Add actuator specific ObjectMapper

Prior to this commit, Actuator endpoints would use the application
ObjectMapper instance for serializing payloads as JSON. This was
problematic in several cases:

* application-specific configuration would change the actuator endpoint
output.
* choosing a different JSON mapper implementation in the application
would break completely some endpoints.

Spring Boot Actuator already has a hard dependency on Jackson, and this
commit uses that fact to configure a shared `ObjectMapper` instance that
will be used by the Actuator infrastructure consistently, without
polluting the application context.

This `ObjectMapper` is used in Actuator for:

* JMX endpoints
* Spring MVC endpoints with an HTTP message converter
* Spring WebFlux endpoints with an `Encoder`
* Jersey endpoints with a `ContextResolver<ObjectMapper>`

For all web endpoints, this configuration is limited to the
actuator-specific media types such as
`"application/vnd.spring-boot.actuator.v3+json"`.

Fixes gh-12951

Author: bclozel

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -25,6 +25,7 @@
 import org.springframework.boot.actuate.endpoint.invoke.ParameterValueMapper;
 import org.springframework.boot.actuate.endpoint.invoke.convert.ConversionServiceParameterValueMapper;
 import org.springframework.boot.actuate.endpoint.invoker.cache.CachingOperationInvokerAdvisor;
+import org.springframework.boot.actuate.endpoint.json.ActuatorJsonMapperProvider;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.convert.ApplicationConversionService;
@@ -75,4 +76,9 @@ public CachingOperationInvokerAdvisor endpointCachingOperationInvokerAdvisor(Env
 		return new CachingOperationInvokerAdvisor(new EndpointIdTimeToLivePropertyFunction(environment));
 	}
 
+	@Bean
+	public ActuatorJsonMapperProvider actuatorJsonMapperProvider() {
+		return new ActuatorJsonMapperProvider();
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -20,8 +20,6 @@
 
 import javax.management.MBeanServer;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
-
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.endpoint.ExposeExcludePropertyEndpointFilter;
 import org.springframework.boot.actuate.endpoint.EndpointFilter;
@@ -35,6 +33,7 @@
 import org.springframework.boot.actuate.endpoint.jmx.JmxEndpointsSupplier;
 import org.springframework.boot.actuate.endpoint.jmx.JmxOperationResponseMapper;
 import org.springframework.boot.actuate.endpoint.jmx.annotation.JmxEndpointDiscoverer;
+import org.springframework.boot.actuate.endpoint.json.ActuatorJsonMapperProvider;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -85,12 +84,12 @@ public JmxEndpointDiscoverer jmxAnnotationEndpointDiscoverer(ParameterValueMappe
 	@Bean
 	@ConditionalOnSingleCandidate(MBeanServer.class)
 	public JmxEndpointExporter jmxMBeanExporter(MBeanServer mBeanServer, Environment environment,
-			ObjectProvider<ObjectMapper> objectMapper, JmxEndpointsSupplier jmxEndpointsSupplier) {
+			ActuatorJsonMapperProvider actuatorJsonMapperProvider, JmxEndpointsSupplier jmxEndpointsSupplier) {
 		String contextId = ObjectUtils.getIdentityHexString(this.applicationContext);
 		EndpointObjectNameFactory objectNameFactory = new DefaultEndpointObjectNameFactory(this.properties, environment,
 				mBeanServer, contextId);
 		JmxOperationResponseMapper responseMapper = new JacksonJmxOperationResponseMapper(
-				objectMapper.getIfAvailable());
+				actuatorJsonMapperProvider.getInstance());
 		return new JmxEndpointExporter(mBeanServer, objectNameFactory, responseMapper,
 				jmxEndpointsSupplier.getEndpoints());
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -22,7 +22,10 @@
 import java.util.List;
 
 import javax.annotation.PostConstruct;
+import javax.ws.rs.Produces;
+import javax.ws.rs.ext.ContextResolver;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.glassfish.jersey.server.ResourceConfig;
 import org.glassfish.jersey.server.model.Resource;
 
@@ -32,6 +35,8 @@
 import org.springframework.boot.actuate.autoconfigure.web.server.ManagementPortType;
 import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
+import org.springframework.boot.actuate.endpoint.http.ActuatorMediaType;
+import org.springframework.boot.actuate.endpoint.json.ActuatorJsonMapperProvider;
 import org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver;
 import org.springframework.boot.actuate.endpoint.web.EndpointMapping;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
@@ -84,6 +89,12 @@ private boolean shouldRegisterLinksMapping(Environment environment, String baseP
 				|| ManagementPortType.get(environment).equals(ManagementPortType.DIFFERENT);
 	}
 
+	@Bean
+	ResourceConfigCustomizer actuatorResourceConfigCustomizer(ActuatorJsonMapperProvider jsonMapperProvider) {
+		return (ResourceConfig config) -> config.register(
+				new ActuatorJsonMapperContextResolver(jsonMapperProvider.getInstance()), ContextResolver.class);
+	}
+
 	/**
 	 * Register endpoints with the {@link ResourceConfig}. The
 	 * {@link ResourceConfigCustomizer} cannot be used because we don't want to apply
@@ -145,4 +156,20 @@ private void register(Collection<Resource> resources) {
 
 	}
 
+	@Produces({ ActuatorMediaType.V3_JSON, ActuatorMediaType.V2_JSON })
+	private static final class ActuatorJsonMapperContextResolver implements ContextResolver<ObjectMapper> {
+
+		private final ObjectMapper objectMapper;
+
+		private ActuatorJsonMapperContextResolver(ObjectMapper objectMapper) {
+			this.objectMapper = objectMapper;
+		}
+
+		@Override
+		public ObjectMapper getContext(Class<?> type) {
+			return this.objectMapper;
+		}
+
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -26,6 +26,8 @@
 import org.springframework.boot.actuate.autoconfigure.web.server.ManagementPortType;
 import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
+import org.springframework.boot.actuate.endpoint.http.ActuatorMediaType;
+import org.springframework.boot.actuate.endpoint.json.ActuatorJsonMapperProvider;
 import org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver;
 import org.springframework.boot.actuate.endpoint.web.EndpointMapping;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
@@ -40,8 +42,13 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.web.codec.CodecCustomizer;
 import org.springframework.context.annotation.Bean;
+import org.springframework.core.annotation.Order;
 import org.springframework.core.env.Environment;
+import org.springframework.http.MediaType;
+import org.springframework.http.codec.CodecConfigurer;
+import org.springframework.http.codec.json.Jackson2JsonEncoder;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.util.StringUtils;
 import org.springframework.web.reactive.DispatcherHandler;
@@ -52,6 +59,7 @@
  *
  * @author Andy Wilkinson
  * @author Phillip Webb
+ * @author Brian Clozel
  * @since 2.0.0
  */
 @ManagementContextConfiguration(proxyBeanMethods = false)
@@ -93,4 +101,16 @@ public ControllerEndpointHandlerMapping controllerEndpointHandlerMapping(
 				corsProperties.toCorsConfiguration());
 	}
 
+	@Bean
+	@Order(-1)
+	public CodecCustomizer actuatorJsonCodec(ActuatorJsonMapperProvider actuatorJsonMapperProvider) {
+		return (configurer) -> {
+			MediaType v3MediaType = MediaType.parseMediaType(ActuatorMediaType.V3_JSON);
+			MediaType v2MediaType = MediaType.parseMediaType(ActuatorMediaType.V2_JSON);
+			CodecConfigurer.CustomCodecs customCodecs = configurer.customCodecs();
+			customCodecs.register(
+					new Jackson2JsonEncoder(actuatorJsonMapperProvider.getInstance(), v3MediaType, v2MediaType));
+		};
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -20,12 +20,16 @@
 import java.util.Collection;
 import java.util.List;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.CorsEndpointProperties;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointProperties;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.server.ManagementPortType;
 import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
+import org.springframework.boot.actuate.endpoint.http.ActuatorMediaType;
+import org.springframework.boot.actuate.endpoint.json.ActuatorJsonMapperProvider;
 import org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver;
 import org.springframework.boot.actuate.endpoint.web.EndpointMapping;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
@@ -42,9 +46,15 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
 import org.springframework.core.env.Environment;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter;
 import org.springframework.util.StringUtils;
 import org.springframework.web.servlet.DispatcherServlet;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
 /**
  * {@link ManagementContextConfiguration @ManagementContextConfiguration} for Spring MVC
@@ -91,4 +101,35 @@ public ControllerEndpointHandlerMapping controllerEndpointHandlerMapping(
 				corsProperties.toCorsConfiguration());
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	public static class JsonWebMvcConfigurer implements WebMvcConfigurer, Ordered {
+
+		private final ActuatorJsonMapperProvider actuatorJsonMapperProvider;
+
+		public JsonWebMvcConfigurer(ActuatorJsonMapperProvider objectMapperFactory) {
+			this.actuatorJsonMapperProvider = objectMapperFactory;
+		}
+
+		@Override
+		public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
+			converters.add(new ActuatorJsonHttpMessageConverter(this.actuatorJsonMapperProvider.getInstance()));
+		}
+
+		// WebMvcAutoConfiguration is ordered at 0
+		@Override
+		public int getOrder() {
+			return -1;
+		}
+
+	}
+
+	static class ActuatorJsonHttpMessageConverter extends AbstractJackson2HttpMessageConverter {
+
+		ActuatorJsonHttpMessageConverter(ObjectMapper objectMapper) {
+			super(objectMapper, MediaType.parseMediaType(ActuatorMediaType.V3_JSON),
+					MediaType.parseMediaType(ActuatorMediaType.V2_JSON));
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/web/servlet/WebMvcEndpointChildContextConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -16,9 +16,13 @@
 
 package org.springframework.boot.actuate.autoconfigure.web.servlet;
 
+import java.util.List;
+
 import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextType;
+import org.springframework.boot.actuate.endpoint.json.ActuatorJsonMapperProvider;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -33,11 +37,15 @@
 import org.springframework.boot.web.servlet.filter.OrderedRequestContextFilter;
 import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.core.Ordered;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.web.context.request.RequestContextListener;
 import org.springframework.web.filter.RequestContextFilter;
 import org.springframework.web.servlet.DispatcherServlet;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
 /**
  * {@link ManagementContextConfiguration @ManagementContextConfiguration} for Spring MVC
@@ -108,6 +116,29 @@ RequestContextFilter requestContextFilter() {
 		return new OrderedRequestContextFilter();
 	}
 
+	/**
+	 * Since {@code WebMvcEndpointManagementContextConfiguration} is adding an
+	 * actuator-specific JSON message converter, {@code @EnableWebMvc} will not register
+	 * default converters. We need to register a JSON converter for plain
+	 * {@code "application/json"} still.
+	 * WebMvcEndpointChildContextConfigurationIntegrationTests
+	 */
+	@Configuration(proxyBeanMethods = false)
+	public static class FallbackJsonConverterConfigurer implements WebMvcConfigurer {
+
+		private final ActuatorJsonMapperProvider actuatorJsonMapperProvider;
+
+		FallbackJsonConverterConfigurer(ObjectProvider<ActuatorJsonMapperProvider> objectMapperSupplier) {
+			this.actuatorJsonMapperProvider = objectMapperSupplier.getIfAvailable(ActuatorJsonMapperProvider::new);
+		}
+
+		@Override
+		public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
+			converters.add(new MappingJackson2HttpMessageConverter(this.actuatorJsonMapperProvider.getInstance()));
+		}
+
+	}
+
 	/**
 	 * {@link WebServerFactoryCustomizer} to add an {@link ErrorPage} so that the
 	 * {@link ManagementErrorEndpoint} can be used.

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/endpoint/web/documentation/ScheduledTasksEndpointDocumentationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -52,7 +52,7 @@ class ScheduledTasksEndpointDocumentationTests extends MockMvcEndpointDocumentat
 
 	@Test
 	void scheduledTasks() throws Exception {
-		this.mockMvc.perform(get("/actuator/scheduledtasks")).andExpect(status().isOk())
+		this.mockMvc.perform(get("/actuator/scheduledtasks").accept("application/json")).andExpect(status().isOk())
 				.andDo(document("scheduled-tasks",
 						preprocessResponse(replacePattern(
 								Pattern.compile("org.*\\.ScheduledTasksEndpointDocumentationTests\\$TestConfiguration"),

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -21,6 +21,7 @@
 import org.glassfish.jersey.server.ResourceConfig;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.jersey.JerseyWebEndpointManagementContextConfiguration.JerseyWebEndpointsResourcesRegistrar;
 import org.springframework.boot.actuate.autoconfigure.web.jersey.JerseySameManagementContextConfiguration;
@@ -41,8 +42,8 @@
 class JerseyWebEndpointManagementContextConfigurationTests {
 
 	private final WebApplicationContextRunner runner = new WebApplicationContextRunner()
-			.withConfiguration(AutoConfigurations.of(WebEndpointAutoConfiguration.class,
-					JerseyWebEndpointManagementContextConfiguration.class))
+			.withConfiguration(AutoConfigurations.of(EndpointAutoConfiguration.class,
+					WebEndpointAutoConfiguration.class, JerseyWebEndpointManagementContextConfiguration.class))
 			.withBean(WebEndpointsSupplier.class, () -> Collections::emptyList);
 
 	@Test