Add a shim Endpoint if management context is child

When management endpoints are on a different port the HandlerMappings
are restricted to a single EndpointHandlerMapping, so the error
controller (which is a normal @Controller with @RequestMappings) does
not get mapped.

Fixed by addinga shim Endpoint on "/error" that delegates to the
ErrorController (which interface picks up an extra method).

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

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.actuate.autoconfigure;
 
+import java.util.Map;
+
 import javax.servlet.Filter;
 
 import org.springframework.beans.factory.BeanFactory;
@@ -23,18 +25,25 @@ import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.beans.factory.HierarchicalBeanFactory;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.actuate.endpoint.AbstractEndpoint;
+import org.springframework.boot.actuate.endpoint.Endpoint;
 import org.springframework.boot.actuate.endpoint.mvc.EndpointHandlerAdapter;
 import org.springframework.boot.actuate.endpoint.mvc.EndpointHandlerMapping;
 import org.springframework.boot.actuate.properties.ManagementServerProperties;
+import org.springframework.boot.actuate.web.ErrorController;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.EmbeddedServletContainer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
+import org.springframework.boot.context.embedded.ErrorPage;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.RequestContextHolder;
 import org.springframework.web.servlet.DispatcherServlet;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.HandlerMapping;
@@ -52,6 +61,9 @@ public class EndpointWebMvcChildContextConfiguration {
 	protected static class ServerCustomization implements
 			EmbeddedServletContainerCustomizer {
 
+		@Value("${error.path:/error}")
+		private String errorPath = "/error";
+
 		@Autowired
 		private ListableBeanFactory beanFactory;
 
@@ -69,6 +81,7 @@ public class EndpointWebMvcChildContextConfiguration {
 			factory.setPort(this.managementServerProperties.getPort());
 			factory.setAddress(this.managementServerProperties.getAddress());
 			factory.setContextPath(this.managementServerProperties.getContextPath());
+			factory.addErrorPages(new ErrorPage(this.errorPath));
 		}
 
 	}
@@ -96,6 +109,24 @@ public class EndpointWebMvcChildContextConfiguration {
 		return new EndpointHandlerAdapter();
 	}
 
+	/*
+	 * The error controller is present but not mapped as an endpoint in this context
+	 * because of the DispatcherServlet having had it's HandlerMapping explicitly
+	 * disabled. So this tiny shim exposes the same feature but only for machine
+	 * endpoints.
+	 */
+	@Bean
+	public Endpoint<Map<String, Object>> errorEndpoint(final ErrorController controller) {
+		return new AbstractEndpoint<Map<String, Object>>("/error", false, true) {
+			@Override
+			protected Map<String, Object> doInvoke() {
+				RequestAttributes attributes = RequestContextHolder
+						.currentRequestAttributes();
+				return controller.extract(attributes, false);
+			}
+		};
+	}
+
 	@Configuration
 	@ConditionalOnClass({ EnableWebSecurity.class, Filter.class })
 	@ConditionalOnBean(name = "springSecurityFilterChain", search = SearchStrategy.PARENTS)

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

@@ -33,6 +33,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
+import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration.DefaultTemplateResolverConfiguration;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration;
@@ -72,7 +73,7 @@ public class ErrorMvcAutoConfiguration implements EmbeddedServletContainerCustom
 	private String errorPath = "/error";
 
 	@Bean
-	@ConditionalOnMissingBean(ErrorController.class)
+	@ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT)
 	public BasicErrorController basicErrorController() {
 		return new BasicErrorController();
 	}

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/web/BasicErrorController.java

@@ -33,6 +33,8 @@ import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.ServletRequestAttributes;
 import org.springframework.web.servlet.ModelAndView;
 
 /**
@@ -61,19 +63,27 @@ public class BasicErrorController implements ErrorController {
 
 	@RequestMapping(value = "${error.path:/error}", produces = "text/html")
 	public ModelAndView errorHtml(HttpServletRequest request) {
-		Map<String, Object> map = error(request);
+		Map<String, Object> map = extract(new ServletRequestAttributes(request), false);
 		return new ModelAndView(ERROR_KEY, map);
 	}
 
 	@RequestMapping(value = "${error.path:/error}")
 	@ResponseBody
 	public Map<String, Object> error(HttpServletRequest request) {
+		ServletRequestAttributes attributes = new ServletRequestAttributes(request);
+		String trace = request.getParameter("trace");
+		return extract(attributes, trace != null && !"false".equals(trace.toLowerCase()));
+	}
+
+	@Override
+	public Map<String, Object> extract(RequestAttributes attributes, boolean trace) {
 		Map<String, Object> map = new LinkedHashMap<String, Object>();
 		map.put("timestamp", new Date());
 		try {
-			Throwable error = (Throwable) request
-					.getAttribute("javax.servlet.error.exception");
-			Object obj = request.getAttribute("javax.servlet.error.status_code");
+			Throwable error = (Throwable) attributes.getAttribute(
+					"javax.servlet.error.exception", RequestAttributes.SCOPE_REQUEST);
+			Object obj = attributes.getAttribute("javax.servlet.error.status_code",
+					RequestAttributes.SCOPE_REQUEST);
 			int status = 999;
 			if (obj != null) {
 				status = (Integer) obj;
@@ -89,8 +99,7 @@ public class BasicErrorController implements ErrorController {
 				}
 				map.put("exception", error.getClass().getName());
 				map.put("message", error.getMessage());
-				String trace = request.getParameter("trace");
-				if (trace != null && !"false".equals(trace.toLowerCase())) {
+				if (trace) {
 					StringWriter stackTrace = new StringWriter();
 					error.printStackTrace(new PrintWriter(stackTrace));
 					stackTrace.flush();
@@ -99,7 +108,8 @@ public class BasicErrorController implements ErrorController {
 				this.logger.error(error);
 			}
 			else {
-				Object message = request.getAttribute("javax.servlet.error.message");
+				Object message = attributes.getAttribute("javax.servlet.error.message",
+						RequestAttributes.SCOPE_REQUEST);
 				map.put("message", message == null ? "No message available" : message);
 			}
 			return map;

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/web/ErrorController.java

@@ -16,7 +16,10 @@
 
 package org.springframework.boot.actuate.web;
 
+import java.util.Map;
+
 import org.springframework.stereotype.Controller;
+import org.springframework.web.context.request.RequestAttributes;
 
 /**
  * Marker interface used to indicate that a {@link Controller @Controller} is used to
@@ -31,4 +34,13 @@ public interface ErrorController {
 	 */
 	public String getErrorPath();
 
+	/**
+	 * Extract a useful model of the error from the request attributes.
+	 * 
+	 * @param attributes the request attributes
+	 * @param trace flag to indicate that stack trace information should be included
+	 * @return a model containing error messages and codes etc.
+	 */
+	public Map<String, Object> extract(RequestAttributes attributes, boolean trace);
+
 }

spring-boot-samples/spring-boot-sample-actuator-ui/src/test/java/org/springframework/boot/sample/ops/ui/SampleActuatorUiApplicationPortTests.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.sample.ops.ui;
 
+import static org.junit.Assert.assertEquals;
+
 import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.Callable;
@@ -25,7 +27,6 @@ import java.util.concurrent.TimeUnit;
 
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.springframework.boot.SpringApplication;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -35,8 +36,6 @@ import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.web.client.DefaultResponseErrorHandler;
 import org.springframework.web.client.RestTemplate;
 
-import static org.junit.Assert.assertEquals;
-
 /**
  * Integration tests for separate management and main service ports.
  * 
@@ -80,9 +79,7 @@ public class SampleActuatorUiApplicationPortTests {
 	}
 
 	@Test
-	@Ignore
 	public void testMetrics() throws Exception {
-		// FIXME broken since error page is not rendered
 		@SuppressWarnings("rawtypes")
 		ResponseEntity<Map> entity = getRestTemplate().getForEntity(
 				"http://localhost:" + managementPort + "/metrics", Map.class);

spring-boot-samples/spring-boot-sample-actuator/src/test/java/org/springframework/boot/sample/ops/ManagementAddressSampleActuatorApplicationTests.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.sample.ops;
 
+import static org.junit.Assert.assertEquals;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
@@ -27,7 +29,6 @@ import java.util.concurrent.TimeUnit;
 
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.security.SecurityProperties;
@@ -44,8 +45,6 @@ import org.springframework.security.crypto.codec.Base64;
 import org.springframework.web.client.DefaultResponseErrorHandler;
 import org.springframework.web.client.RestTemplate;
 
-import static org.junit.Assert.assertEquals;
-
 /**
  * Integration tests for separate management and main service ports.
  * 
@@ -93,9 +92,7 @@ public class ManagementAddressSampleActuatorApplicationTests {
 	}
 
 	@Test
-	@Ignore
 	public void testMetrics() throws Exception {
-		// FIXME broken because error page is no longer exposed on management port
 		testHome(); // makes sure some requests have been made
 		@SuppressWarnings("rawtypes")
 		ResponseEntity<Map> entity = getRestTemplate().getForEntity(
@@ -104,9 +101,7 @@ public class ManagementAddressSampleActuatorApplicationTests {
 	}
 
 	@Test
-	@Ignore
 	public void testHealth() throws Exception {
-		// FIXME broken because error page is no longer exposed on management port
 		ResponseEntity<String> entity = getRestTemplate().getForEntity(
 				"http://localhost:" + managementPort + "/health", String.class);
 		assertEquals(HttpStatus.OK, entity.getStatusCode());
@@ -114,9 +109,7 @@ public class ManagementAddressSampleActuatorApplicationTests {
 	}
 
 	@Test
-	@Ignore
 	public void testErrorPage() throws Exception {
-		// FIXME broken because error page is no longer exposed on management port
 		@SuppressWarnings("rawtypes")
 		ResponseEntity<Map> entity = getRestTemplate().getForEntity(
 				"http://localhost:" + managementPort + "/error", Map.class);