Add the ability to provide a default ZuulFallbackProvider. Fixes #1506

docs/src/main/asciidoc/spring-cloud-netflix.adoc

@@ -1755,6 +1755,56 @@ zuul:
     customers: /customers/**
 ----
 
+If you would like to provide a default fallback for all routes than you can create a bean of
+type `ZuulFallbackProvider` and have the `getRoute` method return `*` or `null`.
+
+[source,java]
+----
+class MyFallbackProvider implements ZuulFallbackProvider {
+    @Override
+    public String getRoute() {
+        return "*";
+    }
+
+    @Override
+    public ClientHttpResponse fallbackResponse() {
+        return new ClientHttpResponse() {
+            @Override
+            public HttpStatus getStatusCode() throws IOException {
+                return HttpStatus.OK;
+            }
+
+            @Override
+            public int getRawStatusCode() throws IOException {
+                return 200;
+            }
+
+            @Override
+            public String getStatusText() throws IOException {
+                return "OK";
+            }
+
+            @Override
+            public void close() {
+
+            }
+
+            @Override
+            public InputStream getBody() throws IOException {
+                return new ByteArrayInputStream("fallback".getBytes());
+            }
+
+            @Override
+            public HttpHeaders getHeaders() {
+                HttpHeaders headers = new HttpHeaders();
+                headers.setContentType(MediaType.APPLICATION_JSON);
+                return headers;
+            }
+        };
+    }
+}
+----
+
 [[zuul-developer-guide]]
 === Zuul Developer Guide
 

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

@@ -30,15 +30,25 @@ import org.springframework.cloud.netflix.zuul.filters.route.ZuulFallbackProvider
 public abstract class AbstractRibbonCommandFactory implements RibbonCommandFactory {
 
 	private Map<String, ZuulFallbackProvider> fallbackProviderCache;
+	private ZuulFallbackProvider defaultFallbackProvider = null;
 
 	public AbstractRibbonCommandFactory(Set<ZuulFallbackProvider> fallbackProviders){
 		this.fallbackProviderCache = new HashMap<>();
 		for(ZuulFallbackProvider provider : fallbackProviders) {
-			fallbackProviderCache.put(provider.getRoute(), provider);
+			String route = provider.getRoute();
+			if("*".equals(route) || route == null) {
+				defaultFallbackProvider = provider;
+			} else {
+				fallbackProviderCache.put(route, provider);
+			}
 		}
 	}
 
 	protected ZuulFallbackProvider getFallbackProvider(String route) {
-		return fallbackProviderCache.get(route);
+		ZuulFallbackProvider provider = fallbackProviderCache.get(route);
+		if(provider == null) {
+			provider = defaultFallbackProvider;
+		}
+		return provider;
 	}
 }

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/apache/HttpClientRibbonCommandFallbackTests.java

@@ -33,7 +33,7 @@ import static org.springframework.boot.test.context.SpringBootTest.WebEnvironmen
  * @author Ryan Baxter
  */
 @RunWith(SpringRunner.class)
-@SpringBootTest(classes = HttpClientRibbonCommandIntegrationTests.TestConfig.class, webEnvironment = RANDOM_PORT,
+@SpringBootTest(classes = RibbonCommandFallbackTests.TestConfig.class, webEnvironment = RANDOM_PORT,
 		properties = {
 		"zuul.routes.simple: /simple/**", "zuul.routes.another: /another/twolevel/**",
 		"ribbon.ReadTimeout: 1"})

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/okhttp/OkHttpRibbonCommandFallbackTests.java

@@ -31,7 +31,7 @@ import com.netflix.zuul.context.RequestContext;
  * @author Ryan Baxter
  */
 @RunWith(SpringJUnit4ClassRunner.class)
-@SpringBootTest(classes = OkHttpRibbonCommandIntegrationTests.TestConfig.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, value = {
+@SpringBootTest(classes = RibbonCommandFallbackTests.TestConfig.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, value = {
 		"zuul.routes.simple: /simple/**", "zuul.routes.another: /another/twolevel/**",
 		"ribbon.ReadTimeout: 1"})
 @DirtiesContext

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/restclient/RestClientRibbonCommandFallbackTests.java

@@ -31,7 +31,7 @@ import com.netflix.zuul.context.RequestContext;
  * @author Ryan Baxter
  */
 @RunWith(SpringJUnit4ClassRunner.class)
-@SpringBootTest(classes = RestClientRibbonCommandIntegrationTests.TestConfig.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, value = {
+@SpringBootTest(classes = RibbonCommandFallbackTests.TestConfig.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, value = {
 		"zuul.routes.simple: /simple/**", "zuul.routes.another: /another/twolevel/**",
 		"ribbon.ReadTimeout: 1"})
 @DirtiesContext

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/support/RibbonCommandFallbackTests.java

@@ -18,13 +18,35 @@
 
 package org.springframework.cloud.netflix.zuul.filters.route.support;
 
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.Set;
 import org.junit.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.ErrorAttributes;
 import org.springframework.boot.context.embedded.LocalServerPort;
 import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.cloud.netflix.ribbon.RibbonClient;
+import org.springframework.cloud.netflix.ribbon.RibbonClients;
+import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
+import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
+import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
+import org.springframework.cloud.netflix.zuul.filters.route.RibbonCommandFactory;
+import org.springframework.cloud.netflix.zuul.filters.route.ZuulFallbackProvider;
+import org.springframework.cloud.netflix.zuul.filters.route.apache.HttpClientRibbonCommandFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.web.bind.annotation.RestController;
 
 import static org.junit.Assert.assertEquals;
 
@@ -47,11 +69,90 @@ public abstract class RibbonCommandFallbackTests {
 	}
 
 	@Test
-	public void noFallback() {
+	public void defaultFallback() {
 		String uri = "/another/twolevel/slow";
 		ResponseEntity<String> result = new TestRestTemplate().exchange(
 				"http://localhost:" + this.port + uri, HttpMethod.GET,
 				new HttpEntity<>((Void) null), String.class);
-		assertEquals(HttpStatus.INTERNAL_SERVER_ERROR, result.getStatusCode());
+		assertEquals(HttpStatus.OK, result.getStatusCode());
+		assertEquals("default fallback", result.getBody());
+	}
+
+	// Don't use @SpringBootApplication because we don't want to component scan
+	@Configuration
+	@EnableAutoConfiguration
+	@RestController
+	@EnableZuulProxy
+	@RibbonClients({
+			@RibbonClient(name = "simple", configuration = ZuulProxyTestBase.SimpleRibbonClientConfiguration.class),
+			@RibbonClient(name = "another", configuration = ZuulProxyTestBase.AnotherRibbonClientConfiguration.class)})
+	public static class TestConfig extends ZuulProxyTestBase.AbstractZuulProxyApplication {
+
+		@Autowired(required = false)
+		private Set<ZuulFallbackProvider> zuulFallbackProviders = Collections.emptySet();
+
+
+		@Bean
+		public RibbonCommandFactory<?> ribbonCommandFactory(
+				final SpringClientFactory clientFactory) {
+			return new HttpClientRibbonCommandFactory(clientFactory, new ZuulProperties(),
+					zuulFallbackProviders);
+		}
+
+		@Bean
+		public ZuulProxyTestBase.MyErrorController myErrorController(
+				ErrorAttributes errorAttributes) {
+			return new ZuulProxyTestBase.MyErrorController(errorAttributes);
+		}
+
+		@Bean
+		public ZuulFallbackProvider defaultFallbackProvider() {
+			return new DefaultFallbackProvider();
+		}
+	}
+
+	public static class DefaultFallbackProvider implements ZuulFallbackProvider {
+
+		@Override
+		public String getRoute() {
+			return "*";
+		}
+
+		@Override
+		public ClientHttpResponse fallbackResponse() {
+			return new ClientHttpResponse() {
+				@Override
+				public HttpStatus getStatusCode() throws IOException {
+					return HttpStatus.OK;
+				}
+
+				@Override
+				public int getRawStatusCode() throws IOException {
+					return 200;
+				}
+
+				@Override
+				public String getStatusText() throws IOException {
+					return null;
+				}
+
+				@Override
+				public void close() {
+
+				}
+
+				@Override
+				public InputStream getBody() throws IOException {
+					return new ByteArrayInputStream("default fallback".getBytes());
+				}
+
+				@Override
+				public HttpHeaders getHeaders() {
+					HttpHeaders headers = new HttpHeaders();
+					headers.setContentType(MediaType.TEXT_HTML);
+					return headers;
+				}
+			};
+		}
 	}
 }