Allows multiple patterns in host route predicate.

Each pattern is checked if it matches in order.

fixes gh-589

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

@@ -134,7 +134,7 @@ spring:
 This route matches if the request has a header named `X-Request-Id` whos value matches the `\d+` regular expression (has a value of one or more digits).
 
 === Host Route Predicate Factory
-The Host Route Predicate Factory takes one parameter: the host name pattern. The pattern is an Ant style pattern with `.` as the separator. This predicates matches the `Host` header that matches the pattern.
+The Host Route Predicate Factory takes one parameter: a list of host name patterns. The pattern is an Ant style pattern with `.` as the separator. This predicates matches the `Host` header that matches the pattern.
 
 .application.yml
 [source,yaml]
@@ -146,10 +146,10 @@ spring:
       - id: host_route
         uri: http://example.org
         predicates:
-        - Host=**.somehost.org
+        - Host=**.somehost.org,**.anotherhost.org
 ----
 
-This route would match if the request has a `Host` header has the value `www.somehost.org` or `beta.somehost.org`.
+This route would match if the request has a `Host` header has the value `www.somehost.org` or `beta.somehost.org` or `www.anotherhost.org`.
 
 
 === Method Route Predicate Factory

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/handler/predicate/HostRoutePredicateFactory.java

@@ -17,12 +17,14 @@
 
 package org.springframework.cloud.gateway.handler.predicate;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.function.Predicate;
 
 import org.springframework.core.style.ToStringCreator;
 import org.springframework.util.AntPathMatcher;
+import org.springframework.util.CollectionUtils;
 import org.springframework.util.PathMatcher;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.server.ServerWebExchange;
@@ -44,34 +46,54 @@ public class HostRoutePredicateFactory extends AbstractRoutePredicateFactory<Hos
 
 	@Override
 	public List<String> shortcutFieldOrder() {
-		return Collections.singletonList(PATTERN_KEY);
+		return Collections.singletonList("patterns");
+	}
+
+	@Override
+	public ShortcutType shortcutType() {
+		return ShortcutType.GATHER_LIST;
 	}
 
 	@Override
 	public Predicate<ServerWebExchange> apply(Config config) {
 		return exchange -> {
 			String host = exchange.getRequest().getHeaders().getFirst("Host");
-			return this.pathMatcher.match(config.getPattern(), host);
+			return config.getPatterns().stream()
+					.anyMatch(pattern -> this.pathMatcher.match(pattern, host));
 		};
 	}
 
 	@Validated
 	public static class Config {
-		private String pattern;
+		private List<String> patterns = new ArrayList<>();
 
+		@Deprecated
 		public String getPattern() {
-			return pattern;
+			if (!CollectionUtils.isEmpty(this.patterns)) {
+				return patterns.get(0);
+			}
+			return null;
 		}
 
+		@Deprecated
 		public Config setPattern(String pattern) {
-			this.pattern = pattern;
+			this.patterns = new ArrayList<>();
+			this.patterns.add(pattern);
 			return this;
 		}
 
+		public List<String> getPatterns() {
+			return patterns;
+		}
+
+		public void setPatterns(List<String> patterns) {
+			this.patterns = patterns;
+		}
+
 		@Override
 		public String toString() {
 			return new ToStringCreator(this)
-					.append("pattern", pattern)
+					.append("patterns", patterns)
 					.toString();
 		}
 	}

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/route/builder/PredicateSpec.java

@@ -17,6 +17,7 @@
 package org.springframework.cloud.gateway.route.builder;
 
 import java.time.ZonedDateTime;
+import java.util.Arrays;
 import java.util.function.Predicate;
 
 import org.springframework.cloud.gateway.handler.AsyncPredicate;
@@ -134,9 +135,9 @@ public class PredicateSpec extends UriSpec {
 	 * @param pattern the pattern to check against.  The pattern is an Ant style pattern with {@code .} as a separator
 	 * @return a {@link BooleanSpec} to be used to add logical operators
 	 */
-	public BooleanSpec host(String pattern) {
+	public BooleanSpec host(String... pattern) {
 		return asyncPredicate(getBean(HostRoutePredicateFactory.class)
-				.applyAsync(c-> c.setPattern(pattern)));
+				.applyAsync(c-> c.setPatterns(Arrays.asList(pattern))));
 	}
 
 	/**

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/handler/predicate/HostRoutePredicateFactoryTests.java

@@ -19,11 +19,15 @@ package org.springframework.cloud.gateway.handler.predicate;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.SpringBootConfiguration;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.cloud.gateway.handler.RoutePredicateHandlerMapping;
+import org.springframework.cloud.gateway.route.RouteLocator;
+import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
 import org.springframework.cloud.gateway.test.BaseWebClientTests;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringRunner;
@@ -37,18 +41,57 @@ public class HostRoutePredicateFactoryTests extends BaseWebClientTests {
 
 	@Test
 	public void hostRouteWorks() {
+		expectHostRoute("www.example.org", "host_example_to_httpbin");
+	}
+
+	public void expectHostRoute(String host, String routeId) {
 		testClient.get()
 				.uri("/get")
-				.header("Host", "www.example.org")
+				.header("Host", host)
 				.exchange()
 				.expectStatus().isOk()
 				.expectHeader().valueEquals(HANDLER_MAPPER_HEADER, RoutePredicateHandlerMapping.class.getSimpleName())
-				.expectHeader().valueEquals(ROUTE_ID_HEADER, "host_example_to_httpbin");
+				.expectHeader().valueEquals(ROUTE_ID_HEADER, routeId);
+	}
+
+	@Test
+	public void hostRouteBackwardsCompatiblePatternWorks() {
+		expectHostRoute("www.hostpatternarg.org", "host_backwards_compatible_test");
+	}
+
+	@Test
+	public void hostRouteBackwardsCompatibleShortcutWorks() {
+		expectHostRoute("www.hostpatternshortcut.org", "host_backwards_compatible_shortcut_test");
+	}
+
+	@Test
+	public void mulitHostRouteWorks() {
+		expectHostRoute("www.hostmulti1.org", "host_multi_test");
+		expectHostRoute("www.hostmulti2.org", "host_multi_test");
+	}
+
+	@Test
+	public void mulitHostRouteDslWorks() {
+		expectHostRoute("www.hostmultidsl1.org", "host_multi_dsl");
+		expectHostRoute("www.hostmultidsl2.org", "host_multi_dsl");
 	}
 
 	@EnableAutoConfiguration
 	@SpringBootConfiguration
 	@Import(DefaultTestConfig.class)
-	public static class TestConfig { }
+	public static class TestConfig {
+
+		@Value("${test.uri}")
+		String uri;
+
+		@Bean
+		public RouteLocator testRouteLocator(RouteLocatorBuilder builder) {
+			return builder.routes()
+					.route("host_multi_dsl", r -> r.host("**.hostmultidsl1.org", "**.hostmultidsl2.org")
+							.filters(f -> f.prefixPath("/httpbin"))
+							.uri(uri))
+					.build();
+		}
+	}
 
 }

spring-cloud-gateway-core/src/test/resources/application.yml

@@ -81,6 +81,26 @@ spring:
         predicates:
         - Host=**.forward.org
 
+      # =====================================
+      - id: host_backwards_compatible_test
+        uri: ${test.uri}
+        predicates:
+          - name: Host
+            args:
+              pattern: '**.hostpatternarg.org'
+
+      # =====================================
+      - id: host_backwards_compatible_shortcut_test
+        uri: ${test.uri}
+        predicates:
+        - Host=**.hostpatternshortcut.org
+
+      # =====================================
+      - id: host_multi_test
+        uri: ${test.uri}
+        predicates:
+        - Host=**.hostmulti1.org,**.hostmulti2.org
+
       # =====================================
       - id: hystrix_failure_test
         uri: ${test.uri}