Allows /configprops endpoint to show nested properties

Including maps and lists. Beans with no metadata (in
/META-INF/*spring-configuration-metadata.json) are just serialized
as they come (so might have problems like cycles). Serialization
errors are caught and rendered as an "error" for that bean. Any
problems can be fixed by preparing metadata and specifying which
properties are to be rendered that way.

Fixes gh-1746, fixes gh-1921

Author: dsyer

.gitignore

@@ -9,6 +9,7 @@
 .project
 .settings
 .metadata
+.factorypath
 bin
 build
 lib/
@@ -28,4 +29,5 @@ overridedb.*
 *.ipr
 *.iws
 .idea
-*.jar
+*.jar
+.DS_Store

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

@@ -16,21 +16,32 @@
 
 package org.springframework.boot.actuate.endpoint;
 
+import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.beans.BeanWrapperImpl;
 import org.springframework.beans.BeansException;
 import org.springframework.boot.context.properties.ConfigurationBeanFactoryMetaData;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
-import org.springframework.core.convert.ConversionService;
-import org.springframework.core.convert.support.DefaultConversionService;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 
+import com.fasterxml.jackson.core.JsonParseException;
 import com.fasterxml.jackson.databind.BeanDescription;
+import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationConfig;
 import com.fasterxml.jackson.databind.SerializationFeature;
@@ -64,12 +75,17 @@ public class ConfigurationPropertiesReportEndpoint extends
 
 	private static final String CGLIB_FILTER_ID = "cglibFilter";
 
+	private static final Log logger = LogFactory
+			.getLog(ConfigurationPropertiesReportEndpoint.class);
+
 	private final Sanitizer sanitizer = new Sanitizer();
 
 	private ApplicationContext context;
 
 	private ConfigurationBeanFactoryMetaData beanFactoryMetaData;
 
+	private ConfigurationPropertiesMetaData metadata = new ConfigurationPropertiesMetaData();
+
 	public ConfigurationPropertiesReportEndpoint() {
 		super("configprops");
 	}
@@ -97,7 +113,6 @@ public Map<String, Object> invoke() {
 	 * Extract beans annotated {@link ConfigurationProperties} and serialize into
 	 * {@link Map}.
 	 */
-	@SuppressWarnings("unchecked")
 	protected Map<String, Object> extract(ApplicationContext context) {
 
 		Map<String, Object> result = new HashMap<String, Object>();
@@ -116,8 +131,9 @@ protected Map<String, Object> extract(ApplicationContext context) {
 			String beanName = entry.getKey();
 			Object bean = entry.getValue();
 			Map<String, Object> root = new HashMap<String, Object>();
-			root.put("prefix", extractPrefix(context, beanName, bean));
-			root.put("properties", sanitize(mapper.convertValue(bean, Map.class)));
+			String prefix = extractPrefix(context, beanName, bean);
+			root.put("prefix", prefix);
+			root.put("properties", sanitize(safeSerialize(mapper, bean, prefix)));
 			result.put(beanName, root);
 		}
 
@@ -128,12 +144,31 @@ protected Map<String, Object> extract(ApplicationContext context) {
 		return result;
 	}
 
+	/**
+	 * Cautiously serialize the bean to a map (returning a map with an error message
+	 * instead of throwing an exception if there is a problem).
+	 */
+	private Map<String, Object> safeSerialize(ObjectMapper mapper, Object bean,
+			String prefix) {
+		try {
+			@SuppressWarnings("unchecked")
+			Map<String, Object> result = new HashMap<String, Object>(mapper.convertValue(
+					this.metadata.extractMap(bean, prefix), Map.class));
+			return result;
+		}
+		catch (Exception e) {
+			return new HashMap<String, Object>(Collections.<String, Object> singletonMap(
+					"error", "Cannot serialize '" + prefix + "'"));
+		}
+	}
+
 	/**
 	 * Configure Jackson's {@link ObjectMapper} to be used to serialize the
 	 * {@link ConfigurationProperties} objects into a {@link Map} structure.
 	 */
 	protected void configureObjectMapper(ObjectMapper mapper) {
 		mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
+		mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
 		applyCglibFilters(mapper);
 		applySerializationModifier(mapper);
 	}
@@ -148,7 +183,7 @@ private void applySerializationModifier(ObjectMapper mapper) {
 	}
 
 	/**
-	 * Configure PropertyFiler to make sure Jackson doesn't process CGLIB generated bean
+	 * Configure PropertyFilter to make sure Jackson doesn't process CGLIB generated bean
 	 * properties.
 	 */
 	private void applyCglibFilters(ObjectMapper mapper) {
@@ -239,25 +274,182 @@ private boolean include(String name) {
 
 	protected static class GenericSerializerModifier extends BeanSerializerModifier {
 
-		private ConversionService conversionService = new DefaultConversionService();
-
 		@Override
 		public List<BeanPropertyWriter> changeProperties(SerializationConfig config,
 				BeanDescription beanDesc, List<BeanPropertyWriter> beanProperties) {
 			List<BeanPropertyWriter> result = new ArrayList<BeanPropertyWriter>();
 			for (BeanPropertyWriter writer : beanProperties) {
-				AnnotatedMethod setter = beanDesc.findMethod(
-						"set" + StringUtils.capitalize(writer.getName()),
-						new Class<?>[] { writer.getPropertyType() });
-				if (setter != null
-						&& this.conversionService.canConvert(String.class,
-								writer.getPropertyType())) {
+				boolean readable = isReadable(beanDesc, writer);
+				if (readable) {
 					result.add(writer);
 				}
 			}
 			return result;
 		}
 
+		private boolean isReadable(BeanDescription beanDesc, BeanPropertyWriter writer) {
+			String parenType = beanDesc.getType().getTypeName();
+			String type = writer.getType().getTypeName();
+			AnnotatedMethod setter = beanDesc.findMethod(
+					"set" + StringUtils.capitalize(writer.getName()),
+					new Class<?>[] { writer.getPropertyType() });
+			// If there's a setter, we assume it's OK to report on the value,
+			// similarly, if there's no setter but the package names match, we assume
+			// that its a nested class used solely for binding to config props, so it
+			// should be kosher. This filter is not used if there is JSON metadata for
+			// the property, so it's mainly for user-defined beans.
+			boolean readable = setter != null
+					|| ClassUtils.getPackageName(parenType).equals(
+							ClassUtils.getPackageName(type));
+			return readable;
+		}
+	}
+
+	/**
+	 * Convenience class for grabbing and caching valid property names from
+	 * /META-INF/spring-configuration-metadata.json so that metadata that is known to be
+	 * valid can be used to pull the correct nested properties out of beans that might
+	 * otherwise be tricky (contain cycles or other unserializable properties).
+	 */
+	protected static class ConfigurationPropertiesMetaData {
+
+		private Map<String, Set<String>> matched = new HashMap<String, Set<String>>();
+		private Set<String> keys = null;
+
+		public boolean matches(String prefix) {
+			if (this.matched.containsKey(prefix)) {
+				return matchesInternal(prefix);
+			}
+			synchronized (this.matched) {
+				if (this.matched.containsKey(prefix)) {
+					return matchesInternal(prefix);
+				}
+				this.matched.put(prefix, findKeys(prefix));
+			}
+			return matchesInternal(prefix);
+		}
+
+		private boolean matchesInternal(String prefix) {
+			if (this.matched.get(prefix) != null) {
+				return true;
+			}
+			else {
+				return false;
+			}
+		}
+
+		private Set<String> findKeys(String prefix) {
+
+			HashSet<String> set = new HashSet<String>();
+
+			try {
+				if (this.keys == null) {
+
+					this.keys = new HashSet<String>();
+					ObjectMapper mapper = new ObjectMapper();
+					Resource[] resources = new PathMatchingResourcePatternResolver()
+							.getResources("classpath*:/META-INF/*spring-configuration-metadata.json");
+					for (Resource resource : resources) {
+						addKeys(mapper, resource);
+					}
+
+				}
+			}
+			catch (IOException e) {
+				logger.warn("Could not deserialize config properties metadata", e);
+			}
+			for (String key : this.keys) {
+				if (key.length() > prefix.length()
+						&& key.startsWith(prefix)
+						&& ".".equals(key.substring(prefix.length(), prefix.length() + 1))) {
+					set.add(key.substring(prefix.length() + 1));
+				}
+			}
+			if (set.isEmpty()) {
+				return null;
+			}
+			return set;
+		}
+
+		private void addKeys(ObjectMapper mapper, Resource resource) throws IOException,
+				JsonParseException, JsonMappingException {
+			@SuppressWarnings("unchecked")
+			Map<String, Object> map = mapper.readValue(resource.getInputStream(),
+					Map.class);
+			@SuppressWarnings("unchecked")
+			Collection<Map<String, Object>> metadata = (Collection<Map<String, Object>>) map
+					.get("properties");
+			for (Map<String, Object> value : metadata) {
+				try {
+					if (value.containsKey("type")) {
+						this.keys.add((String) value.get("name"));
+					}
+				}
+				catch (Exception e) {
+					logger.warn("Could not parse config properties metadata", e);
+				}
+			}
+		}
+
+		public Object extractMap(Object bean, String prefix) {
+			if (!matches(prefix)) {
+				return bean;
+			}
+			Map<String, Object> map = new HashMap<String, Object>();
+			for (String key : this.matched.get(prefix)) {
+				addProperty(bean, key, map);
+			}
+			return map;
+		}
+
+		private void addProperty(Object bean, String key, Map<String, Object> map) {
+			String prefix = key.contains(".") ? StringUtils.split(key, ".")[0] : key;
+			String suffix = key.length() > prefix.length() ? key.substring(prefix
+					.length() + 1) : null;
+			String property = prefix;
+			if (bean instanceof Map) {
+				@SuppressWarnings("unchecked")
+				Map<String, Object> value = (Map<String, Object>) bean;
+				bean = new MapHolder(value);
+				property = "map[" + property + "]";
+			}
+			BeanWrapperImpl wrapper = new BeanWrapperImpl(bean);
+			try {
+				Object value = wrapper.getPropertyValue(property);
+				if (value instanceof Map) {
+					Map<String, Object> nested = new HashMap<String, Object>();
+					map.put(prefix, nested);
+					if (suffix != null) {
+						addProperty(value, suffix, nested);
+					}
+				}
+				else {
+					map.put(prefix, value);
+				}
+			}
+			catch (Exception e) {
+				// Probably just lives on a different bean (it happens)
+				logger.debug("Could not parse config properties metadata '" + key + "': "
+						+ e.getMessage());
+			}
+		}
+
+		protected static class MapHolder {
+			Map<String, Object> map = new HashMap<String, Object>();
+
+			public MapHolder(Map<String, Object> bean) {
+				this.map.putAll(bean);
+			}
+
+			public Map<String, Object> getMap() {
+				return this.map;
+			}
+
+			public void setMap(Map<String, Object> map) {
+				this.map = map;
+			}
+		}
+
 	}
 
 }