Improve handling of non-standard status codes in RestTemplate metrics (#1564)

This commit backports spring-projects/spring-boot#17991.

Author: izeye

micrometer-spring-legacy/src/main/java/io/micrometer/spring/web/client/RestTemplateExchangeTags.java

@@ -25,6 +25,9 @@
 
 import java.io.IOException;
 import java.net.URI;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * Factory methods for creating {@link Tag Tags} related to a request-response exchange
@@ -47,6 +50,18 @@ public final class RestTemplateExchangeTags {
 
     private static final Tag OUTCOME_SERVER_ERROR = Tag.of("outcome", "SERVER_ERROR");
 
+    private static final Map<HttpStatus.Series, Tag> SERIES_OUTCOMES;
+
+    static {
+        Map<HttpStatus.Series, Tag> seriesOutcomes = new HashMap<>();
+        seriesOutcomes.put(HttpStatus.Series.INFORMATIONAL, OUTCOME_INFORMATIONAL);
+        seriesOutcomes.put(HttpStatus.Series.SUCCESSFUL, OUTCOME_SUCCESS);
+        seriesOutcomes.put(HttpStatus.Series.REDIRECTION, OUTCOME_REDIRECTION);
+        seriesOutcomes.put(HttpStatus.Series.CLIENT_ERROR, OUTCOME_CLIENT_ERROR);
+        seriesOutcomes.put(HttpStatus.Series.SERVER_ERROR, OUTCOME_SERVER_ERROR);
+        SERIES_OUTCOMES = Collections.unmodifiableMap(seriesOutcomes);
+    }
+
     private RestTemplateExchangeTags() {
     }
 
@@ -141,26 +156,15 @@ public static Tag clientName(HttpRequest request) {
     public static Tag outcome(ClientHttpResponse response) {
         try {
             if (response != null) {
-                HttpStatus statusCode = response.getStatusCode();
-                if (statusCode.is1xxInformational()) {
-                    return OUTCOME_INFORMATIONAL;
-                }
-                if (statusCode.is2xxSuccessful()) {
-                    return OUTCOME_SUCCESS;
-                }
-                if (statusCode.is3xxRedirection()) {
-                    return OUTCOME_REDIRECTION;
-                }
-                if (statusCode.is4xxClientError()) {
-                    return OUTCOME_CLIENT_ERROR;
-                }
-                if (statusCode.is5xxServerError()) {
-                    return OUTCOME_SERVER_ERROR;
+                HttpStatus.Series series = HttpStatus.Series.valueOf(response.getRawStatusCode());
+                if (series != null) {
+                    return SERIES_OUTCOMES.getOrDefault(series, OUTCOME_UNKNOWN);
                 }
             }
-            return OUTCOME_UNKNOWN;
-        } catch (IOException | IllegalArgumentException e) {
-            return OUTCOME_UNKNOWN;
         }
+        catch (IOException | IllegalArgumentException ex) {
+            // Continue
+        }
+        return OUTCOME_UNKNOWN;
     }
 }

micrometer-spring-legacy/src/test/java/io/micrometer/spring/web/client/RestTemplateExchangeTagsTest.java

@@ -0,0 +1,111 @@
+/**
+ * Copyright 2019 Pivotal Software, Inc.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 io.micrometer.spring.web.client;
+
+import io.micrometer.core.instrument.Tag;
+import org.junit.Test;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.mock.http.client.MockClientHttpResponse;
+
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link RestTemplateExchangeTags}.
+ *
+ * @author Nishant Raut
+ * @author Brian Clozel
+ */
+public class RestTemplateExchangeTagsTest {
+
+    @Test
+    public void outcomeTagIsUnknownWhenResponseIsNull() {
+        Tag tag = RestTemplateExchangeTags.outcome(null);
+        assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+    }
+
+    @Test
+    public void outcomeTagIsInformationalWhenResponseIs1xx() {
+        ClientHttpResponse response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.CONTINUE);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("INFORMATIONAL");
+    }
+
+    @Test
+    public void outcomeTagIsSuccessWhenResponseIs2xx() {
+        ClientHttpResponse response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.OK);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("SUCCESS");
+    }
+
+    @Test
+    public void outcomeTagIsRedirectionWhenResponseIs3xx() {
+        ClientHttpResponse response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.MOVED_PERMANENTLY);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("REDIRECTION");
+    }
+
+    @Test
+    public void outcomeTagIsClientErrorWhenResponseIs4xx() {
+        ClientHttpResponse response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.BAD_REQUEST);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("CLIENT_ERROR");
+    }
+
+    @Test
+    public void outcomeTagIsServerErrorWhenResponseIs5xx() {
+        ClientHttpResponse response = new MockClientHttpResponse("foo".getBytes(), HttpStatus.BAD_GATEWAY);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("SERVER_ERROR");
+    }
+
+    @Test
+    public void outcomeTagIsUnknownWhenResponseThrowsIOException() throws Exception {
+        ClientHttpResponse response = mock(ClientHttpResponse.class);
+        given(response.getRawStatusCode()).willThrow(IOException.class);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+    }
+
+    @Test
+    public void outcomeTagIsUnknownForCustomResponseStatus() throws Exception {
+        ClientHttpResponse response = mock(ClientHttpResponse.class);
+        given(response.getRawStatusCode()).willThrow(IllegalArgumentException.class);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+    }
+
+    @Test
+    public void outcomeTagIsClientErrorWhenResponseIsNonStandardInClientSeries() throws IOException {
+        ClientHttpResponse response = mock(ClientHttpResponse.class);
+        given(response.getRawStatusCode()).willReturn(490);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("CLIENT_ERROR");
+    }
+
+    @Test
+    public void outcomeTagIsUnknownWhenResponseStatusIsInUnknownSeries() throws IOException {
+        ClientHttpResponse response = mock(ClientHttpResponse.class);
+        given(response.getRawStatusCode()).willReturn(701);
+        Tag tag = RestTemplateExchangeTags.outcome(response);
+        assertThat(tag.getValue()).isEqualTo("UNKNOWN");
+    }
+
+}