Don’t return 404 when metric or env regex matches entry with null value

Previously, if a regular expression was used when calling the metrics or
environment endpoints, a metric or property with a null value would
result in a 404 response.

This commit updates the two affected endpoints so that any metric or
property whose name matches the regular expression but has a null value
is ignored. This allows all of the matching metrics or properties with
non-null values to be returned in a 200 OK response.

Closes gh-4552

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

@@ -92,6 +92,15 @@ public class EnvironmentMvcEndpoint extends EndpointMvcAdapter
 			}
 		}
 
+		@Override
+		protected Object getOptionalValue(Environment source, String name) {
+			Object result = source.getProperty(name);
+			if (result != null) {
+				result = ((EnvironmentEndpoint) getDelegate()).sanitize(name, result);
+			}
+			return result;
+		}
+
 		@Override
 		protected Object getValue(Environment source, String name) {
 			String result = source.getProperty(name);

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

@@ -67,13 +67,23 @@ public class MetricsMvcEndpoint extends EndpointMvcAdapter {
 		@Override
 		protected void getNames(Map<String, ?> source, NameCallback callback) {
 			for (String name : source.keySet()) {
-				callback.addName(name);
+				try {
+					callback.addName(name);
+				}
+				catch (NoSuchMetricException ex) {
+					// Metric with null value. Continue.
+				}
 			}
 		}
 
+		@Override
+		protected Object getOptionalValue(Map<String, ?> source, String name) {
+			return source.get(name);
+		}
+
 		@Override
 		protected Object getValue(Map<String, ?> source, String name) {
-			Object value = source.get(name);
+			Object value = getOptionalValue(source, name);
 			if (value == null) {
 				throw new NoSuchMetricException("No such metric: " + name);
 			}

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

@@ -71,6 +71,8 @@ abstract class NamePatternFilter<T> {
 
 	protected abstract Object getValue(T source, String name);
 
+	protected abstract Object getOptionalValue(T source, String name);
+
 	/**
 	 * Callback used to add a name.
 	 */
@@ -96,7 +98,10 @@ abstract class NamePatternFilter<T> {
 		@Override
 		public void addName(String name) {
 			if (this.pattern.matcher(name).matches()) {
-				this.results.put(name, getValue(NamePatternFilter.this.source, name));
+				Object value = getOptionalValue(NamePatternFilter.this.source, name);
+				if (value != null) {
+					this.results.put(name, value);
+				}
 			}
 		}
 

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/EnvironmentMvcEndpointTests.java

@@ -16,6 +16,9 @@
 
 package org.springframework.boot.actuate.endpoint.mvc;
 
+import java.util.HashMap;
+import java.util.Map;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -34,6 +37,8 @@ import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.web.servlet.MockMvc;
@@ -89,6 +94,10 @@ public class EnvironmentMvcEndpointTests {
 
 	@Test
 	public void regex() throws Exception {
+		Map<String, Object> map = new HashMap<String, Object>();
+		map.put("food", null);
+		((ConfigurableEnvironment) this.context.getEnvironment()).getPropertySources()
+				.addFirst(new MapPropertySource("null-value", map));
 		this.mvc.perform(get("/env/foo.*")).andExpect(status().isOk())
 				.andExpect(content().string(containsString("\"foo\":\"bar\"")))
 				.andExpect(content().string(containsString("\"fool\":\"baz\"")));

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/MetricsMvcEndpointTests.java

@@ -126,7 +126,6 @@ public class MetricsMvcEndpointTests {
 	public void specificMetricWithDot() throws Exception {
 		this.mvc.perform(get("/metrics/group2.a")).andExpect(status().isOk())
 				.andExpect(content().string(containsString("1")));
-
 	}
 
 	@Import({ JacksonAutoConfiguration.class,
@@ -148,6 +147,7 @@ public class MetricsMvcEndpointTests {
 					metrics.add(new Metric<Integer>("group1.b", 1));
 					metrics.add(new Metric<Integer>("group2.a", 1));
 					metrics.add(new Metric<Integer>("group2_a", 1));
+					metrics.add(new Metric<Integer>("baz", null));
 					return Collections.unmodifiableList(metrics);
 				}
 

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/NamePatternFilterTests.java

@@ -95,6 +95,11 @@ public class NamePatternFilterTests {
 
 		private boolean getNamesCalled;
 
+		@Override
+		protected Object getOptionalValue(Object source, String name) {
+			return name;
+		}
+
 		@Override
 		protected Object getValue(Object source, String name) {
 			return name;