Fallback cause is propagated to fallback provider

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/route/FallbackProvider.java

+/*
+ * Copyright 2017 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.cloud.netflix.zuul.filters.route;
+
+import org.springframework.http.client.ClientHttpResponse;
+
+/**
+ * Extension of {@link ZuulFallbackProvider} which adds possibility to choose proper response
+ * based on the exception which caused the main method to fail.
+ *
+ * @author Dominik Mostek
+ */
+public interface FallbackProvider extends ZuulFallbackProvider {
+
+    /**
+     * Provides a fallback response based on the cause of the failed execution.
+     *
+     * @param cause cause of the main method failure
+     * @return the fallback response
+     */
+    ClientHttpResponse fallbackResponse(Throwable cause);
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/route/ZuulFallbackProvider.java

@@ -23,7 +23,9 @@ import org.springframework.http.client.ClientHttpResponse;
 /**
  * Provides fallback when a failure occurs on a route.
  * @author Ryan Baxter
+ * @deprecated Use {@link FallbackProvider}
  */
+@Deprecated
 public interface ZuulFallbackProvider {
 
 	/**

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/route/support/AbstractRibbonCommand.java

@@ -22,6 +22,7 @@ import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
 import org.springframework.cloud.netflix.zuul.filters.route.RibbonCommand;
 import org.springframework.cloud.netflix.zuul.filters.route.RibbonCommandContext;
 import org.springframework.cloud.netflix.zuul.filters.route.ZuulFallbackProvider;
+import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
 import org.springframework.http.client.ClientHttpResponse;
 import com.netflix.client.AbstractLoadBalancerAwareClient;
 import com.netflix.client.ClientRequest;
@@ -68,7 +69,13 @@ public abstract class AbstractRibbonCommand<LBC extends AbstractLoadBalancerAwar
 	public AbstractRibbonCommand(String commandKey, LBC client,
 								 RibbonCommandContext context, ZuulProperties zuulProperties,
 								 ZuulFallbackProvider fallbackProvider, IClientConfig config) {
-		super(getSetter(commandKey, zuulProperties));
+		this(getSetter(commandKey, zuulProperties), client, context, fallbackProvider, config);
+	}
+
+	protected AbstractRibbonCommand(Setter setter, LBC client,
+								 RibbonCommandContext context,
+								 ZuulFallbackProvider fallbackProvider, IClientConfig config) {
+		super(setter);
 		this.client = client;
 		this.context = context;
 		this.zuulFallbackProvider = fallbackProvider;
@@ -124,11 +131,24 @@ public abstract class AbstractRibbonCommand<LBC extends AbstractLoadBalancerAwar
 	@Override
 	protected ClientHttpResponse getFallback() {
 		if(zuulFallbackProvider != null) {
-			return zuulFallbackProvider.fallbackResponse();
+			return getFallbackResponse();
 		}
 		return super.getFallback();
 	}
 
+	protected ClientHttpResponse getFallbackResponse() {
+		if (zuulFallbackProvider instanceof FallbackProvider) {
+			Throwable cause = getFailedExecutionException();
+			cause = cause == null ? getExecutionException() : cause;
+			if (cause == null) {
+				zuulFallbackProvider.fallbackResponse();
+			} else {
+				return ((FallbackProvider) zuulFallbackProvider).fallbackResponse(cause);
+			}
+		}
+		return zuulFallbackProvider.fallbackResponse();
+	}
+
 	public LBC getClient() {
 		return client;
 	}