Handling custom ErrorDecoder (#6)

* ErrorDecoder handling
* Version update & changelogs

Co-authored-by: SEBASTIEN MONEUSE - E437830 <sebastien.moneuse@ext.mpsa.com>

CHANGELOG.md

@@ -1,3 +1,6 @@
+# Version 1.5.0 (2020-11-06)
+
+* [new] Support configuration of injectable custom error decoders using the `errorDecoder` configuration property.
 # Version 1.4.0 (2020-08-05)
 
 * [new] Support configuration of injectable endpoint request interceptors using the `interceptors` configuration property.

pom.xml

@@ -19,7 +19,7 @@
 
     <groupId>org.seedstack.addons.feign</groupId>
     <artifactId>feign</artifactId>
-    <version>1.4.0-SNAPSHOT</version>
+    <version>1.5.0-SNAPSHOT</version>
     <properties>
         <seed.version>3.10.0</seed.version>
         <feign.version>11.0</feign.version>

src/main/java/org/seedstack/feign/FeignConfig.java

@@ -14,6 +14,7 @@
 import feign.Target.HardCodedTarget;
 import feign.codec.Decoder;
 import feign.codec.Encoder;
+import feign.codec.ErrorDecoder;
 import feign.jackson.JacksonDecoder;
 import feign.jackson.JacksonEncoder;
 import feign.slf4j.Slf4jLogger;
@@ -72,6 +73,7 @@ public static class EndpointConfig {
         @NotNull
         private HystrixWrapperMode hystrixWrapper = HystrixWrapperMode.AUTO;
         private Class<?> fallback;
+        private Class<?extends ErrorDecoder> errorDecoder;
 
         public String getBaseUrl() {
             return baseUrl;
@@ -210,5 +212,13 @@ public List<Class<? extends RequestInterceptor>> getInterceptors() {
         public void addInterceptor(Class<? extends RequestInterceptor> interceptor) {
             this.interceptors.add(interceptor);
         }
+
+        public Class<? extends ErrorDecoder> getErrorDecoder() {
+            return errorDecoder;
+        }
+
+        public void setErrorDecoder(Class<? extends ErrorDecoder> errorDecoder) {
+            this.errorDecoder = errorDecoder;
+        }
     }
 }

src/main/java/org/seedstack/feign/internal/FeignErrorCode.java

@@ -18,5 +18,6 @@ public enum FeignErrorCode implements ErrorCode {
     ERROR_INSTANTIATING_TARGET,
     ERROR_INSTANTIATING_FALLBACK,
     ERROR_INSTANTIATING_LOGGER,
+    ERROR_INSTANTIATING_ERROR_DECODER,
     HYSTRIX_NOT_PRESENT
 }

src/main/java/org/seedstack/feign/internal/FeignPlugin.java

@@ -61,6 +61,9 @@ protected InitState initialize(InitContext initContext) {
             }
             bindings.add(endpointConfig.getEncoder());
             bindings.add(endpointConfig.getDecoder());
+            if(endpointConfig.getErrorDecoder() !=null) {
+                bindings.add(endpointConfig.getErrorDecoder());
+            }
             bindings.add(endpointConfig.getLogger());
             Class<?> fallback = endpointConfig.getFallback();
             if (fallback != null) {

src/main/java/org/seedstack/feign/internal/FeignProvider.java

@@ -12,6 +12,7 @@
 import feign.Target.HardCodedTarget;
 import feign.codec.Decoder;
 import feign.codec.Encoder;
+import feign.codec.ErrorDecoder;
 import feign.hystrix.FallbackFactory;
 import feign.hystrix.HystrixFeign;
 import org.seedstack.feign.FeignConfig;
@@ -53,6 +54,10 @@ public Object get() {
             builder.contract(instantiateContract(endpointConfig.getContract()));
         }
 
+        if(endpointConfig.getErrorDecoder() != null){
+            builder.errorDecoder(instantiateErrorDecoder(endpointConfig.getErrorDecoder()));
+        }
+
         // Logger
         builder.logger(instantiateLogger(endpointConfig.getLogger()));
         builder.logLevel(endpointConfig.getLogLevel());
@@ -155,6 +160,15 @@ private Decoder instantiateDecoder(Class<? extends Decoder> decoderClass) {
         }
     }
 
+    private ErrorDecoder instantiateErrorDecoder(Class<? extends ErrorDecoder> errorDecoderClass){
+        try{
+            return injector.getInstance(errorDecoderClass);
+        }catch (Exception e){
+            throw SeedException.wrap(e, FeignErrorCode.ERROR_INSTANTIATING_ERROR_DECODER)
+                    .put("class", errorDecoderClass);
+        }
+    }
+
     private Target<T> instantiateTarget(EndpointConfig endpointConfig) {
         Class<? extends Target<T>> targetClass = endpointConfig.getTarget(feignApi);
         if (HardCodedTarget.class.equals(targetClass)) {

src/test/java/org/seedstack/feign/AbstractFeignIT.java

@@ -7,8 +7,10 @@
  */
 package org.seedstack.feign;
 
+import feign.FeignException;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.seedstack.feign.fixtures.FeignTestException;
 import org.seedstack.feign.fixtures.Message;
 import org.seedstack.feign.fixtures.TestContract;
 import org.seedstack.feign.fixtures.TestInterceptor;
@@ -51,6 +53,9 @@ public abstract class AbstractFeignIT {
     @Inject
     private TargetableAPI targetableAPI;
 
+    @Inject
+    private ErrorDecoderTestAPI errorDecoderTestAPI;
+
     @Test
     public void feignClientIsInjectable() throws Exception {
         assertThat(testAPI).isNotNull();
@@ -143,4 +148,19 @@ public void testTargetableNominalCall() {
         assertThat(message.getAuthor()).isEqualTo("or i thought so");
     }
 
+    @Test
+    public void testErrorDecoderAPI(){
+        boolean exceptionHasBeenRaised=false;
+        assertThat(errorDecoderTestAPI).isNotNull();
+        try {
+            errorDecoderTestAPI.fakeRequest();
+        }
+        catch(Exception e){
+            assertThat(e.getCause()).isInstanceOf(FeignTestException.class);
+            assertThat(e.getCause().getMessage()).isEqualTo("Feign addon unit test : received HTTP 404 error code");
+            exceptionHasBeenRaised=true;
+        }
+        assertThat(exceptionHasBeenRaised).isTrue();
+    }
+
 }

src/test/java/org/seedstack/feign/fixtures/FeignTestException.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright © 2013-2020, The SeedStack authors <http://seedstack.org>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package org.seedstack.feign.fixtures;
+
+/**
+ * Feign addon test exception
+ */
+public class FeignTestException extends Exception{
+    /**
+     * Statndard constructor
+     * @param message exception message
+     */
+    public FeignTestException(String message){
+        super(message);
+    }
+}

src/test/java/org/seedstack/feign/fixtures/TestErrorDecoder.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright © 2013-2020, The SeedStack authors <http://seedstack.org>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package org.seedstack.feign.fixtures;
+
+import feign.FeignException;
+import feign.Response;
+import feign.codec.ErrorDecoder;
+
+/**
+ * Custom Error Decoder
+ */
+public class TestErrorDecoder implements ErrorDecoder {
+
+    /**
+     * Treat request error, as used in a unit test, resolving with a specific error message in the exception that should be verified in the unit test
+     * @param methodKey The method key
+     * @param response the feign request response
+     * @return Exception
+     */
+    @Override
+    public Exception decode(String methodKey, Response response) {
+        switch (response.status()){
+            case 404 : {
+                return new FeignTestException("Feign addon unit test : received HTTP 404 error code");
+            }
+            default:{
+                return new FeignTestException(response.reason());
+            }
+        }
+    }
+}

src/test/java/org/seedstack/feign/fixtures/TestResource.java

@@ -11,6 +11,8 @@
 import javax.ws.rs.Path;
 import javax.ws.rs.Produces;
 import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+
 import org.seedstack.seed.Logging;
 import org.slf4j.Logger;
 
@@ -52,4 +54,10 @@ public Message timeout() {
     public Message targetSay() {
         return new Message("I was routed trough a custom target", "or i thought so");
     }
+
+    @GET
+    @Path("/testErrorDecoder")
+    public Response notFound(){
+        return Response.status(Response.Status.NOT_FOUND).entity("There is no content here").build();
+    }
 }

src/test/java/org/seedstack/feign/fixtures/apis/ErrorDecoderTestAPI.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright © 2013-2020, The SeedStack authors <http://seedstack.org>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package org.seedstack.feign.fixtures.apis;
+
+import feign.RequestLine;
+import org.seedstack.feign.FeignApi;
+import org.seedstack.feign.fixtures.Message;
+
+/**
+ * Unit test API for error handling
+ */
+@FeignApi
+public interface ErrorDecoderTestAPI {
+
+    /**
+     * Requesting the endpoint responding HTTP 204
+     */
+    @RequestLine("GET /testErrorDecoder")
+    Message fakeRequest();
+}

src/test/resources/application.yaml

@@ -64,6 +64,10 @@ feign:
       logLevel: BASIC
       target: org.seedstack.feign.fixtures.TestTarget
       hystrixWrapper: DISABLED
+    org.seedstack.feign.fixtures.apis.ErrorDecoderTestAPI:
+      baseUrl: ${runtime.web.baseUrl}/feign
+      errorDecoder: org.seedstack.feign.fixtures.TestErrorDecoder
+      hystrixWrapper: DISABLED
 
 security:
   users: