Add an outcome tag to web client metrics

Similar to what's ben done in gh-15420 for Spring MVC and Spring
WebFlux, this commit adds an outcome tag for the client side on both
`RestTemplate` and `WebClient`.

See gh-15594

Author: nishantraut

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/client/DefaultRestTemplateExchangeTagsProvider.java

@@ -28,6 +28,7 @@
  * Default implementation of {@link RestTemplateExchangeTagsProvider}.
  *
  * @author Jon Schneider
+ * @author Nishant Raut
  * @since 2.0.0
  */
 public class DefaultRestTemplateExchangeTagsProvider
@@ -41,7 +42,8 @@ public Iterable<Tag> getTags(String urlTemplate, HttpRequest request,
 				: RestTemplateExchangeTags.uri(request));
 		return Arrays.asList(RestTemplateExchangeTags.method(request), uriTag,
 				RestTemplateExchangeTags.status(response),
-				RestTemplateExchangeTags.clientName(request));
+				RestTemplateExchangeTags.clientName(request),
+				RestTemplateExchangeTags.outcome(response));
 	}
 
 }

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/client/RestTemplateExchangeTags.java

@@ -23,6 +23,7 @@
 import io.micrometer.core.instrument.Tag;
 
 import org.springframework.http.HttpRequest;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.util.StringUtils;
 import org.springframework.web.client.RestTemplate;
@@ -33,12 +34,25 @@
  *
  * @author Andy Wilkinson
  * @author Jon Schneider
+ * @author Nishant Raut
  * @since 2.0.0
  */
 public final class RestTemplateExchangeTags {
 
 	private static final Pattern STRIP_URI_PATTERN = Pattern.compile("^https?://[^/]+/");
 
+	private static final Tag OUTCOME_UNKNOWN = Tag.of("outcome", "UNKNOWN");
+
+	private static final Tag OUTCOME_INFORMATIONAL = Tag.of("outcome", "INFORMATIONAL");
+
+	private static final Tag OUTCOME_SUCCESS = Tag.of("outcome", "SUCCESS");
+
+	private static final Tag OUTCOME_REDIRECTION = Tag.of("outcome", "REDIRECTION");
+
+	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 RestTemplateExchangeTags() {
 	}
 
@@ -115,4 +129,44 @@ public static Tag clientName(HttpRequest request) {
 		return Tag.of("clientName", host);
 	}
 
+	/**
+	 * Creates a {@code outcome} {@code Tag} derived from the
+	 * {@link ClientHttpResponse#getStatusCode() status} of the given {@code response}.
+	 * @param response the response
+	 * @return the outcome tag
+	 * @since 2.2.0
+	 */
+	public static Tag outcome(ClientHttpResponse response) {
+		if (response != null) {
+			HttpStatus status = extractStatus(response);
+			if (status != null) {
+				if (status.is1xxInformational()) {
+					return OUTCOME_INFORMATIONAL;
+				}
+				if (status.is2xxSuccessful()) {
+					return OUTCOME_SUCCESS;
+				}
+				if (status.is3xxRedirection()) {
+					return OUTCOME_REDIRECTION;
+				}
+				if (status.is4xxClientError()) {
+					return OUTCOME_CLIENT_ERROR;
+				}
+			}
+			return OUTCOME_SERVER_ERROR;
+		}
+		return OUTCOME_UNKNOWN;
+	}
+
+	private static HttpStatus extractStatus(ClientHttpResponse response) {
+
+		try {
+			return response.getStatusCode();
+		}
+		catch (IOException ex) {
+			return null;
+		}
+
+	}
+
 }

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

@@ -27,6 +27,7 @@
  * Default implementation of {@link WebClientExchangeTagsProvider}.
  *
  * @author Brian Clozel
+ * @author Nishant Raut
  * @since 2.1.0
  */
 public class DefaultWebClientExchangeTagsProvider
@@ -40,7 +41,8 @@ public Iterable<Tag> tags(ClientRequest request, ClientResponse response,
 		Tag clientName = WebClientExchangeTags.clientName(request);
 		if (response != null) {
 			return Arrays.asList(method, uri, clientName,
-					WebClientExchangeTags.status(response));
+					WebClientExchangeTags.status(response),
+					WebClientExchangeTags.outcome(response));
 		}
 		else {
 			return Arrays.asList(method, uri, clientName,

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

@@ -21,6 +21,7 @@
 
 import io.micrometer.core.instrument.Tag;
 
+import org.springframework.http.HttpStatus;
 import org.springframework.http.client.reactive.ClientHttpRequest;
 import org.springframework.web.reactive.function.client.ClientRequest;
 import org.springframework.web.reactive.function.client.ClientResponse;
@@ -31,6 +32,7 @@
  * performed by a {@link WebClient}.
  *
  * @author Brian Clozel
+ * @author Nishant Raut
  * @since 2.1.0
  */
 public final class WebClientExchangeTags {
@@ -47,6 +49,18 @@ public final class WebClientExchangeTags {
 
 	private static final Tag CLIENT_NAME_NONE = Tag.of("clientName", "none");
 
+	private static final Tag OUTCOME_UNKNOWN = Tag.of("outcome", "UNKNOWN");
+
+	private static final Tag OUTCOME_INFORMATIONAL = Tag.of("outcome", "INFORMATIONAL");
+
+	private static final Tag OUTCOME_SUCCESS = Tag.of("outcome", "SUCCESS");
+
+	private static final Tag OUTCOME_REDIRECTION = Tag.of("outcome", "REDIRECTION");
+
+	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 WebClientExchangeTags() {
 	}
 
@@ -111,4 +125,33 @@ public static Tag clientName(ClientRequest request) {
 		return Tag.of("clientName", host);
 	}
 
+	/**
+	 * Creates a {@code outcome} {@code Tag} derived from the
+	 * {@link ClientResponse#statusCode() status} of the given {@code response}.
+	 * @param response the response
+	 * @return the outcome tag
+	 * @since 2.2.0
+	 */
+	public static Tag outcome(ClientResponse response) {
+		if (response != null) {
+			HttpStatus status = response.statusCode();
+			if (status != null) {
+				if (status.is1xxInformational()) {
+					return OUTCOME_INFORMATIONAL;
+				}
+				if (status.is2xxSuccessful()) {
+					return OUTCOME_SUCCESS;
+				}
+				if (status.is3xxRedirection()) {
+					return OUTCOME_REDIRECTION;
+				}
+				if (status.is4xxClientError()) {
+					return OUTCOME_CLIENT_ERROR;
+				}
+			}
+			return OUTCOME_SERVER_ERROR;
+		}
+		return OUTCOME_UNKNOWN;
+	}
+
 }

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/web/client/RestTemplateExchangeTagsTests.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2012-2018 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.metrics.web.client;
+
+import io.micrometer.core.instrument.Tag;
+import org.junit.Test;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.mock.http.client.MockClientHttpResponse;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link RestTemplateExchangeTags}.
+ *
+ * @author Nishant Raut
+ */
+public class RestTemplateExchangeTagsTests {
+
+	private MockClientHttpResponse response;
+
+	@Test
+	public void outcomeTagIsUnknownWhenResponseStatusIsNull() {
+		Tag tag = RestTemplateExchangeTags.outcome(null);
+		assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+	}
+
+	@Test
+	public void outcomeTagIsInformationalWhenResponseIs1xx() {
+		this.response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.CONTINUE);
+		Tag tag = RestTemplateExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("INFORMATIONAL");
+	}
+
+	@Test
+	public void outcomeTagIsSuccessWhenResponseIs2xx() {
+		this.response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.OK);
+		Tag tag = RestTemplateExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("SUCCESS");
+	}
+
+	@Test
+	public void outcomeTagIsRedirectionWhenResponseIs3xx() {
+		this.response = new MockClientHttpResponse("foo".getBytes(),
+				HttpStatus.MOVED_PERMANENTLY);
+		Tag tag = RestTemplateExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("REDIRECTION");
+	}
+
+	@Test
+	public void outcomeTagIsClientErrorWhenResponseIs4xx() {
+		this.response = new MockClientHttpResponse("foo".getBytes(),
+				HttpStatus.BAD_REQUEST);
+		Tag tag = RestTemplateExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("CLIENT_ERROR");
+	}
+
+	@Test
+	public void outcomeTagIsServerErrorWhenResponseIs5xx() {
+		this.response = new MockClientHttpResponse("foo".getBytes(),
+				HttpStatus.BAD_GATEWAY);
+		Tag tag = RestTemplateExchangeTags.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/client/DefaultWebClientExchangeTagsProviderTests.java

@@ -37,6 +37,7 @@
  * Tests for {@link DefaultWebClientExchangeTagsProvider}
  *
  * @author Brian Clozel
+ * @author Nishant Raut
  */
 public class DefaultWebClientExchangeTagsProviderTests {
 
@@ -66,7 +67,7 @@ public void tagsShouldBePopulated() {
 		Iterable<Tag> tags = this.tagsProvider.tags(this.request, this.response, null);
 		assertThat(tags).containsExactlyInAnyOrder(Tag.of("method", "GET"),
 				Tag.of("uri", "/projects/{project}"), Tag.of("clientName", "example.org"),
-				Tag.of("status", "200"));
+				Tag.of("status", "200"), Tag.of("outcome", "SUCCESS"));
 	}
 
 	@Test
@@ -76,7 +77,8 @@ public void tagsWhenNoUriTemplateShouldProvideUriPath() {
 		Iterable<Tag> tags = this.tagsProvider.tags(request, this.response, null);
 		assertThat(tags).containsExactlyInAnyOrder(Tag.of("method", "GET"),
 				Tag.of("uri", "/projects/spring-boot"),
-				Tag.of("clientName", "example.org"), Tag.of("status", "200"));
+				Tag.of("clientName", "example.org"), Tag.of("status", "200"),
+				Tag.of("outcome", "SUCCESS"));
 	}
 
 	@Test

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

@@ -37,6 +37,7 @@
  * Tests for {@link WebClientExchangeTags}
  *
  * @author Brian Clozel
+ * @author Nishant Raut
  */
 public class WebClientExchangeTagsTests {
 
@@ -113,4 +114,45 @@ public void statusWhenClientException() {
 				.isEqualTo(Tag.of("status", "CLIENT_ERROR"));
 	}
 
+	@Test
+	public void outcomeTagIsUnknownWhenResponseStatusIsNull() {
+		Tag tag = WebClientExchangeTags.outcome(null);
+		assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+	}
+
+	@Test
+	public void outcomeTagIsInformationalWhenResponseIs1xx() {
+		given(this.response.statusCode()).willReturn(HttpStatus.CONTINUE);
+		Tag tag = WebClientExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("INFORMATIONAL");
+	}
+
+	@Test
+	public void outcomeTagIsSuccessWhenResponseIs2xx() {
+		given(this.response.statusCode()).willReturn(HttpStatus.OK);
+		Tag tag = WebClientExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("SUCCESS");
+	}
+
+	@Test
+	public void outcomeTagIsRedirectionWhenResponseIs3xx() {
+		given(this.response.statusCode()).willReturn(HttpStatus.MOVED_PERMANENTLY);
+		Tag tag = WebClientExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("REDIRECTION");
+	}
+
+	@Test
+	public void outcomeTagIsClientErrorWhenResponseIs4xx() {
+		given(this.response.statusCode()).willReturn(HttpStatus.BAD_REQUEST);
+		Tag tag = WebClientExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("CLIENT_ERROR");
+	}
+
+	@Test
+	public void outcomeTagIsServerErrorWhenResponseIs5xx() {
+		given(this.response.statusCode()).willReturn(HttpStatus.BAD_GATEWAY);
+		Tag tag = WebClientExchangeTags.outcome(this.response);
+		assertThat(tag.getValue()).isEqualTo("SERVER_ERROR");
+	}
+
 }