Change LinksEnhancer to user endpoint name

If endpoint name is not available fallback to endpoint path.
Allow multiple hrefs per rel if path is different.

See spring-projectsgh-7132

Author: mbhave

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/LinksEnhancer.java

@@ -16,11 +16,14 @@
 
 package org.springframework.boot.actuate.autoconfigure;
 
-import java.util.HashSet;
-import java.util.Set;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 import org.springframework.boot.actuate.endpoint.mvc.MvcEndpoint;
 import org.springframework.boot.actuate.endpoint.mvc.MvcEndpoints;
+import org.springframework.boot.actuate.endpoint.mvc.NamedMvcEndpoint;
 import org.springframework.hateoas.ResourceSupport;
 import org.springframework.util.StringUtils;
 
@@ -47,23 +50,31 @@ public void addEndpointLinks(ResourceSupport resource, String self) {
 			resource.add(linkTo(LinksEnhancer.class).slash(this.rootPath + self)
 					.withSelfRel());
 		}
-		Set<String> added = new HashSet<String>();
+		Map<String, List<String>> added = new HashMap<String, List<String>>();
 		for (MvcEndpoint endpoint : this.endpoints.getEndpoints()) {
-			if (!endpoint.getPath().equals(self) && !added.contains(endpoint.getPath())) {
-				addEndpointLink(resource, endpoint);
+
+			String rel = getRel(endpoint);
+			List<String> pathsForRel = added.get(rel) == null ? new ArrayList<String>() : added.get(rel);
+
+			if (!endpoint.getPath().equals(self) && !pathsForRel.contains(endpoint.getPath())) {
+				addEndpointLink(resource, endpoint, rel);
+				pathsForRel.add(endpoint.getPath());
+				added.put(rel, pathsForRel);
 			}
-			added.add(endpoint.getPath());
 		}
 	}
 
-	private void addEndpointLink(ResourceSupport resource, MvcEndpoint endpoint) {
+	private String getRel(MvcEndpoint endpoint) {
+		String name = endpoint instanceof NamedMvcEndpoint ? ((NamedMvcEndpoint) endpoint).getName() : endpoint.getPath();
+		return (name.startsWith("/") ? name.substring(1) : name);
+	}
+
+	private void addEndpointLink(ResourceSupport resource, MvcEndpoint endpoint, String rel) {
 		Class<?> type = endpoint.getEndpointType();
 		type = (type == null ? Object.class : type);
-		String path = endpoint.getPath();
-		String rel = (path.startsWith("/") ? path.substring(1) : path);
 		if (StringUtils.hasText(rel)) {
-			String fullPath = this.rootPath + endpoint.getPath();
-			resource.add(linkTo(type).slash(fullPath).withRel(rel));
+			String href = this.rootPath + endpoint.getPath();
+			resource.add(linkTo(type).slash(href).withRel(rel));
 		}
 	}
 

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/LinksEnhancerTests.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright 2012-2016 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.boot.actuate.autoconfigure;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.assertj.core.api.Condition;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.boot.actuate.endpoint.AbstractEndpoint;
+import org.springframework.boot.actuate.endpoint.mvc.AbstractMvcEndpoint;
+import org.springframework.boot.actuate.endpoint.mvc.EndpointMvcAdapter;
+import org.springframework.boot.actuate.endpoint.mvc.MvcEndpoint;
+import org.springframework.boot.actuate.endpoint.mvc.MvcEndpoints;
+import org.springframework.hateoas.Link;
+import org.springframework.hateoas.ResourceSupport;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.web.context.request.RequestContextHolder;
+import org.springframework.web.context.request.ServletRequestAttributes;
+import org.springframework.web.context.support.StaticWebApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link LinksEnhancer}.
+ *
+ * @author Madhura Bhave
+ */
+public class LinksEnhancerTests {
+
+	@Before
+	public void setup() {
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		RequestContextHolder.setRequestAttributes(new ServletRequestAttributes(request));
+	}
+
+	@Test
+	public void useNameAsRelIfAvailable() throws Exception {
+		TestMvcEndpoint endpoint = new TestMvcEndpoint(new TestEndpoint("a"));
+		endpoint.setPath("something-else");
+		LinksEnhancer enhancer = getLinksEnhancer(Collections.singletonList((MvcEndpoint) endpoint));
+		ResourceSupport support = new ResourceSupport();
+		enhancer.addEndpointLinks(support, "");
+		assertThat(support.getLink("a").getHref()).contains("/something-else");
+	}
+
+	@Test
+	public void usePathAsRelIfNameNotAvailable() throws Exception {
+		MvcEndpoint endpoint = new NoNameTestMvcEndpoint("/a", false);
+		LinksEnhancer enhancer = getLinksEnhancer(Collections.singletonList(endpoint));
+		ResourceSupport support = new ResourceSupport();
+		enhancer.addEndpointLinks(support, "");
+		assertThat(support.getLink("a").getHref()).contains("/a");
+	}
+
+	@Test
+	public void hrefNotAddedToRelTwice() throws Exception {
+		MvcEndpoint endpoint = new TestMvcEndpoint(new TestEndpoint("a"));
+		MvcEndpoint otherEndpoint = new TestMvcEndpoint(new TestEndpoint("a"));
+		LinksEnhancer enhancer = getLinksEnhancer(Arrays.asList(endpoint, otherEndpoint));
+		ResourceSupport support = new ResourceSupport();
+		enhancer.addEndpointLinks(support, "");
+		assertThat(support.getLinks()).haveExactly(1, getCondition("a", "a"));
+	}
+
+	@Test
+	public void multipleHrefsForSameRelWhenPathIsDifferent() throws Exception {
+		TestMvcEndpoint endpoint = new TestMvcEndpoint(new TestEndpoint("a"));
+		endpoint.setPath("endpoint");
+		TestMvcEndpoint otherEndpoint = new TestMvcEndpoint(new TestEndpoint("a"));
+		otherEndpoint.setPath("other-endpoint");
+		LinksEnhancer enhancer = getLinksEnhancer(Arrays.asList((MvcEndpoint) endpoint, otherEndpoint));
+		ResourceSupport support = new ResourceSupport();
+		enhancer.addEndpointLinks(support, "");
+		assertThat(support.getLinks()).haveExactly(1, getCondition("a", "endpoint"));
+		assertThat(support.getLinks()).haveExactly(1, getCondition("a", "other-endpoint"));
+	}
+
+	private Condition<Link> getCondition(final String rel, final String href) {
+		return new Condition<Link>() {
+			@Override
+			public boolean matches(Link link) {
+				return link.getRel().equals(rel) && link.getHref().equals("http://localhost/" + href);
+			}
+		};
+	}
+
+	private LinksEnhancer getLinksEnhancer(List<MvcEndpoint> endpoints) throws Exception {
+		StaticWebApplicationContext context = new StaticWebApplicationContext();
+		for (MvcEndpoint endpoint : endpoints) {
+			context.getDefaultListableBeanFactory().registerSingleton(endpoint.toString(),
+					endpoint);
+		}
+		MvcEndpoints mvcEndpoints = new MvcEndpoints();
+		mvcEndpoints.setApplicationContext(context);
+		mvcEndpoints.afterPropertiesSet();
+		return new LinksEnhancer("", mvcEndpoints);
+	}
+
+	private static class TestEndpoint extends AbstractEndpoint<Object> {
+
+		TestEndpoint(String id) {
+			super(id);
+		}
+
+		@Override
+		public Object invoke() {
+			return null;
+		}
+
+	}
+
+	private static class TestMvcEndpoint extends EndpointMvcAdapter {
+
+		TestMvcEndpoint(TestEndpoint delegate) {
+			super(delegate);
+		}
+
+	}
+
+	private static class NoNameTestMvcEndpoint extends AbstractMvcEndpoint {
+
+		NoNameTestMvcEndpoint(String path, boolean sensitive) {
+			super(path, sensitive);
+		}
+	}
+
+}