Throw an error when an 'lb:' scheme is used, but there is no handler.

fixes gh-822

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/GatewayNoLoadBalancerClientAutoConfiguration.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2013-2019 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.gateway.config;
+
+import java.net.URI;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClass;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
+import org.springframework.cloud.gateway.filter.GatewayFilterChain;
+import org.springframework.cloud.gateway.filter.GlobalFilter;
+import org.springframework.cloud.gateway.filter.LoadBalancerClientFilter;
+import org.springframework.cloud.gateway.support.NotFoundException;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
+import org.springframework.web.server.ServerWebExchange;
+
+import static org.springframework.cloud.gateway.filter.LoadBalancerClientFilter.LOAD_BALANCER_CLIENT_FILTER_ORDER;
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR;
+
+/**
+ * @author Spencer Gibb
+ */
+@Configuration
+@ConditionalOnMissingClass("org.springframework.cloud.netflix.ribbon.RibbonAutoConfiguration")
+@ConditionalOnMissingBean(LoadBalancerClient.class)
+@AutoConfigureAfter(GatewayLoadBalancerClientAutoConfiguration.class)
+public class GatewayNoLoadBalancerClientAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean(LoadBalancerClientFilter.class)
+	public NoLoadBalancerClientFilter noLoadBalancerClientFilter() {
+			return new NoLoadBalancerClientFilter();
+		}
+
+	protected static class NoLoadBalancerClientFilter implements GlobalFilter, Ordered {
+
+		@Override
+		public int getOrder() {
+			return LOAD_BALANCER_CLIENT_FILTER_ORDER;
+		}
+
+		@Override
+		@SuppressWarnings("Duplicates")
+		public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
+			URI url = exchange.getAttribute(GATEWAY_REQUEST_URL_ATTR);
+			String schemePrefix = exchange.getAttribute(GATEWAY_SCHEME_PREFIX_ATTR);
+			if (url == null || (!"lb".equals(url.getScheme()) && !"lb".equals(schemePrefix))) {
+				return chain.filter(exchange);
+			}
+
+			throw new NotFoundException("Unable to find instance for " + url.getHost());
+		}
+	}
+}

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/LoadBalancerClientFilter.java

@@ -55,6 +55,7 @@ public class LoadBalancerClientFilter implements GlobalFilter, Ordered {
 	}
 
 	@Override
+	@SuppressWarnings("Duplicates")
 	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
 		URI url = exchange.getAttribute(GATEWAY_REQUEST_URL_ATTR);
 		String schemePrefix = exchange.getAttribute(GATEWAY_SCHEME_PREFIX_ATTR);

spring-cloud-gateway-core/src/main/resources/META-INF/spring.factories

@@ -3,6 +3,7 @@ org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
 org.springframework.cloud.gateway.config.GatewayClassPathWarningAutoConfiguration,\
 org.springframework.cloud.gateway.config.GatewayAutoConfiguration,\
 org.springframework.cloud.gateway.config.GatewayLoadBalancerClientAutoConfiguration,\
+org.springframework.cloud.gateway.config.GatewayNoLoadBalancerClientAutoConfiguration,\
 org.springframework.cloud.gateway.config.GatewayMetricsAutoConfiguration,\
 org.springframework.cloud.gateway.config.GatewayRedisAutoConfiguration,\
 org.springframework.cloud.gateway.discovery.GatewayDiscoveryClientAutoConfiguration

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/config/GatewayNoLoadBalancerClientAutoConfigurationTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2013-2019 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.gateway.config;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.cloud.gateway.route.RouteLocator;
+import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
+import org.springframework.cloud.gateway.test.PermitAllSecurityConfiguration;
+import org.springframework.cloud.test.ClassPathExclusions;
+import org.springframework.cloud.test.ModifiedClassPathRunner;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
+import org.springframework.http.HttpHeaders;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.util.SocketUtils;
+import org.springframework.web.bind.annotation.RestController;
+
+@RunWith(ModifiedClassPathRunner.class)
+@ClassPathExclusions({"spring-cloud-netflix-ribbon-*.jar"})
+public class GatewayNoLoadBalancerClientAutoConfigurationTests {
+
+	private static int port;
+
+	@BeforeClass
+	public static void init() {
+		port = SocketUtils.findAvailableTcpPort();
+	}
+
+	@Test
+	public void noLoadBalancerClientReportsError() {
+		try (ConfigurableApplicationContext context = new SpringApplication(Config.class)
+				.run("--server.port="+port)) {
+			WebTestClient client = WebTestClient.bindToServer().baseUrl("http://localhost:" + port).build();
+			client.get()
+					.header(HttpHeaders.HOST, "www.lbfail.org")
+					.exchange()
+					.expectStatus().is5xxServerError();
+		}
+	}
+
+	@SpringBootConfiguration
+	@EnableAutoConfiguration
+	@RestController
+	@Import(PermitAllSecurityConfiguration.class)
+	public static class Config {
+
+		@Bean
+		public RouteLocator hystrixRouteLocator(RouteLocatorBuilder builder) {
+			return builder.routes()
+					.route("lb_fail", r -> r.host("**.lbfail.org")
+							.uri("lb://fail"))
+					.build();
+		}
+	}
+}