);
+			}
+			if(properties.isEnabledAdditionOfAnnotationsAsMetadata()) {
+				metadata.putAll(
+					getMapWithPrefixedKeys(
+						service.getMetadata().getAnnotations(), properties.getAnnotationKeysPrefix())
+				);
+			}
+
 			for (EndpointSubset s : subsets) {
 				List<EndpointAddress> addresses = s.getAddresses();
 				for (EndpointAddress a : addresses) {
 					instances.add(new KubernetesServiceInstance(serviceId,
 							a,
 							s.getPorts().stream().findFirst().orElseThrow(IllegalStateException::new),
-							labels,
+							metadata,
 							false));
 				}
 			}
@@ -93,12 +111,19 @@ 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();
+	// returns a new map that contain all the entries of the original map
+	// but with the keys prefixed
+	// if the prefix is null or empty, the map itself is returned (unchanged of course)
+	private Map<String, String> getMapWithPrefixedKeys(Map<String, String> map, String prefix) {
+		// when the prefix is empty just return an map with the same entries
+		if (!StringUtils.hasText(prefix)) {
+			return map;
 		}
-		return Collections.emptyMap();
+
+		final Map<String, String> result = new HashMap<>();
+		map.forEach((k, v) -> result.put(prefix + k, v));
+
+		return result;
 	}
 
 	@Override

spring-cloud-kubernetes-discovery/src/main/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryProperties.java

@@ -29,11 +29,36 @@ public class KubernetesDiscoveryProperties extends AutoServiceRegistrationProper
 	@Value("${spring.application.name:unknown}")
 	private String serviceName = "unknown";
 
-	/** 
-	* SpEL expression to filter services 
+	/**
+	* SpEL expression to filter services
 	**/
 	private String filter;
 
+	/**
+	 * When set, the Kubernetes labels of the services will be included as metadata
+	 * of the returned ServiceInstance
+	 */
+	private boolean enabledAdditionOfLabelsAsMetadata = true;
+
+	/**
+	 * When enabledAdditionOfLabelsAsMetadata is set, then the value labelKeysPrefix
+	 * will be used as a prefix to the key names in the metadata map
+	 */
+	private String labelKeysPrefix;
+
+
+	/**
+	 * When set, the Kubernetes annotations of the services will be included as metadata
+	 * of the returned ServiceInstance
+	 */
+	private boolean enabledAdditionOfAnnotationsAsMetadata = true;
+
+	/**
+	 * When enabledAdditionOfAnnotationsAsMetadata is set, then the value annotationKeysPrefix
+	 * will be used as a prefix to the key names in the metadata map
+	 */
+	private String annotationKeysPrefix;
+
 	public boolean isEnabled() {
 		return enabled;
 	}
@@ -49,11 +74,44 @@ public class KubernetesDiscoveryProperties extends AutoServiceRegistrationProper
 	public String getFilter() {
 		return filter;
 	}
-	
+
 	public void setFilter(String filter){
 		this.filter = filter;
 	}
 
+	public boolean isEnabledAdditionOfLabelsAsMetadata() {
+		return enabledAdditionOfLabelsAsMetadata;
+	}
+
+	public void setEnabledAdditionOfLabelsAsMetadata(boolean enabledAdditionOfLabelsAsMetadata) {
+		this.enabledAdditionOfLabelsAsMetadata = enabledAdditionOfLabelsAsMetadata;
+	}
+
+	public String getLabelKeysPrefix() {
+		return labelKeysPrefix;
+	}
+
+	public void setLabelKeysPrefix(String labelKeysPrefix) {
+		this.labelKeysPrefix = labelKeysPrefix;
+	}
+
+	public boolean isEnabledAdditionOfAnnotationsAsMetadata() {
+		return enabledAdditionOfAnnotationsAsMetadata;
+	}
+
+	public void setEnabledAdditionOfAnnotationsAsMetadata(
+		boolean enabledAdditionOfAnnotationsAsMetadata) {
+		this.enabledAdditionOfAnnotationsAsMetadata = enabledAdditionOfAnnotationsAsMetadata;
+	}
+
+	public String getAnnotationKeysPrefix() {
+		return annotationKeysPrefix;
+	}
+
+	public void setAnnotationKeysPrefix(String annotationKeysPrefix) {
+		this.annotationKeysPrefix = annotationKeysPrefix;
+	}
+
 	@Override
 	public String toString() {
 		return "KubernetesDiscoveryProperties{" +

spring-cloud-kubernetes-discovery/src/test/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClientFilterMetadataTest.java

@@ -0,0 +1,239 @@
+/*
+ * Copyright 2013-2018 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
+ *
+ *      http://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.discovery;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+import static org.mockito.Mockito.when;
+
+import io.fabric8.kubernetes.api.model.DoneableEndpoints;
+import io.fabric8.kubernetes.api.model.DoneableService;
+import io.fabric8.kubernetes.api.model.Endpoints;
+import io.fabric8.kubernetes.api.model.EndpointsBuilder;
+import io.fabric8.kubernetes.api.model.EndpointsList;
+import io.fabric8.kubernetes.api.model.Service;
+import io.fabric8.kubernetes.api.model.ServiceBuilder;
+import io.fabric8.kubernetes.api.model.ServiceList;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.fabric8.kubernetes.client.dsl.MixedOperation;
+import io.fabric8.kubernetes.client.dsl.Resource;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.cloud.client.ServiceInstance;
+
+@RunWith(MockitoJUnitRunner.class)
+public class KubernetesDiscoveryClientFilterMetadataTest {
+
+	@Mock
+	private KubernetesClient kubernetesClient;
+
+	@Mock
+	private KubernetesDiscoveryProperties properties;
+
+	@Mock
+	private MixedOperation<Service, ServiceList, DoneableService, Resource<Service, DoneableService>> serviceOperation;
+
+	@Mock
+	private MixedOperation<Endpoints, EndpointsList, DoneableEndpoints, Resource<Endpoints, DoneableEndpoints>> endpointsOperation;
+
+	@Mock
+	private Resource<Service, DoneableService> serviceResource;
+
+	@Mock
+	private Resource<Endpoints, DoneableEndpoints> endpointsResource;
+
+	@InjectMocks
+	private KubernetesDiscoveryClient underTest;
+
+	@Test
+	public void testBothLabelsAndAnnotationsDisabled() {
+		final String serviceId = "s";
+
+		when(properties.isEnabledAdditionOfLabelsAsMetadata()).thenReturn(false);
+		when(properties.isEnabledAdditionOfAnnotationsAsMetadata()).thenReturn(false);
+
+		setupServiceWithLabelsAndAnnotations(
+			serviceId,
+			new HashMap<String, String>() {{
+				put("l1", "lab");
+			}},
+			new HashMap<String, String>() {{
+				put("l1", "lab");
+			}}
+		);
+
+		final List<ServiceInstance> instances = underTest.getInstances(serviceId);
+		assertThat(instances).hasSize(1);
+		assertThat(instances.get(0).getMetadata()).isEmpty();
+	}
+
+	@Test
+	public void testLabelsEnabledAndAnnotationsDisabled() {
+		final String serviceId = "s";
+
+		when(properties.isEnabledAdditionOfLabelsAsMetadata()).thenReturn(true);
+		when(properties.isEnabledAdditionOfAnnotationsAsMetadata()).thenReturn(false);
+
+		setupServiceWithLabelsAndAnnotations(
+			serviceId,
+			new HashMap<String, String>() {{
+				put("l1", "v1");
+				put("l2", "v2");
+			}},
+			new HashMap<String, String>() {{
+				put("l1", "lab");
+			}}
+		);
+
+		final List<ServiceInstance> instances = underTest.getInstances(serviceId);
+		assertThat(instances).hasSize(1);
+		assertThat(instances.get(0).getMetadata()).containsOnly(entry("l1", "v1"), entry("l2", "v2"));
+	}
+
+	@Test
+	public void testLabelsEnabledAndAnnotationsDisabledWithPrefix() {
+		final String serviceId = "s";
+
+		when(properties.isEnabledAdditionOfLabelsAsMetadata()).thenReturn(true);
+		when(properties.getLabelKeysPrefix()).thenReturn("l_");
+		when(properties.isEnabledAdditionOfAnnotationsAsMetadata()).thenReturn(false);
+
+		setupServiceWithLabelsAndAnnotations(
+			serviceId,
+			new HashMap<String, String>() {{
+				put("l1", "v1");
+				put("l2", "v2");
+			}},
+			new HashMap<String, String>() {{
+				put("l1", "lab");
+			}}
+		);
+
+		final List<ServiceInstance> instances = underTest.getInstances(serviceId);
+		assertThat(instances).hasSize(1);
+		assertThat(instances.get(0).getMetadata()).containsOnly(entry("l_l1", "v1"), entry("l_l2", "v2"));
+	}
+
+	@Test
+	public void testLabelsDisabledAndAnnotationsEnabled() {
+		final String serviceId = "s";
+
+		when(properties.isEnabledAdditionOfLabelsAsMetadata()).thenReturn(false);
+		when(properties.isEnabledAdditionOfAnnotationsAsMetadata()).thenReturn(true);
+
+		setupServiceWithLabelsAndAnnotations(
+			serviceId,
+			new HashMap<String, String>() {{
+				put("l1", "v1");
+			}},
+			new HashMap<String, String>() {{
+				put("a1", "v1");
+				put("a2", "v2");
+			}}
+		);
+
+		final List<ServiceInstance> instances = underTest.getInstances(serviceId);
+		assertThat(instances).hasSize(1);
+		assertThat(instances.get(0).getMetadata()).containsOnly(entry("a1", "v1"), entry("a2", "v2"));
+	}
+
+	@Test
+	public void testLabelsDisabledAndAnnotationsEnabledWithPrefix() {
+		final String serviceId = "s";
+
+		when(properties.isEnabledAdditionOfLabelsAsMetadata()).thenReturn(false);
+		when(properties.isEnabledAdditionOfAnnotationsAsMetadata()).thenReturn(true);
+		when(properties.getAnnotationKeysPrefix()).thenReturn("a_");
+
+		setupServiceWithLabelsAndAnnotations(
+			serviceId,
+			new HashMap<String, String>() {{
+				put("l1", "v1");
+			}},
+			new HashMap<String, String>() {{
+				put("a1", "v1");
+				put("a2", "v2");
+			}}
+		);
+
+		final List<ServiceInstance> instances = underTest.getInstances(serviceId);
+		assertThat(instances).hasSize(1);
+		assertThat(instances.get(0).getMetadata()).containsOnly(entry("a_a1", "v1"), entry("a_a2", "v2"));
+	}
+
+	@Test
+	public void testBothLabelsAndAnnotationsEnabledWithPrefix() {
+		final String serviceId = "s";
+
+		when(properties.isEnabledAdditionOfLabelsAsMetadata()).thenReturn(true);
+		when(properties.getLabelKeysPrefix()).thenReturn("l_");
+		when(properties.isEnabledAdditionOfAnnotationsAsMetadata()).thenReturn(true);
+		when(properties.getAnnotationKeysPrefix()).thenReturn("a_");
+
+		setupServiceWithLabelsAndAnnotations(
+			serviceId,
+			new HashMap<String, String>() {{
+				put("l1", "la1");
+			}},
+			new HashMap<String, String>() {{
+				put("a1", "an1");
+				put("a2", "an2");
+			}}
+		);
+
+		final List<ServiceInstance> instances = underTest.getInstances(serviceId);
+		assertThat(instances).hasSize(1);
+		assertThat(instances.get(0).getMetadata()).containsOnly(
+			entry("a_a1", "an1"), entry("a_a2", "an2"), entry("l_l1", "la1"));
+	}
+
+	private void setupServiceWithLabelsAndAnnotations(String serviceId,
+		Map<String, String> labels, Map<String, String> annotations) {
+		final Service service =
+			new ServiceBuilder()
+				.withNewMetadata()
+				.withLabels(labels)
+				.withAnnotations(annotations)
+				.endMetadata()
+			.build();
+		when(serviceOperation.withName(serviceId)).thenReturn(serviceResource);
+		when(serviceResource.get()).thenReturn(service);
+		when(kubernetesClient.services()).thenReturn(serviceOperation);
+
+		final Endpoints endpoints =
+			new EndpointsBuilder()
+				.addNewSubset()
+				  .addNewPort()
+			      .endPort()
+			      .addNewAddress()
+			      .endAddress()
+			    .endSubset()
+			.build();
+
+		when(endpointsResource.get()).thenReturn(endpoints);
+		when(endpointsOperation.withName(serviceId)).thenReturn(endpointsResource);
+		when(kubernetesClient.endpoints()).thenReturn(endpointsOperation);
+	}
+
+
+}

spring-cloud-kubernetes-discovery/src/test/java/org/springframework/cloud/kubernetes/discovery/KubernetesDiscoveryClientFilterTest.java

@@ -37,7 +37,7 @@ import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.when;
 
 @RunWith(MockitoJUnitRunner.class)
-public class KubernetesDiscoveryClientTest {
+public class KubernetesDiscoveryClientFilterTest {
 
 	@Mock
 	private KubernetesClient kubernetesClient;