Fixed feign-micrometer exception handling.

Author: rostislav.dimitrov

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

@@ -19,6 +19,7 @@
 import feign.Capability;
 import feign.Client;
 import feign.FeignException;
+import feign.Request;
 import feign.Response;
 import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationRegistry;
@@ -57,9 +58,12 @@ public Client enrich(Client client) {
 
       try {
         Response response = client.execute(request, options);
+
+        throwExceptionOnErrorStatusCode(response, request);
+
         finalizeObservation(feignContext, observation, null, response);
         return response;
-      } catch (FeignException ex) {
+      } catch (Exception ex) {
         finalizeObservation(feignContext, observation, ex, null);
         throw ex;
       }
@@ -83,8 +87,16 @@ 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(
+                (r, ex) -> {
+                  try {
+                    throwExceptionOnErrorStatusCode(r, request);
+                    finalizeObservation(feignContext, observation, ex, r);
+                  } catch (FeignException statusCodeException) {
+                    finalizeObservation(feignContext, observation, statusCodeException, null);
+                  }
+                });
+      } catch (Exception ex) {
         finalizeObservation(feignContext, observation, ex, null);
 
         throw ex;
@@ -100,4 +112,10 @@ private void finalizeObservation(
     }
     observation.stop();
   }
+
+  private void throwExceptionOnErrorStatusCode(Response response, Request request) {
+    if (response.status() >= 400 && response.status() < 600) {
+      throw FeignException.errorStatus(request.requestTemplate().method(), response);
+    }
+  }
 }

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

@@ -16,6 +16,7 @@
 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;
@@ -29,6 +30,7 @@
 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 +83,22 @@ 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 getTemplatedPathForUriForAsync(WireMockRuntimeInfo wmRuntimeInfo)
       throws ExecutionException, InterruptedException {
@@ -98,6 +116,21 @@ void getTemplatedPathForUriForAsync(WireMockRuntimeInfo wmRuntimeInfo)
     assertTags();
   }
 
+  @Test
+  void getTemplatedPathForUriForAsyncWithException(WireMockRuntimeInfo wmRuntimeInfo) {
+    stubFor(get(anyUrl()).willReturn(badRequest()));
+
+    AsyncTestClient testClient =
+        asyncClientInstrumentedWithObservations(wmRuntimeInfo.getHttpBaseUrl());
+    testClient
+        .templated("1", "2")
+        .whenComplete(
+            (s, throwable) -> {
+              assertThat(meterRegistry.get(METER_NAME).meter().getId().getTag("error"))
+                  .isEqualTo("BadRequest");
+            });
+  }
+
   private void assertTags() {
     Id requestsId = meterRegistry.get(METER_NAME).meter().getId();