Add outcome tag to MVC and WebFlux HTTP request metrics

See gh-14486

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/reactive/server/DefaultWebFluxTagsProvider.java

@@ -35,7 +35,8 @@ public class DefaultWebFluxTagsProvider implements WebFluxTagsProvider {
 	public Iterable<Tag> httpRequestTags(ServerWebExchange exchange,
 			Throwable exception) {
 		return Arrays.asList(WebFluxTags.method(exchange), WebFluxTags.uri(exchange),
-				WebFluxTags.exception(exception), WebFluxTags.status(exchange));
+				WebFluxTags.exception(exception), WebFluxTags.status(exchange),
+				WebFluxTags.outcome(exchange));
 	}
 
 }

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/reactive/server/WebFluxTags.java

@@ -30,6 +30,7 @@ import org.springframework.web.util.pattern.PathPattern;
  *
  * @author Jon Schneider
  * @author Andy Wilkinson
+ * @author Michael McFadyen
  * @since 2.0.0
  */
 public final class WebFluxTags {
@@ -42,6 +43,14 @@ public final class WebFluxTags {
 
 	private static final Tag EXCEPTION_NONE = Tag.of("exception", "None");
 
+	private static final Tag OUTCOME_UNKNOWN = Tag.of("outcome", "UNKNOWN");
+
+	private static final Tag OUTCOME_SUCCESS = Tag.of("outcome", "SUCCESS");
+
+	private static final Tag OUTCOME_CLIENT_ERROR = Tag.of("outcome", "CLIENT_ERROR");
+
+	private static final Tag OUTCOME_SERVER_ERROR = Tag.of("outcome", "SERVER_ERROR");
+
 	private WebFluxTags() {
 	}
 
@@ -112,4 +121,29 @@ public final class WebFluxTags {
 		return EXCEPTION_NONE;
 	}
 
+	/**
+	 * Creates a {@code outcome} tag based on the response status of the given
+	 * {@code exchange}.
+	 * @param exchange the exchange
+	 * @return the "outcome" tag derived from the response status
+	 */
+	public static Tag outcome(ServerWebExchange exchange) {
+		if (exchange != null && exchange.getResponse().getStatusCode() != null) {
+			HttpStatus status = exchange.getResponse().getStatusCode();
+			if (status.is1xxInformational() || status.is2xxSuccessful()
+					|| status.is3xxRedirection()) {
+				return OUTCOME_SUCCESS;
+			}
+			else if (status.is4xxClientError()) {
+				return OUTCOME_CLIENT_ERROR;
+			}
+			else {
+				return OUTCOME_SERVER_ERROR;
+			}
+		}
+		else {
+			return OUTCOME_UNKNOWN;
+		}
+	}
+
 }

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/servlet/DefaultWebMvcTagsProvider.java

@@ -34,7 +34,8 @@ public class DefaultWebMvcTagsProvider implements WebMvcTagsProvider {
 	public Iterable<Tag> getTags(HttpServletRequest request, HttpServletResponse response,
 			Object handler, Throwable exception) {
 		return Tags.of(WebMvcTags.method(request), WebMvcTags.uri(request, response),
-				WebMvcTags.exception(exception), WebMvcTags.status(response));
+				WebMvcTags.exception(exception), WebMvcTags.status(response),
+				WebMvcTags.outcome(response));
 	}
 
 	@Override

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/servlet/WebMvcTags.java

@@ -34,6 +34,7 @@ import org.springframework.web.servlet.HandlerMapping;
  * @author Jon Schneider
  * @author Andy Wilkinson
  * @author Brian Clozel
+ * @author Michael McFadyen
  * @since 2.0.0
  */
 public final class WebMvcTags {
@@ -50,6 +51,14 @@ public final class WebMvcTags {
 
 	private static final Tag STATUS_UNKNOWN = Tag.of("status", "UNKNOWN");
 
+	private static final Tag OUTCOME_UNKNOWN = Tag.of("outcome", "UNKNOWN");
+
+	private static final Tag OUTCOME_SUCCESS = Tag.of("outcome", "SUCCESS");
+
+	private static final Tag OUTCOME_CLIENT_ERROR = Tag.of("outcome", "CLIENT_ERROR");
+
+	private static final Tag OUTCOME_SERVER_ERROR = Tag.of("outcome", "SERVER_ERROR");
+
 	private static final Tag METHOD_UNKNOWN = Tag.of("method", "UNKNOWN");
 
 	private static final Pattern TRAILING_SLASH_PATTERN = Pattern.compile("/$");
@@ -149,4 +158,27 @@ public final class WebMvcTags {
 		return EXCEPTION_NONE;
 	}
 
+	/**
+	 * Creates a {@code outcome} tag based on the status of the given {@code response}.
+	 * @param response the HTTP response
+	 * @return the outcome tag derived from the status of the response
+	 */
+	public static Tag outcome(HttpServletResponse response) {
+		if (response != null) {
+			int status = response.getStatus();
+			if (status < 400) {
+				return OUTCOME_SUCCESS;
+			}
+			else if (status < 500) {
+				return OUTCOME_CLIENT_ERROR;
+			}
+			else {
+				return OUTCOME_SERVER_ERROR;
+			}
+		}
+		else {
+			return OUTCOME_UNKNOWN;
+		}
+	}
+
 }

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/servlet/WebMvcTagsTests.java

@@ -31,6 +31,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Andy Wilkinson
  * @author Brian Clozel
+ * @author Michael McFadyen
  */
 public class WebMvcTagsTests {
 
@@ -91,4 +92,31 @@ public class WebMvcTagsTests {
 		assertThat(tag.getValue()).isEqualTo("UNKNOWN");
 	}
 
+	@Test
+	public void outcomeTagIsUnknownWhenResponseIsNull() {
+		Tag tag = WebMvcTags.outcome(null);
+		assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+	}
+
+	@Test
+	public void outcomeTagIsSuccessWhenResponseIs2XX() {
+		this.response.setStatus(200);
+		Tag tag = WebMvcTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("SUCCESS");
+	}
+
+	@Test
+	public void outcomeTagIsClientErrorWhenResponseIs4XX() {
+		this.response.setStatus(400);
+		Tag tag = WebMvcTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("CLIENT_ERROR");
+	}
+
+	@Test
+	public void outcomeTagIsServerErrorWhenResponseIs5XX() {
+		this.response.setStatus(500);
+		Tag tag = WebMvcTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("SERVER_ERROR");
+	}
+
 }

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/web/reactive/server/WebFluxTagsTests.java

@@ -36,6 +36,7 @@ import static org.mockito.Mockito.mock;
  * Tests for {@link WebFluxTags}.
  *
  * @author Brian Clozel
+ * @author Michael McFadyen
  */
 public class WebFluxTagsTests {
 
@@ -88,4 +89,38 @@ public class WebFluxTagsTests {
 		assertThat(tag.getValue()).isEqualTo("CUSTOM");
 	}
 
+	@Test
+	public void outcomeTagIsUnknownWhenResponseIsNull() {
+		Tag tag = WebFluxTags.outcome(null);
+		assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+	}
+
+	@Test
+	public void outcomeTagIsUnknownWhenResponseStatusIsNull() {
+		this.exchange.getResponse().setStatusCode(null);
+		Tag tag = WebFluxTags.outcome(this.exchange);
+		assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+	}
+
+	@Test
+	public void outcomeTagIsSuccessWhenResponseIs2XX() {
+		this.exchange.getResponse().setStatusCode(HttpStatus.OK);
+		Tag tag = WebFluxTags.outcome(this.exchange);
+		assertThat(tag.getValue()).isEqualTo("SUCCESS");
+	}
+
+	@Test
+	public void outcomeTagIsClientErrorWhenResponseIs4XX() {
+		this.exchange.getResponse().setStatusCode(HttpStatus.BAD_REQUEST);
+		Tag tag = WebFluxTags.outcome(this.exchange);
+		assertThat(tag.getValue()).isEqualTo("CLIENT_ERROR");
+	}
+
+	@Test
+	public void outcomeTagIsServerErrorWhenResponseIs5XX() {
+		this.exchange.getResponse().setStatusCode(HttpStatus.BAD_GATEWAY);
+		Tag tag = WebFluxTags.outcome(this.exchange);
+		assertThat(tag.getValue()).isEqualTo("SERVER_ERROR");
+	}
+
 }