GH-1334: Support for eagerly initializing zuul Ribbon named client contexts

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/RibbonApplicationContextInitializer.java

@@ -0,0 +1,38 @@
+package org.springframework.cloud.netflix.ribbon;
+
+import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.context.ApplicationListener;
+
+import java.util.List;
+
+/**
+ * Responsible for eagerly creating the child application context holding the Ribbon
+ * related configuration
+ *
+ * @author Biju Kunjummen
+ */
+public class RibbonApplicationContextInitializer
+		implements ApplicationListener<ApplicationReadyEvent> {
+
+	private final SpringClientFactory springClientFactory;
+	private final List<String> serviceIds;
+
+	public RibbonApplicationContextInitializer(SpringClientFactory springClientFactory,
+			List<String> serviceIds) {
+		this.springClientFactory = springClientFactory;
+		this.serviceIds = serviceIds;
+	}
+
+	private void initialize() {
+		if (serviceIds != null) {
+			for (String serviceId : serviceIds) {
+				this.springClientFactory.getContext(serviceId);
+			}
+		}
+	}
+
+//	@Override
+	public void onApplicationEvent(ApplicationReadyEvent event) {
+		initialize();
+	}
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/SpringClientFactory.java

@@ -80,28 +80,29 @@ public class SpringClientFactory extends NamedContextFactory<RibbonClientSpecifi
 	}
 
 	static <C> C instantiateWithConfig(AnnotationConfigApplicationContext context,
-										Class<C> clazz, IClientConfig config) {
+			Class<C> clazz, IClientConfig config) {
 		C result = null;
-		
+
 		try {
 			Constructor<C> constructor = clazz.getConstructor(IClientConfig.class);
 			result = constructor.newInstance(config);
-		} catch (Throwable e) {
+		}
+		catch (Throwable e) {
 			// Ignored
 		}
-		
+
 		if (result == null) {
 			result = BeanUtils.instantiate(clazz);
-			
+
 			if (result instanceof IClientConfigAware) {
 				((IClientConfigAware) result).initWithNiwsConfig(config);
 			}
-			
+
 			if (context != null) {
 				context.getAutowireCapableBeanFactory().autowireBean(result);
 			}
 		}
-		
+
 		return result;
 	}
 
@@ -115,5 +116,8 @@ public class SpringClientFactory extends NamedContextFactory<RibbonClientSpecifi
 		return instantiateWithConfig(getContext(name), type, config);
 	}
 
+	@Override
+	protected AnnotationConfigApplicationContext getContext(String name) {
+		return super.getContext(name);
+	}
 }
-

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/ZuulConfiguration.java

@@ -22,6 +22,7 @@ import java.util.Map;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.web.ErrorController;
 import org.springframework.boot.autoconfigure.web.ServerProperties;
 import org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration;
@@ -31,6 +32,7 @@ import org.springframework.cloud.client.actuator.HasFeatures;
 import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
 import org.springframework.cloud.client.discovery.event.HeartbeatMonitor;
 import org.springframework.cloud.context.scope.refresh.RefreshScopeRefreshedEvent;
+import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
 import org.springframework.cloud.netflix.zuul.filters.CompositeRouteLocator;
 import org.springframework.cloud.netflix.zuul.filters.RouteLocator;
 import org.springframework.cloud.netflix.zuul.filters.SimpleRouteLocator;
@@ -161,6 +163,14 @@ public class ZuulConfiguration {
 		return new SendForwardFilter();
 	}
 
+	@Bean
+	@ConditionalOnProperty(value = "zuul.context.startup.enabled", matchIfMissing = false)
+	public ZuulRouteApplicationContextInitializer zuulRoutesApplicationContextInitiazer(
+			SpringClientFactory springClientFactory) {
+		return new ZuulRouteApplicationContextInitializer(springClientFactory,
+				zuulProperties);
+	}
+
 	@Configuration
 	protected static class ZuulFilterConfiguration {
 

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/ZuulRouteApplicationContextInitializer.java

@@ -0,0 +1,41 @@
+package org.springframework.cloud.netflix.zuul;
+
+import org.springframework.cloud.netflix.ribbon.RibbonApplicationContextInitializer;
+import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
+import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Responsible for taking in the list of registered serviceid's (Ribbon client names)
+ * and creating the Spring {@link org.springframework.context.ApplicationContext} on
+ * start-up
+ *
+ * @author Biju Kunjummen
+ */
+
+public class ZuulRouteApplicationContextInitializer extends
+		RibbonApplicationContextInitializer {
+	public ZuulRouteApplicationContextInitializer(SpringClientFactory springClientFactory,
+			ZuulProperties zuulProperties) {
+		super(springClientFactory, getServiceIdsFromZuulProps(zuulProperties));
+	}
+
+	private static List<String> getServiceIdsFromZuulProps(ZuulProperties zuulProperties) {
+		Map<String, ZuulProperties.ZuulRoute> zuulRoutes = zuulProperties.getRoutes();
+		Collection<ZuulProperties.ZuulRoute> registeredRoutes = zuulRoutes.values();
+		List<String> serviceIds = new ArrayList<>();
+		if (registeredRoutes != null) {
+			for (ZuulProperties.ZuulRoute route: registeredRoutes) {
+				String serviceId = route.getServiceId();
+				if (serviceId != null) {
+					serviceIds.add(serviceId);
+				}
+			}
+		}
+		return serviceIds;
+	}
+}

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/ribbon/RibbonApplicationContextInitializerTests.java

@@ -0,0 +1,80 @@
+package org.springframework.cloud.netflix.ribbon;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.netflix.archaius.ArchaiusAutoConfiguration;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.boot.test.util.EnvironmentTestUtils.addEnvironment;
+
+/**
+ * @author Biju Kunjummen
+ */
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = {RibbonAutoConfiguration.class,
+		ArchaiusAutoConfiguration.class, RibbonApplicationContextInitializerTests.RibbonInitializerConfig.class})
+@DirtiesContext
+public class RibbonApplicationContextInitializerTests {
+
+	@Autowired
+	private SpringClientFactory springClientFactory;
+
+	@Test
+	public void testContextShouldInitalizeChildContexts() {
+
+		// Context should have been initialized and an instance of Foo created
+		assertThat(Foo.getInstanceCount()).isEqualTo(1);
+		ApplicationContext ctx = springClientFactory.getContext("testspec");
+
+		assertThat(Foo.getInstanceCount()).isEqualTo(1);
+		Foo foo = ctx.getBean("foo", Foo.class);
+		assertThat(foo).isNotNull();
+	}
+
+	@Configuration
+	static class FooConfig {
+
+		@Bean
+		public Foo foo() {
+			return new Foo();
+		}
+
+	}
+
+	@Configuration
+	@RibbonClient(name="testspec", configuration = FooConfig.class)
+	static class RibbonInitializerConfig {
+
+		@Bean
+		public RibbonApplicationContextInitializer ribbonApplicationContextInitializer(
+				SpringClientFactory springClientFactory) {
+			return new RibbonApplicationContextInitializer(springClientFactory,
+					Arrays.asList("testspec"));
+		}
+
+	}
+
+	static class Foo {
+		private static final AtomicInteger INSTANCE_COUNT = new AtomicInteger();
+
+		public Foo() {
+			INSTANCE_COUNT.incrementAndGet();
+		}
+
+		public static int getInstanceCount() {
+			return INSTANCE_COUNT.get();
+		}
+	}
+}

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

@@ -79,7 +79,7 @@ import com.netflix.loadbalancer.ServerList;
 		"zuul.routes.other: /test/**=http://localhost:7777/local",
 		"zuul.routes.another: /another/twolevel/**", "zuul.routes.simple: /simple/**",
 		"zuul.routes.singleton: /singleton/**",
-		"zuul.routes.singleton.sensitiveHeaders: " })
+		"zuul.routes.singleton.sensitiveHeaders: ","zuul.context.startup.enabled: true" })
 @DirtiesContext
 public class HttpClientRibbonCommandIntegrationTests extends ZuulProxyTestBase {