Cache /health response irrespective of sensitivity and security

Previously, the response from /health was not cached if the request
was secure, i.e. the user has authenticated, or the endpoint was
configured as not being sensitive. 

The commit updates HealthMvcEndpoint to apply the caching logic
all the time. Users that do not want caching can disable it by 
configuring the TTL with a value of zero.

Closes gh-2630

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

 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -137,11 +137,11 @@ public class HealthMvcEndpoint implements MvcEndpoint, EnvironmentAware {
 
 	private Health getHealth(Principal principal) {
 		long accessTime = System.currentTimeMillis();
-		if (isCacheStale(accessTime) || isSecure(principal) || isUnrestricted()) {
+		if (isCacheStale(accessTime)) {
 			this.lastAccess = accessTime;
 			this.cached = this.delegate.invoke();
 		}
-		if (isSecure(principal) || isUnrestricted()) {
+		if (exposeHealthDetails(principal)) {
 			return this.cached;
 		}
 		return Health.status(this.cached.getStatus()).build();
@@ -154,9 +154,8 @@ public class HealthMvcEndpoint implements MvcEndpoint, EnvironmentAware {
 		return (accessTime - this.lastAccess) > this.delegate.getTimeToLive();
 	}
 
-	private boolean isUnrestricted() {
-		Boolean sensitive = this.propertyResolver.getProperty("sensitive", Boolean.class);
-		return !this.secure || Boolean.FALSE.equals(sensitive);
+	private boolean exposeHealthDetails(Principal principal) {
+		return isSecure(principal) || isUnrestricted();
 	}
 
 	private boolean isSecure(Principal principal) {
@@ -164,6 +163,11 @@ public class HealthMvcEndpoint implements MvcEndpoint, EnvironmentAware {
 				.contains("Anonymous"));
 	}
 
+	private boolean isUnrestricted() {
+		Boolean sensitive = this.propertyResolver.getProperty("sensitive", Boolean.class);
+		return !this.secure || Boolean.FALSE.equals(sensitive);
+	}
+
 	@Override
 	public String getPath() {
 		return "/" + this.delegate.getId();

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

 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -44,6 +44,7 @@ import static org.mockito.Mockito.mock;
  *
  * @author Christian Dupuis
  * @author Dave Syer
+ * @author Andy Wilkinson
  */
 public class HealthMvcEndpointTests {
 
@@ -115,23 +116,7 @@ public class HealthMvcEndpointTests {
 	}
 
 	@Test
-	public void secureNotCached() {
-		given(this.endpoint.getTimeToLive()).willReturn(10000L);
-		given(this.endpoint.isSensitive()).willReturn(false);
-		given(this.endpoint.invoke()).willReturn(
-				new Health.Builder().up().withDetail("foo", "bar").build());
-		Object result = this.mvc.invoke(this.user);
-		assertTrue(result instanceof Health);
-		assertTrue(((Health) result).getStatus() == Status.UP);
-		given(this.endpoint.invoke()).willReturn(new Health.Builder().down().build());
-		result = this.mvc.invoke(this.user);
-		@SuppressWarnings("unchecked")
-		Health health = ((ResponseEntity<Health>) result).getBody();
-		assertTrue(health.getStatus() == Status.DOWN);
-	}
-
-	@Test
-	public void unsecureCached() {
+	public void healthIsCached() {
 		given(this.endpoint.getTimeToLive()).willReturn(10000L);
 		given(this.endpoint.isSensitive()).willReturn(true);
 		given(this.endpoint.invoke()).willReturn(
@@ -164,9 +149,8 @@ public class HealthMvcEndpointTests {
 	}
 
 	@Test
-	public void unsecureIsNotCachedWhenAnonymousAccessIsUnrestricted() {
-		this.environment.getPropertySources().addLast(NON_SENSITIVE);
-		given(this.endpoint.getTimeToLive()).willReturn(10000L);
+	public void noCachingWhenTimeToLiveIsZero() {
+		given(this.endpoint.getTimeToLive()).willReturn(0L);
 		given(this.endpoint.invoke()).willReturn(
 				new Health.Builder().up().withDetail("foo", "bar").build());
 		Object result = this.mvc.invoke(null);