Handle ClientException.SERVER_THROTTLED as 503

fixes gh-406

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/post/SendErrorFilter.java

@@ -17,6 +17,7 @@
 package org.springframework.cloud.netflix.zuul.filters.post;
 
 import javax.servlet.RequestDispatcher;
+import javax.servlet.http.HttpServletRequest;
 
 import lombok.extern.apachecommons.CommonsLog;
 
@@ -59,19 +60,28 @@ public class SendErrorFilter extends ZuulFilter {
 	public Object run() {
 		try {
 			RequestContext ctx = RequestContext.getCurrentContext();
+			HttpServletRequest request = ctx.getRequest();
+
 			int statusCode = (Integer) ctx.get("error.status_code");
+			request.setAttribute("javax.servlet.error.status_code", statusCode);
+
 			if (ctx.containsKey("error.exception")) {
 				Object e = ctx.get("error.exception");
 				log.warn("Error during filtering", Throwable.class.cast(e));
-				ctx.getRequest().setAttribute("javax.servlet.error.exception", e);
+				request.setAttribute("javax.servlet.error.exception", e);
 			}
-			ctx.getRequest().setAttribute("javax.servlet.error.status_code", statusCode);
-			RequestDispatcher dispatcher = ctx.getRequest().getRequestDispatcher(
+
+			if (ctx.containsKey("error.message")) {
+				String message = (String) ctx.get("error.message");
+				request.setAttribute("javax.servlet.error.message", message);
+			}
+
+			RequestDispatcher dispatcher = request.getRequestDispatcher(
 					this.errorPath);
 			if (dispatcher != null) {
 				ctx.set(SEND_ERROR_FILTER_RAN, true);
 				if (!ctx.getResponse().isCommitted()) {
-					dispatcher.forward(ctx.getRequest(), ctx.getResponse());
+					dispatcher.forward(request, ctx.getResponse());
 				}
 			}
 		}

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

@@ -79,6 +79,7 @@ public class RibbonRoutingFilter extends ZuulFilter {
 		}
 		catch (ZuulException ex) {
 			context.set("error.status_code", ex.nStatusCode);
+			context.set("error.message", ex.errorCause);
 			context.set("error.exception", ex);
 		}
 		catch (Exception ex) {
@@ -127,13 +128,14 @@ public class RibbonRoutingFilter extends ZuulFilter {
 		}
 		catch (HystrixRuntimeException ex) {
 			info.put("status", "500");
-			if (ex.getFallbackException() != null
-					&& ex.getFallbackException().getCause() != null
-					&& ex.getFallbackException().getCause() instanceof ClientException) {
-				ClientException cause = (ClientException) ex.getFallbackException()
-						.getCause();
-				throw new ZuulException(cause, "Forwarding error", 500,
-						cause.getErrorType().toString());
+			ClientException clientException = findClientException(ex);
+			if (clientException != null) {
+				int statusCode = 500;
+				if (clientException.getErrorType() == ClientException.ErrorType.SERVER_THROTTLED) {
+					statusCode = 503;
+				}
+				throw new ZuulException(clientException, "Forwarding error", statusCode,
+						clientException.getErrorType().toString());
 			}
 			throw new ZuulException(ex, "Forwarding error", 500,
 					ex.getFailureType().toString());
@@ -141,6 +143,19 @@ public class RibbonRoutingFilter extends ZuulFilter {
 
 	}
 
+	protected ClientException findClientException(HystrixRuntimeException ex) {
+		if (ex.getCause() != null
+			&& ex.getCause() instanceof ClientException) {
+			return (ClientException) ex.getCause();
+		}
+		if (ex.getFallbackException() != null
+				&& ex.getFallbackException().getCause() != null
+				&& ex.getFallbackException().getCause() instanceof ClientException) {
+			return (ClientException) ex.getFallbackException().getCause();
+		}
+		return null;
+	}
+
 	private InputStream getRequestBody(HttpServletRequest request) {
 		InputStream requestEntity = null;
 		// ApacheHttpClient4Handler does not support body in delete requests

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/SampleZuulProxyApplicationTests.java

@@ -16,12 +16,16 @@
 
 package org.springframework.cloud.netflix.zuul;
 
+import java.io.InputStream;
+import java.net.URISyntaxException;
 import java.util.UUID;
 import javax.servlet.http.HttpServletRequest;
 
+import com.netflix.client.ClientException;
+import com.netflix.client.http.HttpRequest;
 import com.netflix.loadbalancer.Server;
 import com.netflix.loadbalancer.ServerList;
-import com.netflix.zuul.exception.ZuulException;
+import com.netflix.niws.client.http.RestClient;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -44,9 +48,12 @@ import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.mock.http.client.MockClientHttpResponse;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -84,6 +91,14 @@ public class SampleZuulProxyApplicationTests extends ZuulProxyTestBase {
 		assertEquals(HttpStatus.FORBIDDEN, result.getStatusCode());
 	}
 
+	@Test
+	public void ribbonCommandServiceUnavailable() {
+		ResponseEntity<String> result = new TestRestTemplate().exchange(
+				"http://localhost:" + this.port + "/simple/throwexception/503",
+				HttpMethod.GET, new HttpEntity<>((Void) null), String.class);
+		assertEquals(HttpStatus.SERVICE_UNAVAILABLE, result.getStatusCode());
+	}
+
 	@Test
 	public void ribbonCommandBadHost() {
 		ResponseEntity<String> result = new TestRestTemplate().exchange(
@@ -133,18 +148,41 @@ class SampleZuulProxyApplication extends ZuulProxyTestBase.AbstractZuulProxyAppl
 		}
 
 		@Override
+		@SuppressWarnings("deprecation")
 		@SneakyThrows
 		public RestClientRibbonCommand create(RibbonCommandContext context) {
 			String uri = context.getUri();
 			if (uri.startsWith("/throwexception/")) {
 				String code = uri.replace("/throwexception/", "");
-				throw new ZuulException(new RuntimeException(), Integer.parseInt(code),
-						"test error");
+				RestClient restClient = getClientFactory().getClient(context.getServiceId(),
+						RestClient.class);
+				return new MyCommand(Integer.parseInt(code),
+						context.getServiceId(), restClient, getVerb(context.getVerb()),
+						context.getUri(), context.getRetryable(), context.getHeaders(),
+						context.getParams(), context.getRequestEntity());
 			}
 			return super.create(context);
 		}
 	}
 
+	static class MyCommand extends RestClientRibbonCommand {
+
+		private int errorCode;
+
+		public MyCommand(int errorCode, String commandKey, RestClient restClient, HttpRequest.Verb verb, String uri, Boolean retryable, MultiValueMap<String, String> headers, MultiValueMap<String, String> params, InputStream requestEntity) throws URISyntaxException {
+			super(commandKey, restClient, verb, uri, retryable, headers, params, requestEntity);
+			this.errorCode = errorCode;
+		}
+
+		@Override
+		protected ClientHttpResponse forward() throws Exception {
+			if (errorCode == 503) {
+				throw new ClientException(ClientException.ErrorType.SERVER_THROTTLED);
+			}
+			return new MockClientHttpResponse((byte[])null, HttpStatus.valueOf(this.errorCode));
+		}
+	}
+
 	// Load balancer with fixed server list for "simple" pointing to localhost
 	@Configuration
 	static class BadHostRibbonClientConfiguration {