Fix status handling of /application/env/{propertyName}

This commit makes sure to return a 404 status if the env endpoint is
invoked with a property that does not exist in the environment.

Closes gh-10179

spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/env/EnvironmentEndpointAutoConfiguration.java

@@ -18,7 +18,9 @@ package org.springframework.boot.actuate.autoconfigure.env;
 
 import org.springframework.boot.actuate.autoconfigure.endpoint.condition.ConditionalOnEnabledEndpoint;
 import org.springframework.boot.actuate.env.EnvironmentEndpoint;
+import org.springframework.boot.actuate.env.EnvironmentWebEndpointExtension;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
@@ -55,4 +57,13 @@ public class EnvironmentEndpointAutoConfiguration {
 		return endpoint;
 	}
 
+	@Bean
+	@ConditionalOnMissingBean
+	@ConditionalOnEnabledEndpoint
+	@ConditionalOnBean(EnvironmentEndpoint.class)
+	public EnvironmentWebEndpointExtension environmentWebEndpointExtension(
+			EnvironmentEndpoint environmentEndpoint) {
+		return new EnvironmentWebEndpointExtension(environmentEndpoint);
+	}
+
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/env/EnvironmentWebEndpointExtension.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2012-2017 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.env;
+
+import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
+import org.springframework.boot.actuate.endpoint.annotation.Selector;
+import org.springframework.boot.actuate.endpoint.web.WebEndpointResponse;
+import org.springframework.boot.actuate.endpoint.web.annotation.WebEndpointExtension;
+import org.springframework.boot.actuate.env.EnvironmentEndpoint.EnvironmentEntryDescriptor;
+
+/**
+ * {@link WebEndpointExtension} for the {@link EnvironmentEndpoint}.
+ *
+ * @author Stephane Nicoll
+ * @since 2.0.0
+ */
+@WebEndpointExtension(endpoint = EnvironmentEndpoint.class)
+public class EnvironmentWebEndpointExtension {
+
+	private final EnvironmentEndpoint delegate;
+
+	public EnvironmentWebEndpointExtension(EnvironmentEndpoint delegate) {
+		this.delegate = delegate;
+	}
+
+	@ReadOperation
+	public WebEndpointResponse<EnvironmentEntryDescriptor> environmentEntry(
+			@Selector String toMatch) {
+		EnvironmentEntryDescriptor descriptor = this.delegate.environmentEntry(toMatch);
+		int status = descriptor.getProperty() != null ? WebEndpointResponse.STATUS_OK
+				: WebEndpointResponse.STATUS_NOT_FOUND;
+		return new WebEndpointResponse<>(descriptor, status);
+	}
+
+}

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/env/EnvironmentEndpointWebIntegrationTests.java

@@ -96,6 +96,17 @@ public class EnvironmentEndpointWebIntegrationTests {
 				.jsonPath(forPropertyEntry("placeholder")).isEqualTo("******");
 	}
 
+	@Test
+	public void nestedPathForUnknownKeyShouldReturn404AndBody() throws Exception {
+		client.get().uri("/application/env/this.does.not.exist").exchange().expectStatus()
+				.isNotFound()
+				.expectBody()
+				.jsonPath("property").doesNotExist()
+				.jsonPath("propertySources[?(@.name=='test')]").exists()
+				.jsonPath("propertySources[?(@.name=='systemProperties')]").exists()
+				.jsonPath("propertySources[?(@.name=='systemEnvironment')]").exists();
+	}
+
 	@Test
 	public void nestedPathMatchedByRegexWhenPlaceholderCannotBeResolvedShouldReturnUnresolvedProperty()
 			throws Exception {
@@ -140,6 +151,12 @@ public class EnvironmentEndpointWebIntegrationTests {
 			return new EnvironmentEndpoint(environment);
 		}
 
+		@Bean
+		public EnvironmentWebEndpointExtension webEndpointExtension(
+				EnvironmentEndpoint endpoint) {
+			return new EnvironmentWebEndpointExtension(endpoint);
+		}
+
 	}
 
 }