Add a way to signal that an endpoint request is invalid

This commit adds InvalidEndpointRequestException as a technology
agnostic way to signal that an endpoint request is invalid. When such
exception is thrown, the web layer translates that to a 400.

Rather than overriding the reason, this commit makes sure to reuse the
error infrastructure.

Closes gh-10618

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/InvalidEndpointRequestException.java

+/*
+ * Copyright 2012-2018 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.boot.actuate.endpoint;
+
+/**
+ * Indicate that an endpoint request is invalid.
+ *
+ * @author Stephane Nicoll
+ * @since 2.0.0
+ */
+public class InvalidEndpointRequestException extends RuntimeException {
+
+	private final String reason;
+
+	public InvalidEndpointRequestException(String message, String reason) {
+		super(message);
+		this.reason = reason;
+	}
+
+	public InvalidEndpointRequestException(String message, String reason,
+			Throwable cause) {
+		super(message, cause);
+		this.reason = reason;
+	}
+
+	/**
+	 * Return the reason explaining why the request is invalid, potentially {@code null}.
+	 * @return the reason for the failure
+	 */
+	public String getReason() {
+		return this.reason;
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/invoke/MissingParametersException.java

@@ -17,7 +17,9 @@
 package org.springframework.boot.actuate.endpoint.invoke;
 
 import java.util.Set;
+import java.util.stream.Collectors;
 
+import org.springframework.boot.actuate.endpoint.InvalidEndpointRequestException;
 import org.springframework.util.StringUtils;
 
 /**
@@ -28,14 +30,17 @@ import org.springframework.util.StringUtils;
  * @author Phillip Webb
  * @since 2.0.0
  */
-public class MissingParametersException extends RuntimeException {
+public final class MissingParametersException extends InvalidEndpointRequestException {
 
 	private final Set<OperationParameter> missingParameters;
 
 	public MissingParametersException(Set<OperationParameter> missingParameters) {
 		super("Failed to invoke operation because the following required "
 				+ "parameters were missing: "
-				+ StringUtils.collectionToCommaDelimitedString(missingParameters));
+				+ StringUtils.collectionToCommaDelimitedString(missingParameters),
+				"Missing parameters: " + missingParameters.stream()
+						.map(OperationParameter::getName)
+						.collect(Collectors.joining(",")));
 		this.missingParameters = missingParameters;
 	}
 

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/invoke/ParameterMappingException.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.actuate.endpoint.invoke;
 
+import org.springframework.boot.actuate.endpoint.InvalidEndpointRequestException;
+
 /**
  * A {@code ParameterMappingException} is thrown when a failure occurs during
  * {@link ParameterValueMapper#mapParameterValue operation parameter mapping}.
@@ -23,7 +25,7 @@ package org.springframework.boot.actuate.endpoint.invoke;
  * @author Andy Wilkinson
  * @since 2.0.0
  */
-public class ParameterMappingException extends RuntimeException {
+public final class ParameterMappingException extends InvalidEndpointRequestException {
 
 	private final OperationParameter parameter;
 
@@ -39,7 +41,7 @@ public class ParameterMappingException extends RuntimeException {
 	public ParameterMappingException(OperationParameter parameter, Object value,
 			Throwable cause) {
 		super("Failed to map " + value + " of type " + value.getClass() + " to "
-				+ parameter, cause);
+				+ parameter, "Parameter mapping failure", cause);
 		this.parameter = parameter;
 		this.value = value;
 	}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/jmx/EndpointMBean.java

@@ -31,8 +31,7 @@ import javax.management.ReflectionException;
 
 import reactor.core.publisher.Mono;
 
-import org.springframework.boot.actuate.endpoint.invoke.MissingParametersException;
-import org.springframework.boot.actuate.endpoint.invoke.ParameterMappingException;
+import org.springframework.boot.actuate.endpoint.InvalidEndpointRequestException;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
@@ -103,7 +102,7 @@ public class EndpointMBean implements DynamicMBean {
 			}
 			return this.responseMapper.mapResponse(result);
 		}
-		catch (MissingParametersException | ParameterMappingException ex) {
+		catch (InvalidEndpointRequestException ex) {
 			throw new IllegalArgumentException(ex.getMessage(), ex);
 		}
 	}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/jersey/JerseyEndpointResourceFactory.java

@@ -38,8 +38,7 @@ import org.glassfish.jersey.server.model.Resource;
 import org.glassfish.jersey.server.model.Resource.Builder;
 import reactor.core.publisher.Mono;
 
-import org.springframework.boot.actuate.endpoint.invoke.MissingParametersException;
-import org.springframework.boot.actuate.endpoint.invoke.ParameterMappingException;
+import org.springframework.boot.actuate.endpoint.InvalidEndpointRequestException;
 import org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
 import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
@@ -155,7 +154,7 @@ public class JerseyEndpointResourceFactory {
 				Object response = this.operation.invoke(arguments);
 				return convertToJaxRsResponse(response, data.getRequest().getMethod());
 			}
-			catch (MissingParametersException | ParameterMappingException ex) {
+			catch (InvalidEndpointRequestException ex) {
 				return Response.status(Status.BAD_REQUEST).build();
 			}
 		}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/reactive/AbstractWebFluxEndpointHandlerMapping.java

@@ -26,10 +26,9 @@ import reactor.core.publisher.Mono;
 import reactor.core.publisher.MonoSink;
 import reactor.core.scheduler.Schedulers;
 
+import org.springframework.boot.actuate.endpoint.InvalidEndpointRequestException;
 import org.springframework.boot.actuate.endpoint.OperationType;
-import org.springframework.boot.actuate.endpoint.invoke.MissingParametersException;
 import org.springframework.boot.actuate.endpoint.invoke.OperationInvoker;
-import org.springframework.boot.actuate.endpoint.invoke.ParameterMappingException;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
 import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
 import org.springframework.boot.actuate.endpoint.web.WebEndpointResponse;
@@ -52,6 +51,7 @@ import org.springframework.web.reactive.result.condition.ProducesRequestConditio
 import org.springframework.web.reactive.result.condition.RequestMethodsRequestCondition;
 import org.springframework.web.reactive.result.method.RequestMappingInfo;
 import org.springframework.web.reactive.result.method.RequestMappingInfoHandlerMapping;
+import org.springframework.web.server.ResponseStatusException;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.util.pattern.PathPatternParser;
 
@@ -288,10 +288,9 @@ public abstract class AbstractWebFluxEndpointHandlerMapping
 		private Mono<ResponseEntity<Object>> handleResult(Publisher<?> result,
 				HttpMethod httpMethod) {
 			return Mono.from(result).map(this::toResponseEntity)
-					.onErrorReturn(MissingParametersException.class,
-							new ResponseEntity<>(HttpStatus.BAD_REQUEST))
-					.onErrorReturn(ParameterMappingException.class,
-							new ResponseEntity<>(HttpStatus.BAD_REQUEST))
+					.onErrorMap(InvalidEndpointRequestException.class, (ex) ->
+							new ResponseStatusException(HttpStatus.BAD_REQUEST,
+									ex.getReason()))
 					.defaultIfEmpty(new ResponseEntity<>(httpMethod == HttpMethod.GET
 							? HttpStatus.NOT_FOUND : HttpStatus.NO_CONTENT));
 		}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/servlet/AbstractWebMvcEndpointHandlerMapping.java

@@ -27,9 +27,8 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.springframework.beans.factory.InitializingBean;
-import org.springframework.boot.actuate.endpoint.invoke.MissingParametersException;
+import org.springframework.boot.actuate.endpoint.InvalidEndpointRequestException;
 import org.springframework.boot.actuate.endpoint.invoke.OperationInvoker;
-import org.springframework.boot.actuate.endpoint.invoke.ParameterMappingException;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
 import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
 import org.springframework.boot.actuate.endpoint.web.WebEndpointResponse;
@@ -44,6 +43,7 @@ import org.springframework.util.StringUtils;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.mvc.condition.ConsumesRequestCondition;
@@ -243,8 +243,8 @@ public abstract class AbstractWebMvcEndpointHandlerMapping
 				return handleResult(this.invoker.invoke(arguments),
 						HttpMethod.valueOf(request.getMethod()));
 			}
-			catch (MissingParametersException | ParameterMappingException ex) {
-				return new ResponseEntity<Void>(HttpStatus.BAD_REQUEST);
+			catch (InvalidEndpointRequestException ex) {
+				throw new BadOperationRequestException(ex.getReason());
 			}
 		}
 
@@ -300,4 +300,13 @@ public abstract class AbstractWebMvcEndpointHandlerMapping
 
 	}
 
+	@ResponseStatus(code = HttpStatus.BAD_REQUEST)
+	private static class BadOperationRequestException extends RuntimeException {
+
+		BadOperationRequestException(String message) {
+			super(message);
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/annotation/AbstractWebEndpointIntegrationTests.java

@@ -42,6 +42,7 @@ import org.springframework.context.annotation.Import;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.Resource;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.lang.Nullable;
 import org.springframework.test.web.reactive.server.WebTestClient;
@@ -157,8 +158,13 @@ public abstract class AbstractWebEndpointIntegrationTests<T extends Configurable
 
 	@Test
 	public void readOperationWithMappingFailureProducesBadRequestResponse() {
-		load(QueryEndpointConfiguration.class, (client) -> client.get()
-				.uri("/query?two=two").exchange().expectStatus().isBadRequest());
+		load(QueryEndpointConfiguration.class, (client) -> {
+			WebTestClient.BodyContentSpec body = client.get()
+					.uri("/query?two=two").exchange().expectStatus().isBadRequest()
+					.expectBody();
+			validateErrorBody(body, HttpStatus.BAD_REQUEST, "/endpoints/query",
+					"Missing parameters: one");
+		});
 	}
 
 	@Test
@@ -275,8 +281,13 @@ public abstract class AbstractWebEndpointIntegrationTests<T extends Configurable
 
 	@Test
 	public void readOperationWithMissingRequiredParametersReturnsBadRequestResponse() {
-		load(RequiredParameterEndpointConfiguration.class, (client) -> client.get()
-				.uri("/requiredparameters").exchange().expectStatus().isBadRequest());
+		load(RequiredParameterEndpointConfiguration.class, (client) -> {
+			WebTestClient.BodyContentSpec body = client.get()
+					.uri("/requiredparameters").exchange().expectStatus().isBadRequest()
+					.expectBody();
+			validateErrorBody(body, HttpStatus.BAD_REQUEST,
+					"/endpoints/requiredparameters", "Missing parameters: foo");
+		});
 	}
 
 	@Test
@@ -321,6 +332,14 @@ public abstract class AbstractWebEndpointIntegrationTests<T extends Configurable
 
 	protected abstract int getPort(T context);
 
+	protected void validateErrorBody(WebTestClient.BodyContentSpec body,
+			HttpStatus status, String path, String message) {
+		body.jsonPath("status").isEqualTo(status.value())
+				.jsonPath("error").isEqualTo(status.getReasonPhrase())
+				.jsonPath("path").isEqualTo(path)
+				.jsonPath("message").isEqualTo(message);
+	}
+
 	private void load(Class<?> configuration,
 			BiConsumer<ApplicationContext, WebTestClient> consumer) {
 		load(configuration, "/endpoints", consumer);

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/jersey/JerseyWebEndpointIntegrationTests.java

@@ -37,6 +37,8 @@ import org.springframework.boot.web.servlet.context.AnnotationConfigServletWebSe
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
+import org.springframework.http.HttpStatus;
+import org.springframework.test.web.reactive.server.WebTestClient;
 
 /**
  * Integration tests for web endpoints exposed using Jersey.
@@ -64,6 +66,12 @@ public class JerseyWebEndpointIntegrationTests extends
 		return context.getWebServer().getPort();
 	}
 
+	@Override
+	protected void validateErrorBody(WebTestClient.BodyContentSpec body,
+			HttpStatus status, String path, String message) {
+		// Jersey doesn't support the general error page handling
+	}
+
 	@Configuration
 	static class JerseyConfiguration {
 

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/reactive/WebFluxEndpointIntegrationTests.java

@@ -23,6 +23,8 @@ import org.junit.Test;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
 import org.springframework.boot.actuate.endpoint.web.annotation.AbstractWebEndpointIntegrationTests;
 import org.springframework.boot.actuate.endpoint.web.annotation.WebEndpointDiscoverer;
+import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration;
 import org.springframework.boot.endpoint.web.EndpointMapping;
 import org.springframework.boot.web.embedded.netty.NettyReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext;
@@ -95,6 +97,7 @@ public class WebFluxEndpointIntegrationTests
 
 	@Configuration
 	@EnableWebFlux
+	@ImportAutoConfiguration(ErrorWebFluxAutoConfiguration.class)
 	static class ReactiveConfiguration {
 
 		private int port;

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/servlet/MvcWebEndpointIntegrationTests.java

@@ -23,6 +23,13 @@ import org.junit.Test;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
 import org.springframework.boot.actuate.endpoint.web.annotation.AbstractWebEndpointIntegrationTests;
 import org.springframework.boot.actuate.endpoint.web.annotation.WebEndpointDiscoverer;
+import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
+import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration;
 import org.springframework.boot.endpoint.web.EndpointMapping;
 import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
 import org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext;
@@ -32,8 +39,6 @@ import org.springframework.core.env.Environment;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.web.cors.CorsConfiguration;
-import org.springframework.web.servlet.DispatcherServlet;
-import org.springframework.web.servlet.config.annotation.EnableWebMvc;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -89,7 +94,10 @@ public class MvcWebEndpointIntegrationTests extends
 	}
 
 	@Configuration
-	@EnableWebMvc
+	@ImportAutoConfiguration({ JacksonAutoConfiguration.class,
+			HttpMessageConvertersAutoConfiguration.class,
+			ServletWebServerFactoryAutoConfiguration.class, WebMvcAutoConfiguration.class,
+			DispatcherServletAutoConfiguration.class, ErrorMvcAutoConfiguration.class })
 	static class WebMvcConfiguration {
 
 		@Bean
@@ -97,11 +105,6 @@ public class MvcWebEndpointIntegrationTests extends
 			return new TomcatServletWebServerFactory(0);
 		}
 
-		@Bean
-		public DispatcherServlet dispatcherServlet() {
-			return new DispatcherServlet();
-		}
-
 		@Bean
 		public WebMvcEndpointHandlerMapping webEndpointHandlerMapping(
 				Environment environment, WebEndpointDiscoverer endpointDiscoverer,