Reduce noise in /end actuator docs

Update the `/env` sample used in the actuator docs to use only a limited
set of keys.

Fixes gh-5849

spring-boot-actuator-docs/src/restdoc/java/org/springframework/boot/actuate/hypermedia/LimitedEnvironmentEndpoint.java

+/*
+ * 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.hypermedia;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.springframework.boot.actuate.endpoint.EnvironmentEndpoint;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+
+/**
+ * {@link EnvironmentEndpoint} with reduced output to look better in the documentation.
+ *
+ * @author Phillip Webb
+ */
+public class LimitedEnvironmentEndpoint extends EnvironmentEndpoint {
+
+	private static final MultiValueMap<String, String> INCLUDES;
+
+	static {
+		Map<String, List<String>> includes = new LinkedHashMap<String, List<String>>();
+		List<String> systemProperties = new ArrayList<String>();
+		systemProperties.add("java.runtime.name");
+		systemProperties.add("sun.boot.library.path");
+		systemProperties.add("java.vendor.url");
+		systemProperties.add("path.separator");
+		systemProperties.add("sun.java.launcher");
+		systemProperties.add("java.runtime.version");
+		systemProperties.add("os.arch");
+		systemProperties.add("line.separator");
+		systemProperties.add("os.name");
+		systemProperties.add("user.timezone");
+		systemProperties.add("file.encoding");
+		systemProperties.add("java.vm.specification.version");
+		systemProperties.add("sun.java.command");
+		systemProperties.add("sun.arch.data.model");
+		systemProperties.add("user.language");
+		systemProperties.add("awt.toolkit");
+		systemProperties.add("java.awt.headless");
+		systemProperties.add("java.vendor");
+		systemProperties.add("file.separator");
+		includes.put("systemProperties", systemProperties);
+		List<String> systemEnvironment = new ArrayList<String>();
+		systemEnvironment.add("SHELL");
+		systemEnvironment.add("TMPDIR");
+		systemEnvironment.add("DISPLAY");
+		systemEnvironment.add("LOGNAME");
+		includes.put("systemEnvironment", systemEnvironment);
+		INCLUDES = new LinkedMultiValueMap<>(Collections.unmodifiableMap(includes));
+	}
+
+	@Override
+	public Object sanitize(String name, Object object) {
+		System.out.println(name);
+		if (name.equals("gopherProxySet")) {
+			return object;
+		}
+		return null;
+	}
+
+	@Override
+	protected Map<String, Object> postProcessSourceProperties(String sourceName,
+			Map<String, Object> properties) {
+		List<String> sourceIncludes = INCLUDES.get(sourceName);
+		if (sourceIncludes != null) {
+			Set<Entry<String, Object>> entries = properties.entrySet();
+			Iterator<Map.Entry<String, Object>> iterator = entries.iterator();
+			while (iterator.hasNext()) {
+				if (!sourceIncludes.contains(iterator.next().getKey())) {
+					iterator.remove();
+				}
+			}
+
+		}
+		return properties;
+	}
+
+}

spring-boot-actuator-docs/src/restdoc/java/org/springframework/boot/actuate/hypermedia/SpringBootHypermediaApplication.java

@@ -20,6 +20,7 @@ import groovy.text.GStringTemplateEngine;
 import groovy.text.TemplateEngine;
 
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.actuate.endpoint.EnvironmentEndpoint;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration;
 import org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration;
@@ -36,6 +37,11 @@ public class SpringBootHypermediaApplication {
 		return new GStringTemplateEngine();
 	}
 
+	@Bean
+	public EnvironmentEndpoint environmentEndpoint() {
+		return new LimitedEnvironmentEndpoint();
+	}
+
 	public static void main(String[] args) {
 		SpringApplication.run(SpringBootHypermediaApplication.class, args);
 	}

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

@@ -61,11 +61,14 @@ public class EnvironmentEndpoint extends AbstractEndpoint<Map<String, Object>> {
 			String sourceName = entry.getKey();
 			if (source instanceof EnumerablePropertySource) {
 				EnumerablePropertySource<?> enumerable = (EnumerablePropertySource<?>) source;
-				Map<String, Object> map = new LinkedHashMap<String, Object>();
+				Map<String, Object> properties = new LinkedHashMap<String, Object>();
 				for (String name : enumerable.getPropertyNames()) {
-					map.put(name, sanitize(name, enumerable.getProperty(name)));
+					properties.put(name, sanitize(name, enumerable.getProperty(name)));
+				}
+				properties = postProcessSourceProperties(sourceName, properties);
+				if (properties != null) {
+					result.put(sourceName, properties);
 				}
-				result.put(sourceName, map);
 			}
 		}
 		return result;
@@ -104,4 +107,17 @@ public class EnvironmentEndpoint extends AbstractEndpoint<Map<String, Object>> {
 		return this.sanitizer.sanitize(name, object);
 	}
 
+	/**
+	 * Apply any post processing to source data before it is added.
+	 * @param sourceName the source name
+	 * @param properties the properties
+	 * @return the post-processed properties or {@code null} if the source should not be
+	 * added
+	 * @since 1.4.0
+	 */
+	protected Map<String, Object> postProcessSourceProperties(String sourceName,
+			Map<String, Object> properties) {
+		return properties;
+	}
+
 }