Fixed feign-micrometer exception handling.

micrometer/src/main/java/feign/micrometer/MicrometerObservationCapability.java

@@ -19,9 +19,12 @@
 import feign.Capability;
 import feign.Client;
 import feign.FeignException;
+import feign.Request;
 import feign.Response;
+import feign.Util;
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationRegistry;
+import java.io.IOException;
 
 /** Wrap feign {@link Client} with metrics. */
 public class MicrometerObservationCapability implements Capability {
@@ -57,9 +60,13 @@ public Client enrich(Client client) {
 
       try {
         Response response = client.execute(request, options);
-        finalizeObservation(feignContext, observation, null, response);
+        FeignException exception = null;
+
+        exception = getFeignExceptionOnErrorStatusCode(response, request);
+
+        finalizeObservation(feignContext, observation, exception, response);
         return response;
-      } catch (FeignException ex) {
+      } catch (Exception ex) {
         finalizeObservation(feignContext, observation, ex, null);
         throw ex;
       }
@@ -83,8 +90,15 @@ public AsyncClient<Object> enrich(AsyncClient<Object> client) {
       try {
         return client
             .execute(feignContext.getCarrier(), options, context)
-            .whenComplete((r, ex) -> finalizeObservation(feignContext, observation, ex, r));
-      } catch (FeignException ex) {
+            .whenComplete(
+                (response, ex) -> {
+                  FeignException exception = null;
+
+                  exception = getFeignExceptionOnErrorStatusCode(response, request);
+
+                  finalizeObservation(feignContext, observation, exception, response);
+                });
+      } catch (Exception ex) {
         finalizeObservation(feignContext, observation, ex, null);
 
         throw ex;
@@ -100,4 +114,25 @@ private void finalizeObservation(
     }
     observation.stop();
   }
+
+  private boolean isErrorStatusCode(int statusCode) {
+    return statusCode >= 400 && statusCode < 600;
+  }
+
+  private FeignException getFeignExceptionOnErrorStatusCode(Response response, Request request) {
+    try {
+      if (isErrorStatusCode(response.status())) {
+
+        if (response.body() != null) {
+          response =
+              response.toBuilder().body(Util.toByteArray(response.body().asInputStream())).build();
+        }
+
+        return FeignException.errorStatus(request.requestTemplate().method(), response);
+      }
+    } catch (IOException ignored) { // NOPMD
+    }
+
+    return null;
+  }
 }

micrometer/src/test/java/feign/micrometer/FeignHeaderInstrumentationTest.java

@@ -16,10 +16,13 @@
 package feign.micrometer;
 
 import static com.github.tomakehurst.wiremock.client.WireMock.anyUrl;
+import static com.github.tomakehurst.wiremock.client.WireMock.badRequest;
 import static com.github.tomakehurst.wiremock.client.WireMock.equalTo;
 import static com.github.tomakehurst.wiremock.client.WireMock.get;
 import static com.github.tomakehurst.wiremock.client.WireMock.getRequestedFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.noContent;
 import static com.github.tomakehurst.wiremock.client.WireMock.ok;
+import static com.github.tomakehurst.wiremock.client.WireMock.serverError;
 import static com.github.tomakehurst.wiremock.client.WireMock.stubFor;
 import static com.github.tomakehurst.wiremock.client.WireMock.urlEqualTo;
 import static com.github.tomakehurst.wiremock.client.WireMock.verify;
@@ -29,6 +32,7 @@
 import com.github.tomakehurst.wiremock.junit5.WireMockTest;
 import feign.AsyncFeign;
 import feign.Feign;
+import feign.FeignException;
 import feign.Param;
 import feign.Request;
 import feign.RequestLine;
@@ -81,6 +85,53 @@ void getTemplatedPathForUri(WireMockRuntimeInfo wmRuntimeInfo) {
     assertTags();
   }
 
+  @Test
+  void getTemplatedPathForUriWithException(WireMockRuntimeInfo wmRuntimeInfo) {
+    stubFor(get(anyUrl()).willReturn(badRequest()));
+
+    TestClient testClient = clientInstrumentedWithObservations(wmRuntimeInfo.getHttpBaseUrl());
+
+    try {
+      testClient.templated("1", "2");
+    } catch (FeignException e) {
+      assertThat(e).isInstanceOf(FeignException.BadRequest.class);
+    }
+
+    assertThat(meterRegistry.get(METER_NAME).meter().getId().getTag("error"))
+        .isEqualTo("BadRequest");
+  }
+
+  @Test
+  void getTemplatedPathForUriWithExceptionBody(WireMockRuntimeInfo wmRuntimeInfo) {
+    stubFor(get(anyUrl()).willReturn(serverError().withBody("\"error\": \"Server Error\"")));
+
+    TestClient testClient = clientInstrumentedWithObservations(wmRuntimeInfo.getHttpBaseUrl());
+
+    try {
+      testClient.templated("1", "2");
+    } catch (FeignException e) {
+      assertThat(e).isInstanceOf(FeignException.InternalServerError.class);
+    }
+
+    assertThat(meterRegistry.get(METER_NAME).meter().getId().getTag("error"))
+        .isEqualTo("InternalServerError");
+  }
+
+  @Test
+  void getTemplatedPathForUriWithNoContent(WireMockRuntimeInfo wmRuntimeInfo) {
+    stubFor(get(anyUrl()).willReturn(noContent()));
+
+    TestClient testClient = clientInstrumentedWithObservations(wmRuntimeInfo.getHttpBaseUrl());
+
+    try {
+      testClient.templated("1", "2");
+    } catch (FeignException e) {
+      assertThat(e).isInstanceOf(FeignException.BadRequest.class);
+    }
+
+    assertThat(meterRegistry.get(METER_NAME).meter().getId().getTag("error")).isEqualTo("none");
+  }
+
   @Test
   void getTemplatedPathForUriForAsync(WireMockRuntimeInfo wmRuntimeInfo)
       throws ExecutionException, InterruptedException {
@@ -98,6 +149,22 @@ void getTemplatedPathForUriForAsync(WireMockRuntimeInfo wmRuntimeInfo)
     assertTags();
   }
 
+  @Test
+  void getTemplatedPathForUriForAsyncWithException(WireMockRuntimeInfo wmRuntimeInfo)
+      throws InterruptedException {
+    stubFor(get(anyUrl()).willReturn(badRequest()));
+
+    AsyncTestClient testClient =
+        asyncClientInstrumentedWithObservations(wmRuntimeInfo.getHttpBaseUrl());
+
+    try {
+      testClient.templated("1", "2").get();
+    } catch (ExecutionException e) {
+      assertThat(meterRegistry.get(METER_NAME).meter().getId().getTag("error"))
+          .isEqualTo("BadRequest");
+    }
+  }
+
   private void assertTags() {
     Id requestsId = meterRegistry.get(METER_NAME).meter().getId();