Adds ability to customize simple host conn pool

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

 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2017 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.
@@ -33,6 +33,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
 
 import static com.netflix.hystrix.HystrixCommandProperties.ExecutionIsolationStrategy.SEMAPHORE;
 
@@ -40,6 +41,7 @@ import static com.netflix.hystrix.HystrixCommandProperties.ExecutionIsolationStr
  * @author Spencer Gibb
  * @author Dave Syer
  * @author Mathias Düsterhöft
+ * @author Bilal Alp
  */
 @Data
 @ConfigurationProperties("zuul")
@@ -326,6 +328,14 @@ public class ZuulProperties {
 		 * The maximum number of connections that can be used by a single route.
 		 */
 		private int maxPerRouteConnections = 20;
+		/**
+		 * The lifetime for the connection pool.
+		 */
+		private long timeToLive = -1;
+		/**
+		 * The time unit for timeToLive.
+		 */
+		private TimeUnit timeUnit = TimeUnit.MILLISECONDS;
 	}
 	
 	@Data

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

 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2017 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.
@@ -92,6 +92,7 @@ import static org.springframework.cloud.netflix.zuul.filters.support.FilterConst
  *
  * @author Spencer Gibb
  * @author Dave Syer
+ * @author Bilal Alp
  */
 public class SimpleHostRoutingFilter extends ZuulFilter {
 
@@ -235,7 +236,8 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 			}
 			final Registry<ConnectionSocketFactory> registry = registryBuilder.build();
 
-			this.connectionManager = new PoolingHttpClientConnectionManager(registry);
+			this.connectionManager = new PoolingHttpClientConnectionManager(registry, null, null, null,
+					hostProperties.getTimeToLive(), hostProperties.getTimeUnit());
 			this.connectionManager
 					.setMaxTotal(this.hostProperties.getMaxTotalConnections());
 			this.connectionManager.setDefaultMaxPerRoute(

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

@@ -19,8 +19,10 @@ package org.springframework.cloud.netflix.zuul.filters.route;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.lang.reflect.Field;
 import java.nio.charset.Charset;
 import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
 import java.util.zip.GZIPOutputStream;
 
 import javax.servlet.http.HttpServletResponse;
@@ -49,6 +51,7 @@ import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringRunner;
 import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
@@ -87,11 +90,25 @@ public class SimpleHostRoutingFilterTests {
 
 	@Test
 	public void connectionPropertiesAreApplied() {
-		addEnvironment(this.context, "zuul.host.maxTotalConnections=100", "zuul.host.maxPerRouteConnections=10");
+		addEnvironment(this.context, "zuul.host.maxTotalConnections=100",
+				"zuul.host.maxPerRouteConnections=10", "zuul.host.timeToLive=5",
+				"zuul.host.timeUnit=SECONDS");
 		setupContext();
 		PoolingHttpClientConnectionManager connMgr = getFilter().newConnectionManager();
 		assertEquals(100, connMgr.getMaxTotal());
 		assertEquals(10, connMgr.getDefaultMaxPerRoute());
+		Object pool = getField(connMgr, "pool");
+		Long timeToLive = getField(pool, "timeToLive");
+		TimeUnit timeUnit = getField(pool, "tunit");
+		assertEquals(new Long(5), timeToLive);
+		assertEquals(TimeUnit.SECONDS, timeUnit);
+	}
+
+	protected <T> T getField(Object target, String name) {
+		Field field = ReflectionUtils.findField(target.getClass(), name);
+		ReflectionUtils.makeAccessible(field);
+		Object value = ReflectionUtils.getField(field, target);
+		return (T)value;
 	}
 
 	@Test