From 97e5e32496a29410f93ff40566780aeac26e3eef Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <awilkinson@pivotal.io>
Date: Thu, 3 Nov 2016 20:08:31 +0000
Subject: [PATCH] Make sure the MetricsFilter uses committed response's status

Previously, if an exception was thrown during request handling after
the response had been committed, i.e. after the status and headers
had been written, the metrics filter would assume that it was a 500
response. This was potentially inaccurate as the status had already
been sent to the client and before the exception was thrown and it
may have been something other than a 500.

This commit updates MetricsFilter so that it will use the
status from the response if the response has been committed even when
an exception is thrown.

Closes gh-7277
---
 .../actuate/autoconfigure/MetricsFilter.java  |  3 ++
 .../MetricFilterAutoConfigurationTests.java   | 31 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricsFilter.java b/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricsFilter.java
index c011237aeea..cfcd6fc1098 100644
--- a/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricsFilter.java
+++ b/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricsFilter.java
@@ -109,6 +109,9 @@ final class MetricsFilter extends OncePerRequestFilter {
 		}
 		finally {
 			if (!request.isAsyncStarted()) {
+				if (response.isCommitted()) {
+					status = getStatus(response);
+				}
 				stopWatch.stop();
 				request.removeAttribute(ATTRIBUTE_STOP_WATCH);
 				recordMetrics(request, path, status, stopWatch.getTotalTimeMillis());
diff --git a/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/MetricFilterAutoConfigurationTests.java b/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/MetricFilterAutoConfigurationTests.java
index 73f90a53326..62b3aa1bb7f 100644
--- a/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/MetricFilterAutoConfigurationTests.java
+++ b/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/MetricFilterAutoConfigurationTests.java
@@ -365,6 +365,37 @@ public class MetricFilterAutoConfigurationTests {
 		context.close();
 	}
 
+	@Test
+	public void whenExceptionIsThrownResponseStatusIsUsedWhenResponseHasBeenCommitted()
+			throws Exception {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.register(Config.class, MetricFilterAutoConfiguration.class);
+		context.refresh();
+		Filter filter = context.getBean(Filter.class);
+		final MockHttpServletRequest request = new MockHttpServletRequest("GET",
+				"/test/path");
+		final MockHttpServletResponse response = new MockHttpServletResponse();
+		FilterChain chain = mock(FilterChain.class);
+		willAnswer(new Answer<Object>() {
+			@Override
+			public Object answer(InvocationOnMock invocation) throws Throwable {
+				response.setStatus(200);
+				response.setCommitted(true);
+				throw new IOException();
+			}
+		}).given(chain).doFilter(request, response);
+		try {
+			filter.doFilter(request, response, chain);
+			fail();
+		}
+		catch (IOException ex) {
+			// Continue
+		}
+		verify(context.getBean(CounterService.class))
+				.increment(eq("status.200.test.path"));
+		context.close();
+	}
+
 	@Configuration
 	public static class Config {