Add the ability to configure the max connections and max per route on PoolingHttpClientConnectionManager.

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

@@ -1033,6 +1033,8 @@ http://www.slideshare.net/MikeyCohen1/edge-architecture-ieee-international-confe
 
 Zuul's rule engine allows rules and filters to be written in essentially any JVM language, with built in support for Java and Groovy.
 
+NOTE: The configuration property `zuul.max.host.connections` has been replaced by two new properties, `zuul.host.maxTotalConnections` and `zuul.host.maxPerRouteConnections` which default to 200 and 20 respectively.
+
 [[netflix-zuul-reverse-proxy]]
 === Embedded Zuul Reverse Proxy
 

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

@@ -30,6 +30,7 @@ import org.springframework.cloud.client.discovery.event.ParentHeartbeatEvent;
 import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
 import org.springframework.cloud.netflix.zuul.filters.ProxyRequestHelper;
 import org.springframework.cloud.netflix.zuul.filters.RouteLocator;
+import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
 import org.springframework.cloud.netflix.zuul.filters.discovery.DiscoveryClientRouteLocator;
 import org.springframework.cloud.netflix.zuul.filters.discovery.ServiceRouteMapper;
 import org.springframework.cloud.netflix.zuul.filters.discovery.SimpleServiceRouteMapper;
@@ -105,8 +106,8 @@ public class ZuulProxyConfiguration extends ZuulConfiguration {
 	}
 
 	@Bean
-	public SimpleHostRoutingFilter simpleHostRoutingFilter(ProxyRequestHelper helper) {
-		return new SimpleHostRoutingFilter(helper);
+	public SimpleHostRoutingFilter simpleHostRoutingFilter(ProxyRequestHelper helper, ZuulProperties zuulProperties) {
+		return new SimpleHostRoutingFilter(helper, zuulProperties);
 	}
 
 	@Bean

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

@@ -70,6 +70,8 @@ public class ZuulProperties {
 
 	private boolean ignoreLocalService = true;
 
+	private Host host = new Host();
+
 	public Set<String> getIgnoredHeaders() {
 		Set<String> ignoredHeaders = new LinkedHashSet<>(this.ignoredHeaders);
 		if (ClassUtils.isPresent(
@@ -170,6 +172,14 @@ public class ZuulProperties {
 
 	}
 
+	@Data
+	@AllArgsConstructor
+	@NoArgsConstructor
+	public static class Host {
+		private int maxTotalConnections = 200;
+		private int maxPerRouteConnections = 20;
+	}
+
 	public String getServletPattern() {
 		String path = this.servletPath;
 		if (!path.startsWith("/")) {

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

@@ -64,6 +64,8 @@ import org.apache.http.message.BasicHeader;
 import org.apache.http.message.BasicHttpRequest;
 import org.apache.http.protocol.HttpContext;
 import org.springframework.cloud.netflix.zuul.filters.ProxyRequestHelper;
+import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
+import org.springframework.cloud.netflix.zuul.filters.ZuulProperties.Host;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
@@ -91,6 +93,7 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 			"SimpleHostRoutingFilter.connectionManagerTimer", true);
 
 	private ProxyRequestHelper helper;
+	private Host hostProperties;
 	private PoolingHttpClientConnectionManager connectionManager;
 	private CloseableHttpClient httpClient;
 
@@ -107,12 +110,9 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 		}
 	};
 
-	public SimpleHostRoutingFilter() {
-		this(new ProxyRequestHelper());
-	}
-
-	public SimpleHostRoutingFilter(ProxyRequestHelper helper) {
+	public SimpleHostRoutingFilter(ProxyRequestHelper helper, ZuulProperties properties) {
 		this.helper = helper;
+		this.hostProperties = properties.getHost();
 	}
 
 	@PostConstruct
@@ -209,10 +209,9 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 					.build();
 
 			this.connectionManager = new PoolingHttpClientConnectionManager(registry);
-			this.connectionManager.setMaxTotal(Integer
-					.parseInt(System.getProperty("zuul.max.host.connections", "200")));
-			this.connectionManager.setDefaultMaxPerRoute(Integer
-					.parseInt(System.getProperty("zuul.max.host.connections", "20")));
+			this.connectionManager.setMaxTotal(hostProperties.getMaxTotalConnections());
+			this.connectionManager
+					.setDefaultMaxPerRoute(hostProperties.getMaxPerRouteConnections());
 			return this.connectionManager;
 		}
 		catch (Exception ex) {

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

@@ -189,14 +189,18 @@ class SampleCustomZuulProxyApplication {
 	@Configuration
 	@EnableZuulProxy
 	protected static class CustomZuulProxyConfig extends ZuulProxyConfiguration {
+
 		@Bean
 		@Override
 		public SimpleHostRoutingFilter simpleHostRoutingFilter(
-				ProxyRequestHelper helper) {
-			return new CustomHostRoutingFilter();
+				ProxyRequestHelper helper, ZuulProperties zuulProperties) {
+			return new CustomHostRoutingFilter(helper, zuulProperties);
 		}
 
 		private class CustomHostRoutingFilter extends SimpleHostRoutingFilter {
+			public CustomHostRoutingFilter(ProxyRequestHelper helper, ZuulProperties zuulProperties) {
+				super(helper, zuulProperties);
+			}
 
 			@Override
 			public Object run() {

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

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2013-2016 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.netflix.zuul.filters.route;
+
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
+import org.junit.After;
+import org.junit.Test;
+import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.cloud.netflix.zuul.filters.ProxyRequestHelper;
+import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.junit.Assert.assertEquals;
+import static org.springframework.boot.test.EnvironmentTestUtils.addEnvironment;
+
+/**
+ * @author Andreas Kluth
+ * @author Spencer Gibb
+ */
+public class SimpleHostRoutingFilterTests {
+
+	private AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+
+	@After
+	public void clear() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void connectionPropertiesAreApplied() {
+		addEnvironment(this.context, "zuul.host.maxTotalConnections=100", "zuul.host.maxPerRouteConnections=10");
+		setupContext();
+		PoolingHttpClientConnectionManager connMgr = getFilter().newConnectionManager();
+		assertEquals(100, connMgr.getMaxTotal());
+		assertEquals(10, connMgr.getDefaultMaxPerRoute());
+	}
+
+	@Test
+	public void defaultPropertiesAreApplied() {
+		setupContext();
+		PoolingHttpClientConnectionManager connMgr = getFilter().newConnectionManager();
+
+		assertEquals(200, connMgr.getMaxTotal());
+		assertEquals(20, connMgr.getDefaultMaxPerRoute());
+	}
+
+	private void setupContext() {
+		this.context.register(PropertyPlaceholderAutoConfiguration.class,
+				TestConfiguration.class);
+		this.context.refresh();
+	}
+
+	private SimpleHostRoutingFilter getFilter() {
+		return this.context.getBean(SimpleHostRoutingFilter.class);
+	}
+
+	@Configuration
+	@EnableConfigurationProperties(ZuulProperties.class)
+	protected static class TestConfiguration {
+		@Bean
+		SimpleHostRoutingFilter simpleHostRoutingFilter(ZuulProperties zuulProperties) {
+			return new SimpleHostRoutingFilter(new ProxyRequestHelper(), zuulProperties);
+		}
+	}
+}